Physiology Exam 9 Study Guide Thyroid gland continued Thyroid hormones TH T3 T4 nonpolar bind to nuclear receptors impact DNA Metabolic effects regulate energy Stimulate metabolism Increases equation 2 produces ATP and heat Ex can stay comfy walking to class in frigid weather maintains body temp Generates heat Enhance use of metabolic fuels glucose protein fats Use whatever necessary to ensure engine is running properly body Enhance results of sympathetic nervous system Stimulates ATP energy production needed for fight or flight response Less likely to escape in situation if thyroid gland issues Neural development Necessary for neurons to have environment in which they can survive Promote effects of growth hormone to make a bigger you need more energy Thyroid Disorders Thyroid gland problem most common endocrine disease Hypothyroidism too little T3 T4 production Commonly known as iodine deficiency worldwide Not in US b c it s added to table salt In US it is primarily due to an autoimmune disease but on the rise due to au natural No T3 T4 to do negative feedback from thyroid hormones E3 has 3 jobs T0 2 cannot bind to receptors in nucleus wrong shape charge not specific When body has need for metabolic stimulation releases TRH TSH released bind to receptors on follicular cells to cause production of T3 T4 NOT there to do job Body continues to send signal b c seeing no response of metabolic stimulation Leads to excess TSH secreted low levels of T3 T4 Overstimulated follicular cells trying to become bigger gland to increase production capacity of T3 T4 TSH keeps telling them to do so Goiter enlarged gland in mammals too Symptoms Cold intolerance don t generate heat Increase weight not running metabolism Fatigue more easily no ATP generation Hyperthyroidism Too much T3 T4 production Commonly known as Grave s disease autoimmune disease soldiers we create cause problems Antibodies created activate TSH receptor on follicular cells of thyroid gland Competitors for T3 T4 same response agonists same shape and charge T3 T4 doing negative feedback decreases TSH TRH levels DOES NOT decrease TH production Ineffective on controlling production of antibody increased TH production T3 T4 don t affect immune system can t stop antibodies Enlarged gland goiter Symptoms Heat intolerant already producing lot of heat Losing weight revving that furnace Increases sympathetic activity tons of energy quick flight fight response Adrenal Gland named as a result of anatomy not physiology Sits above kidney renal but NOT associated with kidney function Production CRH E1 APG releases ACTH E2 adrenal gland releases corticosteroids Cortisol E3 Actions Mediates stress historically about food Cortisol turns on system assumes you are starving Focuses on short term energy levels NOW enough to survive How does cortisol help maintain energy Metabolic endocrine mainly impacts liver helps you get energy Increases glucose utilization more easily used to increase energy Breaks down fat if not enough glucose can lose weight when stressed Breakdown protein in muscles can lose muscle mass If stress continues can lose bone Increases vascular smooth muscle responsive to Epi Norepi sympathetic Able to move nutrients around BP increases when stressed Cortisol must shut down some systems to conserve energy for survival Negative feedback to lower need for energy Anti inflammatory higher cortisol levels inhibit immune response Inflammation from injury athlete gets cortisol shot to suppress it Inflammation immune response trying to fix area Ex During after finals sick b c high cortisol levels suppress immune system Must survive until tomorrow then you can treat sickness Lower immune system temporarily to save energy now Growth suppressed high cortisol levels stunt growth If I can t feed myself now don t need to feed a larger me Reproduction suppressed high cortisol levels inhibit sexual drive Take a girl to a chick flick Disorders No cortisol dead within days Needed to maintain specific levels to survive Adrenal insufficiency too little cortisol Symptoms Weak not enough energy decreased glucose levels decreased BP AKA Addison s syndrome Cushing s syndrome Too much cortisol not from stress Symptoms decrease bone strength increased glucose high BP decreased immune response obesity storing energy near vital areas belly fat not used in metabolism Can be diagnosed early wrong as diabetes Somatic Growth current growth here and now not future reproduction Somatic growth requires protein synthesis for all processes to work cell division Height due to growth of bones specific location Adding new cells at epiphyseal plates growth plates where growth occurs Steroids sex endocrines fuse plates during puberty stop getting taller and fill out Careful when kids break bones want in middle away from growth plates Adults don t have these issues plates sealed Growth of other tissues based on cell proliferation via mitosis same DNA identical cells Regulated by endocrines Growth Hormone GH released by GHRH inhibited by Somatostatin Unique E2 is main talking point as opposed to E3s for thyroid adrenal See highest level during development growing the most Actions Primarily to stimulate IGF 1 E3 released from liver and bones Causes cell proliferation sends message to liver to release IGF into blood and to bone to stimulate plates directly Other option GH impacts cell directly by stimulating muscle development To make a bigger you need bigger muscles b c bigger loads Different message sent not making muscle cells but adding to inside of muscle cells Mobilizes nutrients to have energy for process growth spurts Periods of getting taller then fill out repeat TH needed for GH synthesis and effect Need right levels of T3 T4 to stimulate proper amount GH amount of metabolism to provide energy for growth to occur Cortisol Can inhibit growth by inhibiting GH secretion in APG similar to SS If can t sustain self now don t want to grow bigger Opposes the effects of GH in tissues Athletes don t realize that as cortisol levels increase stress from poor stats decreases impacts of GH Insulin Promotes growth Helps pack away nutrients you ingest to energize growth Sex Steroids stimulate secretion of GH and IGF 1 Historically bigger male reproductive advantage in finding a mate heavier female more success in carrying a baby Closure of epiphyseal plates grow wide not tall Testosterone anabolic redundant all sex endocrines build tissue Unique GH has many roles impacts muscle
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