Unit 3 The Endocrine System Taktak Endocrine Glands

Unit 3 The Endocrine System Taktak

Endocrine Glands • Secrete hormones into the extracellular spaces around their cells, which diffuse into capillaries and are carried away by blood. • The science of this system is called Endocrinology.

What do hormones do? 1. Regulate the internal environment, metabolism, and energy balance 2. Regulate smooth and cardiac muscle contractions, glandular secretions, and immune responses 3. Role in growth, development, “fight or flight response, and reproduction.

Hypothalamus and Pituitary Glands Thyroid and Parathyroid Glands Adrenal glands Pancreas Testis Ovaries

Endocrine System Summary • http: //www. youtube. com/watch? v=WVrl. HH 14 q 3 o

Hypothalamus and Pituitary • Major link between the nervous and endocrine systems. • Located in the middle of the base of the brain. • Hypothalamus sends messages chemically to Pituitary to release various hormones

• Hypothalamus sits on the Pituitary • Pituitary is divided into 2 regions: • Anterior and Posterior

Hormones of the Hypothalamus • Somatostatin: inhibits release of growth hormone • Dopamine: inhibits release of prolactin • Gonadotropin-releasing factor (Gn. RF): stimulates release of FSH and LH • Growth hormone-releasing factor (GHRF): stimulates the release of h. GH • Thyroid Releasing Factor: Stimulates the release of TSH

Hormones of the Anterior Pituitary Gland 1. Human Growth Hormone (h. GH or Somatotropin): stimulates growth; controlled by Growth hormone inhibiting hormone (GHIH). Disorders: Acromegaly, Dwarfism, & Giantism. 2. Thyroid Stimulating Hormone (TSH): Regulates thyroid gland activities. 3. Follicle-Stimulating Hormone (FSH): Regulates activities of the ovaries and testes. 4. Luteinizing hormone (LH): Regulates the activities of the ovaries and testes

5. Prolactin (PRL): helps initiate milk secretion. 6. Melanocyte Stimulating Hormone (MSH): increases skin pigmentation. 7. Adrenocorticotropic hormone (ACTH): regulates activities of the adrenal glands.

• enlarged hands • enlarged feet • widened fingers or toes due to skin overgrowth with swelling, redness, and pain • enlarged jaw (prognathism) • enlarged facial bones • thickening of the skin Acromegaly • enlarged sebaceous glands

Effects of Prolactin

Hormones of the Posterior Pituitary Gland 1. Oxytocin (OT): Stimulates contraction of the uterus during labor and delivery. (Synthetic Pitocin is often given to induce labor) 2. Antidiuretic Hormone (ADH): Stimulates water reabsorption by the kidneys.

Hypothalamus & Pituitary Summary • http: //www. youtube. com/watch? v=9 d. S 7 bc _2 b. UE

Thyroid Gland • Located just below the larynx has right and left lateral lobes. • Controls many body functions, including: heart rate, temperature, and metabolism.

• The Thyroid gland has a "butterfly" shape, with two lateral lobes • Thyroid glands are brownish-red in color

Thyroid Hormones • Thyroxine (T 4) & Triiodotyronine (T 3): Stimulate metabolic activities, work with h. GH to regulate growth, also assist with activities of the central nervous system, reproduction, & cardiovascular function.

Disorders of the Thyroid • Hypothyroidism: thyroid hormone deficiency. Iodine deficiency and disease are common causes. • Symptoms: fatigue, hair loss, reproductive failure, and weight gain. With severe iodine deficiency, a goiter may result.

Goiter: An enlarged thyroid gland

• Hyperthyroidism – Results from over-secretion of thyroid hormones. – Most common form is called Graves Disease – Symptoms: high heart rate, nervousness, weight loss, eye disease, anxiety

Parathyroid Hormones • The parathyroid glands are located on the posterior surfaces of the lateral lobes of the thyroid. • Secrete Parathyroid Hormone (PTH): Regulates the homeostasis of calcium levels in the blood.

Thyroid Summary • http: //www. youtube. com/watch? v=x. KQa. Mb. ZUPY • http: //www. youtube. com/watch? v=SVSBo 065 hmw

Adrenal Glands • Located above the kidneys. • Divided into 2 distinct sections: the medulla and the cortex.

Adrenal Cortex Glands 1. Mineralocorticoids: increase Na and H 2 O absorption decreases K absorption. 2. Glucocorticoids: promote metabolism, resist stress, assist in anti-inflammatory response. (ex. Cortisone creams) 3. Gonadocorticoids: “sex hormones”

Adrenal Medullary Glands Epinephrine and Norepinephrine (Adrenaline): Help the body resist stress. Released by the autonomic nervous system. Responsible for the “Fight or Flight” response.

Adrenal Glands Summary • http: //www. youtube. com/watch? v=Xgq_al EB 2 zw • http: //www. youtube. com/watch? v=4 WJj 8 IE 83 o. M

The Pancreas • A flat organ located slightly below the stomach adjacent to the intestines. • Has 2 Roles: –Produce Hormones (Endocrine) –Secrete Digestive Enzymes (Exocrine)

Pancreatic Enzymes • Secretes three exocrine enzymes that assist with the breakdown of food: carbohydrates, protein, and lipids – Amylase – breaks down carbohydrates – Protease – breaks down protein – Lipase – breaks down lipids (fat)

Pancreatic Hormones 1. Alpha Cells: secrete Glucagon which increases blood glucose levels. 2. Beta Cells: secrete Insulin which decreases blood glucose levels 3. Delta cells: regulate sectretion of Pancreatic hormones

Pancreas Summary • http: //www. youtube. com/watch? v=NZ 4 zcr Tz. Uj. A • http: //www. youtube. com/watch? v=1 c 6 a 0 B Nsyek

Ovaries and Testes • Ovaries: secrete estrogen and progesterone. Gives rise to female sexual characteristics, reproductive cycle, pregnancy and lactation. • Testes: produce testosterone. Gives rise to male sexual characteristics and reproductive functions. • Major anatomical structures in the Reproductive System.

Thymus Gland • Located behind the sternum and up into the neck • Functions in several hormones related to immunity. (Home for maturing T Cells) • http: //www. youtube. com/watch? v=SYgy. L 0 _-t 0 Q

Pineal gland • Located in the brain • Secretes Melatonin linked to a person’s “Circadian Rhythm”/Internal Clock Seasonal Affective Disorder (SAD): depression during winter months when day length is short due to overproduction of melatonin. Bright light therapy can provide relief.