Erythrocyte physiology

Question 1

Describe the function of erythrocytes

Answer 1

• delivery O2 and nutrients
• removal of waste products
• homeostasis
• immune

Question 2

Blood composition

Answer 2

• plasma

- cellular (formed elements)(RBC, WBC, platelets)

Question 3

hematocrit

Answer 3

% of blood that is cells (vast majority are RBCs)

Question 4

what stimulates erythropoiesis

Answer 4

• tissue hypoxia

- low O2 delivery to kidney

Question 5

what does tissue hypoxia lead to

Answer 5

accumulation of hypoxia inducible factor (HIF) (normal oxygenation is ubiquinated)

Question 6

what does deficiency of heme cause?

Answer 6

microcytic anemia

Question 7

what does deficiency of vit B12 cause

Answer 7

• macrocytic anemia

- def in B12 due to pernicious anemia

Question 8

was does def in folate cause?

Answer 8

macrocytic anemia

Question 9

oxygen capacity

Answer 9

how much O2 can be carried by heme

1.34 x measures (Hb)

Question 10

oxygen content

Answer 10

How much oxygen IS being carried by heme

= o2 capacity x o2 saturation

Question 11

oxygen saturation

Answer 11

% available spots on heme with O2 bound

-measure with pulse ox

Question 12

what is ATP used for in RBC

Answer 12

• keeping iron in Fe2+ state
• maintaining membrane flexibility
• ion ATPases
• preventing oxidation of hemoglobin

Question 13

consequences of RBC not having enough ATP

Answer 13

• membrane becomes stiff
• RBC snags spleen=ruptures
• iron can move into Fe3+ -alters O2 transport for worse

Question 14

what happens to old RBC

Answer 14

filtered in spleen

Question 15

what happens to old hemoglobin molecules

Answer 15

peptide chains: broken into AA

heme: broken down by liver kidneys gut through bilirubin
iron: recycle to new heme

Question 16

Polycythemia

Answer 16

Too many RBCS

• more O2 carrying capacity but,
• blood becomes thicker
• heart works harder to pump blood

Question 17

Hemochromatosis

Answer 17

Genetic mutation/ decrease in hepcidin

iron overload

Question 18

primary Polycythemia

Answer 18

• bone marrow making RBC when no need to

- related to mutation in receptor for thrombopoietin?

Question 19

methemoglobinemia

Answer 19

Ferrous iron converted to Ferric form (Fe 3+)

• in this state can’t bind O2 (anemia)
• decreases O2 carrying capacity of blood

Question 20

how is ferrous iron affected in methemoglobinemia

Answer 20

• increase affinity for O2
• unable to release O2 to tissue
• tissue is hypoxic
• confusion and cyanosis