NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids

NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids Notes and select need one. NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids Question Answers Download PDF. NIOS Study Material of Class 12 Biology Notes Paper 314.

NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids

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Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Biology Chapter 15 Circulation of Body Fluids Solutions, NIOS Senior Secondary Course Biology Solutions for All Chapter, You can practice these here.

Circulation of Body Fluids

Chapter: 15




1. Give one example each of animals with open and closed circulatory system.

Ans: Open circulation = Prawn (insect) = Closed circulation = Vertebrates such as man, birds and fishes.

2. Where in the heart are the following valves located?

(i) Bicuspid.

Ans: Between left auricle and left ventricle.

(ii) Tricuspid.

Ans: Between right auricle and right ventricle.

3. Name the following:

(i) Structure where the wave of contraction originates in heart to begin heart beat.

Ans: Sinuatrial Node (SA Node).

(ii) Structure connecting arteries with the veins.

Ans: Capillaries.

(iii) Blood vessel that brings oxygenated blood from the lungs to the heart.

Ans: Pulmonary Vein.

(iv) The blood vessel which collects and brings deoxygenated blood from brain and shoulder region to the heart.

Ans: Superior Vena Cava.


1. Name the following:

(i) The term given to the production of blood cells.

Ans: Haemopoiesis.

(ii) The three proteins present in the plasma.

Ans: Serum albumin, serum globulin, fibrinogen.

(iii) Cell fragments of blood involved in the clotting of the blood.

Ans: Blood Platelets.

2. Fill in the blanks:

(i) Transfer of blood from donor to recipient is called __________.

Ans: Blood transfusion.

(ii) Antigens are present on ___________ and antibodies in the ___________.

Ans: Cell mem-brane of RBC; plasma.

(iii) People from blood group O can receive blood from blood group/groups ___________.

Ans: Only from blood group O.

(iv) Blood pressure is measured by an instrument called __________. The reading for a person with normal blood pressure will be around __________.

Ans: Sphygmomanometer, 80, 120 mercury. 


1. Fill in the Blanks:

(i) The clear colourless liquid following out of the blood capillary walls is called __________.

Ans: Lymph.

(ii) Lymphatic system consists of __________ lymph nodes and __________.

Ans: Lymph ducts and Lymph vessels.

(iii) A number of __________ are present in lymph nodes and attack bacteria.

Ans: Lymphocytes.

2. Give one example of lymphoid organ in your body.

Ans: Tonsils and spleen (write any on only).

3. Give two examples of Immuno Deficiency Syndrome.

Ans: (i) AIDS. and 

(ii) SCID.

4. Name the two kinds of lymphocytes of your immune system.

Ans: (i) B-cells. and 

(ii) T-cells. 

5. Name two heart related disorders.

Ans: (i) Hypertension.

(ii) Arterioscleresis.


1. Give one function of each of the following:

(i) R.B.C.

Ans: Function of RBC: Transport of oxygen and CO₂ gases.

(ii) Platelets.

Ans: Function of Platelets: They initiate blood clotting mechanism.

(iii) Plasma.

Ans: Function of Plasma: The plasma provides immunity through antibodies.

2. With the help of a flow chart describe the steps involved in the coagulation of blood.

Ans: Flow-chart of the steps involved in the coagulation of blood:

Fig. 15.10. Chart of coagulation of blood.

3. Why is a person with blood group AB called universal recipient?

Ans: A person with blood group AB is called universal recipient because it can receive blood from all other groups. It has no antibodies. 

4. Differentiate between the systolic and diastolic pressures. What are the values of these pressures for a normal human adult?

Ans: Differences Between Systolic and Diastolic Pressures:

Systolic PressureDiastolic Pressure
1. It is higher than dia-stolic pressure.It is lower than the sys-tolic pressure.
2. It is about 120 mm Hg. in human.It is about 80 mm Hg. in human.
3. It occurs during ventri-cular contraction.It occurs during ventri-cular expansion.

The values for these pressures for a normal adult are:

Systolic pressure: 120 mm of Hg.

Diastolic pressure: 80 mm of Hg.

Typical reading 120 ± 5/70 ± 5 mm of mercury (Hg).

5. Give three differences between lymph and blood.

Ans: Three differences between Lymph and Blood:

1. It flows slowly.It flows rapidly.
2. It is colourless fluids.The colour is red due to haemoglobin (Hb).
3. It has plasma and W.B.C’s. It has no R.B.Cs. It has less blood proteins.It consists of plasma and blood corpuscles-R.B.C., W.B.C., Blood-platelets. It has more proteins than lymph.

6. What is immunity? Differentiate between active and passive immunity.

Ans: Immunity: It is defined “as the ability of body to resist against the diseases”. Acquired immunity is acquired during lifetime.

Differentiate between active and passive immunity:

Active ImmunityPassive Immunity
1. It is life long immunity.It is temporary and short lived immunity.
2. It is developed when the body is exposed to a disease causing germ. It is developed when anti- a bodies are injected into the body. 
3. Example: DPT vacc-ine produces active immunity against T.B. (Tuberculosis disease).Example: ATS (anti tetaus serum) gives short lived and temporary immunity against the tetanus disease.

7. What are (i) hypertension and (ii) atherosclerosis?

Ans: (i) Hypertension: It refers “to the state of high blood pressure, the blood pressure is more than normal.” It is called high blood pressure and mostly related to stress, age, overweight and faulty diet, etc.

(ii) Atherosclerosis: It refers “to the formation of atheroma (fat deposit) on inner walls of arteries.” The lumen of arteries become narrow that interfere with normal functioning of human heart.

8. What is an ECG and what is its function?

Ans. ECG = Electrocardiogram: It is a graph that shows heart beat record by a machine (electrocardiograph). Electrocardiograph records heart beat that is essential for diagnosis of heart disease by a doctor.

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