... in bile.Action of Thyroid HormonesThe target cells include hepatocytes,renal cells,cardiac cells,neurons,lymphocytes and pituitary somatotrophs.The biological effects of thyroid hormones are -calorigenic effect thyroid hormones considerably enhance O2 consuption and oxygen coefficient in many tissues except brain ,testes and spleen and increase the heat production and BMR of the organism .-groth and differentiation effects thyroide hormones act synergistically ith groth hormone to promote N retention,protein synthesis positive N balance,body groth and tissue diferention,by and enhancing the transcription of genes for tissue proteins.-effects on carbohidrate metabolismthyroid hormones raise the blood sugar,reduce glucose tolerance and increase glucose utilisation.-effects on lipid metabolismthyroid hormones potentiate the lipolytic action of adrenaline by up-regulating the beta-adrenergic receptors on the adipocyte membrane.-effects on protein metabolismthyroid hormones produce protein anabolic effects in moderate doses,but inhibit protein synthesis and increase blood amino acid level and urinary NPN in large doses.Hypothyroidism causes Cretinism in children and Myxoedema in adults.Groth in children is retarded and the child is mentally defective.He has coarse scanty hair and thick yelloish scaly skin.Cretinism occurs in areas here goitre is prevalent.In Myxoedema occurs the puffiness of the face and hands in adults,the retention of ater and NACl in the body,body temperature and pulse rate are subnormal,body eight is increased due to deposition of fat and retention of ater,mental faculties are retarded and blood cholesterol and lipid levers are increased. Hashimotos deseaseThyroglobulin escapes from the cells of the gland and excites the production of antibodies hich produce reactions ith thyroid.Fibroses of the thyroid tissue develop leading to complete loss of thyroid function.Severe hyperthyroidism leads to toxic goiter in hich the patient complains of nervousness,restlessness,tiredness,undue seating,breathless on exertion,tachycardia and palpitations,the subject cannot tolerate arm climate but can tolerate severe cold climate.Hyperthyroidism is characterised bynervousness,eight loss,hyperphagia,heat intolerance,increased pulse pressure,a fine tremor of the outstretched fingers.Hypothalamic hormonesHypothalamus secrets several peptide hormones hich regulate secretion of the anterior pituitary hormones. These hypophysiotropic hormones include-thyrotropine releasing hormone-corticotropin releasing hormone-gonadotropin-groth-somatostatin-prolactin release-vasoactive intestinal peptide.They are synthesised by hypotalamic peptidergic neurones.Groth hormone releasing is a peptide made of 44 aminoacids. Vasoactive intestinal peptide stimulates the lactotroph and corticotrophin cell of anterior pituitary to secrete respectively prolactin and corticotrophin.Thyrotropin releasing hormone is a natural tripeptide. It stimulates the transcription of the thyrotrophyne gene in pituitary thyrotropin cells to increase the synthesis of thyrotropin.Gonadotropin releasing hormone is a decapeptide stimulates the pituitary gonadotroph cell to increase syinthesis as ell as secretion of both the pituitary gonadotropins,FSH and LH. Somatostatin secreted from gastrointestinal mocouse and pancreas also ,inhibits the release of groth hormonefrom pituitary somatotrop cell by loering the intracellular Ca2concentration .Dopamine ,relesed from some of the hypothalamic neurones, acts as a prolactin release-inhibiting hormone.The posterior pituitary hormones are vasopresin or Arginin Vasopresin and Oxytocyn.Vasopressin is an antidiuretic hormone.It resorbs ater from the kidneys by distal tubules and collecting ducts.Contraction of smooth muscles is the primary function of oxytocyn.There are basically to effectsone on mammary glands called as galactobolic effect and other on u ... Download