Endocrinology PDF - The Endocrine System: Past Paper

 The Endocrine System Individual Cells : ↓ combo of effects of biochemica reactions => cells behaviour + appearance can be changed by altering pathways : ·...

 The Endocrine System Individual Cells : ↓ combo of effects of biochemica reactions => cells behaviour + appearance can be changed by altering pathways : · ↳ mainly be of enzyme activity ↳ to modify + adapt to changes in its external environment. Multicellular organisms : (Control via hormones]. ↓ cells need to influence biochemistry of other cells. ↓ Y over Short/long distances short/long periods of over time ↳ to maintain the extra cellular flud [ECF)/environment :. 1 each cell makes direct/indirect contribution to the ECF maintance [homeostasis). 2. + selfish activies - keeping itself alive. ↳+ , development + reproduction manage growth LEVELS OF CONTROL : AUTOGRINE : "Secreted Compound effects same cell - Eg. Cytokinesis + Secreted Compounds effect PARACRINE neighbouring cells ↳ relies on diffusion · Limited distance Can be a rapid · response. ENDOCRINE - hormones made in endocrine cells ↳ release in bloodstream (X limited by diffusion) ↳ all sells to hormone exposed ↳ only those w/ suitable receptors respond. NEUROMORMONES - hormones made in neurones ↳ release into bloodstream ↳ all cells exposed ↳ w/suitable receptors respond only those. NEUROTRANSM. from nerve terminal Synaptic Cleft (response to A P - -. to diffusion across -> receptor binding on target cell (couldbe ant a S ↳ highly targetted' contro specific costly in terms of 'wiring · · v. rapid response possible over large distances - PHEROMONES > - organism + organism communication ↳ demonstrate extreme sensitivity + Smile range CLASSIFICATION OF HORMONES : DIFFERENT SCHEMES : CHEMICAL STRUCTURE :. Chemical structure 1. peptide 1 hormones. 2 Receptor binding 2. steroid hormones 3. source of secretion 3. am -ac derived hormones ,  ↑ EPTIDE HORMUNES : ~ most abundant type small peptides Oxytocin ABH - · , large molecules horm.; insulin protein · - Similar Synthesis packaging into ~ + vesicles to other proteins. Transport + Half-Life : 1. 120 solvable. 2 Short (several Min) half-life.. 3 Sustainable response = needs Continous secretion MECHANISM OF ACTION : CSR = integral membrane proteins Changes triggered by peptide hormones :. 1 opening/closing membrane channels. 2 metabolic modulating enzymes 3. Altering gene expression ATP-CAMB CAMP inactived second messenger  S EROID HORMUNES : all derived from Cholester · Only Adrenal Cortex and honads can convert cholester active hormones · -> # ~ # L - Testosterone Cortisol Androgens ~ Estrogen - Aldosterone Progesterone · amounts of SER steroid Secreting cells + large lipophilic easily across · + diffuse membranes. Transport + Half-Life :. 1 X solvable in plasma or bodily fluids 2. Most bound to carrier proteins * 3. some have specific binding proteins Ce y Corticosteroid-binding - globulin).. 4 carrier protein binding protects hormone from enzymatic degradation => extended half-life. 5 carrier proteins block entry + target cells. 6 unbound hormone pass target cells membrane only MECHANISM OF ACTION : receptors within cells · · Ultimate destination of steroid receptor - hormone complexes = nucleus · complex acts as a TF · could have activating/repressing genomic effects.  AMINO-ACID DERIVED HORMONES : to all either from : tryptophan or tyrosine ~ all others 2 N · e.. g Catecholamines + thyroid hormones melatonin serotonin [pineal gland) /got mucosal ~ Y MECHANISM OF ACTION : · the 1 tyrosine derived diff action groups of =. m. 1. catecholamines · bind to cell membranes 2. thyroid hormones · bind to intracellular receptors (like steroid harmone)  MYPOTHALAMUS : hypothalamic-pitritary-axis · Lo allows brain to control endocrine system · Controls Chemical + temperature homeostasis · influenced by limbic system. PITVITARY GLAND : HYPOPHUSIS : · releases 9 peptide hormones ↳ all bind to Membrane receptors & use CAMP as Ind Messenger · I distinct parts :. 1 Neurohypophysis (posterior pituitary) ~ outgrowth of hypothalamus. 2 Adenohypophysis (anterior pituitary) · derived from got tissue MYPOTHALAMIC CONTROL : 3. Contre ofsympathetia b. 1 Secretion of regulatory hormones to control anterior lobe 2.production a o  ADENOHYPOPHUSIS :. 1 Hypothalamic hormones release regulatory factors into capillaries hormones Releasing hormones · Inhibiting · · V. Small amounts released as target cells Close. Once diluted in ~ v. low Conc · systemic blood. HYPOTHALAMUS · Stimulates development of mammary glands + production of milk releasing hormones ! ~ inhibiting hormones Hypothalamic - Pituitary Portal veins Hypothalamic pitivitary gland Control anterior :. 1 PRH 2. PIF [dopamine) ↑ Productin 2 [PRL] Leiutenizing hormone ((H) ~ L V V thyrotropin growth hormone follicle-stimulating hormone [FSH) ITSH) W (aH) adrenocorticotrophin [ACTH L v V ~ triggers release of · Stimulates follicle development thyroid horm (T3 + TH) ~. , · carses ovviation + Hypothalamic control stimulates cell growth + estrogen production & - progesterone production : · ↳ TRM => TSH release replication through release V of Somatomedins/lGF Sperm production. + androgen (males). Hypothalamic Control : ~ stimulates release of. 1 GH-RH glucocorticoids (Ad gland. 2. GH-1H) (Somatostanin) Hypothalamic Control : Hypothalamic Control : ~. 1 Gonadotropin RH [GnRH) S LCRH => ACTH release Promotes Secretion of FSH + IH OTHER MORMONES : Melanocyte Stimulating hormone (MSH) Endorphins : Stimulates production of melanin in melanocytes endogenous peptide Opioid' Neurotransmitter · · ↳ - runner's Analgesic high ~ Stimulates pineal to secrete melatonin (bio Clock/mood] ~ > characterised Hypothalamic Control :. 1 Melanotrophin RH (MRAD)  NEUROMYPOPHYSIS : MORMONES : Hormonemara Body Supraoptic make antidiretic hormone (ADH vasopressin · neurons in nucleus , ↳ ↓ H20 loss by Kidneys ↳ Vesicle transported down cell. ↑ blood pressure resicle w/hormone stored oxytocin · in posterior pituitary. neurons in paraventricular nucleus make ↓ stimulates Smooth muscles in uterus [child birth) mammary glands (let hormones released into the blood. ↳ stimulates contractive cells in down of mish] FEEDBACK MECHANISMS : NEGATIVE : POSITIVE : · response counteracts stimulus shutting response reinforces sending · => stimulus parameter response loop further from set point. Response loopShrT 7 Initial Stimulus Initial Stimulus ~ ~ Response Response S outside factor 9 required to shot Off loop. + feedback cycle 2 2 ↓ stimulus ↑ Stimulus ↳ vast majority of cycles in body work except in Childbirth ~ on negative feedback LE g. : Hypo-GRH-Ant pit-ACTH - Adr. Cr+ X- Cortisol ~ Cortisol inhibits Ant pit & Hypo  THYROIDS : normal mass = 30g hormones & Calcitonin · secretes thyroid Lo synthesis : Thyroid follicles follicular enzymes/glycoproteins > cells - make [thyroglobulin) for hormone synthesis Nat/1- Symporter (NIS] free T3 + Th. enter circulation - e cell. Pendrin transports 1- Colloid FollicueSynthes a for Colloid Intracellular enzymes separate +z &Th from protein thyroglobin taken back into cell by vesides functions thyroid preoxidase addS ↑ e tyrosine => TzTy  THYROXINE + IT'S PRECURSORS : STRUCTURE + SYNTHESIS · derivatives of thyrosine Covalently bond to 1· · poor solubility in H20 ~ 99% of T3 + Ty in blood bound to carrier proteins - thyroid binding globulin ACTION OF THYROID HORMONES ON CELLS :. 1 free Tu/Tz can diffuse into cells o Ty/Tz binds to intracellular receptor ·. 2 effect of gene expression exerts. 3 overall effect is to set BMB + temperature ~ + growth development , 4. Influence long-lasting ~ follicles act as a store hormone acts as a store bound Circulating · · changes in protein synthesis = effects presist