section 6

Question 1

state the 3 main functions of the RBC membrane

Answer 1

• maintain shape and deformability
• maintain osmotic balance
• supporting structural components for surface Ag receptors

Question 2

what happens to a cell in hypertonic sol

Answer 2

shrinkage/crenated cell -> too much solutes in solution

Question 3

what is the purpose of salic acid in the rbc membrane

Answer 3

to maintain negative cell charge

Question 4

describe the role of spectrin in the rbc membrane

Answer 4

to maintain shape/depformability

Question 5

what are the steps of extravascular hemolysis

Answer 5

• pyrole ring opens becoming biliverdin (unconjugated) and globin is recycled
• albumin+unconjugated go to liver
• in liver unconjugated + glucuronic acid = conjugated (water sol)
• conjugated into intestines
• conjugated+bacteria= urobilinogen
• either passed in stool w/ urobilin or reenters kidney

Question 6

what are the steps of intravascular hemolysis

Answer 6

10-20% of breakdown
- dimers+haptoglonin=liver transport
- unbound dimers to kidney of no hapto
- ox to metheme +hemopexin = liver
- ox to methemealbumin and recirculates

Question 7

name and describe the 4 main rbc metabolic pathways

Answer 7

• Embden-Meyerhoff: anaerobic glycolysis (energy) uses pyruvate kinase
• hexose-monophosphate: prevents OX injury to rbcs, uses G6PD
• Rapoport-luebering: regulates oxygen movement, uses 2,3BPG
• methemoglobin: maintains hgb in reduced Fe2 state, uses methemoglobin reductase

Question 8

what are the 3 main adult hgb and compositions

Answer 8

• hgbA = alpha2beta2 (>95%)
• hgbA2 = alpha2delta2 (~2%)
• hgbF = alpha2gamma2 (1-2%)

Question 9

what are the 2 main baby hgb compositions

Answer 9

• hgbF = alpha2gamma2 (60-90%)
• hgbA = alpha2beta2

Question 10

what is the role of 2,3-BPG when bound and unbound

Answer 10

• bound = lowers O2 affinity of hgb for O2 delivery
• unbound = increases O2 affinity for O2 uptake

Question 11

name the 3 modified hgbs and what causes them

Answer 11

• methemoglobin: hgb in fe3 state from hgbM disease or enzyme deficiency
• sulfhemoglobin: irreversible OX of hgb w/ sulfur bound from drugs
• carboxyhemoglobin: hgb carries CO with higher affinity than O2 and doesn’t release it seen in carbon monoxide poisoning

Question 12

describe a shift to the right and how it affects P50, 2,3-BPG and oxygen delivery

Answer 12

increases oxygen delivered to tissues, increases P50 and lowers 2,3-BPG affinity

Question 13

describe a shift to the left and how it affects P50, 2,3-BPG and oxygen delivery

Answer 13

increases 2,3-BPG affinity for O2, lowers P50 and decreases oxygen delivery to tissues

Question 14

name a cause of shift to the right in regards to oxygen delivery

Answer 14

hypoxia, where tissues need more oxygen

Question 15

name a cause of shift to the left in oxygen delivery

Answer 15

abnormal hgb (sulfa, carboxy, metheme) that increases hgb affinity for O2

Question 16

define and describe: trasnferrin, ferritin, apoferritin, and hemosiderin

Answer 16

• transferrin: protein that transports iron in Fe3 state
• ferritin: iron+apoferritin, storage form of iron
• apoferritin: w/ ferritin to make storage
• hemoseridin: breakdown of ferritin for intracellular storage of iron

Question 17

what form of iron is incorporated into heme molecule

Answer 17

ferrous state, Fe2