Blood And Blood Components

Question 1

What are the 4 constituents of blood and their percentages?

Answer 1

Plasma 55%
Erythrocytes - RBC - 45%
Leucocytes - WBC - < 1%
Thrombocytes - platelets- <1%

Question 2

Function of erythrocytes

Answer 2

Carry haemoglobin which carry O2.
Hb found us cytosol
Membrane made up of glycolipids which are antigens
No nucleus or organelles so can’t reproduce or synthesise

Question 3

What is the erythropoiesis and the stages?

Answer 3

How red blood cells are made
Starts in bone marrow as a stem cell
Differentiates into pro erythroblast
Synthesis of hb and nucleus = reticulocyte
Erythropoeisis stimulated by low O2 levels
Juxtaglomerular cells of kidneys detect low O2, secrete erythropoietin into blood, speeds up maturation in bone marrow to produce more RBCs

Question 4

Characteristics and function of leucocytes

Answer 4

Have a nucleus
Plasma membranes have proteins called MHC antigens for immunological purposes
Different classifications:
Granular - eosinophils (parasitic worms), basophils (attack other WBCs), neutrophils (viruses)
Agranular - lymphocytes and monocytes (become macrophages)
Combat infection by phagocytosis

Question 5

Characteristics and function of thrombocytes

Answer 5

Formed from fragments of megakaryocytes under thrombopoietin in red bone marrow, then enter circulation
Disc shaped
No nucleus
Many vesicles
Involved in haemostasis, clotting

Question 6

What are the 4 main blood types?

Answer 6

A,B,AB,O

Question 7

When does Rhesus incompatibility in pregnancy occur? When mother is Rh Neg

Answer 7

RhD antigens from fetus mix with maternal blood.
Mother makes anti D antibodies, IgG cross across the placenta because of their size
These anti D attack fetal erythrocytes

Question 8

What is haemopoeisis?

Answer 8

Stages of development of blood cells
Refer to diagram

Question 9

What is erythropoiesis?

Answer 9

Development of erythrocytes