Physiology - CH 19 - Blood
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- What are the five functions of the cardiovascular system?
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To transport materials to and from cells:
-oxygen and carbon dioxide
-nutrients
-hormones
-immune system components
-waste products - What type of tissue is blood?
- connective tissue
- What are the five functions of blood?
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-Transport of dissolved substances
-Regulation of pH and ions
-Restriction of fluid losses at injury sites
-Defense against toxins and pathogens
-Stabilization of body temperature - What does fractionation do?
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Seperates blood into:
Plasma (fluid + proteins)
Formed elements (cells and solids) - Whare are the three types of formed elements within the blood?
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Erythrocytes
Leukocytes
Platelets (cell fragments) - What is the majority of plasma?
- water(90%)
- What does plasma contain?
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-Water
-Dissolved proteins
-Other solutes
Similar to interstitial fluid & can exchange with IF
Matrix for other formed elements - What types of materials are exchanged between plasma and IF?
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-Water
-Ions
-Small solutes - What is the main difference between Plasma and IF?
- Proteins do not pass the endothelial wall of vessels and IF contains none of the proteins
- What are the three classes of plasma proteins?
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Albumin - Transport (Fatty acids, thyroid/hormone transport)
Glubulin - Antibodies/Immunoglobins, Transport globulines
Fibrinogen - Form clots, form long insoluble strands of fibrin - What is serum?
- Liquid part of blood once fibrin has "fallen out"
- Where are a majority of the plasma proteins made?
- liver(90%)
- Where are antibodies made?
- plasma cells (not the same plasma as blood)
- What is the approximate percentage of total body weight due to blood?
- 7%
- What is the majority of formed elements within blood?
- Erythrocytes (99%)
- What is a hematocrit?
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Reports percentage of RBCs in whole blood
Normal:
Male 40-52%
Female 36-47% - What is the important of RBCs shape and size?
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High surface-to-volume ratio:
quickly absorbs and releases oxygen
Discs form stacks:
smoothes flow through narrow blood vessels Discs bend and flex entering
small capillaries:
7.8 µm RBC passes through 4 µm capillary - What are the basics of erythrocytes?
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Lack nuclei, mitochondria, and ribosomes
Live about 120 days
Contain hemoglobin for oxygen and CO2 transport - What transports respiratory gases in blood?
- hemoglobin
- What is special about fetal hemoglobin?
- Has VERY strong affinity for oxygen and is able to steal oxygen from mothers blood via placenta
- What is anemia?
- Mematocrit or hemoglobin levels are below normal
- What is Hemoglobinuria?
- hemoglobin breakdown products in urine due to excess hemolysis in blood stream
- What is Hematuria?
- whole red blood cells in urine due to kidney or tissue damage
- What is hemopoiesis?
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Process of producing formed elements of blood by:
Myeloid stem cells
Lymphoid stem cells - What are hemocytoblasts?
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Stem cells in bone marrow divide to form:
myeloid stem cells: (become RBCs, some WBCs)
lymphoid stem cells: (become lymphocytes) - What is Erythropoiesis?
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-Red blood cell formation
-Occurs only in red bone marrow (myeloid tissue)
-Stem cells mature to become RBCs - What does building a red blood cell require?
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amino acids
iron
vitamins B12, B6, and folic acid
Low RBC production due to unavailability of vitamin B12 is pernicious anemia - What stimulates erythropoieses?
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Erythropoietin (EPO):
secreted when oxygen in peripheral tissues is low (hypoxia)
due to disease or high altitude - What are the most numerous cells in the body?
- Red Blood Cells
- How long do red blood cells circulate before being recycled?
- Four months
- What are red blood cell antigens known as?
- agglutinogens
- What are the four basic blood types?
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A (surface antigen A)
B (surface antigen B)
AB (antigens A and B)
O (neither A nor B) - What is the Rh factor?
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Also called D antigen
Either Rh positive (Rh+) or Rh negative (Rh—)
Only sensitized Rh— blood has anti-Rh antibodies - What is universal donor?
- O-
- What is the main purpose of white blood cells?
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Defend against pathogens
Remove toxins and wastes
Attack abnormal cells - What are three white blood cell disorders?
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Leukopenia: abnormally low WBC count
Leukocytosis: abnormally high WBC count
Leukemia: extremely high WBC count - What are the five types of White Blood Cells?
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Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes - Which of the white blood cells are non-specific defenses and which are specific defenses?
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Non-specific:
Neutrophils
Eosinophils
Basophils
Monocytes
Specific:
Lymphocyte - What are neutrophils?
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Also called polymorphonuclear leukocytes
50–70% of circulating WBCs
Pale cytoplasm granules with:
lysosomal enzymes
bactericides (hydrogen peroxide and superoxide) - What do neutrophils do?
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Very active, first to attack bacteria
Engulf pathogens
Digest pathogens
Digestive enzymes
Defensins - peptides from lysosomes
Release prostaglandins and leukotrienes
Form pus - What is degranulation?
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Removing granules from cytoplasm
Defensins:
peptides from lysosomes
attack pathogen membranes - What are eosinophils?
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Also called acidophils
2–4% of circulating WBCs
Attack large parasites
Excrete toxic compounds:
nitric oxide
cytotoxic enzymes
Are sensitive to allergens
Control inflammation with enzymes that counteract inflammatory effects of neutrophils and mast cells - What are basophils?
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Are less than 1% of circulating WBCs
Are small
Accumulate in damaged tissue
Release histamine: dilates blood vessels
Release heparin: prevents blood clotting - What are monocytes?
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2–8% of circulating WBCs
Are large and spherical
Enter peripheral tissues and become macrophages
Engulf large particles and pathogens
Secrete substances that attract immune system cells and fibroblasts to injured area - What are lymphocytes?
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20–30% of circulating WBCs
Are larger than RBCs
Migrate in and out of blood
Mostly in connective tissues and lymphatic organs
Are part of the body’s specific defense system - What are the three classes of lymphocytes?
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T Cells
B Cells
Natural Killer Cells - What are T-Cells?
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Cell-mediated immunity
Attack foreign cells directly - What are B-Cells?
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Humoral immunity
Differentiate into plasma cells
Synthesize antibodies - What are natural killer cells?
- Detect and destroy abnormal tissue cells (cancers)
- What do all blood cells originate from?
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All blood cells originate from hemocytoblasts:
which produce myeloid stem cells and lymphoid stem cells - How do white blood cells develop?
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WBCs, except monocytes:
develop fully in bone marrow
Monocytes:
develop into macrophages in peripheral tissues - What are the 4 colony-stimulating factors (CSFs)?
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Hormones that regulate blood cell populations:
M-CSF: stimulates monocyte production
G-CSF: stimulates granulocyte productionneutrophils, eosinophils, and basophils
GM-CSF: stimulates granulocyte and monocyte production
Multi-CSF: accelerates production of granulocytes, monocytes, platelets, and RBCs - What are platelets?
- Cell fragments involved in human clotting system
- What is platelet circulation?
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Circulates for 9–12 days
Are removed by spleen
2/3 are reserved for emergencies - What are two platelet related conditions?
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Thrombocytopenia:
abnormally low platelet count
Thrombocytosis:
abnormally high platelet count - What are three functions of platelets?
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Release important clotting chemicals
Temporarily patch damaged vessel walls
Actively contract tissue after clot formation - How does platelet production occur?
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Also called thrombocytopoiesis:
occurs in bone marrow
Megakaryocytes - giant cells
Manufacture platelets from their cytoplasm - What are the three stages of hemostasis?
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The cessation of bleeding:
vascular phase (vascular spasm/contraction)
platelet phase (Platelet adhesion/aggregation)
coagulation phase (coagulation, fibrinogen -> fibrin) - What is prostacyclin?
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Released by platelets during clotting to prevent uneeded clots
Inhibits clotting
Negative Feedback - What is the purpose of a blood clot?
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Fibrin network
Covers platelet plug
Traps blood cells
Seals off area - What are the three pathways of coagulation?
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Extrinsic pathway:
begins in the vessel wall outside blood stream
Intrinsic pathway:
begins with circulating proenzymes within bloodstream
Common pathway:
where intrinsic and extrinsic pathways converge - What is the common pathway for coagulation?
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Activation of Factor X
Forms enzyme prothrombinase
Converts prothrombin to thrombin
Thrombin converts fibrinogen to fibrin - What is the purpose of thrombin?
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Stimulates formation of tissue factor
stimulates release of PF-3:
forms positive feedback loop
(intrinsic and extrinsic):
accelerates clotting - What pulls a wound together during healing?
- Platelets
- What is fibrinolysis?
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Slow process of dissolving clot:
thrombin and tissue plasminogen activator (t-PA): activate plasminogen
Plasminogen produces plasmin: digests fibrin strands