8 Anterior P. Homeostatic Imbalances Growth hormone (GH or hGH)Promotes mitosis, cell divisionElongation of long bones, etc.Healing of wounds Lack of hGH retards growthHypersecretion in youth produces giantismHyposecretion in childhood produces pituitary dwarfismHypersecretion in adult produces acromegaly
9 Posterior Pituitary Axonal transport to Posterior Pituitary aka neuro hypo physis“nerve” “under” “growth”Hypothalamic cell bodies synthesizeoxytocinADH
10 Pituitary—Posterior lobe OxytocinStimulates smooth muscle contraction of uterus & mammary glands.Antidiuretic H.Stimulates water reabsorption in collecting ducts.Stimulates vasoconstriction (vasopressin)Lack diabetes insipidus
11 Posterior Pituitary Homeostatic Imbalances ADHHyposecretion produces diabetes insipidus “tasteless”Excessive thirst and urinationcentral or neurogenic DIgestagenic or gestational DInephrogenic DIdipsogenic DIDiabetes Insipidus Foundation, Inc.11
13 Thyroid Gland Location in neck Composed of follicles Inferior to larynxAnterior & lateral to tracheaComposed of folliclesFollicle cells produce thyroglobulinThyroxin (T4)Triiodothyronine (T3)Both “thyroid hormone”, body’s major metabolic hormoneParafollicular/ C cellsCalcitoninDecreases blood Ca2+ by depositing it in bones
14 Homeostatic imbalances Hypothyroidism resultsMyxedema (in adults)Goiter—low levels of iodineCretinism (in children)Hyperthyroidism resultsGraves disease
15 Parathyroid Glands Four small glands embedded in posterior of thyroid Parathyroid hormone (PTH)Stimulates osteoclasts to free Ca2+ from boneStimulates Ca2+ uptake from intestine & kindeyHormonal Regulation of Calcium
16 Parathyroid Homeostatic Imbalances Severe hyperparathyroidism causes massive bone destructionIf blood Ca2+ fall too low, neurons become overactive, resulting in tetany
17 Feedback LoopNegative feedback in calcium homeostasis. A rise in blood Ca2+ causes release of calcitonin from the thyroid gland, promoting Ca2+ deposition in bone and reducing reabsorption in kidneys.A drop in blood Ca2+ causes the parathyroid gland to produce parathyroid hormone (PTH), stimulating the release of Ca2+ from bone.PTH also promotes reabsorption of Ca2+ in kidneys and uptake of Ca2+ in intestines.
18 Adrenal Glands Cortex Medulla One on top of each kidney Corticosteroid glandularMedullaCatecholaminesneurohormonalEpinephrineNorepinephrine
19 Adrenal Cortex Cortex Activity stimulated by ACTH Controls prolonged responses by secreting corticosteroids.MineralcorticoidsAldosterone regulate salt and water balanceGlucocorticoidsCortisol regulate glucose metabolism and the immune system.GonadocorticoidsAndrogensEstrogens
20 Adrenal Cortex Imbalances Hypersecretion leads to Cushing’s diseaseACTH-releasing tumors or side effects of corticoid drugs.Hyposecretion leads to Addison’s DiseaseDeficits in glucocorticoids and mineralcorticoids
21 Adrenal Medulla Medulla The adrenal medulla mediates short–term responses by secreting catecholamine hormones.Cells are modified neurons (lack axons)Epinephrine (adrenaline)Norepinephrine (noreadrenaline)enable a rapid ( fight-or-flight ) responses to stress by increasing blood glucose and blood pressure and directing blood to the heart, brain, and skeletal muscles.
23 PancreasConsists of two major types of secretory tissues which reflects its dual functionExocrine glandsecretes digestive juicelocalized in the acinar cellsEndocrine glandreleases hormoneslocalized in the islet cells (islets of Langerhans)
24 Pancreatic Islets “About a million” embedded in pancreas Control centers for blood glucoseInsulin from beta cellsGlucagon from alpha cells
28 Feedback LoopA rise in blood glucose causes release of insulin from beta cells the pancreas, promoting glucose uptake in cells and storage as glycogen in the liver.A fall in blood glucose stimulates alpha cells in the pancreas to secrete glucagon, which causes the liver to break down glycogen and release glucose.
30 Gonads Ovaries Testes Estrogens Progesterone Testosterone Reproductive functions when we study reproductive system.
31 Pineal gland Melatonin ? Inhibits early puberty ? Day/night cycles Timing of sleep, body temperature, appetiteSecretes melatonin during darknessParticipates in setting the body’s clockMelatonin is a potent antioxidantMelatonin is high when young and is reduced as we age
32 Thymus Thymus gland Thymopoietins, thymic factor, thymosins Influence development of T lymphocytes