Ch 11.2A -- Erythrocytes -- VTPP 435

Ch 11.2A -- Erythrocytes -- VTPP 435

Erythrocyte Structure

-flat, disc shaped cells shaped like a donut
-flexible membrane to deform and fit thru capillaries
-hemoglobin to carry O2
-no nucleus or organelles

Hemoglobin (Hb)

-large iron-bearing protein molecule in RBCs
-binds with and transports most O2 and CO2 and H+ in blood
-made of Globin and Heme groups

Globin

-protein made of 4 highly folded polypeptide chains
-2 alpha subunits and 2 beta subunits

Heme Groups

-4 iron containing nonprotein groups
-each group bound to one of the polypeptides
-each iron atom can bind with one O2 molecule

Hemoglobin can bind with 4 things other than O2

1) CO2
2) H+
3) CO
4) NO

Glycolytic Enzymes

-needed to make energy to fuel active transport mechanisms
-used by RBCs

Carbonic Anhydrase

-enzyme that catalyzes direct conversion of CO2 and H2O into H+ and HCO3-
-found in RBCs, kidney tubular cells, and other specialized cells
-RBCs convert CO2 to HCO3- to carry it

Spleen

-a lymphoid tissue in upper left abdomen
-stores lymphocytes and platelets
-destroys old RBCs

Bone Marrow

-soft highly cellular tissue
-fill internal cavities of bones
-performs Erythropoiesis

Red Bone Marrow

-area of bone that does Blood Cell production

Yellow Bone Marrow

-fatty, gradually replaces Red Bone Marrow
-cannot do erythropoiesis

Pluripotent Stem Cells

-precursor cells in bone marrow
-source of all blood cells

Erythropoietin (EPO)

-hormone released from kidneys in response to a reduction in O2 delivery to kidneys
-stimulates bone marrow to increase erythrocyte production

Reticulocytes

-immature erythrocytes
-released into blood by bone marrow to meet RBC demands

Anemia

-low hematocrit
-caused by decreased rate of erythropoiesis, excessive losses of erythrocytes, or a deficiency in hemoglobin content of erythrocytes

Nutritional Anemia

-dietary deficiency of factor needed for erythropoiesis
-could be iron deficiency

Pernicious Anemia

-inability to absorb enough ingested Vitamin B12 from digestive tract
-a deficiency of Vitamin B12 or intrinsic factor

Aplastic Anemia

-bone marrow fails to make enoguh RBCs even though all ingredients are available
-red marrow got destroyed
-RBC output is reduced

Renal Anemia

-results from kidney disease
-lack of EPO from kidneys

Hemorrhagic Anemia

-caused by loss of a lot of blood
-loss is either acute or chronic

Hemolytic Anemia

-rupture of too many circulating erythrocytes

Malaria

-parasites invade RBCs and multiply till cell ruptures
-causes anemia