Circulation Question and Answer | 11th & 12th NCERT / BOARD Questions Answers | - USA History 

1) What is blood ? What is the normal quantity of blood in an adult human being?

Ans :- 1. Blood is the fluid connective tissue that circulates in the body.

2. Blood is derived from mesoderm.

3. It is bright red, slightly alkaline fluid having pH about 7.4. It is salty, viscous fluid heavier than water.

4. The average sized adult has about 5 liters of blood in his/her body which constituents about 8% of the total body weight.

2) Describe in details the composition of human blood.

Ans :- 1. Blood consists of two main components, viz, 55% plasma and 45% blood corpuscles.

2. Plasma is a straw coloured, slightly alkaline and viscous fluid having 90% water and 10% solutes. Such as proteins, nutrients, nitrogenous wastes, hormone sand ions.

3. Blood corpuscles are of three types, viz., erythrocytes (RBCs), Leucocytes (WBCs), and thrombocytes (Platelets).

4. RBCs contain respiratory pigment haemoglobin.

5. WBCs are of two main types. viz., granulocytes and agranulocytes, Granulocytes are of three types, viz., neutrophils, basophils and eosinophils depending upon their staining properties and structure. Agranulocytes are monocyters and lymphocytes.

6. Blood platelets contain thromboplastin required for blood clotting.

3) Write a short note on erythrocytes ? (March 17) 

Ans :- a) Structure :- 

1. Erythrocytes or red blood corpuscles. They are circular, biconcave, enucleated cells.

Note : there is a nucleus in RBCs during development later it disappears, therefore they are called enucleated and not non-nucleated.

2. The RBC size 7 µm in diameter and 2.5 µm in thickness.

3. The RBC coutn 5.1 to 5.8 million RBCs/cu mm of blood in an adult male and 4.3 to 5.2 million/cu mm in an adult female.

4. The average life span of RBC is 120 days.

5. RBCs are formed by the process of erythropoiesis. In foetus, RBC formation takes place in liver and spleen whereas in adults it occurs in red bone marrow.

6. The old and worn out RBCs are destroyed in liver and spleen.

7. Polycythemia is an increase in number of RBCs while erythrocytopenia is decrease in their RBCs number.

b) Functions of RBC :- 

1. Transport of oxygen from lungs to tissues and carbon dioxide from tissues to lungs with the help of haemoglobin.

2. Maintenance of blood pH as haemoglobin acts as a buffer.

3. Maintenance of the viscosity of blood.

4. What is haemoglobin count in normal human beings ? What is the function of haemoglobin ?

Ans :- 1. The normal haemoglobin content in adult male is 13-18 mg/100 ml of blood.

2. In a normal adult female, it is about 11.5-16.5 mg/100 ml of blood.

3. In Anaemic individuals, there is lesser amount of haemoglobin.

4. Functions of haemoglobin is to transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs.

5. Haemoglobin acts as a buffer and maintains the blood pH.

5) Describe different types of leucocytes. ? 

OR

Describe five types of leucocytes, with the help of diagrams. Add a note on their functions. ? (July 16) 

Ans :- 1. Leucocytes or White Blood Corpuscles (WBCs) are colourless, nucleated, anoeboid, and phagocytic cells.

2. Their size ranges between 8 to 15 µm. Total WBC cout is 5000 to 9000 WBC/cu mm of blood. The average life span of WBC is about 3 to 4 days.

3. They are formed by leucopoiesis in red bone marrow, spleen, lymph nodes, tonsils, thymus and payer's patches, whereas the dead WBC are destroyed by phagocytosis in blood, river and lymph nodes.

4. Leucocytes are Mainly divided into two types, viz., granulocytes and agranulocytes.

5. Granulocytes : Granulocytes are cells with granular cytoplasm and lobed nucleus. Based on their staining properties and shape of nucleus, they are of three types viz., neutrophils, eosinophils and basophils.

a) Neutrophils :- 

(i) In neutrophils, the cytoploasmic granules take up neutral stains.

(ii) Their nucleus is three to five lobed.

(iii) It may undergo changes in structure hence they are called polymorphonuclear leucocytes or polymorphs.

(iv) Neutrophils are about 70% of total WBCs.

(v) They are phagocytic in function and engulf micro-organisms.

b. Eosinophils or acidophils :- 

(i) Cytoplasmic granules of eosinophils take up acidic dyes such as eosin. They have bilobed nucleus.

(ii) Eosinophils are about 3% of total WBCs.

(iii) They are non-phagocytic in nature.

(iv) Thier number increases (i.e. eosinophilia) during allergic conditions.

(v) They have anti-histamine property.

c. Basophils :- 

(i) The cytoplasmic granules of basophils take up basic stains such as methylene blue.

(ii) They have twisted nucleus.

(iii) In size, they are smallest and constitute about 0.5% of total WBCs.

(iv) They too are non-phagocytic.

(v) their function is to release heparin which acts as an anticoagulant and histamine that is involved in inflammatory and allergic reaction.

6. Agranulocytes : There are two types of agranulocytes, viz., monocytes and lymphocytes Agranulocyts do not show cytoplamic granules and their nuclesu is not lobed. They are of two types viz., lymphcytes and monocytes.

a. Lymphocytes :- 

(i) Agranulocytes with a large round nucleus are called lymphocyte.

(ii) They are about 30% of total WBCs.

(iii) Agranulocytes are responsible for immune response of the body by producing antibodies.

b. Monocytes :- 

(i) Largest of all WBCs having large kidney shaped nucleus are monocytes. They are about 5% of total WBCs.

(ii) They are phagocytic in function.

(iii) They can differentiate into macrophages for engulfing micro-organisms and removing cell debris. Hence they are also called scavengers.

(iv) At the site of infections they are seen in more enlarged form.