Haematopoiesis (physiology)

Question 1

Process that gives rise to formed elements?

Answer 1

Haematopoiesis

Question 2

Define the monophylatic theory of haematopoiesis

Answer 2

All formed elements are derived from a common ancestral cell, a stem cell.

Question 3

What is the route of erythrocyte formation from stem cell?

Answer 3

-Hemocytoblast (stem cell)
-Proerythroblast (committed cell)
-Early erythroblast (ribosome synthesis, phase1)
-Late erythroblast (hemoglobin accumulation, 2)
-Normoblast (ejection of nucleus, phase 3)
-Reticulocyte
-Erythrocyte

Question 4

Where does erythropoiesis occur?

Answer 4

In red bone marrow.

Question 5

Which substances/molecules does erythropoiesis require? (6)

Answer 5

-Lipids, proteins and carbohydrates.
-Iron, vit b12 and folic acid.

Question 6

Main function of platelets

Answer 6

Blood clotting

Question 7

Where are platelets recycled and what recycles them?

Answer 7

In the spleen, by phagocytes.

Question 8

Role of platelets in hemostasis (3)

Answer 8

-Plugging holes to the blood vessels to prevent bleeding.
-Promoting the formation of clots to further prevent bleeding.
-Help to repair the damaged blood vessels.

Question 9

From which cell do platelets derive, and where does the thrombopoiesis occur?

Answer 9

Megakaryocyte, in the bone marrow.

Question 10

Two ways in which platelets are released from megakaryocytes.

Answer 10

-Pinching off from the megakaryocyte into circulation.
-Passage of mature megakaryocyte into circulation and fragmentation in pulmonary vascular bed.

Question 11

Diff btwn inactivated and activated thrombocytes.

Answer 11

Inactive are small, disc-like fragments.
Active have a spiky outer surface and they adhere to each other.

Question 12

Hormonal control of thrombopoiesis

Answer 12

-Interleukin 6
-Thrombopoietin
-Multi-CSF