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Endocrine Glands
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Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Dec 18, 2015

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Martha Walters
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Page 1: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Endocrine Glands

Page 2: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.
Page 3: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Endocrine Glands• Hypothalamus• Pituitary

– Anterior lobe– Posterior lobe

• Thyroid gland• Parathyroid

glands• Adrenal Glands

– Cortex– Medulla

• Islets of Langerhans

• Gonads– Ovaries– Testes

• Pineal gland• Thymus• others

Hormonal Communication

Page 4: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 5: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 6: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Anterior Pituitary

Page 7: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.
Page 8: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 9: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Posterior Pituitary

• Axonal transport to Posterior Pituitary akaneuro hypo physis

“nerve” “under” “growth”

• Hypothalamic cell bodies synthesize – oxytocin – ADH

Page 10: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 11: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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.

Page 12: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.
Page 13: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Thyroid Gland• Location in neck

– 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

Page 14: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Homeostatic imbalances• Hypothyroidism results

– Myxedema (in adults)

– Goiter—low levels of iodine

– Cretinism (in children)

• Hyperthyroidism results– Graves disease

Page 15: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 16: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Parathyroid Homeostatic Imbalances

• Severe hyperparathyroidism causes massive bone destruction

• If blood Ca2+ fall too low, neurons become overactive, resulting in tetany

Page 17: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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.

Page 18: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Adrenal Glands

One on top of each kidney

• Cortex– Corticosteroid– glandular

• Medulla– Catecholamines– neurohormonal

• Epinephrine• Norepinephrine

Page 19: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 20: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 21: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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.

Page 22: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.
Page 23: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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)

Page 24: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Pancreatic Islets• “About a million”

embedded in pancreas• Control centers for

blood glucose– Insulin from beta cells– Glucagon from alpha

cells

Page 25: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Insulin Glucagon

Page 26: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Islets of Langerhans• Insulin stimulates

glucose uptake, glycogenesis

• Glucagon stimulates glycogenolysis, glucose release from liver (vs gluconeogenesis)

Page 27: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.
Page 28: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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.

Page 29: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Pancreas Homeostatic ImbalancesDiabetes “siphon” mellitus mel= “honey”

Symptoms:•Polyuria•Polydipsia•Polyphagia

Blood Level Regulation in Diabetics

Page 30: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Gonads• Ovaries

– Estrogens– Progesterone

• Testes– Testosterone

• Reproductive functions when we study reproductive system.

Page 31: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

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

Page 32: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Thymus

• Thymus gland• Thymopoietins,

thymic factor, thymosins– Influence

development of T lymphocytes

Page 33: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Non-Endocrine Gland Hormones

• Stomach (gastrin)• Small intestine (duodenumintesetinal

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)

Page 34: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Functions regulated by the Endocrine System

• Growth• Healing• Water balance & Blood Pressure• Calcium Metabolism• Energy Metabolism• Stress• Regulation of other Endocrine

Organs

Page 35: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Growth

• Growth hormone-releasing hormone

• Human growth hormone (hGH)• Thyrotropin (TSH)• Thyroxine & triiodothyronine• Calcitonin • Somatostatin (GHIH)

Page 36: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Healing

• Growth hormone-releasing hormone

• Human growth hormone (hGH)• Thyrotropin (TSH)• Thyroxine & triiodothyronine• Calcitonin • Glucagon, Insulin• Erythropoietin

Page 37: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Water balance & Blood pressure

• ADH• Aldosterone• Angiotensin II• Atrial natriuretic H.• Epinephrine

Page 38: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Calcium Metabolism

• Calcitonin• Parathyroid H. (PTH)• Estrogens/androgens• Growth hormone

Page 39: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Energy Metabolism

• Thyroxine & triiodothyronine• Thyroid-stimulating H. (thyrotropin,

TSH)• Epinephrine & norepinephrine• Insulin• Glucagon• Adrenocorticotropic H. (ACTH) • Cortisol

Page 40: Endocrine Glands. Hypothalamus Pituitary –Anterior lobe –Posterior lobe Thyroid gland Parathyroid glands Adrenal Glands –Cortex –Medulla Islets of Langerhans.

Stress

• Epinephrine & norepinephrine

• T4 &T3 ??

• ACTH• Cortisol