unit -3

Human biology and Health

Food and Nutrition
 Food is the source of nutrient and energy for body
 Nutrition- is the process of obtaining and utilizing food.
 We use our food in three main ways. These are:
 To provide raw material for growth
 To fight disease and maintain healthy body
 To provide energy for our cell to carry out their function
 Food contains 6 major groups of nutrients .These are:
-Carbohydrate -Vitamins
-Protein -minerals
-Fat(lipid ) -water
 Nutrients found in a food can be grouped as:
a. Macronutrients – required by the body in large amount.
eg. Carbohydrate, protein and lipids
b. Micronutrients –needed by the body in small amount.
eg. minerals and vitamins
1 Carbohydrates ( has C, O.H elements)
 The quickest source of energy for the body
 The most common carbohydrate are sugar and starches .
 Carbohydrate-rich foods are injera, fatira, honey, potatoes, dabo, rice and etc.
 There are 3 types of carbohydrate based on sugar units
a. Monosaccharide’s (simple sugar)
 The simplest and soluble forms of carbohydrates
 They are composed of one sugar unit
 All of them are soluble in water and have sweet taste
 The best known simple sugar is glucose and its chemical formula is C6H12O6.
 The other simple sugars are fructose and Galactose
b. Disaccharides (double sugars)
 They are composed of two sugar units
 They are formed by condensation reaction
 All of them are soluble in water and have sweet taste


 Eg. -Glucose + fructose = Sucrose + H2O

- Glucose + Galactose = Lactose + H2O
- Glucose + glucose =Maltose + H2O

C. Polysaccharides (complex sugar)

 Thy composed of long chain of sugar units
 They are stable and cannot be used effectively by our body
 They are insoluble in water and have no sweet taste
 Eg. starch –storage forms of carbohydrate in plant
Glycogen – storage forms of carbohydrate in animal muscle and liver
Cellulose- the major component of cell wall in plants.

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2. Protein
 Protein contains C, H, O, N and some P, S elements.
 Proteins are used to build and repair the body tissues.
 They are broken down in digestion into amino acids.
 There are 20 different naturally occurring amino acids.
 Amino acids are joined together in the condensation reaction and a molecule of water is lost.
 The bond formed between the amino acid is called peptide link.
 Amino acids are the building block of proteins

 Some protein rich food are milk,egg,fish , meat, pulse like bean, chick pea
 About 17-18% of your body is made up of protein.
 Proteins are used to make hair, skin, nails, enzymes, hormones, muscles.
 Some proteins are insoluble in water ,while others are soluble
 Water
insoluble Mineral Their uses Sources Effects of deficiency
proteins calcium -Making bones and teeth Dairy products, fish, Rickets
bread, vegetables
found in
phosphorus -Making bones and teeth Most foods Poor growth of
connective bone and teeth
tissues, Sodium and -In body fluids, eg. blood Common salt, Muscular cramps
tendons, chlorine most foods
bone Magnesium -Making bones Green vegetables Skeletal problem
matrix ,kerati Iron -Make hemoglobin Red meat, egg, liver Anemia or low RBCs
n, muscles
and etc.
 Water soluble proteins form antibodies, enzymes, cytoplasm and some hormones.
 Lack of protein in the diet causes disease in the children like kwashiorkor and Marasmus.
3. Lipids
 Lipid Has C,H and less O elements.
 The best known lipids are fats and oils
 Fats contain twice as much energy than carbohydrates
 Lipid –rich foods are butter, beef fat, sesame oil, nug, olive oil, groundnut, coconut
 All lipids are insoluble in H20 but dissolved in organic solvents like alcohol
 Lipids are build from fatty acid and glycerol
a. Glycerol (C3H8O3)
 A syrupy sweet liquid obtained from fats and oils
 Combine with 3 fatty acid to form lipids
b. Fatty Acid
 Long hydrocarbon chain (COOH or carboxyl group)
 Fatty acids vary by two ways. These are:
 The Length of carbon chain
 It might be Saturated or unsaturated
a. Saturated Fatty
 Contain single covalent bonds between carbon atoms
 Are mostly solid at room temperature. Eg. Stearic acids, palmitic acid
b. Unsaturated fatty acids
 Contain double bond between carbon atoms.
 Many of them obtained from plants
 Are liquid at room temperature. Eg. Corn oil ,linolenic acid(linseed oil)
 They contain less number of cholesterol

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  Cholesterol –is produced in our liver
 Used to produce cell membrane, sex hormone and hormones of survival from stress.
 Without cholesterol, you wouldn’t survive.
 Its high level increases risk heart disease or diseased Blood vessels.
4. Minerals
 The needed by the body in small amount
 Lack of them result some kind of deficiency disease
5. Vitamins
 They are useful for regulation of body chemistry and maintenance of healthy body.
 They are need in very small amounts
 Lack of them result some kind of deficiency disease
 Water soluble vitamins- are vitamin B and C
 Fat soluble vitamins-are A, D, E, and K
Vitamins Sources Effects of deficiency
A (retinol) Liver, fish liver, butter, Night blindness
carrots
B1 (thiamin) Yeast, liver, milk, cereals Beriberi
B2(Riboflavin) Yeast, liver, cheese, egg slow growth ,eye
disease
B3 (Niacin) Milk, meat, fresh Pellagra
vegetables
C (Ascorbic acid) Fresh fruits and vegetables Scurvy
D(Calciferol) fish liver, sunlight Rickets; poor teeth

Food test-is a laboratory technique used to check the presence of one food in a given sample .
 This table expresses type of foods and chemical used to show the presence of food in a given sample.

Type of foods Chemical used Color shows presence of

food
starch iodine Blue-black
Reducing sugar Benedict’s test Orange-red
(simple and double sugar)
proteins Biuret test(KOH, Purple to pink/blue to
NaOH) violet/
Fats and oils ethanol White, cloudy
Vitamin -C Dichloro phenol (DCPIP) Blue-black to colorless
6. Water
 The body actually have between 60-70% water
 It is universal solvent or for every chemical reaction in the body.
 It involving in the temperature regulation
 Removal of waste material from the body
 Needed for the osmotic stability of the body
Roughage( Fibre) -Is substance that cannot be break down in the human gut
-The presence of roughage in food used for:
 The movement of food in the alimentary canal
 Prevent constipation
Balanced diet-is taking food from all major food group in order to maintain a healthy body
 By eating a good combination of food daily we can easily achieve a balanced diet.
 Eg. - Breakfast- bread and groundnut or chickpeas with tea or milk.
- Lunch- key wet with injera and banana or orange.
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 - Dinner- shiro wet with injera and chill.
Malnutrition:-is lack of important elements or balanced needed for a healthy body.
-It can be: 1. under nutrition - when too little food is eaten
2. Over nutrition –when too much food is eaten
Eg. Obesity –over weightiness
Homework: Do review question on page 67-68 Q1-7

3.2 The digestive system

Digestion:- is the mechanical or chemical break down of foods into small ,soluble molecule as they pass through the gut.
-The Process of digestion has the following steps.
1 Ingestion: - is taking food into the mouth
2 Digestion: - is break down of food into small units.
3 Absorption: - movement of digested food by the body
4. Assimilation:- taking in and use of digested food by body
5. Egestion:-is removing of undigested food from the body
-There are two types of digestion. These are:
1. Mechanical (physical) digestion - Is breaking down of large food particles in to smaller by grinding
and chewing action of teeth
2. Chemical digestion – is breaking down of food into small by action of enzymes.
Enzymes
 Enzymes are proteins that speed up the rate of chemical reaction.
 Some enzymes are work outside of your cells and called extracellular enzymes. Eg: digestive
enzymes.
 Some enzymes are work inside your cells and called intracellular enzymes. eg. Respiratory
enzymes.
Properties of enzymes
 Enzymes are protein. they are made up of complex protein
 Enzymes are specific. They catalyses only one type of reaction.
 Enzymes are sensitive to temperature and PH
 Enzymes can be reused because they remain unchanged at the end of the reaction.

Table: Enzymes of the human digestive system.

Enzymes Where it is act on Final products
found
Carbohydrases eg. -Salivary -Starch -Starch amylase maltose
- Amylase gland -maltose -Maltose maltase glucose
-Maltase -pancreas
-small
intestine

Protease eg. -Stomach -protein

-Pepsin, -pancreas -Protein pepsine peptone
-Trypsin -small -Peptone trypsin peptides
- Erepsin intestine -Peptide erepsin aminano
Acids
Lipase -Pancreas -Lipids -Lipids lipase fatty acid +
-small (fats and glycerol
intestine oil)

Digestion in the mouth

 Carried out by : -the biting, grinding and chewing action of teeth
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 -The rolling action of the tongue
 There are 4 types of teeth :
1. Incisor - used for biting 3. premolar
2. Canine 4. Molar - used for chewing
and crushing
 The vertical section of the teeth consists of crown, neck and root.
 The cross sectional area of the teeth is consists of:
 Enamel- is the upper surface and non-living thing layer of the teeth.
 Dentine- is living layer underneath tooth enamel.
 Pulp cavity- is the inner sensitive layer of the teeth consist of blood vessels and nerves.
 Cement- is fibrous layer that holds the teeth into the jaw bone.

How tooth can decayed?

 There are different bacteria in mouth that combine with food and saliva, form thin film called plaque on
the teeth.
 If these bacteria get sugar –rich food, they produce a lot of acid waste.
 This bacteria attacks and dissolves the tough enamel coating of your teeth.
 Gradually bacteria and acid can eat away your teeth and break up completely if you don’t get dental
treatment.
 Bacterial infection of the gum is called periodontal disease.
Ways to avoid tooth decay are:
 Regular brushing of teeth and gums twice a day
 Avoiding sweet ,sugary food
 Regular dental check up

Digestion in the stomach

 Oesophagus is a narrow tube that carries the swallowed food into the stomach.
 The muscular movement of the food along the oesophagus is called peristalsis.
 At the lower end of the oesophagus your food passes through a ring of muscle called a sphincter into
stomach.
 This sphincter is usually closed except when you are swallowing food or being sick.
 The main protease enzyme made in the stomach is pepsin.
Stomach is a muscular bag that produces:
 protease enzymes- to digest protein.
 HCL – to kill bacteria that are taken with food and also indirectly used in the breakdown of protein
 Mucus –to protect muscle walls of stomach from being digested by protease enzymes and the acid
 Chyme –grey and soup like mixture of food formed and passes into Small intestine.
Digestion in the small intestine
 Partly digested food is squeezed out of the stomach through another sphincter into the first part of
small intestine called duodenum.
 As soon as it arrives the food is mixed with two more liquids: bile and enzymes.
 Bile – is a greenish-yellow alkaline liquid that is produced in the liver.
 Liver – is a large reddish-brown organ that carries lots of important jobs in the body.
 Bile is made in the liver cells and stored in the gall bladder until it is needed.
 As food comes into the duodenum from the stomach, bile squirted onto the
stomach contents.
 Bile has two jobs :-
 To neutralizes the acid from stomach
 To emulsifies fat into fat droplets
 Small intestine Has 3 parts :
1. Deudemum – is upper part of small intestine which cannot make its own enzyme ,but supplied by
pancreases
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 -Part of the pancreas makes the hormone insulin to control blood sugar level.
-The rest of pancreas makes and stores enzymes that digest carbohydrate
Proteins and fats.
2. Jejunum- has no any digestive role.
3. Ileum –is the lower part of small intestine
-Place where digestion ends and absorption takes place
Villi - are millions of finger like projections where absorption of digested food take place
- The glucose, fructose and amino acids go directly into the blood.
-Fatty acid and glycerol move initially into the lacteal, b/c they are too large to be
absorbed by villa.
-villi are adapted for absorption of digested food, because:
 They have folds to Increase surface area for absorption
 They are surrounding by a net work of blood capillaries
Large intestine
 Undigested food like – cellulose, bile pigment, dead cells and mucus pass from small intestine into
large intestine.
 Large intestine has 3 parts:
 Colon - absorbs water from undigested foods and returns back into the small intestine.
 Rectum – is a part where faeces are stored temporarily.
 Anus – opening through which faeces is removed.

Digestive Health
 The digestive system may be affected by:
 Constipation - if faces remain too long in the large intestine and difficult to evacuate from the body
-Caused by lack of fibre in diet and not drinking enough water
Diarrhea - loose, watery faeces
Eg. Salmonella- is cause diarrhea and vomiting if we eat raw meat and eggs.
Food Care
 There are a number of food–borne diseases that can affect our health.
 You need to maintain very strict food hygiene when you are preparing food to avoid these diseases .
 Ways of preserving food are:
1. Canning - sealed food and heat at high temperature
2. Bottling: - uses glass bottles
3. Vacuum:- Packing
4. Drying: - remove of water
 precaution should be done before using canned or packaged foods:
 Check best before date stomped on can or package
 Check cans or packages for damages that could exposé food to air
 Eat contents of preserve food quickly.
 Seal leftover food and store it in cool place
 Check can or package for building
Homework: Do review question on page 81 Q1-5
3.3 Respiratory system
Breathing- is the process of taking air into the lung and removing air from it.
Breathing Structures
1. Nose (Nasal passenger) contains:
 Cilia and mucus : is used to filter dust and small particles like bacteria
 Blood capillaries : is used to warm the air
2. Pharynx (throat):- is common passage of air and food
3. larynx (voice box) :- found at the opening of trachea
4. Trachea: - connecting the larynx with the lungs and have incomplete rings of cartilage which support it.
5. Bronchi: - branched part of trachea
6. Bronchioles: - small branches arise from bronchi
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7. Alveoli:- small air sacs in a lung where gases exchange takes place.
The Mechanism of Breathing
 The movement of air into and out of the long is called Ventilation.
a. During inhalation (inspiration)
 Internal intercostals muscles contract –pulling ribs up and out
 Diaphragm contracts and flattens
 Ribcage moves up word and out wards
 Volume of chest cavity increases
 Pressure of the chest or thorax decrease
 Air moves into the lungs
B. During Exhalation (expiration)
 Internal intercostals muscles relax -pulling ribs down and in.
 Diaphragm relaxes and moves upwards to dome shaped
 Ribcage move downward and inwards
 Volume of the Chest cavity or thorax decreases
 Pressure of the chest is increase
 The air moves out of the lungs
Process of Gaseous exchange
 Breathing in supplies o2 for the cellular respiration
 Breathing out remove co2 from the body
 When the air breathed into the lung, at the same time:
 Oxygen passes into the blood
 Co2 passes out of the blood by diffusion along a concentration gradient.
Table: An analysis of gases taken in and breathed out of the lungs.
Atmospheric gas Air breathed in Air breathed out
N 80% 80%
O2 21% 16%
CO2 0.04% 4%
 Gase exchange in alveoli depend on:
 Large surface area
 Moist surfaces
 Short distances of diffusion
 A rich blood supply maintaining steep concentration gradients
Factors Affecting Breathing
 Normally the total capacity of the lung Is about 6 liter.
 At resting the average of breathing rate is 12-14 times per minutes.
 Breathing rate is the number of breath per minutes.
 The volume at the air inhaled and exhaled by man under normal resting condition is called Tidal volume
 This is about 500cm3(0.5 liter)of breath
 The maximum volume of air that can be exhaled after maximum inhalation is called Vital capacity
 The two ways of getting more air (O2) into our body is by:
 Breathing faster
 Breathing more deeply.
 The main factors affecting breathing are:
a. Exercise-during exercise the rate and depth of breathing increase the lung become bigger.
b. Anxiety- it increases the rate and depth of breathing.
c. Drugs:
Stimulants- like coffee and Khat increases the rate and depth of breathing
Depressants- like alcohol may lower the rate breathing
e. Altitude – is the height of land above the sea level or 3650m.
-As altitude increase the atmospheric pressure and the air or O2 decrease.
-The people live around higher altitude have increased number of:
-Lung volume with many more alveoli - to supply O2 fastly to the cells
- More blood capillaries and
-red blood cells.
f. Weight-over weightiness increases the accumulation of fat on the abdominal cavity.
g. smoking- consists of more 4000 chemicals that are inhaled into the lung.
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Some components of cigarette are:
a. Carcinogenic substance :- cancer causing substance
b. Tar - Sticky black chemical in tobacco smoke that is not absorbed into the bloods stream
- residue of cigarette smoke in the lung.
- turning lungs from pink to grey and cause irritation of lungs, nose and throat.
c. Nicotine : is addictive chemical in cigarette smoke
d. Carbon monoxide :- very poisonous gas decrease the o2 carrying capacity the blood
 Effects of smoking are:
 Cancer of lungs, lip and a throat
 Chronic obsractive pulmonary disease (COPD) - breakdown of alveoli
 Bronchitis –is inflammation of bronchi tube
 Effects on the heart and blood vessels
 Depression
Hygiene of Breathing
 Good personal hygiene – cleaning teeth, tongue etc
 Breathing deeply and avoid smoking cigarette
 Consult a doctor for any problem with respiratory organ
 Breathing through nose rather than mouth
Artificial breathing
 Breathing activity of a person may fail because of drowning, accidents, electric shock
 We can keep them alive until medical support arrives by using mouth to mouth method.
Steps
1. Call for help loudly
2.Check to if the casualty is conscious
3. open air way and check for breathing
4. Check the airway is open and head is filted back
5. Take deep breathe on casualty’s mouth
6. Remove your lips and let the chest fall naturally
7. Repeat these steps at about 12 breaths per minute
Homework: Do review question on page 98 Q1-4

3.4 Cellular Respiration

 All of your cells need energy to carry out the reactions of life.
 This is energy released from the food we eat and used by cells of our body.
 The energy that is used by the cells is stored in the form of ATP (adenosine triphosphate)
 Fuel is substance that is used to change the chemical energy in food into heat energy.
eg. food + oxygen heat energy + Co2 + H2o
ATP Formation
 ATP is direct and immediate energy source for our cells
 It composed of Adenosine and 3 phosphate group
 ATP is energy currency of the cells
a. When energy is needed ATP is breakdown into ADP (adenosine diphosphate) and phosphate(p):
ATP + H 2O ADP + Pi + energy
A-P-P-P + H2O A-P-P + P + energy
b. during respiration ATP is made from ADP and phosphate:
ADP + P + energy ATP + H2O
A-P-P + P + energy A-P-P-P + H 2O

The Main function ATP is:

 For both anabolism and catabolism =metabolism
 In making muscles contract
 In warm blooded animals to keep body temperature
 Provide energy for active transport during aerobic respiration
Types of respiration
1.Aerobic respiration
 Good form of respiration that provides more energy than that of anaerobic respiration.
 Aerobic respiration takes place in the inner membrane of mitochondria.

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  Cells that use a lot of energy, like muscle cells, liver cells, rods and cones of your eye contain lot of
mitochondria.
 Glucose reacts with oxygen to release energy that can be used by the cells.
 Carbon dioxide and water are produced as waste products.
C6H12O6 + 6O2 6CO2 + 6H2O + Energy (36/ 38ATP)
2. Anaerobic respiration
 Normally humans use aerobic respiration but during vigorous exercise the muscles cells may become
short of O2 to oxidize glucose to lactic acid. Eg.
C6H12O6 2C3H6O3 (lactic acid) + 2ATP
 Lactic acid produce accumulates on the muscle and causes pain on muscle called muscle fatigue or scramp
 After exercise lactic acid is oxidized by O2 to produce CO2 and H2o
 The amount of O2 needed to break down lactic acid is called oxygen dept
Lactic acid +O2 CO2 + H2O
 Anaerobic respiration is very good use, both in our industries and in our homes.
 One of the microorganisms that is most useful to people is yeast.
 When yeasts have plenty of O2 they respire aerobically
 Alcoholic fermentation is prepared by yeasts in the process of anaerobic respiration.
 Anaerobic respiration of yeast is called fermentation
C6H12O6 yeast 2C2H5OH (Ethanol) + 2CO2 + 2ATP
Fermentation

Comparison of aerobic and anaerobic respiration

Aerobic respiration Anaerobic respiration
 Utilizes Oxygen to release energy  They do not utilize Oxygen
for the cells
 High amount of energy is  Less amount of energy is
produced (36/38 ATP) produced ( 2ATP)
 takes place in mitochondria of the  Mostly occurs in the
cells cytoplasm of a cell

3.5 The Circulatory System

 The transport system is useful to supply the needs of the body cells and remove the waste materials
they produce
 The blood circulation system is the main transport system in humans.
 It consists of 3 elements. These are:
 The pipes (blood vessels)
 The pump (heart)
 The medium (blood )
The blood Vessels
 They are pathways through which transport takes place.
 There are 3 types of blood vessels. These are:
1. Artery:
 carry blood away from the heart
 They have bright red blood.
 Have thick and elastic wall
 They have pulse and narrower lumen
They have no valves
 The blood in arteries is under pressure so it is dangerous if arteries cut.
 They largest artery is aorta while smallest is arterioles
 Most of them carry oxygenated blood except:
 pulmonary artery- is carry blood away from the heart to the lung.
 umbilical arteries carry –is blood away from the foetus to placenta.
2. Veins
 carry blood towards the heart.
 They have low oxygen which is deep purple-red color.
 The blood in them is under lower pressure b/c they a long way away from the heart.
 Have thin and less elastic wall
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  They do not have pulse
 They have valves and wider lumen.
 The largest Venaacava while the smallest Veins are venuoles
 Most vein carry deoxygenated blood except:
 Pulmonary vein- carry oxygenated blood back from lung to the heart.
 umbsical vein- carry oxygenated blood from placenta back to the foetus.
3. Capillaries
 They are the site of the exchange of substances within the body.
 They have one cell thick wall
 They have no valves
 Help to connect artery with vein.
The Human Heart
 Human heart is reddish-brown structure which is made up of cardiac muscle
 It is surrounded by double membrane called pericardium
 The muscles of the heart are supplied oxygenated blood by the coronary arteries.
 The deoxygenated blood is carried away from the muscles by the coronary veins.
 The heart is made up of two pumps that beats at the same time.
 At normal condition the heart beats about 72 time per minutes.
 Human heart has of 4 chambers. These are:

1.Right auricle(atria) are upper chambers

2.left auricle (atria)
3. right ventricles are lower chambers
4. left ventricle

 The two ventricles have thick and muscular walls than the two auricles.
 Left ventricle has thicker wall than right ventricles
 The muscle walls of the left-hand side of the heart is thicker than the right side. Because:
-The left- hand side pump blood to the whole body where as
-Right-hand side pumps only to the lungs.
 Septum –separate left side of heart from right side
 Left side of the heart carries oxygenated blood
 Right side of the heart carries deoxygenated blood
 Valves –are used to prevent the back flow of the blood
Eg.-Tricuspid valves- prevent blood from right ventricles to the right auricles.
-Bicuspid valves- prevent blood from left ventricles to the left auricles.
-Semilunar valves- prevent the back flow of the blood into right ventricles
 Diastole :- when muscles heart relax and it fills with blood
 Systole :- when muscles contract and force the blood out of the heart
 Pulse rate :- is the number of pulse in one minute
Blood pressure:
- Systolic pressure- formed by the contraction of the muscles of the heart.
-Diastolic pressure- formed by the relaxation of the muscles of the heart.
-Normal blood pressure for human =120Hg -shows systolic pressure
80mmHg –shows diastolic pressure
Blood Circulation
 Human circulatory system is double circulation
 a.systemic circulation : circulation of blood between the heart and parts of the body
 b. Pulmonary circulation :- circulation of blood between the heart and lung
The Blood (Medium)
 Blood is a fluid tissue that is used to carry nutrients, gases, metabolic wastes.
 Each adult has 5 liters of blood
 About 45% of blood is made up solid particles(RBC, WBC and platelets)
 55% of blood is made up pale yellow liquid called plasma
 90% of plasma is consists of water
 10% of plasma consists of proteins and other substance like amino acid and glucose
Components of Blood
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1.Red blood Cells (Erythrocytes)
 They transport oxygen in the blood
 They are disc shaped that are concave on both sides
 The shape gives them a large surface area to volume ratio for diffusion of O2 into and out of the cell.
 They made in bone marrow and have no nucleus after they mature.
 They only live 100-120 days in your body
 They have red colour because they contain haemoglobin pigment
 In a high concentration of O2 like in lungs, haemoglobin react with O2 to form oxyhaemoglobin.
 Haemoglobin + oxygen high O2 concentration oxyhaemoglobin(bright scarlet)
 In area of lower O2 concentration like cells and organs of the body, the reaction reverses.
 Oxyhaemoglobin lower O2 concentration oxygen + purple-red haemoglobin

2. White blood cells (leucocytes)

 They are colour less and have nucleus
 They are larger in size than red blood cells
 They have irregular shapes
 They form from bone marrow
 They protects us from disease
 White blood cell have two main types. These are:
1. Phagocytes:- used to engulf invading bacteria
2. Lymphocytes :- used to form antibodies against microbes
3. Platelets (thrombocytes)
 They used for blood clotting at the site wound.
 They protect you from the entry of bacteria and other pathogens.
 They also protect the new skin from damage as it grows.
 They are smaller than red blood cells and white blood cell
 They are irregularly shaped.
 They are formed in red bone marrow.
 They are color less and non –nucleated.
 Platelets are fragments of the cells
Human Blood Groups
 A number of special proteins called antigens are found on the surface of the cells.
 They allows cells to recognize each other and also recognize cells from different organisms.
 A number of different antigens are found specially in the surface of red blood cells.
 This gives us the different human blood grouping system called ABO.
 There are 4 groups of blood .These are A, B, AB and O

Antigens:- are proteins found on the outer surface of red blood cells.
-There two types of antigens, Antigen- A and Antigen-B
Antibody :- are proteins made by white blood cells and found in the plasma of the blood.
-There two types of antibodies, antibody- a and antibody -b
 Antibody-a recognizes antigen-A as foreign protein
 Antibody-b recognizes antigen-B as foreign protein

Blood groups Antigen Antibody

A A b
B B a
AB AB No antibody
O No Antigen ab

Blood transfusion:- is transfer of blood from donor to receiver

-The person who gives blood is called blood donor
-The person who receiving blood is called blood recipient
-The sticking together of red blood cells is called agglutination
-Blood groups which mix without agglutination called compatible
-Blood group “O” is called “universal donor”
-Blood group “AB” is called universal receiver”
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 Blood group Can be given Receive from
A A, AB A, O
B B, AB B, O
AB AB A,B,AB & O
Rh Factor
 It is another specific antigen that found on the surface of RBC
 Individual having Rh antigen are called Rh positive (Rh+)
 Those lack Rh antigen are called Rh negative (Rh- )
 If blood of Rh- and Rh+ contact Rh- produce antibody to destroy Rh+ cells
Two common problem of circulatory system
1. Anemia:- cause by :- too few red blood cells in the body or most common is a lack of iron on the diet
Symptoms : - tiredness because of less o2 in the body cells
-Lack of energy
 Most likely it attacks girls than boys because:
-They lose iron during menstrual bleeding
-They lose their blood after child birth

2. Hypertension:-
 Hypertension is the medical name for high blood pressure
 It is high if : -Systolic pressure is greater than 140 mmHg or
-Diastolic pressure is greater than 90mmHg
It is increased by Decreased by
 Narrower blood vessels or becoming  Regular exercise and losing
more rigid weight
 being overweight and as age  lowering salts level and not
increase smoking
 Excessive salt intake and  If it more raised use
alcoholic drink -diuretic -chemical increase output of urine
 smoking and Kidney disease, -Beta blocked –drug lower blood pressure

Homework: Do review question on page 117 Q1-5

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