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149 Cards in this Set
- Front
- Back
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What are the activities of the Hypothalamus and Pituitary Glands?
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1. Synthesize multiple different hormones
2. Regulate growth and development 3. Regulate Metabolism 4. Regulate Homeostasis 5. Regulate other endocrine glands. |
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Describe the location of the hypothalamus.
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Base of the brain, part of diencephalon.
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Describe the location of the pituitary gland.
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Pituitary at inferior of hypothalamus in an indentation named the "sella turcica" Connected through infundibulum. Pea shaped.
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Infundibulum
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Connects the pituitary gland and the hypothalamus. Axons travel inside and blood vessels along surface.
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Adenohypophysis
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Anterior Lobe of Pituitary. Cells produce and secrete a number of hormones. Each cell type produces a different type of hormone which each affects a different target cell. This is regulated by hypothalamic hormones that are released through the capillary bed.
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Neurohypophysis
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Posterior Lobe of Pituitary Gland. Axons from hypothalamus directly extend into Posterior gland. Axonal Transport Tract relays signal to release hormone. Only stores hormones produced by hypothalamic neurons, doesn't create them.
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Hypothalamo-hypophyseal tract
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bundle of nerves travelling together. Goes from hypothalamus to posterior pituitary.
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Antrograde vs Retrograde
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Signal travels from cell bodies to the axon. Antrograde is forward, and retrograde is backward.
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Hypophyseal Portal system
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Connects hypothalamus and anterior pituitary. Separated by a venule. Basic idea of two capillary beds separated by a venule. Heart-->arterioles-->capillary beds-->venules-->capillary beds-->venus system --> heart.
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Human Growth Hormone
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Tropic -- stimulates another hormone (IGF). Targets skeletal muscle, fat tissue, anything to stimulate growth. Also influences blood glucose. Targeted by GHRH
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Thyroid Stimulating Hormone
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AKA thyrotropin, stimulates endocrine activity, Part of pathway that releases thyroid hormones from thyroid glands.
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Gonadotropins
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Regulates reproductive activities. Follicle stimulating Hormone, Luetenizing hormone, Involved in sperm and ova formation
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Prolactin
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Stimulates production of milk in mammary glands. Typically not active unless pregnant or nursing. Needs permissive effect from other hormones.
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Adrenocortotropic hormone
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ACTH targets outer part of adrenal gland. Cortex produces many hormones. Regulates blood sugar and stress hormones. May suppress immune responses.
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Control of Anterior Pituitary Secretions
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Hypothalamic releasing (corticotropin releasing hormone) and inhibiting (somatostatin) hormone enter capillary beds,
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Negative Feedback System of hormones
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High levels of hormone inhibit their further release
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IGF
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Promote growth, maintenance and repair of bones and skeletal muscles. Produce proteins in order for cells to grow. Increase in amino acid uptake by these cells means increase in protein synthesis. Inhibits breakdown for protein ATP synthesis, can be produced by carbs and fats instead. Growth and maintenance.
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How is hGH regulated?
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GHRH and GHIH are released from hypothalamus. GHRH releases GH and GHIH inhibits it. Both are released in response to blood sugar.
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What happens during hypoglycemia?
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hGH and IGFs are secreted. Glycogenolysis in liver (taking apart glycogen, releasing glucose from glycogen) and blood glucose rises
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What happens during hyperglycemia?
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hGH and IGFs inhibition. Glycogenolysis decreases. Blood glucose decreases.
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GH and fatty acids
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Lower levels of fatty acids causes GH to rise and higher levels of fatty acids causes GH to fall. High amino acid levels cause hGH release and low amino acid levels cause hGH to fall.
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Sympathetic stimulation of GH
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Increased activity of sympathetic division can increase GH levels and thus aid in controlling glucose levels. "Glucose sparing effect."
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Cortisol and GH
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Increased stimulation of cortisol can elevate levels of GH and thus elevate blood sugar.
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Diabetes mellitus
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Hyperglycemia -- chronically elevating blood sugar. Excessive secretion of insulin and decreased sensitivity of receptors due to elevated levels of GH levels.
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Type II diabetes
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lack of sensitivity by target cells or pancreas decreases amount of insulin
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Gigantism
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Stimulates excessive growth -- especially excessive interstitial growth in the bone plates of long bones. Excessive GH.
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Acromegly
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Adult bones grow in thickness and diameter. Excessive thickness in thickness and diameter especially in hands and face
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Dwarfism
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Happens due to hyposecretion of GH. Lack of stimulation of growth plates.
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Oxytocin
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Stored in posterior pituitary. Stimulated by uterine stretching and suckling. Promotes milk ejection. Works on a positive feedback mechanism.
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Anti-diuretic Hormone
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Stored in posterior pituitary. Conserves water. Targets kidneys, sweat glands and smooth muscles of blood vessels (loosing a lot of blood--vasoconstriction to help maintain blood pressure and water loss). Stimulated by high osmotic pressure, detected by hypothalamus, AKA vasopressin.
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Diabetes Insipidus
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Detrimental disease related to ADH hyposecretion. No response to ADH from kidneys...causes severe dehydration and too much urine production
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Thyroid Gland
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located in neck and regulates metabolic activity. Produces thyroid hormones T3 and T4.
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Goiter
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Enlarged thyroid gland.
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Follicular Cells
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Produce T3 and T4 and arranged in circles around follicles
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Colloid
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Protein mixture located in follicles of prehormone or precursor taken up by follicular cells used to produce hormone
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Parafollicular cells
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Located on the sides of follicle cells, produce calcitonin and aid in regulating blood calcium. Isthmus connects the two sides of the thymus.
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Actions of thyroid hormones
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Increase basal metabolic rate (rate at which ATP is produced), produce heat, Stimulate synthesis of Na+/K+ pumps (thermogenic effect)
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Regulation of secretion of thyroid hormones
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TRH released from hypothalamus and TSH is released from anterior pituitary. Increased Thyroid hormone in cold temperatures and pregnancies etc. Low levels of thyroid hormone-->TRH --> TSH-->Thyroid hormones -->Target organs -->Negative feedback
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Three steroids secreted from adrenal Cortex
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mineralocorticoids, androgens, and glucocorticoids.
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Mineralocorticoids
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Secreted by adrenal cortex, like aldosterone. Aids in signal transmission, water balance. Secreted by humoral influence.
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Glucocorticoids
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Cortisol, stimulated by ACTH released by adrenal cortex. Suppress inflammation. Aid in regulating blood sugar, elevate glucose levels. Prolonged stress heightens glucose levels. Glucocorticoid levels drop --> Hypothalamus releases releasing hormone -->anterior pituitary releases ACTH -->Adrenal cortex secretes more glucocorticoids. Lowers immune suppression
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Androgens
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Secreted by adrenal cortex, have masculinizing effects. Only source of estrogen in post-menopausal women.
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Effects of glucocorticoids
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breakdown of proteins, gluconeogenesis from lactose (converting other things other than glucose from blood into glucose), lypolysis, depression in inflammitory responses.
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Anatomy of Adrenal Medulla
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Modified Sympathetic Ganglion that forms clusters near blood vessels and recieve signals from preganglionic neurons from sympathetic division of ANS to release chemicals that are stored.
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Hormones of Adrenal Medulla
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Epinephrine and Norepinephrine (hormones since they both enter the blood stream)
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Effects of the adrenal Medulla hormones
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Intensify sympathetic responses (stimulate glycogenolysisand gluconeogenesis to mobilize sugar)
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Regulation of Adrenal Medulla Hormones
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Neurostimulation via sympathetic neurons and a pathway stimulated during stressful situations. "Fight or flight" response.
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Three cell types of the pancreatic islets
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Alpha cells produce glucagon beta cells produce insulin Delta cells produce ACTH secreted under humoral influence under changing blood sugars
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Regulation of pancreatic secretions Hypoglycemia
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Hypoglycemia stimulus --> Glucagon secreted and targets the liver. (Liver stores a lot of glucagon and sugar) -->Glycogenolysis and gluconeogensis. Glucagon is secreted after fasting
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Regulation of pancreatic secretions in hyperglycemia
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Insulin is secreted --> targets multiple cell types --> lowers blood sugar. Glycogenesis. amino acid uptake, protein synthesis, lipogenesis. Decrease in glucogenolysis and gluconeogenesis
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Insulin and blood sugar
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Increase glucose uptake by cells, stimulates glycogenesis and lipogenesis. Removes sugar from blood
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Glucagon and blood sugar
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elevates blood sugar by stimulating glycogenolysis and gluconeogenesis
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hGH and blood sugar
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decreases uptake of sugar by cells, increases blood sugar in blood. Stimulates glycogenolysis and lypolysis. Secreted in times of stress.
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Cortisol
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Stimulates the release of sugar into the blood for ready uptake. Stimulates gluconeogenesis and lypolysis. Secreted during stressful periods.
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Functions of the blood
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Transportation, Protection (blood loss, infection), Regulation (pH, body temperature, fluid level)
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albumin
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circulates within blood, "transport protein" important in maintaining osmotic pressure. Synthesized by liver when osmotic pressure changes
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globulins
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antibodies that identify foreign agents that come into the body, produced by lymphocytes. Also help transport substances...Ferrin is a tranpsorter.
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fibrinogen
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aids in blood clotting. Forms a network that traps RBC and forms a clot. not activated unless certain chemicals are present.
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How is blood volume maintained?
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ADH, sweating, and urination
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Components of formed elements of blood
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RBC "erythrocytes" 95% WBC leukocytes and platelets
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Hematocrit
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Measure of percent of whole blood volume occupied by RBC. Females about 37-48%, males 42-52%. testosterone stimulates hormone that stimulates RBC production
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Anemia
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low amount of RBC or RBC don't transport O2 adequately
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polycthemia
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too much hematocrit, can be stimulated by moving to a high altitude environment or blood doping in athletes. Dehydration also causes high blood volume
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Where does hemopoiesis occur?
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Red bone marrow located in spongy bone at the ends of long bones and in some flat bones.
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Pluripotent cells
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Stem cells capable of making many different things
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Stem cell lineage
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Pluripotent cells receive a signal to produce a lineage that differentiates into a committed lineage and nothing else
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Process of RBC maturity
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Pluripotent stem cell-->colony-forming unit-->precursor cell (blast cells) generate more and more of their own cells, go through many stages of development-->mature RBC
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sinusoid
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large hole in wall that allows RBC to go through
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Megacariocyte
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pluripotent cells differentiate to become megacariocyte and then attach to sinusoid. They then split off and become platelets.
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Hemopoeisis Regulation
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Kidneys sense low O2 levels --> Release EPO --> EPO stimulates stem cells --> stem cells stimulates RBC formation
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Hypoxemia
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Low O2 levels (works with a negative feedback mechanism)
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Thrombopoietn/platelets
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stimulates stem cells that produce plateles, but the mechanism isn't well understood
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Cytokines
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stimulate WBC, secreted by macrophages, fibroblast, epithelial cells, bone marrow, in response to injury. Taylor themselves to body's needs, not a negative feedback system. "colony stimulating factors"
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Antigens and their roles
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Promotes clumping when binds to antigen sites
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Red blood cell anatomy
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Filled with hemoglobin, no mitochondria (anaerobic respiration), no nucleus.
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Hemoglobin anatomy
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consists of 4 globins, 1 heme group per globin that gives molecule red color, and 1 ferrous group per heme globin .
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Mechanism of oxidation
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Oxygen bind reversibly to ferrous iron and body has higher affinity for oxygen in oxygen poor areas -- fetal oxygen has higher affinity for oxygen than mother.
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oxyhemoglobin vs deoxyhemoglobin
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bright red color when carrying oxygen and dark red color when let go of oxygen
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CO2 vs CO
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CO2 binds to amino acids of globin and therefore doesn't compete with oxygen. CO binds to ferrous iron and therefore does compete and travels through blood and poisons.
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Erythropoiesis
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Takes several days -- pluirpotent cells (receptor of EPO)-->Bone marrow Erythrocyte CFU (have nucleus) and undergo cell division and hemoglobin synthesis --> reticulocyte released from bone marrow, nucleus lost, polyribosome synthesize proteins -->erythrocyte no more polyribosome and now biconccave
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location of RBC breakdown
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Spleen and Liver -- phagocytic cells break down and take out damaged cells and located in liver. Heme broken down and put into bilirubin and bile. removed in feces and urine.
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Essential nutrients for RBC production
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vitamin B12, amino acid, Iron, Folic acid
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Anemia
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Reduced oxygen carrying capacity for RBC, due to low hemoglobin
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Causes of Anemia
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Blood loss, Low RBC count due to inadequate diet or genetic diseases, low hemoglobin or iron deficiency. Leukemia can develope from Anemia.
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Diaapedesis
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WBC squeeze through walls that make up the capillaries
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Chemotaxis
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Attraction via chemical secretions -- how WBC are attracted to infectants
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Phagocytosis
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bringing things into the cell-- WBC use phagocytosis -- reach out, grab substance, then engulf it and digest it.
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Eosinophils
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Granular WBC. Granules large and uniform in size. Stains orange red in color with eosin (acidic). Bilobed nucleus. Engages in phagocytic activity to destroy worms, allergins, and inflammitory chemicals.
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Basophils
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Granular WBC. Appear large black or dark puprle dye (basic dye). Nucleus is hard to see, but is U-shaped. Secretes inflammitory chemicals (heparain, histamine) to intensify allergic reaction. Least common WBC. Allow more blood flow to area
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Neutrophil
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granules stain with both acidic and basic dye, no definitive color. (pale lilac color) polymorphonuclearluekocyte (2-5 lobes). Most numerous, phagocytosis, first WBC on site of injury
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Lymphocytes
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Agranular. Body identifies specific antigens (virus or abnormal cells). T cells, B cells, some produce antibodies that mark antigens. Longest-lived WBC "memory cells." Similar to vaccine. Small, about size of RBC, with large, round nucleus taking up entire cell.
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Monocyte
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Large with round, kidney shaped nucleus. Macrophages --- Some are permanent residents of a particular part of the body. Antigen presentation. Breakdown a cell and display parts of it on its surface for identification. Lymphocyte can then identify it for the future. Monocyte involved in RBC breakdown. High macrophage or monocyte count is identification for long-term illness.
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Three-step response to blood vessel damage and bleeding
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1. vascular spasm. 2. platelet plug. 3. blood clotting
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What is the usefulness of a vascular spasm?
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Platelets secrete substance that stimulates contraction (seratonin) -- Reduces or stops the flow of blood and induces pain receptors
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How is a platelet plug activated?
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When the smooth wall of a blood vessel is damaged, platelets stick to it. It is prostoglandin, which platlets don't stick to, but platelets stick to the inner collagen fibers.
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What is the platelet release action?
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Platelets activate other platelets by secreting chemicals and changing their shape to form finger-like projections which stick to everything and the blood vessel wall.
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Thromboxain
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Main chemical released by platelets in the formation of a platelet plug. Aspirin interferes with thromboxain effectiveness
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Platelet aggragation
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sticks to every other platelet and the wall.
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How is blood clotting controlled and activated?
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Through anti-coagulation factors. Can be activated through a cascade of events.
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What are the coagulants that help stimulate blood clotting?
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Calcium, enzymes that are stimulated in the liver, platelet and damage tissue secretions, Vitamin K from large intestine. Prothrombin activator --> thrombin --> fibrin.
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Chemical pathway of activated fibrin
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Factor X --> prothrombin activator --> prothrombin --> thrombin --> fibrinogen --> fibrin --> linked with thrombin via Factor XIII "fibrin stabilizing factor" that forms crosslinks with thrombin
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Extrinsic pathway
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Initiated by chemicals of damaged tissue -- thromboplastin. Very few steps in this pathway. Quick.
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Intrinsic pathway
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Initiated by chemicals within the blood (platelets) and therefore a lot slower. But, ensures no clot when you don't want one.
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Thrombin effects
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Accelerates formation of prothrombin activator, activates platelets (responsible for entire process). Anticoagulants interfere with thrombin.
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Clot retraction
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clot brings damage tissue walls closer together via actin and myosin action similar to smooth muscle.
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Injury repair
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Platelet derived growth factor secreted from platelets stimulates fibroblasts, smoothe muscle, epithelial muscle, to grow and divide and repair
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fibrinolysis
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Clot removal. Plasminogen --> plasmin breaks down crosslinks. plasmin breaks down fibrin. Secreted by many tissue types
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Methods of clotting control
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Platelets repulsion -- doesn't stick to blood vessel wall. Dilution of cagulation factors in blood, and anticoagulants.
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Pulmonary Circuit
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Reoxygenates blood. Brings blood from right side of the heart to the lungs and back to the left side of the heart (shorter)
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Systemic Circuit
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Supplies O2 to the rest of the body and returns CO2 to the heart. Leaves from the left side of the heart and circulates throughout the body and returns it to the right side of the heart.
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Which circuit does the right side of heart serve?
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Serves the pulmonary circuit through the pulmonary trunk.
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Where do the pulmonary arteries go?
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To the lungs
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Vena Cavae
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Drains O2 depleted blood into the right side of the heart
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Which circuit does the left side of the heart serve?
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Sevres the systemic circuit via the aorta
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Aorta
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receives blood from left ventricle and pumps it throughout the systemic circuit
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Coronary arteries
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First branches of aorta
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Pulmonary veins
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Heart receives O2 rich blood from the veins
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Mediastinum
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Middle compartment between lungs and encased between membranes
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Parietal Pericardium/Pericardial Sac
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Outer fibrous layer and inner serous layer. Fluid secreted with moving organ to lessen friction.
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What covers the inner wall of the heart?
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Visceral pericardium (epicardium). Can have adipose tissue associated with it.
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Pericardial cavity
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Space between the visceral and the parietal cavities. Contains pericardial fluid
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Pericarditis
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When the tissues become inflamed and dry. Can cause friction and pain and form adhesions that interfere with heart function.
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Endocardium
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Lines the heart chambers, covers the cusps, continuous with the blood vessels,
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Endocartitis
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inflammation of inner epithelium -- usually affects the heart valves and is associated with blood-borne bacteria.
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Myocardium
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Cardiac muscle. Very thin on the right atrium compared to the thick wall on the left atrium. Fibers are arranged in a spiral configuration in order to produce a twisting or sqeezing contraction. Apex-base.
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What is the structure of the fibrous skeleton?
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Meshwork of collagen and elastic fibers that have a little stretch and then return back to their original shape.
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What is the location of the fibrous skeleton?
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Located between the chambers and around and between the valves. Also around blood vessels where they enter the heart.
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What is the function of the fibrous skeleton?
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structural support for major valves and vessles, anchors cardiocytes so they have something to pull against, electrical insulation of ventricles and atria. Possible recoil of the heart.
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What is the function of the right atrium?
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Recieves O2 depleted blood from the coronary sinus --> pumps it to the right ventricle, mostly passive movement.
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What is the function of the left atrium?
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Recieves blood from the pulmonary veins. Movement is passive.
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interatrial septum
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separates the atria
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focca ovalis
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indentation where fetal hole existed in interatrial septum.
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What is the function of the right ventricle?
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Pumps blood to the pulmonary arteries and then to the lungs.
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What is the function of the left ventricle?
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Pumps blood throughout the systemic circuit after it recieves it from the left atrium.
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Interventricular septum
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separates the ventricles
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trabaculae carnae
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raised areas of cardiovascular muscle that aids in spreading electrical signal and papillary muscles on inner surface. Refulate closing valves and cusps.
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What do valves consist of?
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cusps
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Describe the structure of the atrioventricular valves.
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Flaps hang down into the ventricle. Right is tricuspid and left is bicuspid. Located between the atrium and the ventricles.
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How do the atrioventricular valves prevent over-extension?
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Prolapse is prevented by chordae tendinae and papillary muslces that don't let cusps go into the atria. Muscles contract when valves close in order to prevent over extension.
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Describe the structure and location of semilunar valves.
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Half-circles. Located between the ventricles and the great vessels that emerge from them. The left ventricle and the aorta and the right ventricle and the pulmonary trunk. Three circular cusps. no chordae tendinae
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How do the valves open and close?
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Based on a pressure gradient
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Stinosis
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valve opening becomes more narrow, thus the heart doesn't pump as much blood through circulation and has to work harder.
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Incompetence
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The valves don't close all the way, thus you get backflow. Valves may be deformed or damaged. Can cause heart failure.
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Prolapse
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When cusp reverts back into the atrium. The blood everts back and you are unable to pump blood efficietly.
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How much oxygen from the blood does your heart recieve?
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5%
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enastamosis
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collateral circulation -- a lot of branches reconnect on the heart. Thus if one is blocked then another should be able to supply blood
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Coronary sinus drainage
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drains into the right atrium -- located on posterior surface of the heart on the central sulcus.
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Thesbian drainage
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Tiny veins that drain directly into the chambers. Small amount (5-10%) of blood enters heart this way.
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angina
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blood vessel constriction
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