0714 820 596 Channa Asela Teacher, S ... System.pdf · 6) Get destroyed in the – liver and spleen. 7) Contains haemoglobin 8) Hb is made up of haem containing iron and a protein

0714 820 596 Channa Asela www.OLscience.com

Teacher, S. Thomas’ College, Mt. Lavinia

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Blood circulatory system

Function of the blood circulatory system

1) Transport substances such as –

Nutrients, gases, nitrogenous waste products, hormones.

2) Provide immunity

3) Maintain the body temperature (37°C or 98.4°F)

The main parts of blood circulatory system

1) Blood

2) Blood vessels

3) Heart

The main parts of blood (5l of blood is found in a healthy adult)

1) Blood plasma

2) Blood corpuscles ( blood cells)

Blood plasma

1) 55 % blood is blood plasma

2) It is straw colour

3) 92% of blood plasma is water

4) 8% of blood plasma are the substances dissolved in water

(i) Nutrients - Monosaccharides, amino acids, fatty acids, glycerol, vitamins

(ii) Hormones – Insuline, thyroxine, oestrogen, testosterone, progesteron

(iii) Nitrogenous waste products – urea, uric acid, creatinin



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(iv) Gases – CO2, N2

(v) Plasma proteins – albumin, globuline, fibrinogen

(vi) Antibodies

(vii) Antigens

(viii) Ions – Na+, K+, Mg2+, Ca2+, Cl-, SO42-, HCO3

-, PO43-

5) Main function of blood plasma

(i) Transport – nutrients, hormone, nitrogenous waste products, & hormones

(ii) Maintain body temperature (37°C or 98.4°F)

The second most abundant compound in blood plasma is plasma proteins

Blood corpuscles (blood cells)

1) 45% of blood is blood corpuscles

2) It is dark red colour

3) Types of corpuscles are

(i) Erythrocyte (Red Blood Cells - RBC)

(ii) Leukocyte (White Blood Cells - WBC)

(iii) Thrombocyte (Platelets)



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Erythrocytes

1) Shape – Biconcave (side view) and disc shape (top view)

2) No nucleus.

3) Produce in the bone marrow of long. (they are called red bone marrow)

4) Count – 5 million per cubic milimeter

5) Life span – 120 days

6) Get destroyed in the – liver and spleen.

7) Contains haemoglobin

8) Hb is made up of haem containing iron and a protein called globulin.

9) Each Hb molecule can bind with 4 oxygen molecules and become oxy-Hb

10) In the tissues, O2 gets detached from Hb. Now it is called de-oxy -Hb.

11) In a healthy adult there is 12.5g/dl – 17.5g/dl of Hb

12) The condition which contains less Hb is called anaemia

13) Main function of RBC – transport oxygen



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Leukocytes

1) Shape – Round shape

2) Contain a nucleus.

3) Size is larger than the RBC.

4) Produced in the bone marror.

5) Count – 4,000 to 11,000 per cubic milimeter

6) RBC : WBC = 600 : 1

7) Function – engulf germs in a process called phagocytosis



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8) The number of WBC will increase during an infection

9) Therefore the ratio of RBC : WBC will reduce

10) But in leukamea the WBC count will increase unusually

11) Some WBC contain granules in their cytoplasm.

12) They are called granulocyte (eg neutrophils, esonophils, basophils)

13) Some WBC do not contain granules in the cytoplasm.

14) They are called non granulocyte (eg. Lymphocytes & Monocyte)

15) Neutrophills

(i) The most common WBC (65% of WBC)

(ii) Has a multilobed nucleus



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16) Esonophills

(i) 4% of WBC

(ii) Has a bilobed nucleus

17) Basophils

(i) 1% of WBC

(ii) Has an irregular shaped nucleus

18) Lymphocyte

(i) 25% of WBC (second most common WBC)

(ii) Has a large round nucleus

19) Monocytes

(i) 5% of WBC

(ii) Has a kidney shaped nucleus.

Thrombocyte

1) They are parts of cells (fragments of cells)

2) Shape – Irregula shaped

3) No nucleus

4) Produced in the bone marrow

5) Count – 150,000 – 400,000 per cubic milimeter

6) Life span – 5-7 days

7) Contains a substance called Thromboplastin which helps to clot blood

8) In dengue the platelet count will be less than 150,000 per cubic milimitre



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9) Therefore dengue patient will have internal and external bleeding.

Diagrams of blood cells

Blood vessels

1) There are 3 type s of blood vessels – arteries, veins and capillaries.

2) The blood vessels which take blood away from the heart are called arteries.

3) The blood vessels which bring blood back to heart are called veins.

4) The blood vessles which found inside tissues are called capillaries.

5) Blood capillaries connect arteries to veins.

6) The walls of the blood capillaries are made up of single thin flat cell layer called

squamous epithelium.



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7) Everything in blood, except blood cells and plasma proteins can diffuse through

the walls of blood ccapillaries

Arteris Veins

Takes blood away from the heart Brings blood back to the heart.

Have high pressure Low pressure

Have thick walls Thin walls

Contain elastic tissues in walls No elastic tissues in walls

No valves Contain valves

Found deep inside body Found closer to the skin.

Contain oxygenated blood except in

pulmonary artery

Contain deoxygenated blood except in

pulmonary vein



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Double circulation



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1) The left ventricle pumps oxygenated blood throught theaorta to the entire body

except the lung.

2) The superior (anterior) vena cava (SVC) brings deoxyginated blood from the

upper part of the body (head, neck and upper limbs) to the right atrium.

3) The inferior (posterior) vena cava (IVC) brings deoxygenated blood from the

lower part of the body (legs, addomen, thorax) to the right atrium.

4) The pulmonary artery takes deoxygenated blood from the right ventricle to the

left and right lungs.

5) The pulmonary vein brings oyginated blood from the left and right lungs to the

left atrium.

6) The blood circulation which starts from the left ventricle through the aorta and

ends in the right atrium through superior (anterior) vena cava (SVC) and inferior

(posterior) venaca (IVC) is called the systemic circulation.



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7) The blood circulation which starts from the right ventricle through the pulmonary

artery and ends in the left atrium through the pulmonary veins is called the

pulmonary circulation.

8) Since there are two circulations namely systemic circulation and pulmonary

circulation, it is called double circulation.



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Heart

1) It is located in the thorax (chest cavity) on the mid line slightly towards the left.

2) The size of a persons heart will be the size of his or her fist.

3) It has four chambers

4) The left and right chambers are separated by atrio ventriculat septum

5) The top two chambers are called L & R atria (singular term is atrium).

6) The lower two chambers are called L & R ventricles.

7) The valve found between the left atrium and left ventricle is called the bi cuspid

valve (Mitral valve) or left atri-ventricular valve.



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8) The valve found between the right atrium and the right ventricle is called the

tricuspid valve or right atrio ventricular valve.

9) Valves will prevent the back flow.

10) The left and right atria have to pump blood to the left and right ventricles which

are also located within the heart.

11) Therefore the left and right atria have to exert a small force to pump blood to the

left and right ventricles.

12) Therefore the walls of the left and right atria are thin.

13) The right ventricle has to pump blood to the left and right lungs which are out

side the heart but located closer to the heart.

14) But the left ventricle has to pump blood to the entire body except the left and

right lungs.

15) Therefore the left ventricle has to pump blood with more force than the right

ventricle.

16) Therefore the walls of the left ventricle is thicker than the walls of right ventricle.

17) Superio (anterior) vena cava (SVC) and inferior (posterior) vena cava (IVC) open

into the right atrium.

18) Four pulmonary veins (2 from each lung) open into the left atrium.

19) Pulmonary artery arise from the right ventricle.

20) The pulmonary atery devides into left and right pulmonary arteries

21) Aorta (the main artery) arise from the left ventricle

22) There are semilunar valves at the beginning of the pulmonary artery and the

aorta.



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Heart sounds

1) Lub sound – due to the closing of bicuspid valve

2) Dubb sound – due to the closing of semilunar valve

Cardiac cycle

1) The atria and ventricles contract and relax according to a rhythm.

2) It starts from from the 6th week in mother’s womb till th time of death.

3) Contraction of atria is called the atrial systole.

4) Contraction of ventricles is called the ventricular systole.

5) Relaxation of atria is called the atrial diastole

6) Relaxation of ventricles is called ventricular diostole

7) Each cardiac cycle produces a heart beat

8) 72 beats occur ina healthy adult per minute

9) Therefore the duration of one cycle is about 0.8s

10) Each cardiac cycle consists of 3 phases

i) Atrial diastole

ii) Atrial systole

iii) Ventricular systole

iv) Ventricular diastole

11) During atrial diastole

i) Left and right atria will relax.



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ii) Superio (anterior) vena cava (SVC) brings deoxygenated blood from the

upper part of the body to the right atrium.

iii) Inferior (posterior) vena cava (IVC) brings deoxygenated blood from the

lower part of the body to the right atrium.

iv) Pulmonary veins bring oxygenated blood from left and right lungs to the

left atrium

12) During atrial systole

i) Left and right atria will contract

ii) Bicuspid and tricuspid valves will open

iii) The deoxygenated blood in the right atrium will flow through the tricuspid

valve (right atrio ventricular valve) to the right ventricle.

iv) The oxygenated blood in the left atrium will flow through the bicuspid

valve (left atrio ventricular valve) or Mitral valve to the left ventricle.

13) During ventricular systole

i) The left and right ventricles will contract

ii) The bicuspid and tricuspid valves will close

iii) Therefore lub sound will occur

iv) This will prevent the blood in the left and right ventricles flowing back to

left and right atria respectively

v) The deoxygenated blood in the right ventricle will flow through the right

semilunar valve (pulmonary valve) into the pulmonary artery.

vi) The oxygenated blood in the left ventricle will flow through the left

semilunar valve (aortic valve) into the aorta.

14) During ventricular diastole



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i) The left and right ventricles will relax.

ii) The left and right semilunar valves (pulmonary & aortic valves) will close

iii) Therefore dub sound will occur

iv) This will prevent the deoxygenated blood in the pulmonary artery flowing

back to right ventricle and the oxyginated blood in the aorta flowing back

to the left ventricle.

Electrocardiogrm (E.C.G.)

1. There will be an electricle potential change during muscular contraction and

relaxation.

2. A graph is drawn according to the electricle potential change when heart muscles

contract and relax.

3. An E.C.G. has 3 components.

4. P wave is due to the contraction of the atrial muscles.

5. QRS complex is due to the contraction of the ventricles.

6. T wave is due to the relaxation of cardiac muscles



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Blood pressure

1. The pressure exerted by blood on the walls of arteries is called the blood

pressure.

2. The blood pressure increases when the blood is forcefully pushed into the

arteries during the contraction of the heart muscles. This blood pressure is called

the systolic blood pressure. It is 120mmHg in a normal healthy adult at rest.

3. The blood pressure reduces when the blood is not pushed into the arteries during

the relaxation of the heart muscles. This blood pressure is called the diastolic

blood pressure. It is 80mmHg in a normal healthy adult at rest.

4. The blood pressure is normally represented as 120/80 mmHg

5. The blood pressure increases with the age, stress, certain sicknesses and during

exercise.

Lymphatic system

1. Arteries take blood from the heart and take to various organs.



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2. These arteries divide into arterioles and further divide into capillaries inside

tissues

3. The walls of the capillaries are made up of a single layer of thin squamous

epithelium.

4. Tissues are made up of group of cells

5. The space among cells is called inter cellular space

6. Therefore WBC and blood plasma diffuce from capillaries Into the inter

cellular space. (RBC, platelets and plasma proteins do not diffuce)

7. The fluid in the inter cellular space is called the inter cellular fluid (ICF) or

tissue fluid.

8. Substances diffuce from blood capillaries to cells and from cells to blood

capillaries through the inter cellular fluid (ICF) or tissue fluid.

9. 90% of the inter cellular fluid (ICF) or tissue fluid will get absorbed back into

cappilaries.

10. The balance 10% will be absorbed into some blind vessels called lymphatic

vessels

11. The inter cellular fluid (ICF) or tissue fluid which got absorbed into the

lymphatic vessel is now called lymph.

12. The lymph in the entire body get together and form two major lymphatic

vessles.

i) Thoracic duct is found on the left side

ii) Right lymphatic duct is found on the right side

13. The thoracic duct opens to the junction of left internal jugular vein and the

left sub clavian vein.



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14. The right lymphatic duct opens to the junction of right internal jugular vein

and the right sub clavian vein.

15. The lymphatic system is made up of lacteals, lyphatic capillaries and lymph

nodes.

16. The main function of the lymphatic system is to destroy bacteria.

17. The lymphocytes (a type of WBC) found in lymph nodes engulph bacteria

using a process called phagocytosis.

18. Then the lymph nodes will swell and they are now known askuddeti.

19. Lymph nodes are mainly found in the lungs, heart, arm pit, groin, troat etc.



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Artherosclerosis

1. Deposition of low density lipo-proteins (LDL) on the walls of arteries and reducing

the size of the lumen is called artherosclerosis

2. Deposition of LDL in coronary arteris will cause angina (chest pain) or even might

cause heart attack

3. Increase consumption of saturated fatty acids such as pork, mutton, beef, liver,

egg yolk, prawns, crabs will increase LDL.

4. Regular exercises can reduce artherosclerosis.

Hypertenstion



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1. Due to deposition of LDL on the walls or arteris reduces the size of the lumen.

2. This will also reduce the elasticity of the blood vessles.

3. Therefore, the blood flow to organs will be reduced.

4. The heart has to pump blood with more force to supply the same volume of

blood to the organs

5. Therefore the blood pressure will increase.

6. Smoking, consumption of alcohol, mental stress, obesity will also cause

hypetension

7. Less blood pressure is called hypotention

8. Hypotension is due to nutrient deficiencies

Thrombosis

1. Lowering of blood flow to an organ due to a formation of a blood clot in a

narrowed blood vessel is called thrombosis

2. If thrombosis occur in the brain, it will result paralysis (stroke)

3. If thrombosis occur in a coronary artery in the heart, it will result myocardial

infarction (heart attack)

4. Reduce mental stress, avoid smoking and alcohol, regular exercise, reduce

obesity and weight, control diabetes, reduce the consumption saturated fatty

acids, consuming more fibres, reduced consumption of salt intake will help to

reduce thrombosis.



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Documents

0714 820 596 Channa Asela Teacher, S ... System.pdf · 6) Get destroyed in the – liver and spleen. 7) Contains haemoglobin 8) Hb is made up of haem containing iron and a protein