PHGY 216 Midterm Exam | Q & A (Complete Solutions)

PHGY 216 Midterm Exam | Q & A (Complete Solutions) What is homeostasis Regulation of the internal environment around a physiological set point Required by cells and maintained through their specialized functions How is endocrine system different from other phgy systems Has glands dispersed throughout the body What are the glands of the endocrine system like Dispersed throughout the body not connected structurally form a coordinate system all secrete hormones What are the main 4 endocrine glands Pituitary parathyroid thyroid adrenal gland also hypothalamus How does the endocrine system work Uses hormones to make homeostatic changes What are 6 functions of the endocrine system Maintain constant internal environment via regulation of metabolism and H2O/electrolyte balance adaptive stress response growth and development reproduction RBC production integrate w the ANS in regulating circ and digestive functions What are hormones Chem substances secreted into the blood at low quantity exert phgy force at a distant target What are the two main categories of hormones Hydrophilic lipophilic What are hydrophilic hormones like Highly water sol low lipid sl unbound to carrier molec in the plasma What are types of hydrophilic hormones Peptides pro amines What are peptides like Hydrophilic hors short chains of aas dissolved in plasma How are peptides syn Pre hor are syn in ER ribos pre hor travel thru ER and golgi and processed into act hor and packed into secretory vesicles these packed hor can be stored until cell recieves appropriate signal when the signal comes exocytosis of the vesicle and the hor is released into the blood What are pros Longer chains of aas What are amines Single AA residues What are the types of amines Catecholamines thyroid What are catecholamines Norepinephrine and epinephrine CAN BE FREE OR BOUND TO CARRIER MOLECULES What hydrophilic hormone is different than most Catecholamines cause can be free or bound to carrier molecules What amine hors are not hydrophilic Thyroid What are lipophilic hor Lipid loving hi sol in lipid low sol in water req carrier molecule for transport thru out body What are the types of lipophilic hor Amine thyroid steroid How are steroid hor syn Ex. Cholesterol prod by tissue (depends on the specific enzymes in the cell of the tissue) because so lipophilic not stored but released when syn How do u regulate lipophilic hors Regulate the synthesis How do hydrophilic and lipophilic hor differ Hydrophilic = stored until signal activates their release lipophilic = not stored hydrophilic = not bound to carrier molec in plasma lipophilic = bound to carrier molec in plasma What hor are dissolved in plasma Peptide What hor are bound to carrier molec Lipophilic steroid and thyroid What hor can be bound or free in plasma Catecholamins What do hor need to be to interact w their target cells FREE What does it mean for a hor to be freee Unbound hormone so can interact w a rs at its target not an issue for hydrophilic hormones and catecholamines issue for lipophilic hormones How is the fact the lipophilic hormones need a carrier molecules a problem Need to be unbound to interact w target so lipophilic hor are in bound to their carriers in a a dynamic equilibrium What does it mean that there is a dynamic equil of the lipophilic hor binding to its carrier At any time not 100p of the lipophilic hor in blood is bound to its carrier they are dynamically binding and unbinding so theres a small part always unbound unbound hor = active and able to act on target cells Predict where the Rs of peptide and catecholamine Rs are located in the cell On the outer surface of the plasma membrane because these hor are hydrophilic - so unable to freely cross the lipid bilayer of the cell Predict where the Rs of steroid and thyroid Rs are located in the cell Inside the plasma mem because these hor are lipophilic - can easily slip thru plasma mem and bind to rs inside the cell What happens after a HYDROPHILIC (peptide and catecholamiens) hormones binds to its rs Bind to surface of cell prod effects within cells by activating secondary messengers systems these pathways are able to amplify the initial signal What are examples of HYDROPHILIC hor binding to their rs Camp Ca2+ What happens when camp binds to its rs Activates G PRO g pro shuttles and activates several ADENYL CYCLASE molecs activated pro converts many molec of ATP to CAMP activates PRO KINASE A the activated pro kinase A enzymes then phosphorylate and activate TARGET pro get result What happens when Ca2+ binds to its Rs Binds via extracellular messenger activates G PRO g pro shuttles to activate several PHOSPHOLIPASE C enzymes P C enzymes convert PIP2 to IP3 and DAG IP3 mobilizes extracellular CA which activates calmodulin the ca calmodulin complex then activates Ca calmodulin dep PROTEIN KINASE (cam kinase) which ps and activates TARGET What happens after a LIPOOPHILIC (steroid and thyroid) hormones binds to its rs Can pass through both the plasma membrane and the nuclear membrane of the cell produced effects by regulating gene transcription and pro syn How do lipophilic hor control pro syn Free lipo hor diffuse across the plasma mem and or nuclear mem to interact w the intracellular rs the hor rs complex (H-R) binds to the hor response element (HRE) in the dna dna binding activates specific genes and produces mrna m rna leaves the nucleas the mrnas binds to a ribo and pros are syn the newly syn pro lead to the response How do hors differ from nts NT = NS hor = endocrine sys NT = transported across syn cleft hor = transported by blood nt = prod by neruons hpr = prod by endocrine glands nt = travel short distance hor = can travel long ass distance What sys does the endocrine sys work closely w NS What are the main ways the NS and endocrine sys differ Response time duration of effects number of targets How does the NS and ES differ in response time NS = rapid response, mili sec ES = slow response, min-hr How does the NS and ES differ in duration of effects NS = brief duration, ends when stim stops ES = long durations, effects persist after stim stops How does the NS and ES differ in num of targets NS = hard wired 2 1 specific target, muscle or gland ES = many different targets in the body, blood circulates What is the pituitary gland V small located in bony cavity at the base of the skull release hor that ref the fx of other endo glands or org divided into 2 lobes What are the lobes of the pit Completely sep - do not communicate w each other posterior anterior What is the posterior pit lobe like Made of neural like tissues neruohypophysis What is the anterior pit lobe like Made of glandular epi tissues adenohypophysis What does the hypothalamus do to the pit Controls the pit hor release How does the hypothal control the post pit lobe Hypothal is connected to the post pit lobe by NEURAL PATHWAYS these neural pathways are 2 different clusters of neurons ( supraoptic nucelus and paraventricular nueclus) and project down the pit stalk to term on bvs on the post pit How does the hypothal control the ant pit lobe The hypothal is connected to thee ant pit by a VASCULAR LINK the HYPOTHALAMIC-HYPOHYSEAL PORTAL SYS What is the HYPOTHALAMIC HYPOHYSEAL SYSTEM The vascular link bw the hypothalamus and the ANT pit How does the hypothalamic hypophyseal portal system work 1. Hypophysiotropic hormones prod by neurosecretory neurons in the hypothalamus enter the hypothalamic capillaries 2. Hypothalamic cap rejoin to form the hypothalamic-hypophyseal portal system 3. The portal sys branches into the cap of the ant pit 4. The hypophysiotropic hormones leave the blood across the ant pit cap and control the release of the ant pit hormones 5. When stim by the proper hypothalamic releaseing homrone the ant pit sec the given hormone into these cap 6. The ant pit cap rejoin to form a vein thru which the ant pit hormones leave for ultimate distribution throughout the body by the system circulation How are hor of the post pit syn and released Syn in HYOPOTHAL neuron cell bodies when syn packed into vesicles and transported down the axons of nerve endings in the post p when proper stim reaches hypothal these neurons release an ap that causes the releaser of the vesicles into the blood What are the hor of the post pit Vasopressin oxytocin Vasopressin Aka antidiuretic hormone (ADH) enhances the retention of water by kidneys causes contraction of arteriolar smooth mus most important! Oxytocin Stimulates contraction of uterine smooth mus cells during childbirth promotes milk ejection during breast feeding How are hor of the ant pit syn and released Ant pit syn and releases all 6 hormones ant pit has distinct cell pop that syn and sec each hor Hormones of the ant pit All are peptide most are tropic GH ACTH LH TSH FSH PRL Growth Hormone GH Reg body growth involved in metabolism Adrenocorticotropic hormone ACTH Adrenocorticotropin stim sec of cortisol by adrenal cortex Leutenizing hormone LH FEMALES ovulation and formation of corpus luteum stim sec of estrogen and progesterone from the ovaries MALES stim release of testosterone from the interstital cells of leydig Thyroid stimulating hormone TSH Thyrotropin stim release of the thyroid hormones from the thyroid gland Follicle stim hor FSH FEMALES growth and development of ovarian follicles promotes the secretion of estrogen by ovaries MALES sperm production Prolactin PRL NOT TROPIC FEMALES breast development milk productions MALES unknown What is the main function of OXYTOCIN Uterine contraction during child birth milk ejection What is the main function of GH Reg of body growth and metabolism What is the main function of FSH Growth and development of ovarian follicles sperm production What is the main function of VASSOPRESSIN Water retention by kidneys arteriolar smooth mus contraction What is the main function of ACTH Cortisol sec by the adrenal cortex What is the main function of PRL Breast development milk production What is the main function of TSH Release of hor from the thyroid gland What is the main function of LH Ovulation corpus luteum formation What is the only non tropic hor of the ant pit PROLACTIN What are the hormones of the ant pit Vasopressin oxytocin What are the hor of the ant pit GH LH ACTH TSH FSH PRL How are ant pit hor controlled Mainly hypothal hor neurosecretory neurons also prod some releasing and inhibiting hormones all released into the hypothalamic-hypohyseal portal sys where they travel to the ant pit to influ the release of its hormones What are the hypothalamic hormones THR gnrh GHIH CRH GHRH PRH PIH act on ant pit! Thyrotropin-releasing hor TRH Stim the release of TSH and prolactin Gonadotropin releasing hormone gnrh Stim the release of FSH and LH Growth hor inhibiting hor GHIH Inhibits the release of TSH and GH Corticotropin-Releasing Hormone CRH Stimulates the release of ACTH Growth Hor releasing Hor GHRH Stimualtes release of GH Prolactin releasing hormone PRH Stimulates release of PRL Prolactin inhibiting hormone PIH Inhibits the release of PRL How are the hypothalamus hor controlled Neurons that release the hor receive both nuronal and hormonal inputs which can be inhibitory or stimulatory because of this hypothalamic control of the pit output is complex What happens to sections of the hypothalamus that do not have a blood brain barrier Blood brain barrier = hi selective and semi perm mmb surrounding the brain and sc that seps the circ b from the CNS causes the hypothal to be able to monitor the b and respond to circ and make changes in plasma osmolarity if needed What is the hypothalamus connected to Area in brain that is involved on stress and emotion - botch can trigger hor release What is the general chain of command for cont of hypothal hor 3 hormone hierarchy chain hypothal hormone is released into the portal sys travels to cause output of a tropic hormone tropic hormone is then trasnported by the system circulation to its target endocrine gland here it regulates the sec of a third hormone producing an effect What is the thyroid gland Located over the trachea and below the larynx is 2 lobes connected by a thinner section of the gland known as the ISTHAMUS no difference between the lobes entire gland has same function FX = TO PRO AND SEC THYROID HORMONES What is the cellular structure of the thyroid gland Follicular cells c cells colloid Follicualr cells Arranged to form hollow spheres throughout the gland appear as ring like structures C cells Secrete calcitonin Colloid Made up of large pro molec called thyroglobulin where the thyroid hor are syn and stored What are the thyroid hormones like Prod from the AA Tyrosine contain Iodine called thyroid hor exert the same effects How do the thyroid hor differ Speed intensity of action What are the thyroid hormones Tetraiodothyronine / T4 / thyroxine Triiodothyrine / T3 T4 Less active 4 I molec about 90% of thyroid hor T3 More active 3 I molec about 10% sec thyroid hor How do we get I for Thyroid hor Diet once ingested I circs as Iodine 1 thyroid is good at taking up all that is ingested thyroid can store it for long time when not ingesting enough canadians rarely dont get enough cause found in table salt Thyroid hor and Iodine Thyroid hor is lipophilic and lipophilic hor are released upon syn EXCEPT THYROID can be protected from secretion while stored bound to thyroglobulin in the colloid of the thyroid gland Syn of thyroid hor 1. Tryosine w thyrogloblin is prod in the follicular cells by the ER golgi comp and is transported to colloid by exocytosis 2. I is taken up by follicular cells thru IODIDE TRAPPING (i is driven against its conc grad by using Na cotransporter that moves Na down its conc grad) 3. I is transferred into the colloid of the follicular lumen 4. I enters colloid then enzyme thyroperoxidase converts I into a highly reactive state (Io) which immed attaches to a tyrosine res on a thyroglobin molec (process is called I organification and produces either a monoidotyrosine MIT or w anothehr I can make a diiodotyrosine DIT) 5. Coupling process combines mits and dits to form the thyroid hormones (1 MIT and 1 DIT = t3 whereas 2 dits = T4) Release of thyroid hor 1. Follicular cells engulf a portion of the thyroglobulin containing colloid by phagocytosis and create hormone filled vesicles 2. Once inside the follicular cell lysosome fuse w the vesicle and digestive enzymes release the MIT DIT T3 and T4 from the thyroglobulin 3. Because T3 and T4 are v lipophilic they immed cross the plasma mem to the blood where they bind w the plasma pro thyroid binding globulin Actions of thyroid hormones Affect most tissues of the body can affect directly or indirectly are relatively slow have relatively long duration What are the actions of thyroid hormones Metabolic rate and heat production intermediary metabolism sympathominmetic cardio sys growth How do thyroid hor affect metabolic rate and heat prod Inc overall basal metabolic rate by inc O consumption and E expenditure inc metabolic rate = inc heat prod How do thyroid hor affect intermediary metabolism Influences enzymes involved in fuel metabolism effects differ dep on the amount of the hor present i.e low conc conversion of glucose to glycogen and pro syn is favored whereas at high conc breakdown of glycogen to glu and the degredation of pro is favoured How do thyroid hor affect sympathomimetic Thyroid hormone can inc a target cells response to catecholamines does this thru inc the num of catecholamine Rs How do thyroid hor affect the cardiovascular sys Due to its sympathomimetic effect on the heart can inc both heart rate and strength to inc CO inc BV and B flow How do thyroid hor affect growth Stim the release of GH and insulin like growth factor promotes their actions to stim the syn of pro and skeletal growth TSH secretion Hypothalamus releases TRH TRH acts on ANT pit ANT pit releases TSH TSH Most important regulator of thyroid hormone secretion influences most of the stages of thyroid hormone release and syn directly affects the thyroid gland - absence = shrinks and excess = follciles grow and inc in num TSH and TRH are regulated via Negative feedback What is hypothyroidism Aka low thyroid or underactive thyroid disorder of the ES occurs when the thyroid gland does not sec enough thyroid hor Causes of hypothyroidism Primary failure of the thyroid gland secondary failure of the thyroid gland inadequate dietary supply of I What happens during primary failure of the thyroid gland Ex. Hashimotos thyroiditis (an autoimmune disorder in which antibodies target the thyroid gland and impair its ability) see low levels of T3 and T3 and elevated levels of TSH What happens during secondary failure of the thyroid gland Occurs when HYPOTHALAMUS and or the pit fails to sec enough TRH and TSH see low levels of T3 or T4 or both and low levels of TSH and ortrh What happens during inadequate dietry supply of I Most common cause see low levels T3 and T4 and elevated TSH What are the symptoms of hypothyrodisim Cold intolerance slower reflexes reduced mental alterness easy to fatigue slow, weak, hear rate weight gain What happens when u have cogenital hypothyrodism Cretinism dwarfism and intellectual disability What is hyperthyroidism Increases levels of thyroid hormone What are the main causes of hyperthyroidism Secondary failure of the thyroid gland graves' disease What happens during secondary failure of the thyroid gland Tumor in hypothalamus = TRH control tumor in ant pit = TSH control both cause neg feedback to be ignored leading to elevated T3 and T4 and TRH and or TSH tumor in thyroid = inc sec cause elevated T3 T4 and DEC TSH What happens graves disease Most common cause autoimmune diease body produces long acting thyroid stimulator lats - an antibody that targets and activates TSH rs (same affect as excessive TSH - cause follciles to grow in size and num) levels of T3 and T4 are high levels of TSH are low What are the symptoms of hyperthyroidism Increase HR excessive heat prod mus weakness due to skeletal mus pro degredation mood swings due to skeletal mus pro degredation mood swings due to inc CNW mental alertness elevated metabolic rate = weight loss Goiter Can be caused by both hyper and hypothyrodism is an enlarged thyroid gland can come from any condit that leads to IN CREASED T SH When do we see a Goiter in hypothyrodisim Primary failure of thyroid lack of dietary I When do we NOT see a Goiter in hypothyrodisim Secondary failure of the thyroid gland When do we see a Goiter in hyperthyrodisim Secondary failure of the thyroid gland (hypothalamus or ant pit tumor) graves disease