Unit 3 Solution 

Blood


LONG ANSWER QUESTION – 10 MARKS

Q. Describe the composition and formation of blood.

👉Composition of Blood

1. Plasma

Blood is composed of plasma (55%) and formed elements (45%).Plasma is the liquid part of blood that transports blood cells, nutrients, hormones, enzymes, antibodies and waste products.

Constituents of Plasma:
Water – 91.5%
Plasma proteins – 7%
Albumin
Globulin
Fibrinogen
Other solutes – 1.5%
Electrolytes, gases, nutrients, hormones, enzymes and waste products

2.Red Blood Cells (RBCs): Contain haemoglobin, biconcave, no nucleus, lifespan 120 days, transport oxygen and carbon dioxide.

3.White Blood Cells (WBCs): Provide immunity; include granulocytes and agranulocytes.

4.Platelets: Help in blood clotting and formation of platelet plug.Formation of Blood (Hematopoiesis)Blood cells are formed in the bone marrow from stem cells.


Q. Explain the functions of blood.

👉Functions of Blood:

1.Transports oxygen and carbon dioxide

2.Transports nutrients to cells

3.Carries hormones to target organs
Removes waste products
Regulates body temperature
Provides immunity and protection
Prevents blood loss by clotting

Q. Describe blood clotting, blood grouping and cross-matching.

👉Blood Clotting (Hemostasis)

Hemostasis is the process by which bleeding is stopped.

Stages:
Vascular spasm – vasoconstriction
Platelet plug formation
Coagulation – fibrin clot formation
Blood Grouping
Blood grouping is classification of blood based on antigens and antibodies.

Types:
ABO system
Rh system
ABO Blood Group System:
Group A – antigen A, antibody B
Group B – antigen B, antibody A
Group AB – antigens A & B, no antibody
Group O – no antigen, antibodies A & B
Rh System:
Rh positive – Rh antigen present
Rh negative – Rh antigen absent

Blood Cross-Matching
Cross-matching is done before blood transfusion to ensure compatibility between donor and recipient.

Types:
Major cross-matching
Minor cross-matching