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