26: Hematopoiesis - Steele Flashcards Preview

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Flashcards in 26: Hematopoiesis - Steele Deck (42):
1

hematopoiesis =

formation of blood cells

2

functions of hematopoiesis

- provides the cellular elements of the peripheral blood; takes place in the bone marrow
- delivery of oxygen to the tissues + providing host cell defense
- replaces of 0.5 x 10to12 cells/day

3

what is a normal hematocrit level?

45-50%

with blood doping and rhEPO it could go up to 80%

4

life spans:
lymphocytes
RBC
platelets
granulocytes
macrophages

years
120 d
7-10 d
6-8 hrs
months - years

5

eosinophls
neutrophils
basophils
are....

granulocytes

6

a smear of the bone marrow would contain mostly...

granulocyte precursors

7

give rise to progenitor cells of all lineages

hematopietic stem cells

self renewal AND differentiation

0.1-0.01% of bone marrow cells; highly proliferative

8

purpose bone marrow stromal cells

maintenance and differentiation of hematopoietic cells

ex: adipocytes, fibroblastoid cells and reticuloendothelial cells

9

more primitive/earlier in differentiation. more ______ bind to stromal cells

tightly/firmly

stem cells/ primitive precursors bind firmly; maturing precursor cells nonadherent

10

G-CSF granulocyte colony stimulating factor -->

released by macrophages at inflammatory sites --> circulates to bone marrow --> production/release of NEUTROPHILS

11

EPO erythropoietin --->

produced/released by peritubular interstitial cells (kidney) in repsonse to hypoxia --> circulates to bone marrow --> production and release of RBC

increased oxygen pressure inhibits production of EPO

12

TGFbeta transforming growth factor beta -->

downregulation of stem cell growth/differentiation by TGFbeta by decreasing cell surface receptors for growth/differentiation cytokines

13

why would you give someone G-CSF?

ex: pt on chemo, need to increase neutrophils,

ex: bone marrow transplantation (some of bone stem cells get into peripheral blood with G-CSF, harvest stem cells from blood)

GM-CSF can do some of the same things but worse side effects

14

why would you give EPO?

anemia as result of renal insufficiency --> increase RBC mass

15

yellow v. red marrow

yellow is inactive and mainly adipose tissue

red- active in hematopoiesis

young all is red, by 18 red only in ribs, sternum and pelvis

16

what is extramedullary hematopoiesis?

takes place in spleen and liver when bone marrow dysfunctional or unable to meet the demands on it

hematopoiesis but not in the bone marrow

17

as a cell matures..
cell size ____
n:c ratio ______
nucleoli _______
cytoplasmic staining _____

decreases
decreases
decrease in number to zero
darker blue to lighter blue because decreasing RNA

18

describe a RBC

smaller cell size
lower N:C ratio
no nucleoli
lighter cytoplasm

reticulocytes and erythrocytes do not have any nucleus

19

the formation or production of RBC

erythropoiesis

20

maturation sequence of RBC

stem cells --> rubriblast --> prorubricyte --> rubricyte --> metarubricyte --> reticulocyte --> mature erythrocyte

21

production of cells in the granulocytic lineage, including neutrophils, eosinophils and basophils

granulopoiesis

22

sequence of development for granulopoiesis

stem cell --> myeloblast --> promyelocyte --> myelocyte --> metamyelocyte --> band --> granulocyte

23

what is a band cell?

almost but not quite mature granulocyte

24

"shift to the left"

shifting back to less mature forms

% of band forms in the blood

bone marrow is releasing cells as immature band cells because trying to keep up with infection for example

25

circulation v. marginating pools of neutrophils

about half neutrophils are zooming around in blood, about half bound to the walls of blood vessels

26

________ remove dead granulocytes from circulation

splenic macrophages

27

histiocytes
kupffer cells
osteoclasts
microglial cells

loose connective tissues
liver
bone
nervous system

all different names for macrophages

28

"baby macrophages"

monocytes

stem cell --> monoblast --> promonocyte --> monocyte --> macrophage

29

production of cells in lymphocytic lineage, including T lymphocytes, B lymphocytes or natural killer NK cells

lymphopoiesis

stem cell --> lymphoblast --> prolymphocyte --> lymphocyte

30

develop entirely in bone marrow and are released into the peripheral blood

only the B lymphocytes and NK cells

31

activated b cells give rise to ...

plasma cells and memory cells

32

t cells are in the bone marrow until prothymocytes are released into peripheral blood to migrate to the ...

thymus

once in thymus termed thymocytes and then differentiate into t lymphocyte subsets

most die in thymus (positive and neg selection)

once leave thymus, populate lymphatic organs

33

production of platelets

thrombopoiesis

34

anuclear cytoplasmic remnants of megakaryocytes

thrombocytes

role in hemostasis --> limit bleeding, repair endothelium

35

which of the lymphocytes are part of innate immuity?

NK cells

36

thrombopoiesis is stimulated by...

thrombopoietin
- promotes megakaryocyte precursor production
-stimualtes endomitosis (mitosis without cytoplasmic divisions)

each megakaryocyte can become 100-1000 platelets

37

maturation sequence for thrombopoiesis

stem cell --> megakaryoblast --> promegakaryocyte --> megakaryocyte --> platelet

38

where is an emergency reserve of platelets found?

spleen

platelets are phagocytized in liver or spleen

39

quantity of each cell type per unit volume

absolute cell count

differential count is a relative count that gives the % of each cell type

40

absolute cell count for a cell type =

total WBC count X % cell type

41

most bone marrow is...

granulocytes 50-70%

only 2% are RBC precursors

stem cells are the least %

42

0.5 - 1.5% of RBC

reticulocytes aka slightly immature red blood cells

shift to left if body is being stressed to make more RBC and sends them out immaturely