Final Exam Study Guide

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University of Toronto Scarborough
Biological Sciences
Ingrid L.Stefanovic

HORMONES: - Endocrine glandscells = secrete chemical messengers directly into blood - Can be transported to distant targets - [4.7L30JO,3843980.7090K4724308 e.g. salivary, sweat, mammary glands - Effect over time sec, min, hour, day, week, month - Low concentration effects HORMONE EFFECTS: - Growth and development, metabolism, regulates temp, pH, water balance, hunger, reproduction - Bind to receptor for response - Acts on multiple tissues - Hormone effect depends on tissue type and development stage - Enzymes degrade it into inactive metabolites liver, kidneys - Excreted in urine and bile - Half life = time needed to decrease hormone concentration in blood by half HORMONE TYPES: 1. Amine hormone - Small molecule - life = seconds - E.g. melatonin, thyroid hormone 2. Peptide hormone - Most common = made all over body - Lipophobic bc binding to membrane receptor - Fast acting life = minutes - Hydrophilic transported easily thru body - E.g. pituitary hormones, pancreas hormones insulin, glucagen Preprohormone - 1+ copies of peptide hormone - Large and inactive from ribosomes - Have signal sequence that directs it to RER PEPTIDE HORMONE SYNTHESIS: 1. 7L-4842082#-L38570574K472430 directed into ER by signal sequence on preprohormone 2. Enzymes in ER chop signal sequences = inactive prohormone 3. Prohormone passes from ER to golgi complex 4. Secretory vesicles w enzymes and prohormone buds of golgi prohormone chopped into 1+ peptide hormones 5. Secretory vesicle releases contents by exocytosis into extracellular fluid 6. Hormone moves into circulation for transport to target 7. Peptide hormone = lipophilic 8. Binds to surface membrane receptor 9. Hormone-receptor complex initiates cell responses 10. Activates 2nd messenger cascade e.g. cAMP 11. Causes openingclosing of ion channels, metabolic enzymes and transport proteins, protein synthesis 3. Steroid hormone - cholesterol - All similar structure - Lipohilic receptor win target cell [cytoplasmnucleus] - Bind DNA to activateturn off protein synthesis - Slow acting life long - Not soluble in plasmabody fluids = hydrophobic need carrier protein for circulation [sometimes specific = corticosteroid binding protein or are general plasma proteins = albumin] - Made in adrenal glands, gonads, placenta - Synthesized in SER - E.g. cortisol, sex hormones STEROID HORMONE ACTION 1. Steroid binds to plasma protein carriers in blood only unbound hormones diffuse into targets 2. steroid hormone receptors in cytosolnucleus some steroid hormones bind to membrane receptors a nd use 2nd messenger systems for rapid cell responses 3. Receptor-hormone complex binds to DNA activatesrepresses 1+ genes 4. Activated genes create new mRNA that moves into cytoplasm 5. Translation produces new proteins for cell processes ADRENAL GLAND - Specialized neuroendocrine tissye of SNS - Secretes 3 steroid hormones: - Aldosterone = mineralocorticoid controls watersodium retention in kidneys - Glucocorticoids = cortisol - Sex hormones = androgens, estrogen, progesterone PANCREAS - Controls digestionabsorption of nutrients - Secretes insulin and glucagon - Female gonads secrete estrodiol and progesterone - Male gonads secrete adrogens = testosterone and androsrenedione THYROID - Secretes thyroid hormones = triiiodthyronin T3 and tetraiodothyronin T4 - Controls metabolic rate, growth, development - Calcitonin = controls calcium levels PARATHYROID - PTH = parathyroid hormone controls calcium levels THYMUS GLAND - Secretes thymosin = maintains levels of cytoplasmic G-actin - Controls IS - Secretes T lymphocytes = T cells - Pineal gland releases melatonin - Influence circadian rhythms - Inhibits sexual behavior - Stimulates IS - Endocrine cell senses stimulus and responds by secreting hormone - Endocrine cell acts as sensorreceptor and integration system - E.g. insulin and glucagon secreted from pancreas to modulate blood glucose PTH - Monitors plasma calcium - Parathyroid cells linked to GPCR that binds calcium - When calcium bound to GPCR, PTH secretion inhibited - When plasma calcium falls, less calcium bound to GPCR and PTH inhibition stops - PTH secreted into blood stream act on bone, kidney, intestine to increase calcium ANTERIOR PITUITARY GLAND - True endocrine gland of epithelial origin - Synthesizessecretes 6 hormones POSTERIOR PITUITARY GLAND - Extension of neural tissue - Storessecretes hormones synthesized in hypothalamus trafficked by infundibulum - Posterior pituitary gland secretes hormones synthesized in hypothalamus - Vasopressin = antidiuretic hormone, controls water balance - Oxytocin = ejection of milk, contraction of uterus in labor ANTERIOR PITUITARY GLAND - wout it, die in 2-3 days - Secretes: prolactin, thyroid stimulating hormone = thyrotropin, adenocorticotrophin, growth hormone, follicle stimulating hormone, lutenizing hormone - Secretion of ANTPIT hormones controlled by hypothalamus - All ANTPIT hormones regulate secretion of another hormone in endocrine target cell - Antpit hormones = trophic hormones 9434:7L8K - Antpit hormones named by target HHPS = hypothalamic-hypophyseal portal system - Specialized region of circulation connects antpit and hypothalamus to closed circuit of blood vessels - Transports hypothalamic trophic neurons to antpit regulates antpit hormone secretion - Portal allows smaller amounts of hormone to be released to elicit given response compare dot hormones released into general circulation - Complex feedback look regulates secretion of hypothalamicpituitary hormones - More complex than simple feedback loop - 3 integrating centers:
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