Endocrine System Notes PDF

 Endocrine system I · Acts with nerous system to coordinate and integrate of body cells activity · Influences metabolic activities lia hormones transported in blood...

 Endocrine system I · Acts with nerous system to coordinate and integrate of body cells activity · Influences metabolic activities lia hormones transported in blood hormones : Long distance Chemical signals Autocrines : chemicals that exert effects on some cells that secrete them Paracrines : Locally acting chemicals that affect cells other than those that Secrete them Homone Release Endo glandsStimulated to Syntresize/release hormones in response to 1) Humoral Stimuli 2) Neural Stimuli 3) HormandStimuli  Blood levels of hormones= controlled feedback by negative · systems. I hormone effects on target organs O can X inhibit further homore release. Hormone ReleaseIn 1) Nene Stimuli - Newe fibers stimulate hormone release. Csumpathetic nervous system FibersStimulde adrena medulla to secete catecholamines. S 2) HormalStimuli Chormones stimulate other endocrine organs to release hormones Hypothalamus H-A-Adrenal corticotropin releasing homone ( ↓ Anterior Pituitary (Adrenocorticotropic horme N Adrenal Cortex (Cortisol)  Hormone-cell specificity hormones Though systematically ; A circulate w/ hormone specific receptors only cells are affected * target cell activation depends on 3 factors 1. Blood levels of hormone of 1 in 2. Relative number receptors on target Cell (strength) of binding between receptor and. 3 Affinity hormone · Up-Regulation : Target Cells form more receptors in response to low hormone levels more receptors formed Whormone levels * Down-Regulation : Target cells lose receptors to high hormone levels. from high levels home Ahormones target alter cell activity - The Dalter plasma membrane permeability and/or membrane potential Stimulate of - Syntesis enzymes Activate enzymes - - serte mitosis ② classes of Hormones ① Amino acid-base hormones - water soluble ; Amino acid derivatives peptides, , and proteins (ex epinephrine : Melatonin , and insulin ② steroids - Lipid soluble synthesized from cholestero - lex: gonadal / adrenocortical hormones Specific Actions of hormones ① water-soluble hormones - All amino acid-based hormones except thyroid hormone - They act on plasma membrane receptors (GPCR) ② Lipid-soluble hormones (Steroid/thyroid hormones - they act on intracellular receptors that directly activate genes - Can enter cell. Half-life & Onset Duration # Half-life , onset , and duration of hormone activity are dependent on whether the hormone is water or lipid soluble  Hormones circulate in blood either free or bound Stenoids - and Thyroid hormone are attached to plasma proteins Concentration of hormone reflects circulating ① Rate of release ② Speed at which it is inactivated/removed from body Hormones can be removed from blood by ① Degrading enzymes Kidneys , liver , * Half-life : Time required for level of hormone in blood to decrease by half (I min-1week) · Hormones have different response times Can be immediate some are inactive until trily - , enter target cells steroide take hours to days , Duration limited · is ; Effects disappear may rapidly as blood levels drop. Endocrine Glands (Pituitary ant Connected · => Has Secretes 2 8 to hypothalamus major homones lobes gg -post major ① Posterior pituitary (neusohypophysis) : Composed of neural tissue that secretes heurohormones. ② Anterior pituitary Cadenohypophysis) : Consists of glander tissue hypothalcusa : ↓ )) % Posterior relation ship % Pituitery * Posterior Lobe growth of is brain neural tissue derived -- from down ↓ pot * Maintains j to T neural connection hypothalamus released * Secretes 2 Neuro-hormones (Oxytocin and ADI * Hormones stored in axon terminds in posterior are released into blood when pituitary and neurons fire. #Hormones feed Oxytocin : A positive back mechanism and a neurotransmitter in brain CexiActss hormand trigger of milk ejection ADH : Too much= secretion of ADI ; High concentrations cause vasoconstriction Anterior Pitlitory hormones * All are peptide hormones. * Tropic hormones regulate Secretion of other hormones Mechanism : ①Hypothalamic neurons secrete releasing/inhibiting hormones ② hormones travel through portal veins where stimulate/inhibit hormones hormones ③ In response, Anterior Pitritary scretes ↳ secondaryCapillary pers as into  Anterior hormones Dituitary · - Growth hormone : Has direct actions on metabolism levels Example : Increases amino acid by blood uptake cells , increases glycolysis of for fuel fatty acids use as , Triggers liver to do And Glucose sparing actions decrease rate of cellular glucose uptake and metabolism) Indirect growth- promoting actions * Growth hormone stimulle most cells and divide due to insulin-like growth hormones. * Major targets are bone and skeletal muscle of Regulation Secretion Hormone GHRII GH release. · Releasing is , stimulating triggered by high amino acid levels ; hypoglycemia - or low blood pressure , # Inhibiting hormons-(GHIH/SST) inhibits Glt relesse - miggered by increase in GH and insulin- like factors growth Anterior Pitutory Hormones ① ACTH : Secreted by corticotopicells and Stimulates adrenal Cortex to release corticosteroids * ACTH release is by hypothalamic triggered hormone (CRH), it is highest levels releasing in the morning. - Other factors that inhibit release of CRI cre fevers , hypogemina , and Biological Stressors ② Gonadotropins (FSHELH) * FSH (follicle Stimulating hormone) and (nutenizing (hormone) LI are secreted by gonadotropic cells of anterior pituitary & FSH Stimulates production gamete = * LH hormone production. In females, promotes gonadal = L helps mature follicles of egs/release of estrogen. An Males ,It stimulates test 1 gym) Endocrine Glands Thy bid is the body's major metabolic hormone Two forms : ① T4 (Thyroxine) - Major form circulating in blood (It has 4 Iodines atoms attacheal ②T (thiodothyronin) - More active in tissues (3 iodines attached  Endocrine Glands Thyroids. Affect every cell - Binds to intracellular - receptors within a cell's nucleus , and triggers transcription of metabolic genes The Effects · increases basal metabolic rate and heat prod. aka calorigenic effect · Regulates tissue growth · Maintains blood pressure by increasing advenergic receptors in blood vessels. T4 and T3 transported by thyroxine binding globulins · Both bind to target receptors Periphere tissues convert · To to ts by using on that memacs enzyme one iodine  1 Calcitonin Cat levels by. : Regulates lowering # produced parafollicular (cells by in response to high Cat levels * Antagonist to parathyroid hormre (PTH) by inhibiting osteoclast activity due to high cat it caused was by. 2 Parathyroid : Regulates Cat levels by highering -Est : transmission of nerve impulses/muscle contraction. - Low Cat = Stimulation of Osteoclasts Adrena's - 2 Glands in 1 ⑧ ( media a > O Adrenal cortex : Synthesizes / secrete , different cormones ② Adrenal medulla : Nervous tissue part OS SNS - Adrenal Cortex : Produces Corticosteroids * steroid hormones not stored in cells (release depends on synthesis) of 3 Layers cortical cells produce different corticosteroids I Zona Mineral corticoids glomerulosa. -. 2 zona fasciculate - Glucocorticoids. 3 zong reticularis - Gonadocorticoids. Mineralocorticoids = Regulate electrolyte concentration Nat and K + ↓ ↓ affects resting membrane ECF and blood potential of volume cells Aldosterone (most potent) = Stimulates Not reabsorption by Kidnes , increasing B. U. and B P. and stimulates K+ elimination by Kidneys * Renin-angiotensin- alderston mechanism #I regulator of aldosterone secretion  Minerekorticoids Renin-Agiotensin-Aldosterone Mechanism # Decreased blood pressure Stimulates Special Kidneys to releaserenin in blood. · Renin cleares Off part of plasma protein, angiotensingen. * actor Angiotensnosenstein and stimulates Aldosterone  G lucocorticoids * Influences metabolism of the cells against stressors * keeps glucose levels Stable Maintains b P vasoconstrictor.. by incessing actions # Cortisol : large amounts Only one in -causes increase in blood levels of glucose , fatty acids , a amino acids - Prime metabolic effect is gluconeogenesis , formation of glucose from fats and proteins - Vasoconstriction : Rises blood pressure to distribute nutrients to cells quickly Adrenal Medulla - Medullary cells synthesize : epinephine (80 % ) and Noepinephrine (20 ) % · Effects of catecholamines (Epin/ noepin) -vasto constriction , increased heart rate ,& increased glucose levels Epinephrine Stimulates metabolic activities = Noepinephrine-Influences vasoconstriction and blood pressure Long term stressors win through achenal cortex short term stressors adrenal run through medulla  Pancreas # Has exocrine and endocrine cells - Acinar cells (exocrine) produce juice for digestion * Pancectic islets contains endocrine cells Xalpha cells = glucagon Chyperglycemic B bota tells insulin Chypoglycemic Glucagon = Raises blood glucose , so is triggered by low glucose levels , rising amino acids # for and Targets livers glycogenolysis , gluconeogenisis to release glucose into blood Insulin= Lovers blood glucose triggered , When glucose levels are increased of way lovering 1. Catalyze glucose oxidation of ATP production z. Polymerize glucose. 3 Convert to fat glucose Triggers : High glucose , Hormones such G H And as glucagon , Epinephring.. SNS inhibit insulin release  DIGESTIUE ① Alimentary Cand - organs : Mouth, Pharynx , esophagys , anus , small/large intes * food breaks down into Function : Digests , smaller fragments , absorb fragments through lining. ② Accessory digestive organs (not port of tobe · Teeth , tongue , gallbladder , liver , pancreas ↳ Digestive glands : (Salivary glands , lives , pancreas , they help break down food Digestive system process I food from mouth. Ingestion-taking in. Mechanical 2 breakdown-month tearing food apart/chewing food down. 3 Propulsion - Getting the tube wl aid breaks molecules. Digestion-starts at mouth 4 , enzymes. Absorption 5 - Happens in small intestines and absorbs from tube water is absorbed , Go Defacation to push Anus is mainly used - out fects  Enteric Nervous system Located sheaths of tissues lining the esophagus · in , stomach , small intestine, colon · Works independent cNs then · Aplexus intertwine of neurons 1) submucosal nerve plexus = Regulates glands and smooth muscle in Mucosa 2) Myenteric newe plexus = controls hI ENS short reflexes : medicted plexus by enteric nerve respond of GI stimulus long relexes : Response to stimuli inside/ outside of get such as to nervous system Parasymathetic = Enhance digestive system Sympathetic = Inhibits digestion Digestive Organs Mouth : Salivary Glands Secretory cells : 1. SerousCells : Produce watery secretion , enzymes, ions, and bit of mucin.. 2 Mucous Cells : Produce mucus. Functions of saliva-cleanses mouth , dissolves food chemicals for taste # Saliva composed of and is salivary amylase salivary lipase control of salivation Activated by parasympathetic ingested - N.. S When food sends signals to brain salivatory nuclei in stem that Stimulate parasympathetic activity. Stomach tenk that starts temporary storage = chemical breakdown food -stores into small ingestion starts its digestion Converts # bolus of food to paste-like Chyme # Stomach mucosa forms folds called many ngae # Empty has mL volume but Stomach 50 expands to L (Stomach Digestive process 1) carries out bleskdon of food 2) HCI denature proteins 3) Enzyme pepsin denatures proteins 4) absorbed Lipid-soluble alcohol into blood 5) Holds food 6) Deliver chyme to small intestine * 7) Intrinsic factor is important for Vitamin B2 absorption (B12 is needs for red blood cells to nature)  Chief Cells Pepsinogen An inactive enzyme that is activated · = to by HCl and itself (a positive feedback pepsin by pepsin mechanism · Lipases % Digest 15 of lipids · Parietal Cells *Secretions include - HC) : denatures protein activates pepsin , kills bacteria - Intrinsic factor : Glycoprotein that absorbs vitamin B12 in small intestine Enteroendocrine Cells * Secrete chemical messengers into lamina propia - Serotonin histamine , CCK : Act as paracrines , - Somatostatin Calso acts as parcrine) and gastrine acts as hormones.  Gastric Glands 1. Cephalic reflex phase · occurs before food enters stomach triggered by aroma, taste sight , , for * vagus newe stimulates gastric glands to get ready digestion. 2 Gastric Phase * occurs once food hits stomach A sensory neurons send signals related to food to our spind cord to activate gastric glands for food Regulation of Gastric secretions Gastric phase * stimulation of secretions when food is these -- * Distension activates Stretch receptors , initiating both / short reflexes long Chemical * stimuli (partially digested proteins , Caffeine, and PH) rising ; stimulates enteroendocrine cells to secrete gastrin * Release of gastrin initiates HC) release from parietal cells and stimulates enzyme Secretion (Buffering action of ingested proteins cause stimulate Secretical PH to rise to gastrin Inhibition of secretions (When food is no longer there * Low ph inhibits gastrin Secretion * occurs between meals # occurs during digestion more protein = More HC) secreted. Intestinal 3 phase : food entering into small intestine results in inhibition of Secretions Inhibition · of secretions 1) Distension of duodenum due to entry of chyme 2-4) Presence of acidic , fatty , and hypertonic chyme # These effects protect intestine from being overwhelmed by too much chyme or acidity Achieved 2 ways 1 reflex Duodenem inhibits. Enterogastric : acid secretion in stomach 2. Entergastrones : Duodenal enterdendocrine cells release too important hormones that inhibit gastric secretion = secretin &CCK Propulsion = more towards Pylorus Grinding=small amounta Retropulsion = pyloric value closes.  Regulation of Gastric Emptying * Stomach fully empties in 4 hours -carb-rich Chyme moves quickly through duodenum takes to Fatty Chyme longer digest - # Duodenum receptors responds to stretch and chemical signals Enterogastric fexlex and enterogastrones - inhibit gastric secretion. Accessory Organs and pancreas liver , gallbladder , liver : produces bile gallbladder : stores bile pancreas : supplies enzymes needed to digest chyme and bicarbonate to neutralize stomach acid. Liver (This what produces contains hepatocytes is · bile in liver that have increased rough and Smooth ER , gol i apparatus and peroxisome Produces ~900 mL gbile Her day · BileSalts : Emulsties fat (ex : Washing your hands and soap Dirt from hands emulsifying Bilirubin : Digment formed from waste , bactria break it down and turn it poop brown Cholesterol phospholipids , selectrolytes : Triglycerides , gallbladder : Releases bile via cystic duct which flows into bile duct. * Pancreas has both exocrine and endocrine Exocrine gets secreted caurty/ · through a duct Endocrine = seceted into bloodstream gets · Exocrine purposes : produces pancreatic juice Endocrine purpose : Secretion of insulin and glucagon by pancreatic islet cells Pancreatic Juice composition : - Water (pH8) HCO3 - Digestive enzymes - Proteases · : (For proteins) = prevents self-digestion inactive form= trypsinogen ; active form (typsin) · Amylase = for carbohydrates · Lipase = for lipids · Nuclease = for nucleic acids  Pepsin = protease in stomach trypsin = professe in small intestine needed in its inactive form trypsinogen is · to prevent self-digestion small intestine · Major organ of digestion and absorption · Duodenum, jejunum , and ileum Superior meseneric artery brings blood supply · · Veins blood drain (carrying Oxygen rich into superior mesenteric veins # Parasympathetic innervation via vagus nerve # SypatheticInnervation from thoracic/splanchnic nerves. chyme from stomach contains partially · digested carbs and proteins · takes small intestine 3-6 hours to digest Digestion - catabolic process breaks down macromolecules into monomers · Intrinsic/accessory gland Enzymes are involved in digestion  Carbohydrate Digestion # down monosaccharides Breaking things into starts in mouth through salivary amylase > Then - goes to pancreatic amylase Protein Digestion acid monomers #Breaking it into amino Starts - W/ Pepsin > - Trypsin in small intestine Lipid Digestion 1) Emulsify : Bile salts emulsifies large fats into small cres 2) Pancreatic lipases break down fat Digestion : 3) They go through small intestine wall For carbs & Proteins wall go through the #To molecules must , go through epithelial tissue (goes through cell membrane - must pass carbs and amino acids throng apical part of cell otheris -thentheygothrough the  For absorption for lipids be absorbed * They can passively through the membrane , other polar molecules are absorbed by active transport # since they are so big , they go straight to lymphatic system. carbs Proteins Lipids T assive de Active transport #LargeIntestine absorbs more water then defacates.  uninoy system * Mineral corticoids Renin-Angiotensin-Aldosterone Mechanism - Decreased blood pressure stimulates special to renin cells in kidneys release * Renin cleaves off of plasma protein , - angiotensiogen cascade Triggering on enzyme Angiotensinogen > - angiotensin #I ↓ Stimulates aldosterone release Renal Afferent Gomerous artery arteriole > > - - Capillaries efferent X renal ↳ Vein criericle * Renal arteries deliver 14 of cardiac output to Kidneys * two main parts : Lenal corpuscle & renal tubule  · podocyte = cells that vital play a role in the glomerular filtration Renal Corpuscle Glomerus Capillaries composed of : endothelium , and allows for filtrate formation #filtrate = plasma-derived fluid that renal process to form urine. Glomerular Capsule (Bowman's Capsule) : Outside around glomerus cupping * 2 layers : Parietal (outer) is simple squamous epithelium and visceral (inner) which clings to glomerular capillies  a n ↳distre pro Renal Sur Tubute D => nephron A collectia n 3 Parts : Proximal convalated tubule , Nephron loop, and distal convolated tubule * proxima convolated tubule · Has a lot of microvilli to increase surface area and is confined to rend cortex , as it functions in secretion/reabsorption - Nephron Loop (thin) · consists (thick) of descending and ascending * Distal convolated tubule Confined · in remal cortex and functions More in Secretion  * collecting Ducts Fuse to deliver unine · together Recieve fitrate from many nephrons · Types of Nephrons : I. Cortical nephron - Makes up 83 % of rephions and almost entirely in Cortex Juxtamedullary nephron-long loops deeply. 2 invade medulla IMPORTANT production and in of concentrated urine. E Unne Formation · Slurp. - Glomerular filtration Produces cell free/ protein free filtrate * Passive process #hydrostatic forces fluids and solutes pressure membrane through filtration into glomerular Capsule.  Glomerular filtration * Has pourous membrane # Allows water and solutes smaller than plasma proteins to pass #Plasma proteins remain in blood Main layers 1) Fenestrated endothelium of glomcular capillaries 2) Visceral layer of glomerular Capsule Glomerular filtration Rate GFR = volume of filtrate formed per minute by both (120-125 ML/min Kidneys * Proportional to : - Net filtrationPressure Total surface available for filtration - area filtration membrane permeability - GFR pressure · Hydrostatic presse in glomerular Capillaries blood is essentially glomerular pressure · Force pushes H20/solutes out of blood Inward pressures : forces inhibiting filtrate formation 1. Hydrostatic pressure in capsular Space : Filtrate Pressure in Capsule (15 mm Htg) 2. Colloid osmotic pressure in capillaries "pull of proteins in blood (30 mm Hgl Net filtration pressure : Sum of forces - 55 mgHg forcing out minus 45 mmity Opposing - wet outward force of mig * main controllable factor determing glomerular filtration rate (GFR) · GFR allows Kicheys to make filtrate and maintain extracellular homeostasis. # Extrinsic Controls : Maintain body Blood Pressure ↑ GFR causes Turine output - lowers Extrinsic controls BP vasodilation & increased GFR causes increase urine output which lowers B. P / lovers Bloodvorme conserved Decreased GFF causes decrease urine out put which Increases BP/Blood volve Vasco constrictionA conserved - # Renal Autoregulation feedback mechanism Myogenic mechanism & Tubular controls #unsic Increased BP = Afferent arteriole constriction to from Glomerulus protect damaging high Blood pressure Decreased BP = Afferent artericle dialates * Extrinsic controls override intrinsic controls if volume needs to be increased Extrinsic controls SNS : under normal conditions - Renal blood vessels didated under Low systemic B P. · SNS releases norepinephrine &adven modula releases epinephrine -what it does Vasco constriction = NGFR = ↓ Urine output = More Blood volume = High BP Tubular 99 % reabsorption from Selectively : to returns of substances filtrate blood and in renal tubules collecting ducts Tubular section : selectively moves substances from blood to filtrate in rena tubuses and ducts collecting