School Science Lessons
Biology experiments
2009-09-17
Please send comments to: J.Elfick@uq.edu.au
Table of contents
9.5 Infections
9.1.0 Blood and circulation, temperature
9.2.0 Digestion, teeth
9.3.0 Human body, skeleton, weight, skin, hair
9.4.0 Respiration, aerobic respiration
9.4.1 Excretion, kidney, urine, liver, faeces
9.5.0 Sense-organs, ear, eye, smell, touch
9.6.0 Nervous system
9.254.0 Human genetics
16.4.1 Vitamins
10.0.0 Sexuality education
11.0.0 Drug abuse
9.1.0 Blood and circulation, temperature
5.17 Body temperature
5.18 Feel our pulse, electrocardiogram (Primary)
9.214 Constituents of blood
9.215 Blood cells
9.215.1 Immunity
9.216 Osmotic behaviour of red blood cells
9.217 Blood flow in a fish
9.218 Blood in a frog
9.219 Do women usually feel colder then men?
9.45.7 Diurnal variation in body temperature
12.3.01 Blood pressure
15.05 Electrolytes in the blood and urine
9.2.0 Digestion, teeth
2.13 Count our teeth (Primary)
4.2.11 Glycemic index (GI) GI value and GI load
5.20 Digesting our food (Primary)
9.220 Digestion in the mouth, reaction of the enzyme ptyalin, salivary amylase
9.221 Digestion in the stomach, reaction of pepsin
9.221.1 Reflux and heartburn
9.222 Digestibility of different protein foods
9.223 Function of bile, bile salts
9.224 Digestion in the intestines, pancreatin suspension
9.225 Digestibility of fats
9.226 Teeth and toothpaste, calcium hydroxyl apatite, calcium hydroxyapatite
9.227 Model small intestine, dialysis tubing
9.228 Body Mass Index (BMI)
9.229 Children with diarrhoea, ORS special drink
9.3.0 Human body, skeleton, weight, skin, hair
1.13 Same and different (Primary)
1.14 Mark our height (Primary)
1.19 Length game (Primary)
1.20 Pace distances (Primary)
2.14 Measure in hand spans (Primary)
2.15 Measure with your body (Primary)
2.16 Compare our weights (Primary)
2.19 Our skin and hair (Primary)
3.13 Describe our bones (Primary)
3.14 Feel our bones (Primary)
3.15 Record our heights (Primary)
3.16 Move our arms (Primary)
3.18 Volume of our fist (Primary)
4.21 Measure our weight (Primary)
5.16 Fingerprints (Primary)
6.14 Shakir test (Primary)
9.230 Bones and skeleton
9.231 Measure our height
9.232 Muscles in our arms
9.233 Skin, hair and fingerprints
9.234 Volume of our fist
9.235 Measure our weight
9.236 Shakir strip and malnourished child
9.4.0 Respiration, aerobic respiration
4.20 Measure chest expansion (Primary)
5.15 Breathing in and out (Primary)
5.17 Body temperature (Primary)
5.18 Feel our pulse, electrocardiogram (Primary)
9.5.7 Elimination of carbon dioxide during human respiration
9.5.8 Measure the rate of respiration of small animals and plants
9.5.9 Activities in animal organs, grasshopper respiration
9.5.7 Elimination of carbon dioxide during human respiration
9.5.8 Measure the rate of respiration of small animals and plants
9.5.9 Activities in animal organs, grasshopper respiration
9.237 Oxygen content of inhaled and exhaled air
9.238 Elimination of wastes when we breathe
9.239 Respiratory rate, heart rate
9.242 Simulated diaphragm breathing
9.241 Volume of air in a breath
9.242.0 Measure oxygen absorbed in the lungs
9.242.1 Expired air resuscitation (EAR), Adult
9.242.2 Expired air resuscitation (EAR), Infant (under 1 year), and Child (aged 1 to 8)
9.242.3 Cardiopulmonary resuscitation(CPR), Adult
9.242.4 Cardiopulmonary resuscitation (CPR), Child (aged 1-8)
9.242.5 Cardiopulmonary resuscitation (CPR), Infant (under 1 year)
9.4.1 Excretion, kidney, urine, liver, faeces
9.5.10 Urine tests
9.5.0 Sense-organs
9.5.1 Ears and hearing, balance
9.5.2 Eyes and sight
9.5.3 Nose and smelling, taste
9.5.4 Touch and feeling
9.5.5 Voice and speaking
9.5.0 Sense-organs
1.15 Our five senses (Primary)
9.5.1 Ears and hearing, balance
1.16 Hearing sounds game (Primary)
4.101 The ear and hearing
9.247 Direction of sound heard
26.6.0 Ear, voice, hearing, voice, audible limits
9.5.2 Eyes and sight
2.17 Move our eyes (Primary)
5.19 Test our eyesight (Primary)
6.15 How far you can see? (Primary)
9.248 Distance of object seen
9.250 Test our eyes
28.12.0 The eye, structure and physiology (physics)
9.5.3 Nose and smelling, taste
2.18 Smelling game (Primary)
9.245 Sense of smell, the olfactory system
9.246 Sense of taste, the gustatory system
9.5.4 Touch and feeling
1.17 Touch and feel game (Primary)
1.18 Feelie bag game (Primary)
9.243 Sense of touch
9.244 Sense of feeling temperature
9.5.5 Voice and speaking
4.102 The voice and speaking
26.6.0 Ear, voice, hearing, voice, audible limits
9.6.0 Nervous system
4.22 Memory game (Primary)
4.23 Test our reflexes (Primary)
4.24 Speed of reaction (Primary)
9.249 Test the reaction distance
9.251 Test the reflexes
9.252 Memory game
9.214 Constituents of blood
See diagram 16.3.5.2: Haeme
12.8.15 Detect iron in fruit juice using back tea (haeme and non-haeme iron)
Blood circulates through the body tissues carrying oxygen, nutrients, hormones and waste products to the excretory organs. It contains red cells (erythrocytes), white cells (leukocytes), platelets (thrombocytes, fragments of cytoplasm needed for blood coagulation)) , water (77 to 79%) proteins, lipids, enzymes, hormones blood sugar, vitamins and some inorganic substances. The The blood cells are suspended in the straw-coloured watery blood plasma. Blood serum is the liquid that separates from clotted blood or when blood plasma is allowed to stand. Blood serum is blood plasma without fibrinogen and other substances involved in the mechanism of blood clotting. Red blood cells contain the red pigment haemoglobin, a protein of four polypeptide chains each with the haeme prosthetic group, the oxygen binding site. Blood is slightly alkaline and has relative density 1.054 to 1.00. Haeme contains iron. Methaemoglobin forms if iron in the haeme molecule is oxidized from the ferrous (Fe2+) to the ferric state (Fe3+) caused by certain drugs, water contaminated with nitrates, nitrites, drinking antifreeze and is a rare genetic deficiency causing "blue" people, e.g. the Hindu god Shiva and some native American tribes. The medical condition methaemoglobinaemia is treated with high flow oxygen or methylene blue that converts the haeme back to the ferrous state. Arteries appear red and veins appear blue because of the relative concentration of haeme carrying oxygen in the blood.
9.215 Blood cells
See diagram 9.215: Human blood cells (Romanowsky stain)
A. Erythrocyte (red blood cell) 1.
B. Leucocytes (white blood cells)
1. Lymphocytes: 2. 3. 4.
2. Monocyte 5.
3. Granulocytes: 6. basiphil, 7. eosinophil, 8. neutrophil
Do not take blood samples from other people in the class or from yourself!
Use frog blood, mammalian blood from a slaughterhouse or butcher shop or whole blood from a hospital. You may have to seek approval to work with animal blood or human blood because blood may spread disease. Wear safety glasses, protective clothing and disposable surgical gloves for handling animal tissue and blood products. Instead of using human blood use prepared slides of mammalian blood cells purchased from a laboratory supply company. Prevent mammalian blood clotting by adding a 2% sodium citrate solution in the ratio 1 part of solution to 4 parts of blood. Human blood contains red blood cells (erythrocytes) white blood cells (leukocytes) and platelets (thrombocytes). The erythrocyte count is 4.2 to 5.9 x 1012 cells per litre. The hematocrit, packed cell volume, measures the proportion of blood volume occupied by red blood cells, males 40% to 54%, females 37% to 47%. The ratio of white blood cells to red blood cells constitutes 1 white blood cell for every 600 to 700 red blood cells. White blood cells are larger than red blood cells and have nuclei with variable shapes. Platelets are irregular in shape and are usually seen in small groups like piles of coins. Platelets help the blood clotting processes. Blood cells are suspended in the straw-coloured blood plasma, a solution of inorganic salts and proteins. Blood serum is blood plasma with fibrinogen and other blood-clotting agents removed..
1. Study frog blood and mammalian blood with a microscope for a comparison of blood cells with a nucleus and without a nucleus.
2. Make a staining bath. Push two pairs of paper clips opposite each other halfway down the side of a flat transparent dish, so that each clip forms an eyelet above the edge of the dish. Push a long glass rod through each pair of eyelets and then push the paper clips to secure the glass rods in a parallel position. The glass rods become a bridge for the flat transparent dish staining bath.
3. Put the slide with the drop of blood at an acute angle about one centimetre from the shorter edge of a second slide on the bench. Push the slide along the second slide to spread the blood evenly as a smear over its surface. Allow the smear to dry then place it, smear upwards, across the bridge of the staining bath. For fixing the air-dried blood smear, cover the entire surface of the slide with methanol, methyl alcohol. After three minutes, tip off the methanol and cover the slide with dilute Giemsa solution (Giemsa stain can be purchased from a laboratory supply company). After twenty minutes tip off the Giemsa solution, rinse under running water then leave to dry. Examine the preparation under high power.
Observe the following:
3.1 red blood corpuscles, erythrocytes, with no nuclei, have dumbbell shape seen in profile and pale in the centre is seen from broad surface.
3.2 nucleated white blood corpuscles, leukocytes, and
3.3 irregular shaped platelets, thrombocytes.
Red blood cells will appear pinkish grey, platelets will appear deep pink, and white blood cells will have purple-blue nuclei and a lighter cytoplasm.
4.1 Fill a 100 mL graduated cylinder to the 100 mL mark with mammalian oxalated blood purchased from a qualified supplier and allow it to stand. You may have to seek approval to work with animal blood or human blood because blood may spread disease. Wear safety glasses, protective clothing and disposable surgical gloves for handling animal tissue and blood products. Within 24 hours, the blood separates into an opaque, red fraction at the bottom with a yellowish liquid above. For horse blood, the red fraction is 55% by volume. Oxalated blood usually contains potassium oxalate.
4.2. Transfer a drop of the yellow liquid to a microscope slide with a glass rod. Apply a coverslip and examine under high power. Note the non-suspended bodies.
4.3. Pour the yellow liquid only out of the graduated cylinder. Use a glass rod to transfer a drop of physiological (0.9%) saline (sodium chloride in deionized water) to a microscope slide. Add to this drop some opaque red sediment from the measuring cylinder and mix well. Apply a coverslip and examine under high power. Note the numerous round pale yellow-red cells without nuclei, the red blood corpuscles, erythrocytes. They appear shaped like a dumbbell when viewed from the side because of the central indentation of both sides. Some lie close together like cylindrical heaps of coins.
4.4 Let the oxalated blood stand so that the blood cells settle. The yellow blood plasma above contains no corpuscles or other bodies. The white blood corpuscles can be seen only if the iris diaphragm is almost closed. Usually, they are stained with Giemsa stain (methylene blue and eosin).
9.215.1 Immunity
1.1. Antigens are usually  foreign proteins that stimulate an immunity reaction.
1.2. Antibodies are the globular proteins (immunoglobulins) produced to conteract the effect of specific antigens in an antibody-antigen reaction.
1.2.1 Bacteria may produce toxins that may be counteracted by specific antitoxins.
2. Immunity is the ability to resist infection, diseasese and  unwanted biological invasion by the action of lymphocytes, phagocytes and antibodies in an immune reaction. 
2.1.1 The T lymphocytes attract phagocytes, cause inflammation, control B lymphocytes, and contain the memory of past infection  to allow long-term immunity.
2.1.2 The B lymphocytes in the lymphatic tissue and lymph nodes produce plasma cells that secrete antibodies.
2.2 Phagocytes, i.e. leucocytes and monocytes, engulf bacteria.
2.3 Antibodies can:
2.3.1 clump, pierce, coat and inactivate bacteria,
2.3.2 neutralize toxins,
2.3.3 as the protein interferon, prevent viruses multiplying.
3. Natural immunity is the immunity we are born with without any previous contact with disease.
3.1 Acquired (passive) immunity is additional short-term immunity from:
3.1.1 Antibodies that cross the placenta and antibodies from colostrum before breast milk secretion and from breast milk.
3.1.2 Injection of antibodies in an antiserum, e.g. snake poison antibodies in horse antiserum
3.1.3 Injection of  immunoglobulins into a sick person from another person who has been infected by the same disease, e.g. chickenpox, hepatitis C.
4. Active immunity is the long-lasting immunity from a host producing antibodies in response to:
4.1 Natural infection
The "hygiene hypothesis" is that childhood exposure to pathogens primes the immune system and that children reared in the very clean environments of affluent families do not develop a mature immune system.
4.2 Injection of a non-potent form of antigen (attenuated antigen) in a vaccine to produce a slow primary immune response but which leads to a fast secondary immune response to later infection by this antigen because of the new memory stored in the T lymphocytes.
  Vaccinations given in Australia
Disease Vaccine

1. Diphtheria, Tetanus, Pertussis, Hepatitis B

 DTPa-hepB
2. Haemophilus Influenzae type B Hib (PRP-OMP) or Hib (PRP-OMP)-hepB
3. Poliomyelitis OPV
4. Measles, Mumps, Rubella MMR
5. Diphtheria, Tetanus Td
6. Pneumococcal disease Pneumococcal vaccine
7. Influenza Influenza vaccine
Make list of the vaccinations given to persons in your class or family.
9.216 Osmotic behaviour of red blood cells
1. Use a glass rod to transfer one drop of deionized water on a microscope slide. Let a drop of blood fall into the drop of water on the slide. Mix the blood and water well. Place a coverslip over the mixture and examine the preparation immediately under a microscope, magnification 400 X. Describe any changes in the red blood cells. The contents of the red blood cells are hypertonic to the outside solution so the blood cells swell because of endosmosis, gain of water.
2. Use a glass rod to transfer one drop of deionized water on a microscope slide. Let a drop of blood fall into the drop of water on the slide. Add one drop of 6% sodium chloride solution to the slide and mix well. Apply a coverslip and examine under a microscope, magnification 400 X. Describe any changes in the red blood cells. The contents of the red blood cells are hypotonic to the outside solution so the blood cells shrink because of osmosis, loss of water.
3. Use a glass rod to transfer one drop of deionized water on a microscope slide. Let a drop of blood to fall into the drop of water on the slide. Add one drop of 0.9%, sodium chloride solution to the slide. Apply a coverslip mixture and examine under a microscope, magnification 400 X. Compare the observations made in the three experiments. The 0.9% salt solution is called physiological saline, salt solution. Describe any changes in the red blood cells. The contents of the red blood cells are isotonic with the outside solution so the blood cells stay the same size with no gain or loss of water.
9.217 Blood flow in a fish
See diagram 9.217: Blood flow in a fish
Study the circulatory system of a fish. Show the circulation of blood in the tail of a fish. Wear safety glasses, protective clothing and disposable surgical gloves for handling animal tissue and blood products. You may have to seek approval to work with live fish. Put a goldfish, 5 cm long with a light colour caudal fin in a beaker containing 200 mL of 1.2% ethyl carbamate solution. Be careful! Ethyl carbamate is a possible carcinogen so work in a well-ventilated area. The fish becomes paralysed. Remove it from the solution and lay it on a glass dish. Cover the entire body of the fish, except the caudal fin, with wet absorbent paper placed close to the skin. Drop water from a pipette on the caudal fin to keep it moist. Put the caudal fin on the stage of a microscope. Use low power to see the movement of blood through the capillaries and the movement of the red blood corpuscles. Put the fish back in water where it will become mobile again.
9.218 Blood flow in a frog
See diagram 9.218: Blood flow in a frog
Study the circulatory system of a frog and observe the blood cells. Wear safety glasses, protective clothing and disposable surgical gloves for handling animal tissue and blood products. You may have to seek approval to work with live frogs or toads. Be careful! Do not use frogs or toads that release toxins. Wrap the frog in a wet cloth and pin it to a soft board with a hole in the cloth for observing with a microscope. Mount the webbing between the toes of the frog under the hole and put the board and frog on a microscope stage. Observe blood cells squeezing through the extremely small blood vessels of the thin webbing between the toes.
9.219 Do women usually feel colder then men?
Women are usually smaller so they have a higher surface area to volume ratio than men and thus shed heat faster. Heat generation is proportional to volume (radius3) but heat dissipation is proportional to skin surface area (radius2). The smaller your size, the lower your heat generation to heat dissipation ratio, and the colder you are. So a woman with a higher surface area to volume ratio than a man, will lose heat more quickly and feel colder. Women usually have a slightly lower metabolic rate because of their typically smaller size, so they generate less heat. Men have more heat-generating muscle mass. The more muscle, the more blood flow and warmth. Women have a higher percentage of body fat but that does not insulate them. Women usually have less insulating fat on the upper body and around the waist but more padding on hips and thighs. Men may have extra fat around the waist and upper torso, where it may help insulate vital organs and prevent the core temperature from decreasing. Women have less vigorous blood circulation to arms and legs, so their hands and feet are often the first to feel the cold.
9.220 Digestion in the mouth, reaction of the enzyme ptyalin, salivary amylase
You may have to seek approval to work with human saliva because it can spread disease. Instead of using human saliva, use salivary amylase from a laboratory supply company.
1. Put 10 mL of 1% starch solution in three test-tubes standing in beakers containing water at 40oC.
1.1 Add 5 drops of dilute (10%) hydrochloric acid to the first test-tube.
1.2 Add 5 drops of human saliva to the second test-tube. 3. The third test-tube contains only the starch solution and is the control. Every 30 seconds remove a drop from each test-tube and add 2 drops of dilute iodine solution to do the iodine tests for starch. Repeat the experiment with beakers of water heated to 100oC. Saliva contains the enzyme, salivary amylase.
2. Cut the crust off a slice of white bread and divide the rest of the slice into two pieces. Chew the first piece quickly and swallow it as soon as possible. Chew the second piece for 5 minutes before swallowing. Describe the tastes of the two slices.
3. Do not make any chewing motion, then let 5 mL of saliva drop from the lower lip into a beaker. Dilute the saliva with an equal amount of water. Put 10 mL of starch solution into each of three test-tubes. Do the iodine tests for starch drop by drop into each test-tube until a clear blue colour appears to show the presence of starch.
3.1 Put diluted saliva into the first test-tube, then do Fehling's tests for simple sugars.
3.2 Put an equal volume of water in the second test-tube, then do Fehling's tests for simple sugars.
3.3 Do Fehling's tests for simple sugars on the contents of the third control test-tube. Compare the colours of the contents of the three test-tubes.
9.221 Digestion in the stomach, reaction of pepsin
You may have to seek approval to work with human saliva because it can spread disease. Instead of using human saliva, use salivary amylase from a laboratory supply company.
Gastric juice contains the enzyme pepsin and 0.2-0.5% hydrochloric acid. You may notice the acid in the gastric juice if you belch. The pain of "heartburn" (reflux oesophagitis) is caused by excessive gastric juice irritating the lower oesophagus.
1. Add the following solutions to four test-tubes:
1.1 10 mL of water in the first test-tube.
1.2 9 mL of 1% pepsin solution + 1 mL of water in the second test-tube.
1.3 9 mL of water + 1 mL 5% hydrochloric acid in the third test-tube.
1.4. 9 mL 1% pepsin solution + 1 mL 5% hydrochloric acid in the fourth test-tube.
Put a piece of boiled fish into each test-tube. Put the test-tubes in a beaker of water at 37oC. Try to keep the water in the beaker at that temperature overnight, then compare the contents of the test-tubes.
2. Put uncooked starchy food, e.g. flour, rice, spaghetti, potato, in a first test-tube. Put an equal volume of the same food cooked in a second test-tube. Add the same volume of diluted saliva solution to both test-tubes then stir them with glass rods. Leave for two hours. Compare the contents of the two test-tubes.
3. Cut cooked meat, uncooked meat, egg, and cheese into very small pieces. Wear safety glasses, protective clothing and disposable surgical gloves for handling animal tissue and blood products. Put the cut food into different test-tubes. Add 5 mL of 1% pepsin solution and 2 drops of dilute (10%) hydrochloric acid to each test-tube. Shake the test-tubes occasionally for one hour. Compare the contents of the four test-tubes. A similar process occurs in the human stomach.
9.221.1 Reflux and heartburn
Reflux, gastro-oesophageal reflux (GORD), is caused by stomach acid rising into the oesophagus  and irritating it as a painful burning sensation, heartburn. Heartburn has nothing to do with the heart. The burning sensation may be accompanied by a bitter taste in the throat, burping, bloating and difficulty of swallowing. The contents of the stomach are normally prevented from moving into the oesophagus by the lower oesophageal sphincter muscle (LOS) that acts as a valve to let food enter the stomach but prevents the acid contents from reaching the sensitive oesophagus. Heartburn occurs in many people after a large meal and when lying down.. It may be caused by a particular food, e.g. chocolate, peppermint, deep fried foods, onions , garlic, coffee, alcoholic beverages, citrus juice, soda water, tomatoes, and spices. The most common immediate treatment is to take antacids as tablets, e.g. aluminium hydroxide, magnesium hydroxide, calcium carbonate,  bismuth subsilicate , or as a solution, e.g. sodium bicarbonate. Persistent heartburn requires medical attention.
9.222 Digestibility of different protein foods
Fill four test-tubes with 9 mL of 1% pepsin solution + 1 mL of 5% hydrochloric acid. 1. Put a piece of boiled egg white in the first test-tube. 2. Put an equal volume of boiled fish in the second test-tube. 3. Put an equal volume of low fat cheese in the third test-tube. 4. Put an equal volume of lean boiled beef in the fourth test-tube. Put all the test-tubes in a beaker of water at 37oC. Leave for one hour then compare the contents of the four test-tubes.
9.223 Function of bile, bile salts
Bile salts emulsify fats to increase their surface area for digestion. Ox bile can be purchased from a laboratory supplier.
Add 10 drops of olive oil to the first test-tube that is half full of water. Hold the thumb over the mouth of the test-tube, shake it several times then place it in a test-tube rack. Add an equal volume of 40% ox bile solution to the second test-tube that is a quarter full of water. Add 10 drops of olive oil. Hold the thumb over the mouth of the test-tube and shake it several times, then place it in a test-tube rack. Compare the contents of the two test-tubes.
9.224 Digestion in the intestines, pancreatin suspension
The pancreas secretes several enzymes in the pancreatic juice. Pancreatin suspension is a mixture of pancreatic enzymes.
1. Fill two test-tubes each with 5 mL of 1% starch solution. Add 2 drops of dilute iodine solution to do the iodine tests for starch.
1.1 Add 5 mL of water to the first test-tube.
1.2 Add 5 mL of 1% pancreatin suspension to the second test-tube. Note: digestive enzymes can be purchased by laboratory suppliers. Cover each test-tube with the thumb, invert it to mix the contents, and put them in a test-tube rack. Compare the contents of the two test-tubes.
2. Fill four test-tubes with 9 mL of 1% pancreatin suspension.
2.1 Put a piece of boiled egg white in the first test-tube.
2.2 Put an equal volume of boiled fish in the second test-tube.
2.3 Put an equal volume of low fat cheese in the third test-tube.
2.4 Put an equal volume of lean boiled beef in the fourth test-tube. Put all the test-tubes in a beaker of water at 37oC. Leave for one hour then compare the contents of the four test-tubes. The pieces of food in the test-tubes gradually disintegrate.
9.225 Digestibility of fats
The bile and the enzymes of the digestive juices can attack and decompose melted fats more easily because of their larger surface area.
Prepare three squares of copper gauze, 150 X 150 mm.
1. Put a cube of margarine on the first gauze square.
2. Put an equal volume of lard (pig fat) on the second gauze square.
3. Put an equal volume of beef suet (solid kidney fat) on the third gauze square. Fold each gauze square to enclose the sample of fat completely, then put each in a separate beaker of water at 37oC. Put the beakers on black paper. Look down to observe the melting fats. Note droplets of fat rising to the surface of the warm water. Note which fat is the most digestible.
9.226 Teeth and toothpaste
See diagram 9.226: Teeth 1 | See diagram 9.226.1: Teeth 2
Teeth are important for the first stages of the digestion process. However, tiny particles of food collect plaque around them and provide a breeding place for bacteria. The breakdown of sugary foods by bacteria, e.g. Streptococcus mutans, in the mouth produces organic acids that dissolve the teeth. Tooth decay occurs if the food contains sugars or starches, e.g. sweets, biscuits, cakes and soft drinks containing sucrose. Avoid these foods between meals. Cleaning of the teeth immediately after meals will lessen decay, especially if the last food eaten is fruit or raw vegetable. Another way to reduce dental decay is to drink tap water containing sodium fluorides and to use fluoridated toothpaste. The enamel in teeth is mostly calcium hyroxyl apatite, Ca5(PO4)3OH  usually written as Ca10(PO4)6(OH)2, that can be converted by fluorine to Ca10(PO4)F2 that is an even tougher enamel. Fluoride in water supplies dosed at 1 ppm = 1 mg fluoride per litre is a level harmless to humans and may cause a 12.5% decrease in dental caries. However, in some individuals, but it may cause long-term problems of dental fluorosis and skeletal fluorosis leading to brittle teeth and bones in old age. Solid sodium silicofluoride or fluorosilicic acid is usually added. Other sources of fluorine are tea, spinach, bone meal, and fish protein. Fluoridated toothpaste may contain the active ingredient 0.76% W/W sodium monofluorophosphate or 0.22 % W/W sodium fluoride,  and microparticles of calcium as an abrasive and polishing agent, with Mohs' scale below 5.5. Modern toothpaste contains no sugars. The solid phase, polishing agent, is suspended in polyalcohols, e.g. aqueous glycerol or sorbitol or propylene glycol, and a suspending agent, sodium carboxy methylcellulose. A toothpaste is designed to remove food residue, plaque, and calculus (tartar, calcium phosphate, Ca3(PO4)2.2H2O). Calculus is calcified plaque.
Plaque bacteria change carbohydrates, e.g. sugar in food and drink, left on teeth to acid. This acid demineralizes teeth like the action of acid on an eggshell. Some foods already contain acid so dentists recommend avoiding sweet sticky foods and acidic drinks particularly between meals to reduce the frequency of acidic episodes. Chewing pressure forces food to be trapped between teeth and inside the pits and fissures where most cavities develop. Expansive fillings or fissure sealants prevent food being trapped and greatly reduce decay. Some sugarless foods, e.g. like nuts, are hard to displace and act as temporary sealants and displace previously trapped food to reduce acid demineralization. Chewing also provides better access for saliva and fluoride to neutralise acid and remineralize demineralized tooth. Tooth decay is the most common disease particularly in teenagers, even with fluoridation. Though most food is left trapped between teeth after every meal or snack, more than 80% of cavities develop inside pits and fissures in grooves on chewing surfaces. Most cavities occur between the age of 12 and 21. Tooth caries disease has an economic impact comparable with that of heart disease and diabetes.
1. Examine your diet and teeth cleaning habits and decide whether they lessen the chance of tooth decay. Examine a toothpaste packet and note the contents.
2. Look at your teeth in a mirror and note the four different kinds.
2.1 The front teeth, incisors, are for cutting food.
2.2 The "eye teeth" or canines are for tearing food. Dogs have big tearing teeth.
2.3 The premolars are crushing teeth.
2.4 The back teeth or molars, are for grinding. Cattle have big grinding teeth. Biting teeth, incisors, move up and down to bite in a cutting action. Bite an apple and examine the bite marks. To use tearing teeth, canines, bite into the food and pull back on it, like a dog. Chewing teeth, premolars and molars, move from side to side to grind food into little pieces.
3. Compare the teeth of a child, 5 to 7 years of age with the teeth of an adult or use images from the internet. Humans have two sets of teeth in their lifetime. The first teeth, milk teeth, consist of four incisors, two canines, two premolars and one molar. The second teeth, permanent teeth, consist of four incisors, two canines, two pre-molars and three molars.
4. Compare the molars of a 10 years old child with the molars of a person 17 to 25 years, or older. The older person usually has the extra third molar each side of the jaw called the "wisdom tooth". However, sometimes the wisdom teeth do not erupt properly and remain imbedded in the jawbone, requiring serious dental surgery.
5. Examine the jawbone of a rat or a rabbit or use images from the internet. Compare the arrangement of their teeth with human adult teeth.
9.227 Model small intestine, dialysis tubing
You may have to seek approval to work with human saliva because it can spread disease. Instead of using human saliva, use salivary amylase from a laboratory supply company.
Before cutting dialysis tubing, rub the end of the tubing between thumb and finger under water. When the surfaces of the tube begin to slide, select the length needed and blow into the wet end. Hold an end of the dialysis tubing under water until it is soft. Tie a knot in it and pull the tubing so that the knot is tight. Hold the other end of the tubing under water until it is soft. Rub your fingers back and forth on that end to open it. Cut three lengths of tubing, 10 cm long.
1. Pour starch solution into the first piece of tubing to a depth of 5 cm, then rest it in a beaker.
2. Pour the same volume of starch solution into the second piece of tubing and add 2 mL of dilute saliva solution. Shake the piece of tubing to mix the starch and saliva, then rest it in a beaker.
3. Add glucose solution to a depth of 5 cm in the third piece of tubing, then rest it in a beaker. Add water at 37oC to each beaker so that the level of water in each beaker is the same as the level of the solutions in the tubing. Leave the beakers until the next day. Dialysis tubing and sausage skin are similar to the membrane lining the small intestine.
9.228 Body Mass Index (BMI)
BMI is a ratio calculated from weight in kilograms divided by (height in metres)2. BMI provides an indicator of body fitness and can be used to screen for weight categories that may lead to health problems. BMI categories: BMI 30 (obese) BMI 25-29.9 (overweight) BMI 18.5-24.9 (normal) BMI < 18.5 (underweight). BMI obese patients may have a higher risk of heart-related disease, but BMI overweight patients may have better survival value and fewer heart problems than BMI normal or underweight patients. In some countries, fashion models with BMI < 18.5 are not allowed to walk the catwalk in fashion parades because some very thin models allegedly died of over-dieting. Calculate your BMI.
9.229 Children with diarrhoea, ORS special drink
1. Diarrhoea means frequent watery stools. Often children with diarrhoea also have vomited and have a swollen belly with cramps. The stools smell different from normal stools, faeces. Children die of diarrhoea usually because their bodies lose too much water, dehydration. The signs of dehydration are as follows:
1.1 almost no urine that is dark yellow,
1.2 dry mouth,
1.3 sunken tearless eyes,
1.4 sunken soft spot (fontanelle) on top of a baby's head,
1.5 skin loses its stretching. If you lift up the skin and you can still see the fold after you let go, the child is dehydrated.
2. In many places, diarrhoea is the most common cause of death in small children, and is specially frequent in babies between six months and two years. It is more common and dangerous in children who are malnourished. Bottle-fed babies have diarrhoea more often than breast-fed babies. Diarrhoea can be prevented by breast-feeding babies for as long as possible, good nutrition and cleanliness. Take the child with diarrhoea to a doctor if the child shows any signs of dehydration, cannot drink or will not drink, makes no urine for six hours, has diarrhoea too often and cannot drink one glass of water per stool, has blood in the stool, and if diarrhoea lasts more than two days.
3. Children with diarrhoea must be given food, if they can take it. Replace the water lost through diarrhoea and vomiting with coconut water or the ORS drink (oral rehydration salts drink) sometimes called the "special drink". To make the ORS special drink, dissolve 4 teaspoons of sugar (sucrose) and half a level teaspoon of salt in 1 litre of clean water. Taste the drink before giving it to a sick child. It should taste no more salty then tears. Too much salt can be dangerous for a sick child. Start giving the sick child the ORS special drink, or coconut water, when diarrhoea begins. The child should drink a glass of special drink each time a stool is passed. If the child vomits up the drink, keep giving more because some will stay in the stomach. Give the drink in sips every two or three minutes. If the child does not want to drink, gently insist that the child try to drink something. Keep giving the drink, day and night until the child urinates normally. If the child will not drink and you are concerned about dehydration, seek professional medical advice. The sugar and salt for the ORS special drink is often available in special packets from the pharmacy or health workers in rural areas.
4.2.11 Glycemic index (GI) GI value and GI load
Glycemia refers to the rise in blood sugar. GI is a ranking of carbohydrates in food depending on their immediate effects on blood sugar levels. Carbohydrates that breakdown rapidly during digestion and release glucose quickly into the blood have a high GI Carbohydrates with a low GI are called "smart carbs". Low GI diets help people with type 1 and type 2 diabetes, pregnancy diabetes, overweight, excess abdominal fat, too high blood glucose levels, high levels of triglycerides and low levels of HDL cholesterol ("good cholesterol"). GI values: high GI = 70+, medium GI = 59-69, low GI = <55. Glycemic load = GI X grams of carbohydrate per nominal serving size / 100, e.g. apple GI = 40, GL = (40 X15) / 100 g = 6, potato GI = 90 GL = (90 X 20) / 100 = 18.
9.230 Our bones and skeleton
See diagram 9.230: Skeleton 1 | See diagram 9.231: Skeleton 2
1. Examine different animal bones and describe their function, e.g. skull bones, backbones, ribs, shoulder bones, hip bones, arm and leg bones. The skull protects the brain. The jaws move the mouth and the teeth are attached to them. The vertebrae join to form the spine that connects all the bones. The shoulder and hip bones connect arms and legs to the spine. The ribs protect the lungs and heart, and allow the chest to get bigger and smaller. The arm and leg bones allow movement of arms and legs. Compare a young bone with an old bone. The young bone is softer and contains haemopoietic tissue that makes blood. Old bones are strong and may contain fat. Broken bones are very dangerous for old people because fat may leak out of the broken bone into the bloodstream and cause blockages.
2. A joint is where a bone joins another bone.
2.1 Hinge joints allow forwards and backwards movement, like a door, e.g. the knee joint.
2.2 Ball joints allow movement in a circle, swinging the arm in a circle, e.g. the shoulder joint.
2.3 Pivot joints allow turning movement, turning the handle of a door, e.g. the forearm.
2.4 Fixed joints do not move, but allow plates of bones to grow, e.g. the bones in the skull. A foetus and a very young baby have joints in the skull, fontanelles, where the bones have not joined. These joints allow the skull to expand and grow. When putting a baby down to sleep always have one hand under the head.
3. Examine the different kinds of joints in the body: jaw (hinge) elbow (hinge and pivot) finger (hinge) foot (pivot) upper leg (ball) backbone (pivot) neck (pivot and hinge).
4. The formula for the height of a full grown adult is as follows:
height of adult = average of heights of the two parents (+ 7 cm for men) (-7 cm for women)
9.231 Measure our height
A student stands against the wall with feet together, heels against the wall, back against the wall, hands to the sides, head against the wall, looking straight out. Use a ruler, book, pencil or chalk, metre stick or tape measure on the head and at right angles to wall. Push down bushy hair. Push the back of the head, shoulders, buttocks and heels against the back of the wall. Use a metre stick or tape measure with zero on the floor or draw a metric scale or attach a metre stick to wall. Mark heights on the wall with a ball point pen or felt pen. Measure the heights in centimetres and to a nearest millimetre. Draw a bar graph of heights to the nearest centimetre. Record heights and dates in a book on the same day every month.
9.232 Feel muscles
See diagram 9.232: Arm muscles
1. The three kinds of muscle are as follows:
1.1 Striated muscle, voluntary muscle, attached to bones in the skeleton
1.2 Smooth muscle, involuntary muscle, in the walls of the stomach, intestines, bladder and blood vessels
1.3 Cardiac muscle in the wall of the heart
Muscles work only by contraction, i.e. pulling, so for each muscle that bends a limb, another muscle can straighten it again. Pairs of muscles with opposite action are called antagonists. For example, the biceps muscle bends the arm at the elbow and the triceps muscle straightens the arm again. When a muscle contracts it changes in shape but it does not change in volume. Grab the upper arm with the left hand with the fingers above the arm and thumb below the arm. While bending and straightening the right arm, feel the muscles contract and expand.
2. Close one hand, form a fist, then bend that arm at the elbow, while feeling the muscle of the upper arm with the other hand. Feel the change in shape of the muscle as the arm is raised and lowered. As the arm is raised, the muscle becomes short, fat and hard.
3. Lie on the ground on the back and feel the stomach while raising the legs.
4. Try different movements, e.g. walking on the toes, lifting objects, press-ups, standing on hands, knee-bends. Feel and see the muscles and joints working.
5. Keep a straight back then bend the knees until the hands touch the floor. Note where you feel pain. Feel behind the legs above the knees, when you bend, when you straighten. Feel the muscle that straightens the legs.
9.233 Skin, hair and fingerprints
See diagram 9.233: Skin, hair and fingerprints
1. Examine fingerprints and finger length. Use a magnifying glass to examine the lines in the skin of the fingertips. Make a print of the thumb with a stamp pad or ink poured on absorbent paper. Also, hold a piece of aluminium foil in a candle flame so that it becomes covered with a layer of carbon and press your thumb on the foil. Press the thumb on a sheet of clean white paper. Use a magnifying glass to examine the thumbprint. Look for arches, whorls, and loops. Examine the thumbprints of others. No two thumbprints are the same, not even in identical twins, so police use fingerprints to identify people.
2. Measure the lengths of your fingers. Calculate the ratio: length of middle finger to the length of little finger. Note whether the ratio is the same for other people. Note whether the ratio is the same for boys and girls.
3. List the places where hair grows on the body. List the places where hair does not grow on the body, e.g. palms of the hands, soles of the feet.
4. Find the longest hair of all the people in the class. Note whether the longer hairs come from males or females.
5. Pull out a hair from the head with a quick pull and put it on the sheet of white paper. Note the part of the hair from above the skin, which is dead, and the hair root from below the skin. At the end of the root is the bulb where cells divide to increase the length of the hair.
6. Use a magnifying glass to examine the skin on the back of the hand and on the palm of the hand. Note the hair follicles where the hairs come out of the skin.
9.234 Volume of our fist
Draw a line along the first line on the skin of the wrist. Put the elbow on the desk and look at the palm of the hand. Above the line is the hand. Below the line is the wrist. Curl the fingers and thumb together to form a fist above the line. Mark the original level of water in a container. Put the fist into the water up to the line on the wrist. Mark the new level of water in the container. Open the fist under water. The new level of water remains the same. Take out the fist. Pour water from a measuring jug until the level is at the new level of water. Discuss how to measure the volume of a whole student.
9.235 Measure our weight
Use a bathroom scale or sling scale to record the weight in kilograms of each student on the same day each month, e.g. 15th day of the month. Record the weights on a wall chart. At the end of the year each student draws a graph of the recorded weights. Calculate the average weight of the students each month. Discuss how to measure the weight of your head.
9.236 Shakir strip and malnourished child
See diagram 9.236: Shakir strip
Learn to use the Shakir Strip. When babies are about one year old, they have much fat under the skin of their arms. By the time they are five years old the fat is replaced by muscle, so the circumference of the upper arm is almost the same between the ages of one and five. To detect malnourished children, measure around the middle of the upper arm of children between the ages of one to five years with a specially marked tape, the Shakir strip. It is made of unstretchable material one centimetre wide and forty centimetres long. The colours along the length of the strip in sequence are grey 6 cm, red 6.5 cm, yellow 1 cm, green 6.5 cm and a length of grey to make up a total of 40 cm. Measure from the grey zone end. If the circumference of the upper arm > 13.5 cm, green zone, the child is healthy and not malnourished. If the circumference of the upper arm is between 12.5 and 13.5 cm, yellow zone, the child is probably malnourished. If the circumference of the upper arm is < 12.5 cm, red zone, the child is certainly malnourished. Make a Shakir strip and measure the circumference of the upper arms of children before their fifth birthday.
9.237 Oxygen content of inhaled and exhaled air
Compare the oxygen content of inhaled and exhaled air with a burning candle. Candles can only burn in the presence of oxygen. The more oxygen present, the longer they burn. Fix a candle into a candle holder. Light the candle and put it quickly into a glass container and at the same time cover the glass container with a glass disk. Insert a glass tube in the glass container and again cover it with a glass disk. Exhale through the glass tube 20 times so that only exhaled air remains in the vessel. Take out the glass tube, introduce the candle holder with the burning candle and immediately cover the glass container. Note how long the candle burns. Use the data to compare the oxygen content of inhaled and exhaled air.
9.238 Elimination of wastes when we breathe
See diagram 3.34.1: Limewater tests for carbon dioxide
1. Use a rubber bulb to pump air into a beaker containing limewater. Note the change in the limewater
2. Fit a short glass tube into the bore of a stopper that can fit into the neck of a bottle of aerated water, soda water. Attach rubber tubing to the glass tube. Fit the stopper into the neck of an opened bottle of aerated water. Put the other end of the rubber tubing into a beaker of limewater. Warm the bottle of aerated water with the hands. Note the change in the limewater. The aerated water contains carbon dioxide that forms bubbles and escapes when the bottle is opened.
3. Blow exhaled air into the limewater. Note the change in the limewater.
9.239 Respiratory rate and heart rate
See diagram 9.239: Feel the pulse
See 3.4.6: Gas or vapour inhalation, EAR, CPR
Heartburn (pyrosis) has nothing to do with the heart. It is a burning feeling behind the breastbone and sometimes acid or bitter taste in the mouth caused by regurgitation of stomach contents after a heavy meal.
1. The respiratory rate is the number of breaths per minute. Measure it by observing the chest rising and falling with every breath. Rest for ten minutes and measure the respiratory rate again. Normal values for resting persons, per minute: 3 months 30-50, 10 years 18-30, adult 8-18.
2. After ten minutes rest, measure the heart rate by feeling the pulse. The heart rate is the number of beats per minute, bpm. Put the forearm on the desk, palm up with the wrist on the edge of the desk and hand in the air. Press the four fingers of the other hand down on the side of the wrist. Keep still and feel the pulse. Feel the pulse in the radial artery on the palm side of the wrist in the same direction as the thumb. Start counting the pulse. Note the number of beats per minute. It is from 60 to 100, usually about 70. Do ten knee bends and measure the activity pulse. The pulse rate tells us how fast the blood is pumped around the body. After ten minutes rest, measure the recovery pulse. Note whether the pulse has returned to the original resting pulse. If a student is sick or just had a big meal, the pulse increases. During sleep the respiratory rate is slower. The best resting pulse is taken when awakening in the morning. Normal values for resting persons, per minute: 3 months 70-170, 10 years 70-110, adult 50-95.
3. Roll up some paper to make a tight tube. Hold it against the chest of another student. Press the ear against the other end. Hear the heart pumping the blood. The doctor uses a stethoscope instead of a paper tube for listening to the different sounds in the body, auscultation.
9.242 Simulated diaphragm breathing
See diagram 9.242: Simulated diaphragm
Breathing movements cause the change of air in the lungs necessary for breathing, because the lungs have no muscles and cannot inhale or exhale air by themselves.
1. Breathe deeply in an out. Note that the volume of the chest cavity changes in two ways.
1.1 When you inhale, the thorax expands to produce decreased pressure in the airtight chest cavity that causes air to flow into the lungs. When you exhale, the thorax contracts to decrease the size of the chest cavity, compress the elastic lung tissue and force air out of the lungs. The thorax rises and falls because of the action of the muscles between the ribs. In this way you can increase breathing to allow stronger bodily activity.
1.2 In diaphragm breathing, abdominal breathing, the diaphragm rises and falls because of the action of the diaphragm muscle controlled by the respiratory centre. At rest, or during with low bodily activity, breathing acts mainly in this manner.
2. Show the mechanism of diaphragm breathing. Pull a rubber balloon over each of the two ends of the glass Y-tube. Smear the ends of the glass tube with glycerine. Pass the long limb of the Y-tube from below through the neck of a 5 litre polystyrene large jar and through a hole in a rubber stopper lubricated with glycerine. Use a rubber cloth with a loop on one side to close the opening at the base of the large jar so that the loop remains outside. Secure the rubber cloth to the large jar with a clamping ring. Press the rubber stopper firmly into the neck of the large jar. Grab the model by the neck in one hand, and pass the other hand through the loop. Move the rubber cloth up and down to simulate the breathing rhythm. Draw down the rubber cloth to inflate the balloons. Push the rubber cloth upwards to collapse the balloons. If the rubber cloth is drawn downwards, the volume in the large jar outside the rubber balloons increases. A decrease in pressure occurs which is immediately equalized by the flow of air into the elastic balloons so they expand. When you press the rubber cloth upwards, the volume in the large jar outside the rubber balloons decreases to produce excess pressure that forces air out of the elastic balloons that then collapse.
9.241 Volume of air in a breath
See diagram 9.241: Volume of air in a breath
1. Fix a glass tube bent at right angles through a one-hole stopper. Push the stopper into the neck of a large jar. Immerse the large jar in the water of a fish tank. Connect one end of rubber tubing to the glass tube. Suck out the residual air in the large jar with a rubber bulb. Close the stopcock and raise the large jar by 10 cm. Connect the other end of the rubber tubing to a glass mouthpiece. Take a few normal breaths, in through the nose and out through the mouth. Blow breaths of air into the large jar. If two litres of air are blown into the large jar with 6 breaths, the volume of air expelled per breath is 330 mL.
2. Normal breathing exchanges 200 to 500 mL of air at each breath. Vigorous inhaling and exhaling exchange 2.5 to 5 litres of air at each breath. This value is called the vital capacity. measured with a spirometer. After the most powerful exhalation, about 1 000 mL of air is left in the lungs, the residual air. The vital capacity + the residual capacity = the total volumetric capacity of the lungs. Measure the vital capacity with a method similar to that used for measuring the volume of air in one breath. Breathe in as much air as possible. Place the glass mouthpiece in the mouth and attempt to blow all the air out of the lungs with one breath into the large jar.
3. Use the rubber bulb to pass air through limewater. The limewater does not turn milky. Immerse the large jar in the water and dip the mouthpiece into limewater so that the air bubbles through the limewater. The limewater has turned milky, showing the presence of carbon dioxide in exhaled air.
4. Measure the volume of air breathed out. Take a deep breath. Blow air out slowly into one jar until all the water has been pushed out. Transfer to the next jar and blow more air out until the lungs are empty. For example, the volume of the air in a student's lungs may be 1 000 cm³ + 1 000 cm³ + 200 cm³ = 2 200 cm³. Make air replace water by blowing air into inverted jars filled with water. Estimate the volume of the lungs by measuring the volume of air pushed out. Be careful! Do not let students blow so hard that they feel sick.
5. Measure chest expansion. Use a tape measure to measure the perimeter of the chest where it is widest. Note the chest measurement after breathing out. Note the chest measurement after breathing in. Calculate the chest expansion. Measure again after breathing really hard out and in. Observe the movement of the ribs when breathing in. Stand up and push one finger into the stomach, up and under the lower rib. Then breathe in. The diaphragm muscle pushes the finger down. The volume of the chest increases when the ribs move up like the handle of a bucket, just when the diaphragm muscle drops down.
6. Record the breathing rate per minute and chest expansion 1. when sitting quietly 2. after running. Breathing rate and chest expansion is greater after running.
9.242.0 Measure oxygen absorbed in the lungs
Air breathed in: O2 21%, CO2 0.04%, Moisture 2% (varies)
Air breathed out: O2 16%, CO2 4.0%, Moisture 5% (varies)
1. Immerse a large jar so that the water level coincides with the 5 litre mark. The large jar then contains 5 litres of air, inhalation air. Insert a burning candle into the large jar. Be careful! Melting wax from a burning candle can cause severe skin burns. Use safety glasses and insulated, heat-proof gloves. Close the neck of the large jar immediately. Record the burning time of the candle. For example, the candle was extinguished after 90 seconds.
2. Insert the mouthpiece in the mouth and fill the large jar to the 5 litre mark with exhalation air. With normal breathing this air has only been in the lungs for a few seconds. Adjust the large jar so that the water level in it is 3 mm lower than in the tank. Remove the stopper and put the candle holder with the lighted candle in the large jar. Close the neck of the large jar immediately. Record the burning time of the candle. The candle burns for a much shorter period than in experiment 1.
3. Repeat experiment 2 with air retained in the lungs for a longer period than normal, e.g. 30 seconds, before breathing it out. The candle in the large jar is extinguished immediately. The longer air remains in the lungs, the more oxygen is absorbed into the bloodstream.
9.242.1 Expired air resuscitation (EAR), Adult
If breathing:
1.0 Clear airway,
1.1 Place patient in recovery position: Patient on back, straighten both legs, lift one leg at knee to make right angle, one arm across chest, other arm at right angle to body, roll patient onto side, knee of leg at right angle touches ground so patient does not roll on face.
1.2 Lift chin and open mouth.
1.3 Use finger to remove any obvious obstruction.
1.4 Tilt head back gently.
1.5 Check breathing for up to 10 seconds..
If not breathing:
2.0 Open airway.
2.1 Turn patient onto back.
2.2 Gently tilt head back.
2.3 Pinch nose closed, using thumb and index finger.
2.4 Open mouth and maintain chin lift.
3.0 Give EAR (mouth-to-mouth resuscitation).
3.1 Take a full breath and place lips on patient's mouth to ensure good seal.
3.2 Blow steadily into mouth for 1.5 to 2 seconds.
3.3 Watch for chest to rise.
3.4 Take mouth away and watch for chest to fall.
3.5 Take another breath and repeat sequence, to give two effective breaths.
4.0 Check for signs of circulation.
4.1 Look for any movement, including swallowing or breathing.
4.2 Observe colour of skin on face.
4.3 Check pulse at neck or wrist.
4.4 If circulation absent, commence CPR.
4.5 If circulation present, continue EAR at 15 breaths per minute.
4.6 Look for signs of circulation about every minute.
5. Place in recovery position when breathing 5 returns.
9.242.2 Expired air resuscitation (EAR), Infant (under 1 year), and Child (aged 1 to 8)
If breathing:
1.0 Clear airway.
1.1 Place infant / child in recovery position: Patient on back, straighten both legs, lift one leg at knee to make right angle, one arm across chest, other arm at right angle to body, roll patient onto side, knee of leg at right angle touches ground so patient does not roll on face.
1.2 Lift chin and open mouth.
1.3 Use finger to remove any obvious  obstruction.
1.4 Tilt head back very gently.
1.5 Check breathing for up to 10 seconds.
If not breathing.:
2.0 Open airway
2.1 Turn patient onto back
2.2 Tilt head back slightly
2.3 Open mouth and lift chin.
3.0 Give EAR (mouth-to-mouth resuscitation)
3.1 Cover mouth and nose with your mouth
3.2 Give two gentle breaths/puffs into child's /infant's mouth and nose
3.3 Check for signs of circulation: swallowing, breathing, colour of skin on face and pulse (infant on inside upper arm, child at neck or wrist)
3.4 If circulation absent, commence CPR
3.5 If circulation present, continue EAR at 20 breaths per minute
3.6 Look for signs of circulation about every minute.
4.0 Place in recovery position if breathing returns.
9.242.3 Cardiopulmonary resuscitation(CPR), Adult
1.0 Position hands for CPR.
1.1 Place patient on back.
1.2 Find groove at neck between collarbones.
1.3 Find lower end of breastbone by running finger along last rib to centre of body.
1.4 Extend thumbs equal distances to meet in middle of breastbone.
1.5 Keep thumb of one hand in position and place heel of other hand below it.
1.6 Place heel of other hand on top of first and interlock fingers of both hands.
2.0 Commence chest compressions.
2.1 Position yourself vertically above patient's chest.
2.2 With your arms straight, press down on breastbone to depress it about 4 to 5 cm.
2.3 Release pressure.
3.0 Continue CPR.
3.1 Complete 15 compressions.
3.2 Give two effective breaths (EAR).
3.3 Continue compressions and breaths in ratio of 15 : 2 at a rate of 4 cycles per minute.
3.4 Check for signs of circulation every minute.
9.242.4 Cardiopulmonary resuscitation (CPR), Child (aged 1-8)
1. Use heel of one hand over lower half of breastbone to give chest compressions.
2. Compress chest approximately 1 / 3 depth of chest.
3. Give 1 effective breath (EAR).
4. Continue compressions and breaths in ratio of 5:1 at a rate of 12 cycles per minute.
9.242.5 Cardiopulmonary resuscitation (CPR), Infant (under 1 year)
1. Place tips of 2 fingers (index and middle) on lower half of breastbone.
2. Compress chest approximately 1 / 3 depth of chest.
3. Give 5 chest compressions in 3 seconds.
4. Give 1 effective breath.
5. Continue compressions  and breaths in ratio of 5 : 1 at a rate of 12 cycles per minute.
6. Check for signs of circulation every minute.
9.5.7 Elimination of carbon dioxide during human respiration
See 12.3.0: Properties of acids
H2O (l) <--> H+ (aq) + OH- (aq)
2H+ (aq) + CO32- (aq) <--> H2CO3 (aq) carbonic acid
CO2 + H2O <--> H3O+ + HCO3-
HCO3- + H2O <--> H3O+ + CO32-
Add one drop of sodium carbonate solution, Na2CO3.10H2O, to a test-tube full of water. Shake the test-tube then pour out the contents leaving 2 cm depth. Add one drop of phenolphthalein solution. The solution in the test-tube turns red. Blow through a straw or glass tube into the solution in the test-tube. The red colour disappears because the carbon dioxide gas in the breath has formed carbonic acid in water and neutralized the sodium carbonate solution.
9.5.8 Measure the rate of respiration of small animals and plants
See diagram 9.155
Attach a 50 cm3 syringe to a 1 cm3 pipette, as in the diagram. The sodium hydroxide solution absorbs carbon dioxide released during respiration. Change in air pressure inside the syringe is caused by the consumption of oxygen by the organism and is shown by change of the water level in the pipette. The rise in the water level per unit time indicates the rate of respiration of the organism. A steady drop of the liquid level in the pipette indicates a leak in the apparatus. When testing green plants, cover the syringe with aluminium foil to exclude light. When the meniscus reaches the upper part of the pipette, move it down again by adjusting the position of the plunger. To correct for changes in air volume inside the syringe because of change in room temperature during the experiment, use a control identical to the experiment except for the organism. Then any difference between the readings of the two sets of apparatus is because of respiration of the organism.
9.5.9 Activities in animal organs, grasshopper respiration
See diagram 9.217.1
Put a grasshopper in a closed jar containing absorbent paper soaked in 0.5% potassium hydroxide solution. Use a two-holes stopper with a fine bore glass tube and graph paper or ruler behind it to measure the movement of a drop of coloured water through the tube. Keep the organism off the absorbent paper by adding crumpled paper or tying the moist paper on a string attached to a drawing pin stuck in the underside of the stopper. The grasshopper breathes in oxygen and breathes out carbon dioxide absorbed by the potassium hydroxide solution causing the coloured drop to move. Record the movement of the coloured drop at regular intervals. Observe the distribution and movement of spiracles on the grasshopper.
9.5.10 Urine tests
See 19.1.20.4: Make artificial urine, or, if using urine from a person, the results of these experiment can be interpreted only by an experienced medical practitioner.
1. Quantity
700 to 2 500 mL per day
Less: during the night, after small intake of food or drink, after sweating on a hot day, after diarrhoea decreases salts and water in the body, vomiting, fever, kidney diseases, obstruction in urinary tract.
More: during the day, after large intake of food or drink, on a cold day, after kidney failure.
2. Colour and odour
Plae yellow amber colour and clear and transparent when first voided but colour darkens on standing caused by oxidation of colourless urobilinogen to coloured urobilin. Red-brown colour caused by urochrome and uroerythrin pigments. Colour may be changed by eating beetroot (red) rhubarb (orange tint) tetracyclines (yellow) methylene blue (green) some bacterial infections (green tint) vitamin B tablets (vivid yellow). Clouded urine caused by some bacterial infections and possibly some foods.
Transparent at body temperature but may precipitate ureates when cooled. Pus, bacteria and phosphates may cause cloudiness.
3 Odour
Aromatic odour but distinct odour if asparagus cionsumes. Acetone odour if diabetic ketoacidosis (fatty acids bereaking down to form ketone bodies).
4. Specific gravity
Usually 1.003 to 1.030. Lower if excessive drinking of water, diabetes insipidus, renal failure.Higher if dehydration, heart failure, high level of glucose (glycosuria). Freezing point can be used to measure concentration of solute particles per unit of solvent. The highest concentration occurs in the first urine passed on rising in the morning.
5. pH
Usually acid, pH 4.5 to 8.
6. Protein
Normally < 100 mg/24 hours. Less protein after excercise, inflammation, kidnney infection. Tests for protein with Albustix commercial reagent strip 16.6.8
7. Tests for protein with the boiling test
If urine sample is alkaline use litmus paper and add drops of 10% acetic acid until urine is pH 5. Hold test-tube at an angle and heat the top of the solution to boiling then view against a dark background. Cloudy solution shows presence of of protein or phosphates because urine is more alkaline after boiling because of loss of carbon dioxide. Add 10% acetic acid, if precipitate disappears cloudiness caused by phosphates, if precipitate stays cloudiness caused by proteins.
8. Glucose
Should be none but present if diabetes mellitus or excess corticosteroid hormones (Cushing's disease)
Tests for sugar, Benedict's tests for reducing sugars 9.141
Tests for glucose 19.1.20.4
Tests for glucose and starch with "Testape", 9.182
Should be no ketones.
9.243 Sense of touch
See diagram 9.243: Touch with dividers
1. Meissner corpuscles are just below the epidermis of the skin and are sensitive to light touch. They occur mainly in the face, fingertips, genitals, lips, palms of hands, soles of feet, and tongue. Merkel nerve endings are in superficial skin layers and fingertip ridges and are sensitive to pressure. Pacinian corpuscles are deep in the skin, in mesenteries (membranes connecting the small intestine to the posterior wall of the abdomen) and around joints and detect vibration and big pressure changes. These mechanoreceptors are not uniformly distributed in the skin, so some parts of the body are more sensitive to touch than others. When the skin is touched in two separate points within a single receptive field, the student will be unable to feel the two separate points. If the two points touched span more than a single receptive field then both will be felt. The closer the receptive fields, the greater the resolution of touch. So mechanoreceptors are more dense in the fingertips and less dense in the palms of the hands.
2. Investigate the sensitivity to touch of different parts of the body. Tie a blindfold over the eyes and touch objects with the fingers, e.g. table top, coins, cup, pins, clothing. Describe the feelings. Repeat the experiment by touching the same objects with the back of the hand. Describe the feelings and whether they are the same as before.
3. Tie a blindfold over the eyes and ask another student to touch gently different parts of the back of the hand with a touching bristle. Note when and where you feel the touching bristle. Repeat the experiment on the end of a finger and on the bare forearm. Do not test on other parts of the body.
4. Use a pair of dividers with the points 40 mm apart or the points of two pins or two hairs. Tie a blindfold over the eyes and ask another student to touch gently different parts of the back of the hand with only one point or with both points. Point to where the body was touched and say whether it was one point or two points. Repeat the experiment by reducing the distance between the points of the dividers. Note the distance between the points when a touch with both points feels like a touch with only one point. When the points touch close together, they feel like one point. Repeat the experiment on the end of a finger and on the bare forearm. Do not test on other parts of the body.
9.244 Sense of feeling temperature
See diagram 9.244: Feeling temperature
Fill three containers with water at 10oC, 20oC and 30oC. Put the containers in one line on the table. Dip the left hand in the water at 10oC. Dip the right hand in the water at 30oC. After two minutes, take both hands out of water and dip them simultaneously in the middle container 20oC. Compare the temperature sensations of the right hand and by the left hand. You do not have an absolute sense of temperature.
9.245 Sense of smell, the olfactory system
See diagram 1.13: Smelling technique
Do not inhale gases directly from a test-tube. Fan the gas towards the nose with the hand and sniff cautiously. If you detect no odour, move closer and try again.
1. The olfactory neuroepithelium is located at the upper area of each nasal chamber. As humans age, the number of olfactory neurones steadily decreases. The sense of smell is caused by stimulation of the olfactory receptor cells by volatile chemicals carried as airborne molecules. An odour's stimulating effectiveness depends on the duration, volume, and velocity of a sniff. Each olfactory receptor cell is a sensory neurone. The average nasal cavity contains more than 100 million sensory neurones generated throughout life by the underlying basal cells. So new receptor cells are generated every 30-60 days. Humans have many hundreds of different olfactory receptors, but each neurone expresses only one receptor type, part of an olfactory "map". An odour activates a set of odour receptors depending on its chemical composition. The vomeronasal organ (VNO) (Jacobson organ) is a membranous structure within pits of the anterior nasal septum. Its opening 2 cm from the nostril is visible in nearly all adult humans. It detects the external chemical signals called pheromones but these signals are not detected as perceptible smells by the olfactory system. Pheromones send messages to all individuals in the species to mediate behaviour, e.g. alarm, food trail for ants, sex responses and possibly synchronization of menstrual cycles among women living together.
2. Pour 1 cm of methylated spirit into a small beaker. Hold the beaker under the nose and note the smell while breathing:
2.1 without inhaling,
2.2. inhaling steadily,
2.3. inhaling with jerky sniffs.
Repeat the experiments with different foodstuffs.
3. Repeat the experiment with one nostril closed. Note whether both nostrils give the same smell sensation.
4. Test the ability to detect the smell of baby powder, chocolate, cinnamon, coffee, mothballs, peanut butter, soap, banana, petrol (gasoline) lemon, onion, paint thinner, pineapple, rose, and turpentine
5. Collect different substances that have different kinds of smell. Be careful! Do not let students smell volatile liquids, e.g. petrol, methylated spirit, alcohol, pesticides, correcting fluid and dry-cleaning fluid. A description of smells may include the following: "fruity" from ripe fruit, "fragrant" from flowers and perfume, "onion" from onion or garlic, sulfur from sulfur or volcanic gases, "burning" from burning meat or coffee or tobacco, "burning feathers' from feathers or silk or wool or rubber or hair, "sweaty", from sweat, old cheese, and goats, "foul" from rotten meat, rotten vegetables and faeces. Repeat the experiment with the students blindfolded.
9.246 Sense of taste, the gustatory system
See 12.3.1: Taste of acids | See 19.3.1: Taste, smell, flavour
1. Taste perception occurs in individual taste buds with multiple receptor cells in each bud. Taste buds are modified epithelial cells, with a life span of about 10 days and arise continuously from the underlying basal cell layer. So if you burn your tongue new taste buds can later replace any damaged taste buds. Taste buds occupy projections embedded in the tongue epithelium called lingual papillae. A single nerve fibre innervates multiple taste papillae. A single nerve fibre can respond to different types of tastes, called "broad tuning". Lingual papillae have 4 forms, each in different areas of the tongue. Taste buds also occur in the soft palate, epiglottis and larynx, and the pharynx.
2. The five different taste qualities are salty, sweet, sour, bitter, and umami (monosodium glutamate). There are no "taste areas" on the tongue. The five taste qualities can be detected in all regions of the tongue, but certain areas of the tongue have lower thresholds for each quality. Sweetness is most readily detected at the tip of the tongue. Salty taste receptors focus on the front and side borders of the tongue. Sour tastes are best perceived along the lateral border, and bitter sensations are tasted most in the posterior one third. Another proposed taste quality is chalky (calcium salts). Salt taste is caused by sodium ions and sour taste is cause by hydrogen ions in solution. Sweet taste, bitter taste and umami taste is caused by reactions with proteins on the surface of the taste buds.
3. Never taste a chemical or any substance in the laboratory! Crush different fruits and vegetables into a pulp using a food chopping mill. Tie a blindfold over the eyes, taste the different foods and record the tastes in order of tasting. Repeat the experiment while holding your nose and breathing only through the mouth. Taste the different foods and record the tastes in the same order of tasting. If the nose is held tight, no air can move through the nasal space and you cannot smell anything. You may notice that different foods taste the same when you have a cold. Flavour is a mixture of taste, smell and feel of the food in the mouth.
4. Report on the taste sensations of your tongue. Dry the surface of the tongue with a clean handkerchief, stretch it out as far as possible and look at the tongue with a mirror to note the many taste buds. Describe the taste sensation after you place on different parts of the tongue a drop of the following:
4.1 dilute solution of sucrose, saccharin or aspartame for sweet taste,
4.2 dilute vinegar solution for sour taste,
4.3 dilute table salt solution for salt taste,
4.4 dilute quinine solution (tonic water) or raw almond for bitter taste
4.5 dilute solution of the amino acid monosodium glutamate, MSG, for "umami" taste.
You can experience all the qualities of taste in all regions of the tongue where taste buds occur. Some people experience differences in sensitivity and people may vary in the number of taste buds in different regions of the tongue.
5. Put a drop of boiled starch solution on your tongue and let it mix with the saliva. Leave it there until you can notice a slight change in taste. The saliva contains an enzyme ptyalin that changes starch to maltose sugar. It causes the sweet taste. Repeat the experiment with a piece of raw meat and a piece of pure fat. You do not notice any change of taste because ptyalin does not act on protein or fat.
9.247 Direction of sound heard
All students form a large circle. One student stands in the middle of the circle with a blindfold tied over the eyes. Each student in the circle claps once, one at a time, in any order. After each clap, the blindfolded student turns in that direction with one arm extended. Record the number of successful turns and their direction relative to the direction at the time of the clap. Repeat the experiment with the right ear of the blindfolded student blocked with cotton wool and with the right index finger pressed into that ear. Repeat the experiment with the student's left ear blocked with cotton wool and the left index finger pressed into that ear. Record the number of successful turns and their direction relative to the direction at the time of the clap. Examine the records and describe the necessary conditions to tell the direction of sound correctly.
9.248 Distance of object seen
1. Hold a pencil in each hand horizontally in front of the face with the points of the pencils 50 cm apart. Move the pencils towards each other so that the points touch. Repeat the experiment with the right eye closed. Repeat the experiment with the left eye closed. Describe the necessary conditions to tell correctly the distance of objects.
2. Look outside the classroom at something far away. Hold up one finger 20 cm in front of the eyes but keep looking at the distant object. Note whether you can see the distant object clearly. Note whether you can, at the same time, see the finger clearly. Note whether you feel any movement in your eyes. Keep looking at the finger and note whether the distant object is clear.
3. Hold a printed page at arms length. Bring the book closer and closer until it is too close to read the letters. Measure the distance from the book to the eyes. Move the book away from the eyes until it is too far to read the letters. Again, measure the distance from the book to the eyes.
4. Work in pairs. One student in a pair puts a hand over one eye. The other student holds up one finger about 40 cm in front of the partner's eyes. The student with one eye covered has to place the tip of one finger on top of the finger that the partner is holding up. Repeat the experiment with both eyes open.
9.249 Test the reaction distance
See diagram 9.249: Dropping the ruler
1. Hold the end of a ruler so that it hangs down vertically with the zero in line with the thumb of an outstretched hand. Drop the ruler through the space between the thumb and fingers held wide apart. Record the distance that the ruler fell before it was caught. The distance the ruler fell is called the reaction distance, i.e. the length of the ruler that fell between the fingers before it was caught.
2. Use the thumb and index finger to hold the bottom end of a vertical ruler. The zero on the ruler must be in line with the thumb. Open then close the thumb and index finger as quickly as possible. Record the distance the ruler travelled as an indication of the reaction distance.
9.250 Test our eyes
See diagram 28.1.1.6
If sheep eyes are used for dissection, soak them lens down in 1.0% sodium chloride solution before freezing, to avoid lens clouding.
1. Work in pairs. Look at the partner's eyes and identify each part seen.
2. Clap your hands in front of the partner's face. The partner blinks.
3. Tell your partner to watch your finger as you move it towards the nose. The partner blinks. Repeat the experiment by staring into your partner's eyes and trying not to blink. The first student to blink loses the game.
4. Tell your partner to walk slowly around you in a big circle. Follow the partner with your eyes but do not move your head or body. See how long you can keep your partner in sight. Put your hand up when you can no longer see your partner.
4. By moving your eyes only and not your head, note how far you can move your hand up and down in front of your face and keep it in sight.
5. Face your partner with both kneeling on the floor. Put a stone between you on the floor. Cover your right eye with one hand. Test who can pick up the stone first.
9.251 Test the reflexes
1. Work in pairs. Stare into each other's eyes. The eyes blink.
2. Wave your hand in front of the other student's eyes. The eyes blink.
3. Tickle the arch of the foot. The big toe wiggles.
4. Sit on the desk with the knee just over the edge. Let the leg below the knee swing slightly. See the place just below the knee cap. Hit this place sharply with the side of the hand. Leg swings up. This is called the "knee jerk reflex".
5. Kick your toe. The reflex is to shift weight on to the other foot.
6. Stand on one leg. The reflex is to wave your arms to help balance.
7. Hold your breath for a long time. The reflex is to breathe. You cannot stop yourself breathing in.
9.252 Memory game
If the school does not allow playing cards, make memory cards with symbols, e.g. black and white triangles or other symbols.
Spread playing cards face down. The first player turns up two cards, e.g. a 7 and a 10, lets the other players see them, then turns the cards face down in the same places. The second player turns up two more cards, e.g. a king and a 10, then turn the cards face down in exactly the same places. The third players remember where the two tens are and turns them face up. That player wins one point, removes the two tens, and has another go by turning up two more cards. That player first turns up a king but cannot remember where the previous king was, and turns up a jack. Then the fourth player turns up two cards. The game finishes when all the cards have been turned up in pairs. The player who has turned up the most pairs wins. This game is called "Pelmanism".
9.45.7 Diurnal variation on body temperature
See diagram 9.242
Body temperature is an example of a circadian rhythm, regular cyclic activity about 24 hours long and the regulator of the sleep wake cycle. In a healthy person average temperature for healthy adults is 36.3°C to 37.1°C for males, 36.5°C to 37.3°C for females, with the highest temperatures between 6.00 a.m. and 6.00 p.m. and lowest temperatures between 2.00 a.m. and 6.00 a.m. An oral temperature between 35.9°C and 37.5°C is usually considered normal. Body temperature is sensitive to hormone level in the female. Blood vessels in the skin expand to carry the excess heat to the skin surface. Also, evaporating sweat cools the body as sweat absorbs the heat of vaporization. Blood vessels in the skin contract to reduce loss of heat. Also, involuntary shivering, contraction of the muscles, generates more heat. A rectal or ear temperature is 0.3°C to 0.6°C higher than an oral temperature reading. An armpit temperature is 0.3°C to 0.6°C lower than an oral temperature reading. The forehead temperature is the same temperature as the arterial blood supply under the skin. It is said to be more accurate that ear temperature because the position of the probe in the ear canal in sequential readings is usually inconsistent. The forehead thermometer scans the forehead area for the temporal artery by positioning the probe flush on the centre of the forehead, midway between the eyebrow and the hairline. Fever is present if rectum temperature or ear temperature > 38.0°C, mouth temperature > 37.5°C, under the arm > 37.2°C.
A lady on a diet finds that after eating her body temperature drops and she feels very cold. She probably experiences what doctors call a post-prandial effect to a rush of blood to the stomach leaving the skin feeling cool as blood carrying body heat is shunted away from below the skin. So she should eat her meals slowly. Similarly, she should not go swimming straight after consuming a heavy meal because the skeletal muscles may be starved of enough oxygen for rapid contraction to cause cramps and death by drowning.
1. Measure the temperature under your tongue every hour and draw a graph of the results.
2. Note the changes in your body at high ambient temperature
2.1 Capillaries in the skin swell (vasodilation) to release more heat.
2.2 The arrector pili muscles in the skin pull the hairs to make them lay flat down on the surface of the skin and allow air to circulate freely over the skin.
2.3 Sweat glands secret sweat onto the skin surface where the latent heat of vaporization of water is lost.
Animals, e.g. dogs, can lose heat by panting. Can you lose heat by panting?
3. Note the change in your body at low ambient temperature
3.1 Capillaries in the skin constrict (vasoconstriction) to release less heat.
3.2 The arrector pili muscles in the skin pull the hairs up to not allow air to circulate freely over the skin. This action of the arrector pili muscles causes "goose pimples". Animals can increase the thickness of their coats and birds can ruffle their feathers.
3.3 The sweat glands stop secreting and the hypothalamus of the brain sends messages to internal muscles to contract violently and cause shivering. The oxygen consumption increases 2 to 5 times and the internal organs are warmed.
Hypothermia begins when body temperature drops to 35°C when normal metabolism slows until the internal organs no longer function and the person dies.