Red Blood cells = rbc’s =erythrocytes I.Structure = function Biconcave discs, no nucleus*, 4-5 million per uL of blood II.Erythropoiesis = erythrocyte formation -Hypoxia and/or low red blood cell count stimulates the release of erythropoietin(EPO)
- Erythropoietin ( from the kidneys) - It stimulates the red bone marrow, called Myeloid tissue, to increase erythropoiesis -Necessary raw materials iron, amino acids, vit B12, copper, cobalt
III.Reticulocytes = immature red blood cells -make up about 1-2% of circulating rbc’s - are larger (why?) still contain many organelles like endoplasmic reticulum
IV.Hematocrit – ml rbc’s per 100ml blood(normal) -affected by altitude, etc - written as just a number, e.g. 45
V.Destruction – after approx days -Three organs to remove old rbc’s liver, spleen, bone marrow -The liver receives all components of rbc breakdown. - Iron is recycled, rest of heme secreted as bilirubin in bile -proteins returned to amino acids -100 million rbc’s formed/destroyed per minute
VI.Hemoglobin (33% wet weight) -300 million molecules per rbc -4 iron atoms per molecule - each iron can bind/carry 1 oxygen molecule - Therefore, each hemoglobin can carry 4 oxygen molecules as oxyhemoglobin -hemoglobin can also bind up to 20% of CO2 forming carbaminohemoglobin
VII.Abnormal erythrocytes a)crenated – shriveled -may be due to anticoagulants or dehydration b) codocytes – target appearance -indicators of iron deficiency c) sickle cells – sickled when low in O2 -genetic- recessive d) schizocytes – rbc fragments -artificial heart valves, atherosclerosis
Crenated
CODOCYTES
Sickle Cells
Schizocytes
VIII. Anemia = Less than 10g hemoglobin / 100ml blood a) pernicious anemia- due to a lack of vit B12. Large, brittle, pale rbc’s b) iron deficiency anemia – codocytes c) hemorrhagic anemia - bleeding d) hemolytic anemia- improper blood transfusion e) aplastic anemia – loss of red bone marrow
f)Normocytic – normal size Microcytic - smaller than normal Macrocytic – larger than normal g)Normochromic – normal color Hyperchromic – darker than normal Hypochromic – paler than normal
IX.Polycythemia -elevated rbc count - elevated hematocrit normal causes – altitude, anemia induced causes – blood doping -- EPO injections