Biology: Body Fluids and Circulation (Solved Examples Part 1)

1. Blood clotting involves the conversion of

A . Prothrombin to thromboplastin

B . Thromoboplastin to prothrombin

C . Fibrinogen to fibrin

D . Fibrin to fibrinogen

Solution:

A wound stimulates the platelets in the blood to release blood coagulating factors to initiate the mechanism of coagulation.1. Platelets release the plasma protein thromboplastin. 2. Thromboplastin converts prothrombin, which is also a plasma protein into the enzyme thrombin. 3. Thrombin converts fibrinogen into fibrin. 4. Fibrin is insoluble protein and forms the threads that bind the clot.Blood clotting prevents the excessive loss of blood from the body.Thus, the correct

Correct Answer : C

2. Blood plasma is ............ nature.

A . Alkaline

B . Acidic

C . Neutral

D . None of the above

Solution:

The pH of the extracellular fluid, including the blood plasma, is normally tightly regulated between 7.32 and 7.42 , by the chemical buffers, the respiratory system, and the renal system. So, the correct answer is 'Alkaline'.

Correct Answer : A

3. Major component of blood plasma is

A . Water

B . Inorganic substances

C . Organic substances

D . Blood cells

Solution:

One half of blood is composed of red blood cells, white blood cells and platelets which are considered as solid part of blood and another half is composed of water, salts and proteins which is the fluid part of blood. The fluid part of blood is known as plasma. Plasma is a straw coloured, viscous fluid it has about  water and  proteins. Hence a major component of blood plasma is water so the correct answer is 'Water'

Correct Answer : A

4. Nucleus of monocyte is

A . two lobed

B . kidney shaped

C . S-shaped

D . multilobed

Solution:

Nucleus of monocytes is bean or kidney shaped.

Correct Answer : B

5. Lymph lacks

A . WBC

B . RBC

C . Tissue fluid

D . All of the above

Solution:

The lymphatic system returns excess interstitial fluid to the blood. Of the fluid that leaves the capillary, about 90 percent is returned. The 10 percent that does not return becomes part of the interstitial fluid that surrounds the tissue cells. It helps in exchange of gasses, nutrients and removes the metabolic waste. It is devoid of RBC. So, the correct answer is option B.

Correct Answer : B

6. Platelets are cell fragments produced from

A . Megakaryocytes in the spleen

B . Megakaryocytes in the bone marrow

C . Thrombocytes in the bone marrow

D . Thrombocytes in the spleen

Solution:

Sol.Platelets are also called thrombocytes. They are cell fragments produced from megakaryocytes (special cells in the bone marrow).

Correct Answer : B

7. Cells formed in bone marrow include\\

A . RBC

B . RBC and leucocytes

C . Leucocytes

D . Lymphocytes

Solution:

Correct Answer : B

8. Which of the following cells are most abundant

A . Basophills

B . Neutrophils

C . monocytes

D . lymphocytes

Solution:

Correct Answer : B

9. The granules of neutrophils are

A . Lysosomes

B . Mitochondria

C . Golgi complex

D . None of these

Solution:

Neutrophils are phagocytic cells, their cytoplasm carries lysosomes with lytic enzymes.

Correct Answer : A

10. Thromboplastin required in blood clotting is secreted by

A . Monocytes

B . Lymphocytes

C . Erythrocytes

D . Platelets

Solution:

Thromboplastin is a protein secreted by platelets at the site of injury during wound. It converts plasma protein prothrombin into thrombin in the presence of calcium ions. In the presence of thrombin, fibrinogen gets converted into fibrin which leads to the formation of a clot forming a type of plugSo, the correct answer is 'Platelets'

Correct Answer : D

11. Antigen - A antibody - B are present in which blood group

A . B

B . A

C . AB

D . 0

Solution:

The correct option is B. Blood group A has A antigens on the red blood cells with anti-B antibodies in the plasma. This combination of antigens and antibodies determine which blood type can be safely transfused for medical purposes.

Correct Answer : B

12. Tricuspid valve is found in between

A . Sinus venosus and right auricle

B . Right auricle and right ventricle

C . Left ventricle and left auricle

D . Ventricle and aorta

Solution:

The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve. It is also called as an atrioventricular valve. It prevents the backflow of blood into the right atrium. Whereas a bicuspid valve guards the opening between the left atrium and the left ventricle.

Correct Answer : B

13. SA node is located in

A . Upper lateral wall of left atrium

B . Lower lateral wall of left atrium

C . Lower lateral wall of right atrium

D . Upper lateral wall of right atrium

Solution:

Sino atrial node is located on the upper lateral wall of the right atrium.

Correct Answer : D

14. SA node has higher rhythmicity and is called pacemaker, it's activity can be moderated by -

A . Cardiac center present in medulla oblongata

B . Cardiac muscles present near SA node

C . It is self-regulated and self-stimulating and can't be moderated.

D . Vasomotor area present in medulla oblongata.

Solution:

Activity of SA node can be moderated from cardiac center present in medulla oblongata.

Correct Answer : A

15. Which vein contains the oxygenated blood in humans?

A . Cardiac vein

B . Hepato pancreatic vein

C . Portal vein

D . Pulmonary vein

Solution:

Option (1) correctly describes the nomenclature of the diagram.

Correct Answer : D

16. The graph of the electrical activity of heart versus time produced by the non-invasive medical procedure is called

A . Electroencephalogram

B . Electrocardiogram

C . Stethoscope

D . None of the above

Solution:

A) Electroencephalogram (EEG) records the electrical activity of the brain. It is usually noninvasive, with the electrodes placed along the scalp.B) Electrocardiogram (ECG) records the electrical activity of the heart over a period of time using electrodes placed over the skin.C) The stethoscope is a medical device used for listening to the internal sounds of the human body.D) The graph of the electrical activity of heart versus time produced by the non-invasive medical procedure is called Electrocardiogram. So the correct answer is 'Electrocardiogram'.

Correct Answer : B

17. During ventricular diastole<br>

A . The auricles relax

B . The heart contracts

C . The heart pumps blood

D . The ventricles relax

Solution:

Ventricular diastole is the period during which the ventricles relax. It is the time when the blood flows in the ventricles. The aortic valve and pulmonary valve remain closed to maintain the pressure inside the ventricles while the atrioventricular mitral and tricuspid valves remain open to allow the blood flow from atria to the ventricle. So, the correct answer is option D.

Correct Answer : D

18. In standard ECG, the P-wave represents

A . Electrical excitation of the atria

B . Depolarisation of the ventricles

C . Repolarisation of the ventricles

D . Repolarisation of the atrium

Solution:

Sol.In standard ECG, the P-wave represents the electrical excitation (or depolarisation) of the atria.

Correct Answer : A

19. Coronary artery supplies blood to

A . Mammary glands

B . Rib muscles

C . Skin

D . Heart

Solution:

The human heart is richly supplied with oxygen. A special coronary system of blood vessels is present in our body exclusively for the circulation of blood to and from the cardiac musculature. Coronary artery supplies blood to the heart.

Correct Answer : D

20. Which of the following parts of heart first receives deoxygenated blood?

A . Right ventricle

B . Left auricle

C . Right auricle

D . Left ventricle

Solution:

The right auricle receives deoxygenated blood from the superior and inferior vena cava. Deoxygenated blood from all over the body comes to the right atrium via the two vena cava for purification.

Correct Answer : C