erythropoiesis

Question 1

hematocrit definition

Answer 1

Relative vol of RBC out of total blood vol

Erythrocytes (out of whole blood)

Question 2

Ht in Male

Answer 2

46%

Question 3

Ht in female

Answer 3

42%

Question 4

RBC function

Answer 4

• Resp gas transport
• Contain Hb, transport O2
• Contain carbonic anhydrase, transport CO2
• Buffer pH in blood

Question 5

shape of RBC

Answer 5

• Biconcave
• Diameter: 7.5um
• Thickness: 2-1um

Question 6

feature of RBC

Answer 6

○ Large SA/vol ratio
○ Easy diffusion of O2
○ Flexible (cap 3-4um)
○ Smooth flow through stack formation

Question 7

other values of RBC??

Answer 7

• 99.9% of formed elements
• ~45% of blood vol
  ○ M: 5.2 x 10* 9 RBC/mL
  ○ F: 4.7 x 10* 9 RBC/mL
• RBC lifespan: 100-120 days

Question 8

RBC composition and numbers

Answer 8

• 97% Hb
• 25-30 x 10* 12 RBC/ human
• 2.5 x 10* 8 Hb molecules/ RBC
  ○ 1 RBC transport 10*9 O2 molecules

Question 9

globin

Answer 9

4 folded pp chains
2 α chains
2 β chains

Aa seq determine affinity to O2

Question 10

Heme

Answer 10

a. Pigment

b. Each heme grp 1 Fe, bind 1 O2 molecule

c. Weak, reversible binding (easy to diffuse)

Question 11

number of O2 binding 1 Hb

Answer 11

1 Hb = 4 chains = 4 heme = 4 Fe = 4 o2

Question 12

colour of bood

name of Co2 bound Hb

Answer 12

oxyHb: bright red
deoxyHb: dark red

CARBAMINOHb

Question 13

Erythropoiesis rate

Answer 13

• Generate erythrocytes 25-30x10*12 RBC/human
• Replace RBC: 2-3X10*6 RBC/s

Question 14

fetus erythropoiesis

Answer 14

yolk sac —-> liver, spleen, lymph node

Question 15

<5yo erythropoiesis

Answer 15

all bone marrow

Question 16

5-20 yo erythropoiesis

Answer 16

bone marrow of ribs, sternum, vertebrae, proximal ends of long bones

Question 17

> 20 yo erythropoiesis

Answer 17

bone marrow in ribs, sternum, vertebrae

Question 18

erythropoietin release (hormone)

Answer 18

○ Release and RBC prod regulated by tissue oxygenation

1. Decr O2 delivery to kidney
2. Decr blood flow to kidney
3. Incr tissue demand for O2
4. Anemia
5. Blood donation
   ○ Release hormone, incr rate of erythropoiesis
6. Once O2 delivery to kidney is sufficient, kidney decr output

Question 19

effect of erythropoietin

Answer 19

• Growth factor
• Enhance proliferation rate of proerythroblasts and erythroblasts
• Enhance Hb synthesis
• Incr RBC production (30x10*6/s)
• 90% secreted by kidneys, 10% in liver

Question 20

WHY Androgen (M) enhance erythropoietin

Answer 20

higher RBC conc than F

Question 21

how does erythropoiesis process work

Answer 21

1. Stimulate hematopoietic stem cells to form proerythroblast
2. Ribosome synthesis in early erythroblast
3. Hb accumulation in late erythroblast & normoblast
4. Eject NUCLEUS from normoblast = form reticulocytes
   a. 0.8-1% reticulocyte
   b. (indicative of erythropoiesis)
5. Continue Hb synthesis, leave bone marrow, complete differentiation to mature erythrocytes in blood

Question 22

when is RBC broken down

Answer 22

• Self destruct, lifespan of 100-120days
• worn-out

Question 23

how is RBC broken down

Answer 23

1. Lack protein synthesis, makes mem fragile + Hb degrade
2. Rupture in spleen tiny vessels (3um diameter)
3. Macrophage take up dying RBC/ components

Question 24

what is recycled in RBC and where

Answer 24

Fe recycled. Reused in BONE MARROW/ stored in LIVER

Question 25

what is metabolised from RBC and where

Answer 25

Hb split --> 4 heme + 4 globulin (a,b chains) ○ Globulin metabolised into AA, released into circ ○ Heme grp degraded to yellow pigment, bilirubin - Excreted via liver and bile --> urine and feces - Excess bilirubin = jaundice

Question 26

end pdt of rbc

Answer 26

heme -- degraded into bilirubin globulin -- meta into aa Fe -- recycled, liver, bone marrow

Question 27

Anemia

Answer 27

reduction of Hb/ erythrocytes below normal capacity of blood to carry O2

Question 28

sx of anemia

Answer 28

blood O2 lvls cannot support normal metabolism, leads to ○ Fatigue, pale, SOB, chills ○ Low RBC, more lq blood, rush too fast into tissues, release little O2 ○ Hypoxia: widens blood vessels and reinforce effect ○ Incr workload for heart, cardiac arrest risk

Question 29

types of anemia HARN TES

Answer 29

nutritional aplastic renal hemorrhagic sickle cell Erythroblastosis fetalis thalassemia

Question 30

nutritional

Answer 30

Dietary deficiencies of factors needed for erythropoiesis □ Fe, folic acid, B12 Pernicious anemia: lack of vit B12, intrinsic factor

Question 31

Aplastic

Answer 31

Failure of bone marrow to make adequate number of RBC * Radiation damage or chemo

Question 32

Renal

Answer 32

Kidney disease, lack of erythropoietin * Not responsive/ unable to produce

Question 33

Hemorrhagic

Answer 33

Due to loss of sig amt of blood vol and RBC

Question 34

malaria

Answer 34

Plasmodium falciparum amplify in RBC, ruptures them. Offspring invades new RBC

Question 35

sickle cell

Answer 35

Mutation in b-globin gene, cause Hb to aggregate in low O2 conditions

Question 36

Erythroblastosis fetalis

Answer 36

Rh+ RBC of fetus are destroyed by anti-Rh antibodies of a Rh- mother * mother's second or later pregnancies. If she is ever carrying another Rh+ positive child, during birth, Rh- antibodies attack child

Question 37

Thalassemia

Answer 37

blood disorder, genetic Low production of Hb

Question 38

excess RBC

Answer 38

Polycythemia/ erythremia Excess RBC in circulating erythrocytes, elevated hematocrit

Question 39

effect of polycythemia

Answer 39

cause viscous blood, potentially plug capillaries, insuff O2 delivery to tissues caused by primary, secondary polycythemia, dehydration

Question 40

primary causes of polycythemia

Answer 40

§ Tumour or tumour-like condition in bone marrow 7-8 X 10*9 RBC/mL

Question 41

secondary causes of polycythemia

Answer 41

§ Erythropoietin-induced, adaptive mechanism to improve O2 carrying capacity blood □ People living at high altitudes. 6-7 x 10*9 RBC/mL