Focus Area 2021 | Questions and Answers | Plus One Zoology | Body Fluids and Circulation


1. (a) Mention the three types of antigens present in a person with AB+ve blood group. (Score 2)
    (b) Which blood group is known as Universal donor?


(a)  Antigen A, Antigen B and Rh factor.

(b)  O group.

2. Person with 'AB' blood group is called 'Universal recipient'. Give a reason. (Score 2)


AB blood group has no antibodies. So AB group persons can receive blood from other groups.

3. …………… is a disorder of the foetus due to an Rh incompatibility between the Rh-ve blood of a pregnant mother and Rh+ve blood of the foetus. (Score 1)

Answer: Erythroblastosis foetalis

4. (a) Make a flowchart showing cardiac impulse conduction using appropriate terms given in bracket. (Score 2)

[SAN, Right atrium, AVN, AV Bundle, Bundle of His, Ventricle]

(b) Which part is known as the pacemaker?


(a)  SAN → Right atrium → AVN → AV Bundle → Bundle of His → Ventricle.

(b) SA node (SAN)

5. Blood coagulation, is a mechanism to prevent the excessive loss of blood. (Score 3)
    (a) Identify the enzyme that helps the conversion of inactive fibrinogen.
    (b) Mention the role of thrombokinase.
    (c) Which ion is necessary for blood clotting?


(a) Thrombin

(b) Activates prothrombin to thrombin.

(c) Calcium ions.

6. Diagrammatic representation of a standard ECG is given below. (Score 3)

    (a) Expand ECG.
    (b) What does ‘P’, QRS & ’T’ waves denote?
    (c) Mention the clinical significance of ECG?


(a) Electrocardiogram.

(b) P wave: Depolarization of atria.

 QRS wave: Depolarization of ventricles

 T-wave: Repolarization of ventricles.

(c) It is used to find out the deviation or abnormality of functioning of heart.

7. a) Person with 'AB' blood group is called 'universal recipient'. Give a reason"
    b) List out any two disorders of the human circulatory system. (Score 2)


a) AB blood group has no antibodies. So AB group persons can receive blood from other groups.

b) Hypertension, Coronary artery disease.

8. a) Select the true statement regarding ECG. (Score 1)
       i) P-wave represents auricular repolarization
       ii) P-wave represents ventricular repolarization
        iii) P-wave represents auricular depolarization
        iv) P-wave represents ventricular depolarization
    b) Observe the diagram. Label A, B, C & D. (Score 2)


(a) (iii) P-wave represents auricular depolarization

(b) A= Aorta, B= Superior vena cava.

      C= Pulmonary artery, D= Chordae tendinae.

9. Longitudinal section of the human heart showing internal structure is given below. Observe the diagram and answer the following questions: (Score 3)

a)     Label the parts marked as A, B, C.

b)    Mention the 3 main stages in the cardiac cycle.


        (a) A= Aorta, B= Semilunar valve, C= Left ventricle

        (b) Joint diastole, Atrial systole, Ventricular systole.

10. “Sinoatrial Node is called pacemaker of our heart.”
        a) Justify the statement.
        b) Define cardiac cycle and cardiac output.


(a) SAN initiates and maintains contraction of heart by generating action potentials. So, it is called the pacemaker.

(b) Cardiac cycle: It is the cyclic contraction and relaxation of heart for pumping blood.

      Cardiac output: It is the volume of blood pumped out by each ventricle per minute.

11.  Name the two types of heart valves and mention their functions. (Score 3)


Tricuspid valve and bicuspid (mitral) valve:  They allow the flow of blood only in one direction, i.e. from atria to ventricles.

Semi-lunar valves: Present at the opening of pulmonary artery and aorta. They prevent backward flow of blood.

12.  Observe the flowchart and answer the questions given below.

a.  Draw the flow chart correctly.

b.  What will happen if the SA node is not working properly? (Score 2)



(b) Contraction and functioning of the heart will be stopped.


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