Endocrine Glands & Hormones1.Endocrine glands lack ducts , so called ductless glands.2. Their secretions are called Hormones – are non nutrient chemicals that act as intercellular messengers & are produced in trace amounts.3.The hormones are released into blood & are transported to a distant ly located target organ
Human Endocrine system1.It consists of endocrine glands & hormones.2 .Endocrine glands of our body are- Pituitary Pineal Thyroid Parathyroid Thymus Pancreas Adrenal Gonads- Ovary & testis Gastrointestinal tract Liver Kidney Heart
Sl. gland location Hormones Action1 Hypothalamus Basal part A) 2Types of hormones produced •stimulate the of forebrain that ant.pituitary to produce Releasing Inhibiting – Stimulate Inhibit Secretion Secretion of of Pituitaty ant.. Pituitaty Hor. Dopamine Somatostatin Thyrotropin-releasing ------------------ Thyrotropin stimulating hormone (TRH) hormone (TSH) •Gonadotropin-releasing--------------- •Follicle stimulating hormone (GnRH) hormone (FSH) •LH in 0+ /ICSH0↗ •Growth hormone-releasing Growth hormone hormone (GHRH) •Corticotropin-releasing Corticotropin hormone (CRH) stimulating hormone •Prolactin H (PRL) Stimulate mammary glands to produce milk B) Few neurons go & terminate at at post, pituitary storing the hormones produced at its ends.
Sl. gland location Hormones Action2 PITUITARY attached to anteriorpituitary lower part of gland brain through thyrotropin a stalk stimulating hormone (tsh) •follicle stimulating hormone (fsh) •lh (leutinising h)in 0+ /icsh (interstitial cell stimulating H) in 0↗
Sl gland location Hormones Action.3 Pineal Dorsal side Melatonin Regulates 24 Hr rhythm of our of body & in addition metabolism forebrain ,pigmentation, menstrual cycle & defence capability4 Thyroid Either side •Tetraiodothyroni •Regulation of BMR ,RBC of trachea ne /Thyroxine(T4) formation, metabolism of •Triiodothyronine carbohydrates, protrins & fats, (T3) Maintenance of water & electrolyte balance •Thyrocalcitonin •Regulates blood Calcium levels (TCT)5 Parathyroid 4 on back Parathyroid Increases Ca2+ levels in blood & side of hormone (PTH) reabsorption of Ca2+ by renal thyroid tubules & in digested food , so known as “Hypercalcaemic Hormone”
Sl gland Location Hormones Action6 Thymus •Dorsal side of the •Thymosin •Play a role in differentiation of T-Lymphocytes heart & the aorta in cell mediated immunity & production of antibodies in Humoral immunity7 Adrenal On anterior part 2 hormones- of each kidney,has Catecholamines 2 types of tissues- (Adrenaline/epinep hrine & •Increase alertness,pupilary dilation, Adrenal Medulla noradrenaline /nor piloerection, sweating, heart beat,respiratory epinephrine) rate, stimulate breakdown of glycogen ,lipids & (Emergency H/ H Of proteins & flight or fight) Adrenal Cortex-3 •Corticoids •In carbohydrate metabolism-stimulate layers- Glucocorticoids(Cor gluconeogenesis,lipolysis& proteolysis& inhibit Zona reticularis tisol) utilisation of aminoacids ,in maintaining cardiovascular system & kidney Zona fasciculata functions , produce anti-inflamatory reactions Zona glomerulosa ,suppresses immune response,stimulate RBC p Production •Mineralocorticoids Regulate water & electrolyte balance -Aldosterone •AndrogenicSteroid Growth of axial ,pubic & facial hair s
Sl gland Location Hormones Action8 Pancreas •Below (2 in 1 stomach- gland) endocrine •Stimulates conversion of glucose to glycogen Insulin- secreted by •(glycogenesis) part(Islet of β cells controls the level of glucose in the blood Langerhans) -act on hepatocytes & adipocytes & has 2 types of increase cellular glucose uptake .So cells-β cells decreased bloodsugar-so called α cells Hypoglycemic Hormone •Glucagon-secreted • hydrolyse glycogen to glucose- by α cells ( glycogenolysis ) acts mainly on the liver cells & stimulate glycogenolysis leading to increased bloodsugar-so called Hyperglycemic Hormone •Prolonged hyperglycemia =Diabetis mellitus
9 Testis In scrotal sacs- Androgens- •Regulate development ,maturation & Has interstitial Testosterone functions of the male accessory sex organs like cells of Leydig epididymis , vas deferens ,seminal vesicles ,prostate gl;and urethra ,etc •Stimulate muscular growth ,growth of facial & axillary hair,aggresiveness low pitch voice •Stimulate spermatogenesis •It is an anabolic hormone as it helps in synthesising proteins & carbohydrates.10 Ovary Abdomen has ovarian follicles that secrete- Estrogen •Stimulation of growth & activities of female secondary sex organs,development of growing ovarian follicles ,appearance of 0+ secondary sexual characters,mammary gland The ruptured development, 0+ sexual behavior. ovarian follicles is converted into Corpus luteum that secrete - Progesterone Supports pregnancy & Stimulates mammary glands to produce milk
Sl TIssues Location Hormones Action10 Heart •Atrial walls •Atrial natriuretic •decreases blood pressure by dilating the factors (ANF) blood ves sels11 Kidney •JGA •Erytropoietin •Stimulates Erytropoiesis(formation of RBC)12 Alimentar •Gastroint- •Gastrin •Acts on Gastric glands & stimulate y canal estinal Tract secretion of HCL & Pepsinogen •Secretin • Acts on exocrine Pancreas & stimulate secretion of water & bicarbonate ions •Cholecystokinin(CCK) •Acts on both Pancres & gallbladder & stimulate secretion of Pancreatic enzymes & bile juice •Gastric Inhibitory •Inhibits gastric secretion & motility Peotide (GIP)13 Other •at most •Growth Factors •Essential for normal growth of tissues & tissues places their repair / regeneration
Mechanism of Hormone Action1.Hormones produce their effect on target tissues by binding to specific proteins called Hormone Receptors located in the cell membrane of target tissues – membrane bound receptors or the receptors found inside the target cell-intracellular receptors specially the in the nucleus forming Hormone Receptor Complex2. These receptors are specific to hormone.3. The complex thus formed leads to biochemical changes in the target tissue. Target tissue metabolism & thus physiological functions are regulated by hormones
5.On the basis of the chemical nature , hormones are classified as i)Peptide , polypep[tide,protein hormones(eg. Insulin ,glucagon, pituitary H ,hypothalamic H ,etc.) ii)Steroids(eg. Cortisol , testosterone, progesterone) iii)Iodothyronines (eg,Thyroid H ) Iv)Aminoacid derivatives (eg.epinephrine)
8,.There are two mechanisms of hormone action on all target cells.9. Nonsteroid Hormones Nonsteroid hormones (water soluble) do not enter the cell but bind to plasma membrane receptors, generating a chemical signal (second messenger) inside the target cell. Five different second messenger chemicals, including cyclic AMP have been identified. Second messengers activate other intracellular chemicals to produce the target cell response.
10.Steroid Hormones – The second mechanism involves steroid hormones, which passthrough the plasma membrane and act in a two step process. Steroidhormones bind, once inside the cell, to the nuclear membranereceptors, producing an activated hormone-receptor complex. Theactivated hormone-receptor complex binds to DNA and activatesspecific genes, increasing production of proteins.1 2.