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Endocrine Glands.

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Presentation on theme: "Endocrine Glands."— Presentation transcript:

1 Endocrine Glands


3 Endocrine Glands Islets of Langerhans Hypothalamus Pituitary Gonads
Ovaries Testes Pineal gland Thymus others Hypothalamus Pituitary Anterior lobe Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands Cortex Medulla Hormonal Communication

4 Hypothalamus Part of brain
Regulates ANS, emotions, feeding/satiety, thirst, body temperature, etc. Hormones related to these functions “Releasing hormones” Axonal transport to posterior lobe

5 Anterior Pituitary “Releasing” hormones regulate AP aka
adeno hypo physis “glands” “under” “growth” All proteins TSH (thryoid stimulating hormone/thyrotropin) ACTH (adrenocorticotropic hormone) FSH (gonadotropin) LH (gonadotropin) Tropins/tropic hormones GH (growth hormone) Prolactin-releasing H Hypothalamic Pituitary Axis Animation : IP Web

6 Anterior Pituitary


8 Anterior P. Homeostatic Imbalances
Growth hormone (GH or hGH) Promotes mitosis, cell division Elongation of long bones, etc. Healing of wounds Lack of hGH retards growth Hypersecretion in youth produces giantism Hyposecretion in childhood produces pituitary dwarfism Hypersecretion in adult produces acromegaly

9 Posterior Pituitary Axonal transport to Posterior Pituitary aka
neuro hypo physis “nerve” “under” “growth” Hypothalamic cell bodies synthesize oxytocin ADH

10 Pituitary—Posterior lobe
Oxytocin Stimulates 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
ADH Hyposecretion produces diabetes insipidus “tasteless” Excessive thirst and urination central or neurogenic DI gestagenic or gestational DI nephrogenic DI dipsogenic DI Diabetes Insipidus Foundation, Inc. 11


13 Thyroid Gland Location in neck Composed of follicles
Inferior to larynx Anterior & lateral to trachea Composed of follicles Follicle cells produce thyroglobulin Thyroxin (T4) Triiodothyronine (T3) Both “thyroid hormone”, body’s major metabolic hormone Parafollicular/ C cells Calcitonin Decreases blood Ca2+ by depositing it in bones

14 Homeostatic imbalances
Hypothyroidism results Myxedema (in adults) Goiter—low levels of iodine Cretinism (in children) Hyperthyroidism results Graves disease

15 Parathyroid Glands Four small glands embedded in posterior of thyroid
Parathyroid hormone (PTH) Stimulates osteoclasts to free Ca2+ from bone Stimulates Ca2+ uptake from intestine & kindey Hormonal Regulation of Calcium

16 Parathyroid Homeostatic Imbalances
Severe hyperparathyroidism causes massive bone destruction If blood Ca2+ fall too low, neurons become overactive, resulting in tetany

17 Feedback Loop Negative 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
glandular Medulla Catecholamines neurohormonal Epinephrine Norepinephrine

19 Adrenal Cortex Cortex Activity stimulated by ACTH
Controls prolonged responses by secreting corticosteroids. Mineralcorticoids Aldosterone regulate salt and water balance Glucocorticoids Cortisol regulate glucose metabolism and the immune system. Gonadocorticoids Androgens Estrogens

20 Adrenal Cortex Imbalances
Hypersecretion leads to Cushing’s disease ACTH-releasing tumors or side effects of corticoid drugs. Hyposecretion leads to Addison’s Disease Deficits 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 Pancreas Consists of two major types of secretory tissues which reflects its dual function Exocrine gland secretes digestive juice localized in the acinar cells Endocrine gland releases hormones localized in the islet cells (islets of Langerhans)

24 Pancreatic Islets “About a million” embedded in pancreas
Control centers for blood glucose Insulin from beta cells Glucagon from alpha cells

25 Insulin Glucagon

26 Islets of Langerhans Insulin stimulates glucose uptake, glycogenesis
Glucagon stimulates glycogenolysis, glucose release from liver (vs gluconeogenesis)


28 Feedback Loop A 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.

29 Pancreas Homeostatic Imbalances Diabetes “siphon” mellitus mel= “honey”
Symptoms: Polyuria Polydipsia Polyphagia Blood Level Regulation in Diabetics

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, appetite Secretes melatonin during darkness Participates in setting the body’s clock Melatonin is a potent antioxidant Melatonin is high when young and is reduced as we age

32 Thymus Thymus gland Thymopoietins, thymic factor, thymosins
Influence development of T lymphocytes

33 Non-Endocrine Gland Hormones
Stomach (gastrin) Small intestine (duodenumintesetinal gastrin, secretin, cholecystokinin) Heart (atrial natriuretic peptide) Kidneys (erythropoietin, active vitamin D3) Adipose tissue (leptid, resistin) Skin Placenta (human chorionic gonadotropin, human placental lactogen, relaxin)

34 Functions regulated by the Endocrine System
Growth Healing Water balance & Blood Pressure Calcium Metabolism Energy Metabolism Stress Regulation of other Endocrine Organs

35 Growth Growth hormone-releasing hormone Human growth hormone (hGH)
Thyrotropin (TSH) Thyroxine & triiodothyronine Calcitonin Somatostatin (GHIH)

36 Healing Growth hormone-releasing hormone Human growth hormone (hGH)
Thyrotropin (TSH) Thyroxine & triiodothyronine Calcitonin Glucagon, Insulin Erythropoietin

37 Water balance & Blood pressure
ADH Aldosterone Angiotensin II Atrial natriuretic H. Epinephrine

38 Calcium Metabolism Calcitonin Parathyroid H. (PTH) Estrogens/androgens
Growth hormone

39 Energy Metabolism Thyroxine & triiodothyronine
Thyroid-stimulating H. (thyrotropin, TSH) Epinephrine & norepinephrine Insulin Glucagon Adrenocorticotropic H. (ACTH) Cortisol

40 Stress Epinephrine & norepinephrine T4 &T3 ?? ACTH Cortisol

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