W5 Flashcards
A MEASURE OF BLOOD’S CAPACITY TO CARRY OXYGEN
HEMOGLOBIN
HEMOGLOBIN MOLECULE THAT CONTAINS IRON
HEME
RBC – IS CRUCIAL TO ITS FUNCTION,
ALLOWING FOR CLOSE TO MAXIMUM SURFACE- TO –VOLUME RATIO
BICONCAVE DISC SHAPE
RBC: AVERAGE - IN VOLUME
90FL
RBC: SURFACE AREA
140UM
A NORMAL RBC= – DEFORMABILITY
INCREASE
RBC IS - TO CATIONS (NA, K, CA)
IMPERMEABLE
RBC IS - TO WATER AND HCO3 AND CL
PERMEABLE
RBC: LIFESPAN
120 DAYS
- RESPOND TO A LOWER THAN NORMAL OXYGEN
CONCENTRATION IN THE BLOOD BY RELEASING THE HORMONE
ERYTHROPOIETIN.
KIDNEYS
KIDNEYS RESPOND TO A LOWER THAN NORMAL OXYGEN
CONCENTRATION IN THE BLOOD BY RELEASING THE HORMONE -
ERYTHROPOIETIN
ERYTHROPOIETIN TRAVELS TO THE - BONE MARROW AND
STIMULATES AN INCREASE IN THE PRODUCTION OF RED BLOOD
CELLS (RBCS).
RED BM
DAMAGED OR OLD RBCS ARE DESTROYED PRIMARILY BY THE -
SPLEEN
THE BODY STORES IRON IN HGB -%
65%
FERRITIN AND HEMOSIDERIN
TRANSFERRIN
TOO FEW RBCS LEADS TO -
TISSUE HYPOXIA
TOO MANY RBCS INCREASES BLOOD -
VISCOSITY
−DIRECT STIMULUS FOR ERYTHROPOIESIS
−RELEASED BY THE KIDNEYS IN RESPONSE TO HYPOXIA
ERYTHROPOIETIN (EPO)
−REDUCED AVAILABILITY OF O2 (E.G., HIGH ALTITUDES)
−INSUFFICIENT HEMOGLOBIN (E.G., IRON DEFICIENCY)
−HEMORRHAGE OR INCREASED RBC DESTRUCTION
REDUCES RBC NUMBERS
HYPOXIA
ALSO ENHANCES EPO PRODUCTION,
RESULTING IN HIGHER RBC COUNTS IN MALES
TESTOSTERONE
ERYTHROCYTE MEMBRANE
Composition:
Proteins
Lipids
Carbohydrates
Proteins -50%
Lipids - 40%
Carbohydrates - 10%
COMPOSITION OF THE ERYTHROCYTE MEMBRANE
EXTERNAL SURFACE OF THE RED CELL
ANTIGENS OF THE ABO BLOOD GROUP
CARBOHYDRATES
COMPOSITION OF THE ERYTHROCYTE MEMBRANE
% FREE UNESTERIFIED CHOLESTEROL
30
COMPOSITION OF THE ERYTHROCYTE MEMBRANE
% GLYCERIDES AND FREE FATTY ACIDS
10
COMPOSITION OF THE ERYTHROCYTE MEMBRANE
% PHOSPHOLIPIDS
60
MOLECULES ARE CHARACTERIZED BY A POLAR
HEAD GROUP ATTACHED TO A NON-POLAR FATTY ACID TAIL
PHOSPHOLIPIDS
IS UNESTERIFIED AND LIES BETWEEN THE
TWO LAYERS OF THE LIPID BILAYER.
CHOLESTEROL
AN IMPORTANT DETERMINANT OF MEMBRANE SURFACE AREA AND FLUIDITY
CHOLESTEROL
INTERACT TO FORM A CYTOSKELETON
PERIPHERAL PROTEINS
ACTS AS A TOUGH SUPPORTING FRAMEWORK FOR THE LIPID BILAYER
CYTOSKELETON
FOUR PERIPHERAL PROTEINS PLAY A KEY ROLE IN THE STRUCTURE OF THE RED CELL CYTOSKELETON
- SPECTRIN
- ANKYRIN
- PROTEIN 4.1
- ACTIN
‘SAPA’
COMPOSITION OF THE ERYTHROCYTE MEMBRANE
THESE PENETRATE THE LIPID BILAYER AND ARE FIRMLY ANCHORED WITHIN IT
INTEGRAL PROTEINS
Cholesterol content of the membrane depends
upon the concentration of plasma cholesterols, bile
acids, and the activity of the enzyme
Lecithin:Cholesterol acyltransferase (LCAT)
OXIDATION OF THE NORMAL FERROUS STATE TO THE FERRIC STATE RESULTS
IN - WHICH DOES NOT DELIVER OXYGEN
NORMALLY 1% TO 3% OF OXYGEN IS OXIDIZED TO -
METHEMOGLOBIN
OXIDATION OF SULFHYDRYL GROUPS CAUSES HEMOGLOBIN PRECIPITATION
HEINZ BODY FORMATION
METABOLISM OF RED BLOOD CELL
Glucose enters the RBC without energy expenditure via the
transmembrane protein GLUT-1
Embden Meyerhof Pathway
METABOLISM OF RED BLOOD CELL
most common enzyme deficiency
PYRUVATE KINASE DEFICIENCY
METABOLISM OF RED BLOOD CELL
is involved for reducing ferric
iron into ferrous state
Cytochrome B5 reductase / methemoglobin reductase
METABOLISM OF RED BLOOD CELL
Generates 2,3 Diphosphoglycerate (2,3-DPG) that decreases hemoglobin affinity to
oxygen
Rapoport – Leubering
Pathway
Rapoport – Leubering
Pathway
↑2,3DG = ↓Hb affinity to Oxygen
(Shift to the -)
Right
Rapoport – Leubering
Pathway
↓2,3DPG = ↑ Hb affinity to Oxygen
(Shift to the -)
Left
METABOLISM OF RED BLOOD CELL
90% glycolysis; anaerobic
Embden Meyerhof Pathway
METABOLISM OF RED BLOOD CELL
10% GLYCOLYSIS; AEROBIC
Hexose
monophosphate
Shunt/ Pentose
Phosphate
pathway
extends the functional life span of the RBC
Hexose
monophosphate
Shunt
METABOLISM OF RED BLOOD CELL
most common inherited enzyme deficiency and is
associated with Heinz bodies
G6PD DEFICIENCY
METABOLIC PATHWAYS IN ERYTHROCYTE
MAINTAINS CELLULLAR ENERGY BY GENERATING ATP
EMBDEN-MEYERHOF PATHWAY
METABOLIC PATHWAYS IN ERYTHROCYTE
PREVENTS DENATURATION OF GLOBIN OF THE HEMOGLOBIN MOLECULE BY OXIDATION
HEXOSE MONOPHOSPHATE SHUNT
METABOLIC PATHWAYS IN ERYTHROCYTE
PREVENTS OXIDATION OF HEME IRON
METHEMOGLOBIN REDUCTASE PATHWAY
METABOLIC PATHWAYS IN ERYTHROCYTE
REGULATES OXYGEB AFFINITY OF HEMOGLOBIN
LUEBERING-RAPAPORT PATHWAY
IS A SPLENIC FUNCTION WHEREIN OLD/AGED/SENESCENT RED
BLOOD CELLS ARE FILTERED AND DESTROYED THROUGH THE PHAGOCYTOSIS
OF SPLENIC MACROPHAGES
CULLING
TYPES OF RBC DESTRUCTION
▪ 90% OF RBC DESTRUCTION
▪ ALSO KNOWN AS THE MACROPHAGE MEDIATED HEMOLYSIS
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ ≤10% OF RBC DESTRUCTION
INTRAVASCULAR/FRAGMENTATION HEMOLYSIS
EXTRAVASCULAR HEMOLYSIS
returned or erythroid precursors in the bone marrow or stored
as ferritin or hemosiderin within the macrophages
IRON
EXTRAVASCULAR HEMOLYSIS
broken down and recycled into amino acid pool
GLOBIN
EXTRAVASCULAR HEMOLYSIS
disassembled with its alpha carbon exhaled in the
form of carbon monoxide while biliverdin is converted to bilirubin and
eventually urobilinogen which is then excreted in the feces and urine.
PROTOPORPHYRIN
TYPES OF RBC DESTRUCTION
▪ Happens when complement is not activated or
incompletely activated.
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ Associated with Rh hemolysis
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ INCREASED UNCONJUGATED BILIRUBIN
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ INCREASED URINE AND FECAL UROBILINOGEN
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ PBS: SPHEROCYTES
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ PBS: SPHEROCYTES
EXTRAVASCULAR HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ Hemoglobin disssociates into alpha-beta dimers picked up by the protein carrier haptoglobin and brought to the liver for processing
INTRAVASCULAR/FRAGMENTATION HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ When haptoglobin is depleted, unbound hemoglobin appears in the
plasma
INTRAVASCULAR/FRAGMENTATION HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ Free hemoglobin also appears in the urine
▪ Hemoglobin not excreted by the kidney or bound to haptoglobin is
oxidized to methemoglobin
INTRAVASCULAR/FRAGMENTATION HEMOLYSIS
TYPES OF RBC DESTRUCTION
▪ Happens when complement is completely activated
▪ Associated with ABO hemolysis
▪ Decreased haptoglobin and hemopexin
▪ Hemoglobinemia
▪ Hemoglobinuria
INTRAVASCULAR/FRAGMENTATION HEMOLYSIS