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