Students can go through AP Inter 2nd Year Zoology Notes Lesson 4(a) Endocrine System and Chemical Coordination will help students in revising the entire concepts quickly.
AP Inter 2nd Year Zoology Notes Lesson 4(a) Endocrine System and Chemical Coordination
→ The term hormone was coined by Starling.
→ Secretin was the first hormone to be detected.
→ Hormones are non-nutrient organic chemicals, which act as intracellular messengers and are produced in trace amounts.
→ Hormones are produced by specific tissues/glands called endocrine glands.
→ The hypothalamus is the master control centre of the endocrine system.
→ Pituitary gland is also called hypophysis.
→ Anterior pituitary gland secretes six hormones namely growth hormone, prolactin, thyroid stimulating hormone, corticotropin, follicular stimulating hormone and luteinizing hormone.
→ Posterior pituitary secretes two hormones oxytocin and vasopressin. (ADH).
→ Thyroid gland is largest endocrine gland, secretes T3 and T4.
→ Pineal gland secretes melatonin, it regulates the 24 hours rhythms.
→ Vitamin D is an inactive form of a hormone, called calcitriol.
→ Thymus gland secretes thymosins, which play major role in development of cell mediated and humoral immunity.
→ Adrenal cortex secretes cortico steroid hormones E.g : Gluco corticoids, mineralo corticoids, androgens and estrogens.
→ Adrenal medulla secretes two hormones called epinephrene and norepihe phrene, these hormones also called as fight (or) flight hormones (or) emergency hormones.
→ α cells and β cells of islets ofLangerhans secretes glucagon and insulin etc.
→ Testes are male gonads. Leydig cells of testes secretes testosterone plays an important role in secondary sexual character development of males and spermatogenesis.
→ Ovaries are the female gonads. They secrete estrogen and progesterone, which plays an important role in secondary sexual characters of female.
→ Erythropoietin secreted from kidney and it contros the RBC formation.
→ Gastrin acts on gastric glands and stimulate the production of HCl and pepsinogen.
→ Secretin is produced by duodenal mucosa act on exocrine part of pancreas to stimulate the secretion of water and bicarbonate ions.
→ Cholecystokinin is produced by duodenum act on pancreas and galls bladder and stimulate the secretion of pancreatic enzymes and release of bite respectively.
→ Hormones act as primary messengers.
→ Cyclic AMP, IP3, Ca2+ acts as secondary messangers.
→ Hypersecretion of somatotropin, before puberty, leads to gigantism.
→ Hyposecretion of somatotropin (GH) resulting in a pituitary dwarf.
→ Hypersecretion of somatotropin in adults results in an abnormality called acromegaly.
→ Prolonged hyposecretion insulin leads to diabetes mellitus.
→ Deficiency of vasopressin causes diabetes insipidus.
→ Hyposecretion of gluco corticoids leads to addison’s disease.
→ Hyposecretion of parathyroid hormone leads to tetany.
→ Over production of gluco corticoids causes Cushing’s syndrome.
→ In adult women hypothyroidism may cause irregular menstrual cycles.
→ In adults the hypothysoidism results in a condition called myxoedema.
→ The endocrime system is a chemical coordination system in the body comprising of endocrine glands, their hormones and the’ir modes of action.
→ Endorcine glands secrete hormones.
→ Hormones are chemical messengers. They are released directly into blood.
→ Hormones bring both physiological and structural changes in the body.
→ Pituitary gland controls the activities of other glands. Hence it is called master gland.
→ Acromegaly is a hormonal disorder that results when the pituitary gland produces hypersecretion of growth hormone (GH).
→ Diabetes inspidus is due to hypo secretion of vasopressin. [IPE]
→ Diabetes mellitus is due to under secretion of insulin. [IPE]
→ Insulin shock is a condition that occurs due to hyper secretion of insulin [IPE]
→ Epinephrine and norepinephrine are known as fight and flight hormones. [IPE]
→ Hypothyroidism is a condition in which production of thyroid hormones T3 & T4 decreases.
→ Hyperthyroidism is a condition in which production of thyroid hormones T3 & T4increases abnormally. [IPE]
→ Thyroid stimulating hormone (TSH) stimulates the synthesis and secretion of thyroid hormones from thyroid gland. [IPE]
→ Addison’s disease is due to hyposecretion of glucocorticoids by adrenal cortex. [IPE]
→ Cushing’s syndrome is due to hypersecretion of glucocorticoids. [IPE]
→ A temporary endocrine gland in the human body is corpus luteum. [NEET-2017]
→ Graves disease is caused due to hypersecretion of thyroid gland [NEET-2016]
→ A chemical signal that has both endocrine and neural roles is epinephrine. [NEET-2015]
→ Fight-or-flight reactions cause activation of the adrenal medulla. [NEET-2014]
→ The posterior pituitary gland is not a ‘true’ endocrine gland because it only stores and releases hormones. [NEET-2016]
→ Hypersecretion of growth hormone in adults does not cause further increase in height, because epiphyseal plates close after adolescence. [NEET-2017]
→ The Steroid hormone influence the cellular activities by ‘binding to DNA and forming a gene hormone complex’. [NEET-2019]
→ Hypo secretion of Insulin causes Diabetes mellitus. [NEET-2019]
→ Presence of Ketonuria and Glycosuria in urea are indicatives of diabetes mellitus.[NEET-2020]
→ Glucocorticoids stimulate gluconeogenesis. [NEET-2020]