Function of thyroid hormones:

Ans: A (Inhibits beta myosin heavy chain) Ref: Pal GK, The Thyroid Gland, In: Textbook of Medical Physiology, 2nd ed, Ahuja Publishing House 2011: 46: 352-55Explanation:Physiological Actions of Thyroid HormoneBasal metabolism| rate of oxygen consumption| Na+ K+ ATPase activityThermogenic actionOn nervous systemProliferation of axons, branching of dendritesDevelopment of synapseFormation of neurotransmitter| receptorsMyelinationOn growth and developmentPromoting gene expression for GHLinear growth of bone| osteoid action, bone remodelingTeeth eruption and developmentOn CVS| Heart rate - | number of b receptors on SA node; | sensitivity of b receptor for catecholamine| Myocardial contractilitydeg By inducing expression of myosin heavy chain (| a MHC activity; suppress b MHC activity)deg | Ca ATPase activityBlood pressuredeg | HR, stroke volume - | systolic BPdeg Thermogenic cutaneous vasodilation - |peripheral resistance - | diastolic BPOn metabolismCarbohydratedeg | glucose absorptiondeg | hepatic gluconeogenesisdeg | glycogenolysisFatdeg | lipolysis, stimulate cholesterol synthesis - also |oxidation and bile excretion - net reduction in plasma cholesterol, total lipidProteindeg Proteolysis and turnoverSvnergize net effect of catecholaminesOn respiratory system| oxygen utilizationStimulate erythropoiesisOn GITEnhance the motility| appetite, food intakeSkeletal muscle| expression of MHC genesOn reproductive systemFemale - follicular maturation, ovulationMale - spermatogenesisOn kidney| renal blood flow, GFR