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72 Cards in this Set
- Front
- Back
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Water soluble hormones
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-Hyrdophillic, easily dissolved in water so blood - Produced in gland cell and stored there until needed (released by exocytosis) - made up of peptide (75%) and catecholamine - made and stored until required |
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Lipid soluble hormones
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-Hydrophobic, unable to mix with water so requires a carrier protein - Steroid hormones made from cholesterol - Thyroid hormones made in thyroid cells - steroids not stored, made as required - thyroid made in thyroid cells and stored until required |
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Function of endocrine system |
Regulate internal environment by secreting hormones that travel through the blood stream to target areas
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Hormones definition |
chemical messengers produced in one location and transported to a second location (target cells) where they exert their effects. |
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Cellular responce to Water Soluble Hormones |
1. WSH bind to cell surface receptor 2. Hormone binding activate G Protein 3. G Protein activates adenylyl cyclase 4. adenyly cyclase converts ATP to AMP (cAMP) 5. cAMP activates protein kinase 6. protein kinase activate specific enzyme 7. enzyme converts specific substrate to product |
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Cellular responce to Lipid Soluble Hormones |
1. Lipid soluble hormone dissociates from carrir protein 2. hormone diffuse across cell membrane 3. hormone bind to Intracelullar receptor 4. hormone rec acts as specific hormone TRANSCRIPTION factor 5. new mRNA generated 6. new protein generated by TRANSLATION of mRNA 7. new protein mediate cells specific responce |
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specific hormone action |
a hormone can only affect cells with specific receptors for that hormone |
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Receptors on water sol and lipid sol |
water sol - on surface lipid sol - intracellular receptors |
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mechanism of action of water and lipid sol |
water sol - 2nd messengers lipid sol - alter gene transcription |
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speed of response in lipid and water sol |
water sol - milli sec to mins lipid sol - hours to days |
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sensitivity of a target cell |
depends on number of receptors expressed for that hormone |
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Compare endocrine and neuronal control systems |
Neuronal - action potentials in axons and neurotransmitter release at the synapse - fast and specific - good for brief response Hormonal - hormones released into the blood - slow but sustained - widespread |
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Hypothalamus and Posterior Pituitary |
- connected by neurons, cell bodies in hypothalamus and axons in posterior lobe - neural communication, freq of AP to posterior lobe determines the rate of hormone secretion |
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Posterior pituitary hormones |
- made in hypothalamus - travel down axon - stored in the axon ends until required
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ADH regulation (PP Hormone) |
PP releases ADH into bloodstream Effector: Kidneys Responce: kidneys conserve water, decrease ECF conc (neg feedback) Stimulis: increase in ECF (dehydration) Sensor: Osmoreceptors Intergrator: Hypothalamus NOTE SENSOR AND INTERGRATOR ARE IN THE HYPOTHALAMUS |
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Anterior Pituitary Hormones |
1. Growth (GH) 2. Adrenocorticospinal (ACTH) 3. Thyroid Stimulating Hormone (TSH) 4. Gondadotropic (FSH and LH) 5. Prolactin (RRL) |
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Posterior Hormones |
1. Artidiuretic (ADH) 2. Oxytocin (OT) |
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ADH Antidiuretic role |
stimulate kidneys to reabsorb water made in hypo and stored until needed |
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Oxytocin role |
- stimulate contraction of uterine muscles during childbirth (positive feedback) - stim breast milk release in breast feeding - made in hypo and stored until needed |
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Milk ejection reflex |
- signal is the sucking on the nipple, sends message via pathways to the hypothalamus and releases the hormone oxytocin so that milk can be released |
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Hypothalamus and Anterior Pituitary |
- hypo and ant connected by blood vessels - communicates by releasing hormones - releasing and inhibitory - ant pit hormones are made in the ant pit by specific cells |
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Feed back regulation of the anterior pit gland |
- hypothalamus - releasing hormone - anterior pituitary gland - pituitary hormone - target organ - hormone - effect Note some go back to hypothalamus and anterior pit to signal to stop. |
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Negative feedback Prolactin |
principal regulator is prolactin inhibiting hormone (PIH) PIH is dopamine prolactin stimulates PIH secretion to inhibit prolactin secretion stimulate breast develop, milk synthesis |
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Hormone associated with this cell: Somatrophs |
Growth Hormone 50% |
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Hormone associated with this cell: Mammotrophs (lacotrophs) |
Prolactin 20% |
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Hormone associated with this cell: Corticotrophs |
Adrenocorticotropichormone 20% |
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Hormone associated with this cell: Thyromophs |
Thyroid stimulating hormone 5% |
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Hormone associated with this cell: Gonadotrophs |
- Luteinizing hormone - Folliclestium 5% |
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Regulation of Growth Hormone |
1. GHRH released from hypothalamus 2. somatrophs release GH and target Liver 3. IGF 1 back to Hypo GHRH in brain 4. IGF 1 also can be positive feedback to the SS neurons |
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Growth hormone |
- peptide hormone - water soluble - 2nd messenger process - cell surface receptor |
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Effects of GH Long and Short term |
LT - Stim bone, muscle and tissue growth by cell division at IGF 1 - stim protein synthesis ST - Incease Blood Glucose - Increase Triglyceride breakdown and free fatty acid in adipose tissue |
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Growth hormone levels peck most when? Gender differences? |
At night time, but fluctuate during the day depending on meals and activities. Gender - Male - small during day major when sleep Female - extended bursts during the day, longer not so pronounced when sleeping. |
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Disorders for GH |
Hypersecretion - too much - giantism Hyposecretion - too little - dwarfism hyposensitive - little or no response in hormone receptors hypersensitive - respond too much |
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Hormones important for growth |
1. Thyroid - increase basal metaboliic rate - essential for nervous system dev 2. Insulin - glucose metabolism 3. Cortisol - glucose metabolism 4. Testosterone - purbety |
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Thyroid gland location and hormones that are made and secreated |
below the layrnx thyroid hormone - basal metabollic rate calcitonin - calcium homeostasis |
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Structure of Thyroid gland |
compsed of follicles and each one surrounded by follicular cells Follicular cells make thyroglobin and secrete it into the folicle c-cell or parafollicular make the hormone calcitonin |
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Thyroid secretion steps |
1. iodised TGB moves into follicular cells 2. thyroid hormones released from the iodised TGB 3. thyroid hormones have two forms 4. T3 (active) and T4 (more plentiful) 5. T3 and T4 secreted into blood travel to carrier protein to target cells. |
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Effects of Thyroid Hormone |
1. Metabolism - increase body heat production - decrease triglceride and chol levels - set basal metabollic rate 2. Growth - normal growth in child - growth retardation in thyroid deficiency - essential for development of fetal brain. |
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Disorders with thyroid hormone |
Hypo secretion - too little - low met rate - weight gain - cold intolerance Hyper secretion - too much - increase met rate - heat intollerant - nervous - increase heart rate |
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Calcitonin hormone |
- controls levels of Ca2+ (controls ca in blood 1%) - parafollicular or c-cells make this hormone |
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Increase in Ca2+ |
calcitonin secretion osteocleast reduce activity - less bone resorption osteoblast increased activity - more bone deposition Blood ca2+ returns to normal |
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Calcitonin improtant in children |
because osteoclasts take 5g of calcium from bone to blood each day where as adults is only 0.8g |
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Parathyroid glands |
secrete parathyroid hormone |
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PTH and Calcitonin effects on Ca2+ |
PTH increases bone break down Ca2+ decreases bone break down together maintain homeostasis |
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Blood Ca2+ levels too low? |
increased excitability of nervous system muscle tremors and cramps begins as ca2+ falls to 6mg at 4mg larynx contracts and suffication |
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Causes of hypocalcemia |
vit D deficent diarrhea thyroid tumor pregnancy and lactiation under active parathyroid glands |
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what is hyercalcemia |
blood levels too high, nerve and muscle cells less responsive and exciteable |
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hyperparathyroidism |
leads to excess PTH secretion caused by parathyroid tumor bones soft raises blood levels of ca2+ kidney stones |
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adrenal glands location and structure |
above the kidneys secretes steroid hormones 2 sections adrenal cortex and adrenal medulla |
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3 layers in the adrenal cortex and what they secrete |
Glomerulosa - aldosterone Fasciculata - Cortisol Reticulas - androgens eg testosterone |
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Inner Medulla |
releases epinepherine and NE Sympathetic nervous system - acute stress Pre ganglionic SNS (ACH) |
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epinephrine binding system used |
uses a 2nd messenger system |
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effects of inner medulla norepinephrine and epinephrine |
- increase fat and glucogen break down - decrease GI - increase heart rate - increase blood flow to muscles |
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Coritsol |
lipid soluble so uses steriod mechanism of action happens in mins to days |
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effects of cortisol |
-gluconegenesis (produce glucose in the body) - increase protein breakdown - decrease glucoes uptake in muscle and fat OTHER - immune systme - Blood pressure maintain - CNS activation - vasculature |
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Feedback Loop of Cortisol |
stress daily variation hypothalamus corticotropin RH Anterior Pituitary Adrenocortiotropic H Adrenal cortex Cortisol |
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Pancreas location |
abdominal cavity |
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sturture of the pancreas |
exocrine glands - secrete digestive enzymes endocrine glands - secrete pancreatic islets |
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pancreatic islets |
beta cells - secrete Insulin (decrease BG) alpha cells - secrete glucagon (Increase BG) |
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Blood glucose fasting range |
3.3 to 4.4 |
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Blood glucose levels are too high |
1. beta cells release insulin into the blood 2. Insulin 3. body cells take up more glucose 4. blood glucose levels decline to a set point |
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Blood glucose levels are too low |
1. alpha cells of the pancreas stimulated to relase glugagon into blood 2. Glugagon 3. liver breaks down glugogen (stored form of glucose) and releases it into the blood. 4. blood glucose levels rise and come to sp |
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target cells when beta secretes insulin are |
muscle and adipose fat (increase glucose uptake) liver cells (increase net glucose uptake) |
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target cells when alpha secretes glucagon |
Liver - increase the breakdown of glycogen - increase glucose synthesis - increase ketone synthesis |
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Hormonal control of blood glucose |
- Pancreatic Islets 1. insulin 2. Glugagon - Pituitary 1. growth hormone - Adrenal glands 1. adrenaline 2. cortisol |
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Insulin action |
1. insulin on receptor 2. allows the glucose channels to open 3. glucose into the cell via GLUT4 4. Hexokinase 5. make glycogen or ATP |
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Insulin resistance |
Fatty acids Diacylglycerol Glucose is not entering the cell as the diacylglycerol switches off the pathways |
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long term isulin resistance leads to |
impaired B cell function |
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ketone synthesis use |
can be used as a last resort for the brain |
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glut 4 and glucose and insulin have no effect on.. |
brain cells |
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Type 1 diabetes |
10 % diabetics Symptoms: high blood glucose Glucose in urine large urine volume Diagnosed: child Cause: Insulin producing beta cells and destroyed Treatment: Insulin injections |
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Type 2 diabetes |
90% diabetics - cells are reisistant to insulin signals to store food, cells are starving as glucose can't be used. - Risk factors: obesity, ethics, genetics Treatment - exercise and diet |
