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Chapter 12 Blood

| Blood composition: |

|Blood, a type of__connective_ tissue, is a complex mixture of what three things? Cells, fluid, and chemicals |

|functions: What are the functions of blood? Transports substances and maintains a stable environment |

| Blood Cells: |

|The blood includes what three types of cells? Red blood cells, white blood cells, platelets |

|Blood Volume and Composition |

|A blood ____hematocrit____ is normally _45___% cells and _____55___% plasma. |

| RBC = erythrocyte: |

|Red blood cells (erythrocytes) are biconcave disks that contain one-third oxygen-carrying _hemoglobin__ by |

|volume. |

|When oxygen combines with hemoglobin bright red__oxyhemoglobin_____ results. |

|Deoxygenated blood (__deoxyhemoglobin_______________) is darker. |

|Red blood cells discard their _ nucleus___ during development and so cannot reproduce or produce |

|proteins. |

| RBC counts: |

|What is a typical RBC count for males? 4.6 to 6.2 million/mm3 For females? 4.2 – 5.4 million/mm3 |

| RBC production: |

|In the embryo and fetus, red blood cell production occurs in the yolk sac, _liver____, and spleen; |

|after birth, it occurs in the red ___bone marrow_____________ _________________________. |

|The average life span of a red blood cell is ___120 days_____________________. |

|Control: The total number of red blood cells remains relatively constant due to a __negative___ |

|feedback mechanism utilizing the hormone _erythropoietin__which is released from the kidneys |

|and liver in response to the detection of low __oxygen____ levels. |

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|Dietary Factors Affecting Red Blood Cell Production |

|Vitamins _B12___ and __folic_ acid are needed for DNA synthesis, so they are necessary for the |

|reproduction of all body cells, especially in hematopoietic tissue. |

|____iron________ is needed for hemoglobin synthesis. |

|A deficiency in red blood cells or quantity of hemoglobin results in a disorder called __anemia___. |

|Destruction of Red Blood Cells |

|With age, red blood cells become increasingly fragile and are damaged by passing through __capillaries_. |

|Macrophages in the _liver__ and __spleen___ phagocytize damaged red blood cells. |

|Hemoglobin from the decomposed red blood cells is converted into ___heme___ and __globin_. |

|What happens to the heme and iron? Recycled back to be incorporated into new red blood cells |

| WBC = leukocyte: |

|WBC’s are formed from __hemocytoblasts_____ in response to hormones when needed. |

|Five types of white blood cells are in circulating blood and are distinguished by size, granular appearance of the |

|cytoplasm, shape of the nucleus, and staining characteristics. Name these five types of leukocytes. |

|Neutrophils, eosinophils, basophils, monocytes, lymphocytes |

| What is the basic function of the white blood cells? Protection (by defending against disease) |

| WBC counts: |

|Normally a cubic milliliter of blood contains between _5,000___ & __10,000___ white blood cells. |

|A ___differential_________ white blood cell count can help pinpoint the nature of an illness, indicating |

|whether it is caused by bacteria or viruses. |

|This white blood cell count lists the percentages of the types of leukocytes in a blood sample. |

|_____leukocytosis______ occurs after an infection when excess numbers of leukocytes are present. |

|_____leukopenia_____ (too few WBC’s) occurs from a variety of conditions, including AIDS. |

| granulocytes: |

|Why is this group called granulocytes? Granules are observed in their cytoplasm when stained with certain stains |

| neutrophils: |

| |

|Neutrophils have _red__-staining fine cytoplasmic granules and a _multi-lobed nucleus; they comprise |

|what percentage of leukocytes? 54 to 62% |

| |

|What is their function? Phagocytize bacteria, fungi, and some viruses |

| |

|What does diapedesis mean? Squeezing between cells in blood vessel walls |

| eosinophils: |

|Eosinophils have coarse granules that stain deep , a _bi__-lobed nucleus, and make up only ___1 to 3___% of |

|circulating leukocytes |

|What are their functions? Moderate allergic reactions, defend against certain parasites |

| basophils: |

|Basophils have fewer granules that stain __deep blue__; they account for fewer than 1_% of leukocytes. |

| |

|Basophils produce chemicals, what are the functions of these chemicals? Increase blood flow to damaged tissues |

| |

|How do they help fight pathogens? Promote inflammation responses |

| agranulocytes: |

|Why are they called agranulocytes? They lack the characteristic cytoplasmic granules |

| monocytes: |

|Monocytes are the ___largest____ blood cells, have _oval_-shaped nuclei. What percentage of |

|circulating leukocytes do they comprise? 3% to 9% |

|What is the function of the monocytes? Phagocytize bacteria and cellular debris |

| lymphocytes: |

|Lymphocytes are long-lived, have a large, __spherical___ nucleus, and account for ___25 - 33_% of |

|circulating leukocytes. |

| |

|What is their function? Involved in immunity responses |

| platelets = thrombocytes: |

|Blood platelets are fragments of big cells called ___megakaryocytes_______. |

|Platelets help repair damaged blood vessels by adhering____ to their broken edges. |

|Normal counts vary from __130,000___ to __360,000___________ platelets per mm3. |

| Plasma |

|Plasma is the clear, straw-colored fluid portion of the blood. |

|Plasma is mostly ___water_____ but contains a variety of substances. |

|What are plasma’s functions? Transjport of nutrients and gases, regulates fluid and electrolyte balance, maintains acid base balance |

| Plasma proteins: The plasma proteins are the most abundant dissolved substances in the plasma. |

|Briefly describe the functions of the following plasma proteins. |

|albumin: maintain the correct osmotic pressure of the plasma |

| |

|globulin: transport of lipids and fat-soluble vitamins, some are a type of antibody |

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|clotting proteins: play an important role in blood clotting process |

| |

|hormones: Regulate and control physiological function |

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|Other Plasma Components: |

|Nutrients and Gases |

|What are the two most important blood gases? Oxygen and carbon dioxide |

|The plasma nutrients include amino acids, monosaccharides, nucleotides, and lipids. |

|Types of lipoproteins include HDL, LDL, VLDL, and chylomicrons. |

|Nonprotein Nitrogenous Substances generally include amino acids, urea, and uric acid. What are they from? |

|Plasma electrolytes are absorbed by the intestine or are by-products of cellular metabolism. They include |

|sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and sulfate ions. |

|Hemostasis: |

|Hemostasis refers to the ___stoppage of bleeding___________________________________ |

|Following injury to a vessel, three steps occur in hemostasis: blood vessel spasm, platelet plug formation, and blood coagulation |

| |

|trauma ----> Cutting a blood vessel causes the muscle in its walls to contract in a reflex, or engage in |

|_vasospasm_______ This reflex lasts only a few minutes, but it lasts long enough to initiate the second and |

|third steps of hemostasis. |

|spasm of injured vessel ----> platelet plug ----> Platelets stick to the exposed edges of __damaged__ blood vessels, |

|forming a _net___ with spiny processes protruding from their membranes. A platelet plug is most effective |

|on a small vessel. |

|Platelets release a factor leading to the third step of hemostasis. |

| |

|Coagulation: |

|Blood coagulation is the most effective means of hemostasis. It is very complex and uses clotting factors. |

|Damaged tissues release a chemical called tissue __thromboplastin__, which activates the first in a series of |

|factors leading to the production of _prothrombin__ activator. |

|This activator converts inactive _prothrombin___ in the plasma into __thrombin_______. This in turn, |

|catalyzes a reaction that converts soluble _fibrinogen_ into netlike __fibrin_____ causing the blood |

|cells to catch in the net. |

|Once a blood clot forms, it promotes still more clotting through __positive__ feedback system. |

|What happens after the clot forms? Fibroblasts produce fibers throughout the clot |

|A clot that forms abnormally in a vessel is a ___thrombus_____; if it dislodges, it is an _embolus_____________. |

| |

|What is hemophilia? Abnormal bleeding because blood fails to clot normally |

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|Blood Groups and Transfusions |

|After mixed success with transfusions, scientists determined that blood was of different types and only certain |

|combinations were compatible. |

|Clumping of red blood cells following transfusion is called __agglutination________________________. |

|This clumping is due to the interaction of proteins on the surfaces of red blood cells called __antigens__ with |

|certain proteins called _antibodies___ carried in the plasma. |

| |

|blood types: A, B, AB, O: |

|What is an antigen? Special proteins found on the surface of cells |

|What is an antibody? Special protein in the blood plasm that interact with specific antigen |

|type A has what type of antigens and antibodies? |

|Has A type antigens and anti-B antibodies |

|type B has ….. B-type antigens and anti-A antibodies |

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|type AB has …. Both A-type and B-type antigens and neither type of antibodies |

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|Type O has …. Neither type of antigen but both types of blood antibodies |

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|RH Blood Types |

|The Rh factor was named after the __rhesus______ monkey. |

|If the Rh factor surface protein is present on red blood cells, the blood is Rh __positive_______; if not, it |

|is Rh __negative______. |

|There are no corresponding antibodies in the plasma unless a person with Rh-negative blood is transfused with Rh- |

|positive blood; the person will then develop antibodies for the Rh factor. |

|____erythroblastosis fetalis______ develops in Rh-positive fetuses of Rh-negative mothers but can now |

|be prevented. |

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