SEE Science (Blood Circulation) Notes

 

            Blood Circulation

1)    Write average number of RBC and WBC in 5ml blood of human.

Ans: 5ml = 5cm³ = 5 × 10 × 10 × 10 mm³ (^..^. 1cm = 10mm)

                          = 5000mm³

Now, 1 mm³ of blood contains = 4750000 RBC (average)

^..^. 5000mm³ of blood contains = 4750000 × 5000 RBC

                                               = 2.375 × 10¹⁰ RBC

Similarly, 1 mm³ of blood contains = 7000 WBC (average)

^..^. 5000mm³ of blood contains = 7000 × 5000 WBC

                                               = 3.5 × 10⁷ WBC

2)    Write the function of pericardium?

Ans: Function of pericardium: It protects the heart from mechanical injuries.

3)    What happens if the pericardial fluid decreases?

Ans: Mechanical injuries may occur in the heart, if the pericardial fluid decreases.

4)    Write the name of blood vessels which carry blood from lungs to heart.

Ans: Pulmonary vein is the blood vessels which carry blood from lungs to heart.

5)    What happens when the amount of platelets increases and decreases?

Ans: If the amount of platelets increases, the clotting of blood will be faster which may cause blockage of blood and if the amount of platelets decreases the blood clots very slowly and there is more chances of loss of blood.

6)    Which blood cells' numbers is less than the average in a person suffering from anaemia?

Ans: Red Blood Cells' numbers is less than the average in a person suffering from anaemia.

7)    Write the names of four valves found in human heart.

Ans: The names of four valves found in human heart are:

a)    Bicuspid/Mitral Valve

b)    Tricuspid Valve

c)    Aortic Valve

d)    Pulmonic Valve

8)    Differences between systematic and pulmonary circulation.

Systematic circulation	Pulmonary circulation
It is the circulation of blood in between the heart and different parts of the body except lungs.	It is the circulation of blood in between the heart and the lungs.
Oxygenated blood becomes deoxygenated.	Deoxygenated blood becomes oxygenated.

9)    Where does bicuspid valve lie in a heart?

Ans: Bicuspid valve lies in between left auricle and left ventricle in a heart.

10)    Write an effect due to lack of fibrinogen in blood.

Ans: Fibrinogen helps in the clotting of the blood at wounds. Therefore, lack of fibrinogen in blood will directly affect the clotting i.e. clotting won't be seen and blood will flow continuously due to lack of fibrinogen.

11)    What happens if there is shortage of WBC in blood?

Ans: If there is shortage of WBC in blood, a person will suffer from leucopenia i.e. the immunity power in a person will decrease and suffers from various types of diseases.

12)    What is systematic and pulmonary circulation?

Ans: The circulation of blood in between the heart and different parts of the body except lungs is called systematic circulation.

                        The circulation of blood in between the heart and the lungs is called pulmonary circulation.

13)    Differences between artery and vein.

Artery	Vein
It carries blood away from the heart to different body organs.	It carries blood from different body organs to the heart.
The arteries carry oxygenated blood. (Expect pulmonary arteries)	The veins carry deoxygenated blood. (Expect pulmonary veins)
They have thick walls.	They have thin walls.

14)    Among artery and vein, which blood vessel carries blood from longs to heart and which has high blood pressure?

Ans: Among artery and vein, vein carries blood from longs to heart and artery has high blood pressure.

15)    Rupture in artery is dangerous than that in vein, why?

Ans: Oxygenated blood flows with high pressure in the artery. Any injury in artery may cause the continuous flow of blood without getting coagulated. This makes the heavy loss of oxygenated blood that even may cause the death of a person. But inside vein, deoxygenated blood flows with low pressure and the loss of blood will be less. Therefore, rupture in artery is dangerous than that in vein.

16)    Which disease is caused by the excess of WBC?

Ans: Leukaemia is caused by the excess of WBC in blood.

17)    Where RBC, WBC and platelets are formed and their function.

Ans: 

RBC – Formed in bone marrow, life-span is about 4 months (127 days) and destroys       in liver and spleen.

Function: 

a) It helps to transport oxygen from lungs to tissues and carbondioxide from tissues to lungs.

 b) The surface of red blood cells absorbs the amino acids and transports them to the cells from the alimentary canal.

c) It helps to maintain the viscosity of the blood and iron balance.

WBC - Formed in bone marrow, life-span is about 15 days and destroys in spleen.

Function:

a) WBCs protect the body from micro-organisms and provide immunity to the body.

b) They produce anti-bodies and anti-toxins which neutralize or kill the germs that enter our body.

c) They help in removal of injured tissues and promotion of healing.

Platelets – Formed in bone marrow, life span is about 2-3 days and destroys in                     spleen.

Function: 

a) They are responsible for the clotting of blood at the site of cut or injury. They produce a chemical called thromboplastin that initiates the chain of reaction involved in blood clotting and prevent excess flow of blood from the body.

18)    Define haemoglobin? Write its function.

Ans: The iron rich red coloured respiratory pigment. It is formed of an iron-containing pigment known as haemin (4%) and a protein part known as globin (96%).

Functions of haemoglobin are:

a)     It combines with oxygen, which is responsible for the red colour of blood.

b)     It helps to maintain the balance of acid and base in the blood.

c)     It plays an important role in oxygen and carbondioxide transport.

19)    Write down the functions of the plasma.

Ans: The functions of the plasma are given below:

a) Plasma transports digested food to the various parts of body.

b) It transports waste materials like carbon dioxide, urea, etc, to their respective sites for excretion.

c) It regulates the amount of water and other chemicals in the body.

d) It regulates the body temperature.

e) It contains fibrinogen (protein) and prothrombin (hormone) which help in the clotting of blood at cuts.

20) The person suffering from anaemia feels tired after walking short period.

Ans: The person suffering from anaemia has deficiency of red blood cells or haemoglobin in his/her blood. So, adequate amount of oxygen cannot be supplied to the body and energy will not be provided sufficiently inside the body. Due to the lack of enough energy, the person suffering from anaemia feels tired after walking a short period.

21)    Write down the major functions of blood.

Ans: The major functions of blood are given below:

a)    Blood transports oxygen from lungs to the tissues and carbon dioxide from     the tissues to the lungs.

b)   The carries digested food to different parts of the body.

c)    Blood helps to regulate the body temperature.

d)    It regulates the amount of water and other chemicals in the body.

22)    Differentiate between white blood cells and red blood cells.

White blood cells	Red blood cells
1. They are large cells having amoeboid shape.	1. They are smaller cells having biconcave shape.
2. Nucleus is present.	2. Nucleus is absent.
3. They protect body from micro-organisms.	3. They transport oxygen to the different parts of body.
4. Their life period is about 1-4 days.	4. Their life period is about 120 days.
5. They are colourless.	5. They are red in colour due to the presence of haemoglobin.

23)  Give reasons:

a) The wall of left ventricle is thicker than that of right ventricle.

Ans: Left ventricle pumps out a large amount of blood to the different parts of body through the widest and largest artery i.e. aorta. For this, a great force is required, which is provided by its thick walls but right ventricle supplies impure blood towards lungs through pulmonary artery. For this, a great force is not required. So, the left ventricle has more muscles that that of right ventricle.

b) Right auricle is larger than left auricle.

Ans: In the right auricle, impure blood of whole body is poured through superior venacava and inferior venacava whereas pure blood is poured into the left auricle from lungs through pulmonary veins. Since a larger volume of blood is collected in the right auricle than that of left auricle, right auricle is larger than left auricle.

24)  Where is tricuspid value located in heart?

Ans: Tricuspid value is located between the right auricle and right ventricle.

25)  The wall of artery is made of thick muscles, why?

Ans: Inside arteries, blood pumped by the heart flows with high speed and high pressure. In order to withstand the high blood pressure, the wall of arteries is made up of thick muscles.

26)  Write down the differences between arteries and veins.

Arteries	Veins
1. All arteries carry oxygenated blood except pulmonary artery.	1. All veins carry deoxygenated blood except pulmonary veins.
2. Arteries carry blood from the heart to various body parts.	2. Veins carry blood from different body parts to the heart.
3. In arteries, blood flows with high speed and under high pressure.	3. In veins, blood flows with low speed and under low pressure.
4. Valves are absent.	4. Valves are present.
5. Arteries have thick wall.	5. Veins have thin wall.

27)  What is meant by 'Blood pressure'?

Ans: The pressure exerted by the flow of the blood on the walls of the arteries is called blood pressure.

28)  What is the blood pressure of a healthy young person? Name the instrument which is used to measure blood pressure.

Ans: The normal blood pressure of a healthy young person is 120/80 mm Hg. The instrument used to measure blood pressure is called sphygmomanometer.

29)  The blood pressure of a healthy man is 120/80 mm Hg, what does it mean?

Ans: A person has blood pressure of 120/80 mmHg means that the systolic pressure of the person is 120 mm of Hg and the diastolic pressure of the person is 80 mm of Hg.

30)  What do you understand by heart beat? When does it increase?

Ans: The continuous rhythmic beat throughout the life which is produced due to the contraction and relaxation of the heart muscles is called heartbeat. The heart of a healthy adult person beats 72 times per minute. The heart beats vary according to the age, sex and condition of the body.

The rate of heart beat increases with tension, physical exercise, emotion, fear and fever.

31)  Write function of right and left auricle & right and left ventricle of human heart.

Ans: 

Right auricle receives deoxygenated blood from different parts of the body through superior and inferior venacava and pumps it into the right ventricle.

Right ventricle receives deoxygenated blood from the right auricle and pumps it into the lungs through pulmonary artery for its purification.

Left auricle receives oxygenated blood from the lungs through pulmonary vein and pumps it into the left ventricle.

Left ventricle receives oxygenated blood from the left auricle and pumps it into the different parts of the body through aorta.

32)  What symptoms are seen if leukocytes and erythrocyte, found in our blood, fall below normal level?

Ans:  A person suffers from leucopenia if the number of leukocytes falls below that normal level and a person suffers from anaemia if the number of erythrocytes falls below the normal level.

33)  Give one function of fibrinogen, vein and sphygmomanometer each.

Ans: Function of

Fibrinogen: It helps in the clotting of blood at cuts or wound.

Vein: It carry blood from different body parts to the heart.

Sphygmomanometer: It is used to measure blood pressure.

34)  Explain with a reason why the wall of the artery is thicker than the veins. Write one function of each valve found in human heart.

Ans: Inside arteries, blood pumped by the heart flows with high speed and high pressure. In order to withstand the high blood pressure, the wall of the artery is thicker. But inside veins, blood flows with low speed and under low pressure. Therefore, the wall of the artery is thicker than that of veins.

Function of tricuspid/right autrio ventricular valve: It prevents the back flow of blood from right ventricle to right auricles, when the ventricles are contracted.

Function of bicuspid/mitral/ left autrio ventricular valve: It prevents the back flow of blood from left ventricle to left auricles, when the ventricles are contracted.

Pulmonary/pulmonic valve: It prevents the back flow of blood from pulmonary arteries to the right ventricle, when the ventricles are relaxed.

Aortic valve:  It prevents the back flow of blood from aorta to the left ventricle, when the ventricles are relaxed.