hematopoiesis -Vishy

Question 1

What are granulocytes?

Answer 1

WBCs that have granules: neutrophils, basophils and eosinophils

Question 2

What are agranulocytes?

Answer 2

lymphocytes and monocytes

Question 3

Where are stem cells produced in development and life?

Answer 3

1st in the yolk sac

then in liver and spleen from the 3rd-7th month of development

in bone marrow from 7th month of development–> adulthood (ratio of differentiated: stem cells = 10^5: 1)

Question 4

What are the two lineages of stem cells and what cells does each lineage produce?

Answer 4

1. lymphoid: lymphoblasts–> prolymphocytes–> lymphocytes (T and B cells)
2. myeloid:
   - myeloblasts (monoblasts) –> promyelocyte–> neutrophils, basophils, eosinophils
   - monoblasts–>monocytes

erythrocytes and platelets are also cells of myeloid lineage

Question 5

At what stage is a hemocytoblast (stem cell) committed to becoming a erythrocyte?

Answer 5

proerythroblast
still has a nucleus, nucleolus and organelles at this stage but will eventually lose these when it develops into a mature RBC

Question 6

What controls the development of stem cells into RBCs? (erythropoiesis)

Answer 6

erythropointin, which is secreted by the kidneys when oxygen is low.

iron

amino acids

B vitamins

Question 7

What do primary granules of neutrophils contain? secondary granules?

Answer 7

Primary granules are azurophilic granules contain lysozyme, alpha-defensins and myeloperoxidase (catalyses the reaction producing hypochlorous acid and singlet oxygen, which can have antimicrobial effects)

secondary granules contain lactoferrin

Question 8

Which cytokines regulate the formation of neutrophils from stem cells?

Answer 8

GM-CSF, CSF, IL-3

Question 9

What cells are responsible for leading the body’s defense against parasitic infections?

Answer 9

eosinophils

Question 10

Which cells have granules that contain histamine and play an important role in allergic reactions?

Answer 10

basophils (they are similar in function to mast cells, which also participate in allergic reactions)

Question 11

what cytokine induces the formation of monocytes/macrophages from stem cells?

Answer 11

M-CSF (macrophage colony stimulating factor)

Question 12

What cytokine causes stem cells to differentiate into lymphocytes?

Answer 12

IL-7

Question 13

Describe the process of apoptosis

Answer 13

programmed cell death of blood cells prevents necrosis and the spilling of intracellular contents including enzymes, and preventing inflammation of blood cells.

cells undergoing apoptosis shrink and undergo blabbing. Cells break down into small “apoptotic bodies” which are then phagocytosed by macrophages.

Question 14

What are some of the factors that can initiate apoptosis? Inhibit apoptosis?

Answer 14

initiate apoptosis: p53, Bax, BclXs (Bcl-short), FasL, and caspases

inhibit: Bcl-Xl (Bcl-long)