Hematopoiesis

Question 1

Hematopoisis stages in pre-natal period

Answer 1

Stem cells appear in aorta,gonads,mesonephrons and yolk sac in 3rd weak. The at the start of 3rd month transfer to liver ,spleen and lymph nodes. In 4th month some of them transfer to bone marrow

Question 2

Stages of hematopoesis

Answer 2

—>MSC-> CFU EM-> CFU E
PHSC  |.                              
          —>LSC -> pro nk cells
                       |—> pro T cells
                       | —> pro B cells

^.           ^.             ^.                    ^.    Psc.       MSC.      CSC.             CFU

Question 3

Monocytes in different tissues(lungs,spleen,liver,cns,bones,kidney) as macrophages

Answer 3

Kupfer cells in liver, osteoclast in bone, alveolar macrophages in lungs, langerhan cells in skin , dendritic cells in spleen and lymph nodes, mesengial cells in kidney and microglial cells in cns

Question 4

What’s pancytopenia and leukemua

Answer 4

Pan(All)cyto(cell)penia(poverty)

Leukemia—> malignances of hematopoetic cells and precursor cells

Question 5

Bone marrow transplant injection

Answer 5

Bone marrow is injected in venous system they circulate but settle in bone marrow

Question 6

Role of B-12 and folic acid in hematopoesis

Answer 6

They are must for nuclear maturation because they help in making thymidine phosphate

Question 7

Pernicious anemia

Answer 7

Lack of intrisic factor( stored in liver and combine with vitamin b-12 to make it undigestible

Question 8

Bone marrow aspiration

Answer 8

Pass needle from sternum and iliac crest

Question 9

Heterochromatin and euchromatin

Answer 9

Condensed chromatin is called heterochromatin while loose one is called euchromatin that is for division

Question 10

Erythropoietin release

Answer 10

Inside peritubular capillaries of kidney there are endothelium cells that have ability to sense oxygen concentration and release erythropoietin

Question 11

Pcv(hematocrit)

Hb concentration

MCV

Answer 11

Pect cell volume is the volume of blood occupied by RBCs when they packed together i-e 45ml/dl

Hb concentration is 1/3rd of rbc volume i-e 15% of pcv or 15g hb

Mean corpuscular vol is the vol of rbcs divided by red cell count(i-e 4.5-6L)—> 90fl

Question 12

MCH

Mchc

Answer 12

Total hb divided by red cell count i-e 30pg

MCHC=33%

Question 13

Iron metabolism

Answer 13

In small intestine fe combines with apotransferrin to form transferrin or may combine with ferritin to form ferritin and many ferritin combine to form hemosiderin(insoluble form)

Question 14

Thymus origin and underdevelopment

Answer 14

Double origin—>Encapsulated THymus epithelium is derived from THird pharyngeal pouch( endoderm) whereas thymic lymphocytes are derived from mesoderm

If 3rd and 4th pharyngeal pouch do not develop well than called as 1)digeorge syndrome then problem of thymus and as well as parathyroid gland 2) scid

Question 15

C0rtex and medulla of thymus

Answer 15

Cortex is dense stain dark :’ of tightly packed lymphocytes and contains epithelial cells which are also nursing cells that combine and form pockets where lymphocytes are present Medulla contains Mature t cells and hassle’s corpuscles(remnants of tubes of 3rd nd 4th pharyngeal pouch) which are concentric aggregates of epithelial cells

Question 16

Epithelial cells chemicals and barrier for blood

Answer 16

Thymotexin (chemotactic for lymphoid stem cells)
Thymopoetin+
Serum thymic factor+thymosin —> help in maturation for t-cells

Blood-thymus barrier is formed by 1) processes of epi cells 2) double basal lamina
3) endothelial cells so as to provide private microenvironment to cortex

Question 17

Steps of T cell maturation in thymus

Answer 17

L stem cell[double negative(tcr,cd4,cd8)]
—>pre T cell+TCR
—> +CD4+CD8 [triple +ive]
—>exposed to self class 1 &class2 moleclues
—+ive selection—> T cells[exposed to self antigens
—-ive selection—>mature T cells

Question 18

When T helper and cytotoxic T cells are formed

Answer 18

When T cells interact with Class 1 MHC molecules than CD8 genes become active forever i-e cytotoxic T cell while if Touched with MHC-2 molecules than CD4 with active forever i-e T helper cells
Rule of 8: MHC II × CD4 = 8; MHC I × CD8 = 8.

Question 19

Function of cd4+ t cells and cd8+ t cells in cell mediated immunity

Answer 19

CD4+ T cells help B cells make antibodies and produce cytokines to recruit phagocytes and activate other leukocytes.

CD8+ T cells directly kill virus-infected and tumor cells via perforin and granzymes (similar to NK cells).