Erythrocytes

Question 1

structural characteristics that contribute to it transport of gases

Answer 1

1. Biconcave shape that has a huge surface area
   relative to volume
2. high amount of hemoglobin / 97% hemoglobin
3. Anaerobic respiration, to conserve oxygen

Question 2

two main function of erythrocytes

Answer 2

1. transport of gases

2. buffer blood pH

Question 3

briefly describe the structure of hemoglobin

Answer 3

1. Consists of two α and two β subunits of globin
2. Each subunit binds to a heme group
3. each globin subunit bind to one heme group
4. Each heme group bears an atom of iron, which can bind to one oxygen molecule.
5. hemoglobin transport 4 oxygen molecule

Question 4

Erythropoiesis

Answer 4

refers specifically to erythrocytes production.

Question 5

stem cell for erythrocytes is ……….

Answer 5

hemocytoblast

Question 6

development of erythrocytes

Answer 6

1. hemocytoblast
2. proerythroblast
3. erythroblast ( ribosome synthesis in early erythroblasts )
4. normoblast ( – hemoglobin accumulation in late erythroblasts and normoblasts )
5. reticulocytes ( ejection of the nucleus from normoblasts and formation of reticulocytes )
6. erythrocyte ( Reticulocytes then become mature erythrocytes )

Question 6

development of erythrocytes

Answer 6

1. hemocytoblast
2. proerythroblast
3. erythroblast
4. normablast

Question 7

where is hemotopoiesis take place

Answer 7

the red bone marrow of epiphyses of the humerus and femur, and axial skeletal and girdles.

Question 8

iron is stored in intracellular in the following proteins

Answer 8

1. ferritin

2. hemosiderin

Question 9

in circulating extracellular iron is loosely stored in protein called

Answer 9

transferrin

Question 10

hormone that influence erythropoiesis and organ that produces it

Answer 10

erythropoietin and produced by the kidney

Question 11

what triggers kidneys to produce erythropoietin ( EPO ) hormone

Answer 11

1. hypoxia

Question 12

erythropoietin mechanism

Answer 12

1. reduction in oxygen/ hypoxia stimulates kidneys to produce erythropoietin.
2. erythropoietin stimulates red bone marrow.
3. red bone marrow produces erythrocytes through erythropoiesis.
4. the level of oxygen is restored and the production of erythropoietin stops.

Question 13

what is the differences btn hypoxia and hypoxemia

Answer 13

hypoxia is a low oxygen level in the body tissue while hypoxemia is a low oxygen level in the blood.

Question 14

main causes of hypoxia

Answer 14

1. hemorrhage or excess destruction of erythrocytes
2. pneumonia
3. vigorous physical exercises.

Question 15

what is the fate of erythrocytes

Answer 15

1. after production circulate in the blood for 100 - 120 days/ 4 months.
2. erythrocytes then get phagocytized by phagocytes.
   - cell fragments lost to phagocytes.
   - hemoglobin degraded into heme and globin.
   - heme is digested in the liver to release iron to be stored and heme is turned into biliverdin, then into bilirubin, then into bile, and into feces.
   - globin hydrolyzed into amino acid.

Question 16

important anemia:

1. Hemorrhagic anemia
2. Hemolytic anemia
3. Aplastic anemia
4. Pernicious anemia
5. Sickle-cell anemia

Answer 16

1. is a lack of red blood cells due to acute/chronic hemorrhage.
2. Hemolytic anemia is a blood condition that occurs when your red blood cells are destroyed faster than they can be replaced.
3. deficiency of all types of blood cells caused by failure of bone marrow development. caused by damage of stem cells/ hemocytoblasts in the red bone marrow.
4. a deficiency in the production of red blood cells through a lack of vitamin B12. Caused by a lack of intrinsic factors that are responsible for the absorption of Vitamin B12.
5. • result from the defective gene coding for hemoglobin S /Hb S.
     - it has single amino acid in the beta chain.
     - erythrocytes have a sickle shape that can carry few oxygens.

Question 17

what is polycythemia

Answer 17

excess erythrocytes that cause an increase in viscosity.

Question 18

types of polycythemia

Answer 18

1. polycythemia vera/ primary polycythemia: caused by an abnormality of bone marrow cells that leads to overproduction of erythrocytes.
2. secondary polycythemia: is overproduction that is caused by another factor, not in the bone marrow cells.
3. blood doping is due to introducing your own blood back into circulation after a period of time from the removal point.

Question 19

disorders of shape of erythrocytes

Answer 19

1. spherocytosis: with spherical shape.
2. elliptocytosis: with an elliptical shape.
3. sickle cell: sickle-shaped.
4. acanthocytosis: irregular shaped
5. ovalocytosis/Hereditary elliptocytosis

Question 20

1. Microcytosis

2. Macrocytosis

Answer 20

1. small than normal

2. bigger than normal