Question | Answer |
Main function of RBC | Carry oxygen to tissue and bring carbon dioxide back from tissue |
Hemoglobin is responsible for | transporting oxygen and carbon dioxide |
Mitochondria is responsible for | making ATP for energy use |
ATP must remain viable for what time period | 120 days |
If ATP is depleted what happens to the cell | becomes a shere and becomes rigid and unable to deform |
What organ removes the shere shaped cell | spleen |
What must be present when the nucleus is excluded | enzymes |
Enzymes | produce ATP |
When enzymes are depleted | cell will be removed from circulation by the spleen or hemoglobin will be oxidized |
What happens when hemoglobin is oxidized | oxidized into methemoglobin and turns brown |
ATP production is RBCs is done via | anaerobic glycolysis |
Energy requirements of RBC | cation pump
oxidation protection
1. membrane integrity
2. maintain iron in ferrous form |
4 pathways of energy | Emden-Meyerhof of glycolytic pathway
Hexose Monophosphate Shunt or Phosphogluconate
Methemoglobin Reductase Pathway
Leubering-Rapaport Shunt or Pathway |
Embden-Meyerhof Glycolytic Pathway | non-oxidative/anaerobic pathway
provides 90% ATP |
Hexose Monophosphate Shunt | AKA Phosphogluconate
provides 5-10% of energy
produces pyridine nucleotide NADPH from NADP |
Which enzyme is utilized in Hexose-Monophosphate Shunt | G6PD |
NAPH together with glutathione protects against | oxidative injury from toxic reducing oxidants |
Reducing oxidents include | certain drugs or infections |
Methemoglobin Reductase Pathway | 1. off-shoot of Embden-Meyerhof
2. maintains heme in ferrous state
3. methemoglobin reductase changes ferric to ferrous |
Characteristics of Methemoglobin | 1. Cannot combine with oxygen
2. Cyanosis occurs in the patient
3. Bluish discoloration of the skin due to deoxyhemoglobin in the blood |
Leubering-Rapaport Shunt/Pathway | 1. part of Emden-Meyerhof pathway & 1 ATP used
2. produces 2,3-DPG (diphosphoglycerate) |
2,3-DPG affects | 1. oxygen affinity of hemoglobin
2. when it binds oxygen is released
3. regulates oxygen delivery to tissues |
Erythrocyte (RBC) Membrane requirments | 1. intact membrane is essential to roll and tumble through vessels
2. size is 6-8 microns
3. must squeeze through spleen capillaries
4. becomes microcyte |
Membrane Description | semi-permeable lipid bilayer supported by protein mesh-like cytoskeleton |
Membrane Composition | 52% protein
40% lipid
8% carbohydrate |
Membrane controls | functions of transport, flexibility, & antigenic properties |
Membrane defects cause | altered function leading to premature cell death |
Lipid Matrix is made from | equal amounts of cholesterol and phospholipids interspersed with protein |
Cholesterol is responsible for | passive transport of ions, gases, & active transport of cation |
Cholesterol and Lecithin affect | surface area & creates target cells or acanthocytes developed and destroyed |
Hydrophobic Phospholipids probably determine | membrane fluidity |
Embedded glycolipids carry which RBC antigens | A,B,H, and Lewis red cell antigens |
Proteins contribute to | cell shape, deformability, and membrane stability |
Defects in protein lead to | 1. abnormal cell shape
2. decreased stability
3. hemolytic anemia |
Integral Proteins | 1. located in the lipid bilayer
2. Glycophorins
3. band 3 protein |
Peripheral Proteins | spectrin, actin, ankyrin, and troponyosin |
Sialic acid | gives cells the negative charge |
Carbohydrates | give ABO antigens |
Peripheral Proteins are located where | cytoplasmic surface |
Peripheral Proteins form | skeleton to maintain biconcave shape |
Major Peripheral Protien | Spectrin |
Spectrin binds what together | intirgral and peripheral protein |
Function of RBC membrane | barrier between cell and plasma |
What affects RBC membrane | hydrophobic lipids and integral proteins |
What does the RBC membrane allows through | water and anions |
Lack of deformability of RBC is caused by | decrease in ATP causes a phosphorylation of spectrin causing loss of deformability |
Deformability allows RBCs to | roll and tumble |
Any deviation in membrane's selective permeability causes | influx of sodium and water causing a spherhoid shape and potential rupture which releases Hbg |
Erythrocytes must be impermeable to | cations |
Intracellular to Extracellular Ratio | 1:12 for sodium
25:1 for potassium |
What actively controls ion concentration | hundreds of pumps which require ATP |
80% of intracellular calcium is found in | erythrocyte membrane |
Increased amounts of calcium cause | Echinocytes/Burr cells which are rigid shrunken cells with membrane protrusions |
Cell aging and reduced ATP causes | pumps fail which makes the cell dehydrated and rigid |
Blood group antigens are located on | oligosaccharide groups of the integral protein |
Sialic acid is found on | the surface of glycophorin A |
Zeta Potential | negative charge tht causes cells to repel each other |