MCB 247 Practical 3 endocrine system

Functions of Hormones

-Regulating development, growth and metabolism -Maintaining homeostasis of blood composition and volume -Controlling digestive process -Controlling reproductive activities

Type 1 diabetes

Absent or diminished release of insulin from pancreas

Acromegaly

Bones show abnormal widening in people

The hypothalamic hormone that triggers the release of adrenocorticotropic hormone (ACTH) is

CPH

Cushing syndrome

Chronic exposure to excessive glucocorticoid hormones in people taking corticosteroids for therapy caused by obesity, hypertension, excessive hair growth, kidney stones, and menstrual irregularities

What disease is caused by excessive secretion glucocorticoids, and is characterized by redistribution of body fat to produce characteristic features such as "moon face"?

Cushing disease

Type 2 diabetes

Decreased insulin release or insulin effectiveness

Hyperthyroidism/ Graves Disease

Excessive production of TH which causes an increased metabolic rate, weight loss, hyperactivity, heart intolerance

Hypoglycemia

Glucose levels below 60 mg/DL

Organs/tissues containing endocrine cells

Hypothalamus, skin, thymus, heart, liver, stomach, pancreas, small intestine, adipose connective tissue, kidney, testes, ovaries

Adrenogenital syndrome (AGS)

Inability to synthesize corticosteroids which leads to overproduction of ACTH which causes increased size of adrenal gland and production of hormones with testosterone-like effects

Hypothalamus inhibiting hormones

PIH, GIH

Major endocrine glands

Pituitary gland, pineal gland, parathyroid gland, thyroid gland, adrenal gland

Hypothyroidism

Results from decreased production of TH which results in a low metabolic rate, lethargy, cold intolerance, weight gain

Gestational diabetes

Seen in some pregnant women

Corticotropin-releasing hormone (CRH)

Stimulates release of adrenocorticotropic hormone (ACTH)

Hypothalamus releases hormones

TRH, PRH, Gn-RH, CRH, GHRH

Inhibit (ovaries)

Target organ/tissue: Anterior pituitary Primary function: Inhibits release of FSH from anterior pituitary

Inhibit (testes)

Target organ/tissue: Anterior pituitary Primary function: Inhibits release of follicle-stimulating hormone (FSH) from anterior pituitary

Angiotensinogen (liver)

Target organ/tissue: Blood vessels; kidneys; hypothalamus (thirst center) Primary function: Converted by enzymes released from the kidney and within the blood vessels to angiotensin II; increases blood pressure by causing vasoconstriction and decreasing urine output; stimulates thirst center

Erythropoietin (kidneys)

Target organ/tissue: Bone (red bone marrow) Primary function: Increases production of red blood cells (erythrocytes)

EPO (liver)

Target organ/tissue: Bone (red bone marrow) Primary function: Increases production of red blood cells kidneys are the major producers of EPO

Vitamin D3 (skin)

Target organ/tissue: Bone; kidney; small intestine Primary function: Converted by enzymes of liver and kidney to calcitriol; functions synergistically with PTH and increases calcium absorption from small intestine

Leptin (adipose connective tissue)

Target organ/tissue: Brain Primary function: Helps regulate food intake

CCK (small intestine)

Target organ/tissue: Digestive organs Primary function: Regulates digestion within small intestine by facilitating digestion of proteins and fats within small intestine

Secretin (small intestine)

Target organ/tissue: Digestive organs Primary function: Regulates digestion within small intestine by helping to maintain normal pH within small intestine

Atrial natriuretic peptide (ANP) (heart)

Target organ/tissue: Kidneys; blood vessels Primary function: Decrease blood pressure by stimulating kidneys to increase urine output and the blood vessels to dilate

Glucagon (pancreas)

Target organ/tissue: Liver; adipose connective tissue Primary function: Increases blood glucose levels

Insulin (pancreas)

Target organ/tissue: Liver; adipose connective tissue most body cells Primary function: Decrease blood glucose levels

Estrogen and progesterone (ovaries)

Target organ/tissue: Reproductive organs; various body cells Primary function: Stimulate maturation and function of female reproductive system

Testosterone (testes)

Target organ/tissue: Reproductive organs; various body cells Primary function: Stimulates maturation and function of male reproductive system

Moitlin (small intestine)

Target organ/tissue: Small intestine Primary function: Stimulates small intestine motility

Hepicidin (liver)

Target organ/tissue: Small intestine and macrophages of liver, spleen, and bone marrow Primary function: Regulates iron levels

Gastrin (stomach)

Target organ/tissue: Stomach Primary function: Facilitates digestion within stomach

IGFs (liver)

Target organ/tissue: Various body cells Primary function: Functions synergistically with growth hormones to regulate growth

Epinephrine (EPI) and norepinephrine (NE) (adrenal medulla)

Target organ/tissue: Various body cells Primary function: Prolong effects of the sympathetic division of the autonomic nervous system

Gonadocorticoids (adrenal cortex)

Target organ/tissue: Various body cells Primary function: Stimulate maturation and functioning of reproductive system

ACTH (anterior pituitary gland)

Target organ/tissue: Adrenal cortex Primary function: Stimulates adrenal cortex to release corticosteroids (example: cortisol)

Thyroid hormone (thyroid gland)

Target organ/tissue: All cells Primary function: Increase metabolic rate of all cells; increase heat production (calorigenic effect)

Parathyroid hormone (parathyroid glands)

Target organ/tissue: Bone tissue; kidney Primary function: Increases blood calcium levels by stimulating the release of calcium from bone tissue and decrease loss of calcium in urine; causes formation of calcitriol hormone (a hormone that increases calcium absorption from small intestine)

Calcitonin (thyroid gland)

Target organ/tissue: Bone; kidney Primary function: Decreases blood calcium levels; most significant in children

Melatonin (pineal gland)

Target organ/tissue: Brain Primary function: helps regulate the body's circadian rhythms (biological clock); functions in sexual maturation

Mineralocorticoids (aldosterone) (adrenal cortex)

Target organ/tissue: Kidney Primary function: Regulate blood Na+ and K+ levels by decreasing the Na+ and the K+ excreted in urine

glucocorticods (cortisol) (adrenal cortex)

Target organ/tissue: Liver, adipose connective tissue; all cells Primary function: Participate in stress response; increase nutrients (glucose) that are available in the blood

FSH (anterior pituitary gland)

Target organ/tissue: Ovary; testis Primary function: Controls development of both oocyte and ovarian follicle (spherical structure that houses an oocyte) within ovaries; controls development of sperm within testes

LH (anterior pituitary gland)

Target organ/tissue: Ovary; testis Primary function: Induces ovulation of secondary oocyte from the ovarian follicles; controls testosterone synthesis within testes

Thymosin, thymulin, thymopoietin (thymus)

Target organ/tissue: T-lymphocytes Primary function: Maturation of T-lymphocytes

TSH (anterior pituitary gland)

Target organ/tissue: Thyroid gland Primary function: Stimulates thyroid gland to release thyroid hormone

Regulatory hormones (hypothalamus)

Target organ/tissue: anterior pituitary Primary function: control release of hormones from anterior pituitary

PRL (anterior pituitary gland)

Target organ/tissue: breast Primary function: regulates mammary gland growth and breast milk production in females; function not fully known in males

antidiuretic hormone (ADH) (hypothalamus)

Target organ/tissue: kidney; hypothalamus (thirst center); blood vessels Primary function: stimulates the kidneys to decrease urine output and the thirst center to increase fluid intake when the body is dehydrated; in high doses, ADH is a vasoconstrictor (vasopressin)

GH (anterior pituitary gland)

Target organ/tissue: liver; skeleton muscle; all cells Primary function: release of insulin-like growth factors (IGFs) from liver; GH and IGFs function synergistically to induce growth

Oxytocin (hypothalamus)

Target organ/tissue: uterus; breast(mammary glands); brain Primary function: Contraction of smooth muscle of uterus; ejection of milk from mammary glands; increases feelings of emotional bonding between individuals

Do hormones have any influence on the digestive system?

Yes (gastric, CCK, secretin)

FSH (follicle stimulating hormone) and LH (luteinizing hormone)

act on gonads (testes and ovaries) to stimulate development of gametes (sperm and oocyte), and release hormones

PRL (prolactin)

acts on mammary glands to influence gland growth and stimulate milk production

Adrenocorticotropic hormone (ACTH)

acts on the adrenal cortex to cause release of glucocorticoids (e.g., cortisol) which raises blood level of nutrient molecules (e.g., glucose)

Which lobe of the pituitary is larger and secretes more hormones?

anterior pituitary (TSH, PRL, FSH, LH, ACTH, GH)

Thyroid-stimulating hormone (TSH) is secreted by what and targets what cells of the thyroid gland

anterior pituitary, thyroid follicular

Cretinism

arises from a diet deficient in iodine

Dwarfism

deficiency of growth hormone

Goiter

enlargement of thyroid caused by lack of dietary iodine preventing thyroid from producing thyroid hormone

Gigantism

excessive levels of growth hormones

Acromegaly can occur due to

excessive secretion of growth hormones

What are the target cells for follicle-stimulating hormone?

gonads (testes, ovaries)

Within the infundibulum, the axons from neurons extending into the posterior pituitary are known as the

hypothalami-hypophyseal tract

What is the part of the brain that functions as a "master control center" of the endocrine system?

hypothalamus

Hormones that come from the posterior pituitary are synthesized where and are released from where when nerve signals arrive

hypothalamus and the posterior pituitary

Diabetes mellitus

inadequate uptake of glucose from blood

Addison disease

insufficient production of steroids (glucocorticoids and mineralocorticoids) -weight loss, fatigue and weakness, hypotension, and skin darkening

The small, cone-shaped gland that is in the epithalamus of the brain is the

pineal gland which releases melatonin

Oxytocin and antidiuretic hormone are released from the

posterior pituitary gland

Among their many functions, hormones

regulate blood volume, cellular concentration, and number of platelets

Major hormones produced by the hypothalamus

regulatory hormones, antidiuretic hormone (ADH), oxytocin

GH (growth hormone)

stimulates release of IGFs from the liver, which synergistically act on all body tissues, especially cartilage, bone, muscle, and adipose connective tissue to stimulate growth

Thyrotropin-releasing hormone (TRH)

stimulates the anterior pituitary gland to release TSH

Growth hormone-releasing hormone (GHRH)

stimulates the anterior pituitary to release GH

Gonadotropin-releasing hormone (GnRH)

stimulates the anterior pituitary to release both FSH and LH (gonadotropins)

PRH (prolactin releasing hormone)

stimulates the anterior pituitary to release prolactin, which acts on mammary glands to influence gland growth and stimulate milk production. Prolactin release is inhibited by prolactin-inhibiting hormone

TSH (thyroid stimulating hormone)

stimulates thyroid gland to release thyroid hormone

Hypothalamus

the master control center of the endocrine system because it regulates most endocrine functions of the body