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BIO202-CH17-RBCs

BIO202 - CH17 – Erythrocytes (RBCs) - Marieb/Hoehn - RioSalado - AZ

QuestionAnswer
Hemoglobin (Hb) oxygen carrier protein in blood.
Protein globin built of __. 4 linked polypeptide chains (2 alpha, 2 beta) & a heme group - oxygen molecules bind to iron molecule in center of each heme group.
One red blood cell can carry __ moelecules of oxygen. 1 billion
Network of proteins that maintain biconcave shape of RBC. Spectrin - attached to cytoplasmic face of plasma membrane.
Name 3 characteristics of RBCs that contribute to tis gas transport function. (1) small size & biconcave shape (surface area), (2) 97% hemoglobin, (3) No mitrochondria & generate ATP by anaerobic - no O2 consumption.
Name the major factor contributing to blood viscosity. Erythrocytes
When blood viscosity rises, blodo flows __. More slowly due to increase in number of RBCs
Most oxygen carried in blood is __. Bound to hemoglobin
Oxygemoglobin Oxygenated hemoglobin
Erythropoietin Hormone that signals stem cells to produce red blood cells.
Red blood cells live about __ days. 120
Cell count Tallies of number of cells in a microliter of blood.
Antigen Any large molecule that triggers a defensive attack due to being marked as "nonself".
1 hemoglobin molecule can transport __ molecules of oxygen. 4
A single RBC contains around __ million hemoglobin molecules. 250 million
20% of carbon dioxide in blood combines with hemoglobin how? Called what? To globin's amino acids rather than heme group - carbaminohemoglobin
Hematopoiesis or hemopoiesis Blood cell formation that occurs in red bone marrow.
As blood cells mature, they migrate through __ to enter blood stream. Blood sinusoids - wide blood capillaries in red bone marrow.
Erythropoiesis Erythrocyte production
Erythropoiesis begins when a hemocytoblas myeloid stem cell is transformed into a __. Proerythroblast
Stages of erythropoiesis Myeloid stem cell -> proerythroblast -> erythroblast ->normoblast -> reticulocyte -> erythrocyte
Early (basophilic) erythroblasts do what? Produce huge number of ribosomes so cells can divide many times.
As early erythroblast transforms into late erythroblast __. Hemoglobin synthesis & iron accumulation occur.
When a normoblast has accumulated almost all its hemoglobin, it __. Ejects its organelles & pinches off its nucleus.
When normoblast ejects organelles & nucleus, it becomes a __. reticulocyte - becuase it ocntains some reticulum of clumped ribosome.
Reticulocyte counts provide what? A rough index of the rate of RBC formation - should be about 1-2% of all erythrocytes in blood.
Too few erythrocytes leads to? Hypoxia - oxygen deprivation
New erythrocytes are produced at more than __ per second. 2 million
Erythrocyte production depends on? Hormonal condition, iron, amino acids, & certain B vitamins
The direct stimulus for erythrocyte formation is provided by __, a glycoprotein hormone. erythropoietin (EPO)
The __ plays the major role in EPO production. kidneys
When certain kidney cells become hypoxic, they accelerate release of __. EPO - erythropoietin - due to hypoxicia
The rate of erythropoiesis is controlled by __. their ability to transport oxygen to meet tissue demand.
Bloodborn erythropoietin (EPO) stimulates red marrow cells __. that are already committed to becoming erythrocytes to mature more rapidly
Hypoxia doesn't activate bone marrow directly, instead it __. stimulates the kidneys which then provide hormonal stimulus that activates bone marrow
Renal dialysis patients have kidneys that __. have failied & produce too little EPO
Why do renal dialysis patients have low RBC counts? Their kidneys produce too little EPO to support normaly erythropoiesis.
Which natural hormone can enhance EPO production by kidneys? Testosterone
Iron is stored in protein-iron complexes such as __. ferritin & hemosiderin
Iron in blood is loosley bound to a transport protein called __. transferrin
Which B-complex vitamins are necessary for normal DNA synthesis? B12 & folic acid - deficits jeopardize rapidly dividing cell populations.
RBCs have useful life span of __. 100-120 days
What is the "red blood cell graveyard"? Spleen
Most erythrocyte disorders can be classified as __ or __. anemias or polycythemias
3 common causes of anemia are __. Low # of RBCs, low Hb content, or abnormal Hb.
3 conditions that reduce RBC count are? Blood loss, excessive RBC destruction, & bone marrow failure.
Hemorrhagic anemia is treated how? Stop source of blood loss & blood replacement
What are hemolytic anemias & how are they caused? When erythrocytes rupture (lyse) - Hb abnormalities, mismatched transfusion, & bacterial/parasitic infections.
What is aplastic anemia & how caused? Destruction or inhibition of red marrow - by drugs, chemicals, radiation, or viruses.
How to treat apalastic anemia? Blood transfusion, marrow transplant, tranfusion of umbilical blood (stem cells).
What are microcytes? Small & pale erythrocytes due to iron-deficiency anemia.
Pernicious anemia is due to __. deficiency of B12 - deficient intrinsic factor - autoimmune disease
What are macrocytes? Large, pale erythrocytes due to pernicious anemia
2 genetic basis for abnormal hemoglobin. Thalassemia & sickle-cell anemia
What are thalassemias? one of the globin chains is absent or faulty - mediterranean ancestry - abnormal Hb.
What causes sickle-cell anemia? Abnormal Hb - genetic - causes beta chains of globin molecule to link together under low oxygen conditons.
Standard treatment for sickle-cell? Blood transfusions
What does hydroxyurea do? Drug used to treat leukemia that switches back on the gene fro fetal hemoglobin to help sickle cell anemia.
What is polycynthemia? Abnormal excess of erythrocytes that increase blood viscosity.
What is plycynthemia vera? Plycythemia due to bone marrow cancer - hematocrit can be as high as 80%.
Types of anemias Iron deficiency, megaloplastic "pernicious", aplastic (red bone marrow distroyed), hemolytic (premature destruction of RBCs), sickle cell, & malaria.
SEcondary polycthemias occur when? Less oxygen is available or EPO production increases - high altitudes
Blod doping is artificially induced __. polycthemia
Created by: Ladystorm