Blood Cells & Haemopoeisis

Question 0

Describe the function of neutrophils

Answer 0

Migrate out of circulation to site of infection (chemotaxis), phagocytosis. Multi-lobed.

Question 1

Outline the process of haemopoiesis

Answer 1

Proliferation - two cells produced; clone and a cell that differentiates. Haemopoietic progenitor will differentiate into either myeloid blast (RBC, WBC or platelets) or lymphoid blast (immunoresponse cells).

Question 2

What stimulates neutrophils?

Answer 2

Cytokines (e.g. G-CSF) increase neutrophil prodcution, increase chemotaxis and therefore increase phagocytosis

Question 3

Describe the action of eosinophils

Answer 3

Capable of phagocytosis. Release cytotoxic particles to damage larger particles. Used in allergic/atopic responses

Question 4

Describe the appearance of eosinophils

Answer 4

Bi-lobed nucleus, orange colour due to granules (arginine)

Question 5

Describe the action of basophils

Answer 5

Mediate acute inflammatory responses - release histamine, heparin and hyaluronate

Question 6

Describe the appearance of basophils

Answer 6

Bi- or tri-lobed nuclei, dark purple colour

Question 7

Describe the action of B lymphocytes

Answer 7

Used for humoural immunity - produce plasma cells which produce antibodies. Stimulated by antigens to transform into plasma cells.

Question 8

Describe the action of T lymphocytes

Answer 8

T helper - express CD4 receptors on surface, can be killer cells, permit transformation of B cells to plasma cells

Question 9

Describe the appearance of lymphocytes

Answer 9

Small, round nucleus. Pale blue in colour

Question 10

Describe the action of monocytes

Answer 10

Move out of circulation to become macrophages, capable of phagocytosis and interact with T cells. Diapedesis to tissues.

Question 11

Describe the appearance of a monocyte

Answer 11

Kidney shaped nucleus

Question 12

Outline the life cycle of a red blood cell

Answer 12

Bone marrow - peripheral red blood cell - removal by the reticulo-endothelial system.

Question 13

What are the functions of red blood cells?

Answer 13

Deliver O2 to tissues, carry Hb, osmotic equilibrium, generate ATP anaerobically

Question 14

What is the structure of red blood cells?

Answer 14

Biconcave discs, have four globin chains, each molecule carries a haem

Question 15

What are the functions of reticular cells?

Answer 15

Direct T and B lymphocytes to specific regions with the lymphatic tissues

Question 16

What is the structure of reticular cells?

Answer 16

Synthesise reticular fibres and surround them with cytoplasm

Question 17

What is the reticuloendothelial system?

Answer 17

A part of the immune system containing phagocytic cells. They identify and mount an appropriate immune response to foreign antigens. Main organs - liver, spleen and lymphatic nodes

Question 18

Which cells are included in the reticuloendothelial system?

Answer 18

Monocytes, macrophages, kupffer cells, tissue histiocytes, microglial cells in the central nervous system

Question 19

How long do red blood cells last in circulation?

Answer 19

120 days

Question 20

How long do platelets remain in circulation?

Answer 20

10 days

Question 21

How long do neutrophils last in circulation?

Answer 21

2-4 days

Question 22

How long do lymphocytes last in circulation?

Answer 22

1 day - years

Question 23

Outline two pathways for metabolism in a red blood cell

Answer 23

By the Embden Meyerhof pathway - glucose is metabolised to lactate resulting in ATP generation. Hexose monophosphate pathway - glucose-6-phosphate metabolised, NADPH produced

Question 24

What are the functions of platelets?

Answer 24

Used in the blood clotting cascade, adhere to cell walls and aggregate

Question 25

Describe the structure of platelets

Answer 25

Complex surface membrane, produced in megakaryoctes in bone marrow, cytoplasm contains alpha and dense granules, alpha contains fibrinogen and von Willebrands Factor, dense contains Ca2+ and ADP

Question 26

Describe RBC destruction and catabolism

Answer 26

Bilirubin from haem goes to liver which then goes to the spleen where it is converted to bile. It moves to the large intestine where its converted to urobilinogen and goes to kidney to be excreted. Cn also be converted to stercobilin and excreted in the faeces