Unit One – Concept Two Endocrine System and Homeostasis VrlHH14q3o Crash course

A.Intro. to the Endocrine System The endocrine system is designed to maintain control of various organs and tissues. Unlike the nervous system that allows the body to make quick adjustments to stimuli, the endocrine system maintains this control over a longer duration

1. Definition of endo/exocrine endocrine: non-ducted: goes into extracellular fluid (ECF), secretion ends up in the blood stream where it is picked up by capillaries exocrine: ducted – materials end up outside (saliva, sweat, mammary glands) playnext=1&list=PLEEE5A627695E1E4A

2. Definition of hormone Hormones are chemicals that have targets (needed only in trace amounts) Hormones are regulators, speeding up or slowing down certain body processes When hormones encounter their target cells they bind to receptor proteins on the target cell membrane The two main classes of hormones are lipid-based (steroid) and protein-based

2. Definition of hormone aTIA aTIA Steroid hormones are made of cholesterol and are not soluble in water they combine with receptor molecules in the cytoplasm of cells the hormone receptor complex moves into the nucleus and attaches to DNA

Examples of lipid based hormones Testosterone Estrogen Cortisol

2. Definition of hormone protein and protein related hormones contain chains of amino acids combine with receptors on the cell membrane the hormone receptor complex activates the production of adenylyl catalase which causes the cell to convert ATP into cyclic AMP cyclic AMP functions as a messenger that activates enzymes in the cytoplasm to perform their normal functions

Examples of protein based hormones Epinephrine Human growth hormone Thyroxine Insulin

B.Principle Endocrine Glands and Their Hormones

1. Hypothalamus/Pituitary Complex

a. terms anterior lobe – in the front, produces its own hormones posterior lobe – in back, hormones stored here neurosecretion – nerve cells secreting hormones in the posterior lobe – happens in adrenal gland pituitary portal system (pg. 445) – releasing factors in the hypothalamus control releasing factors in the anterior lobe Tropic hormone – a hormone that targets other endocrine glands (many of the hormones of the hypothalamus/pituitary are trophic)

b. Hormones Hypothalamus Hormones released from the posterior pituitary were manufactured in the hypothalamus Other hypothalamus hormones: Releasing hormones – stimulate the release of hormones from the pituitary Somatostatin – a regulating hormone that inhibits the release of growth hormone Dopamine – a regulating hormone that inhibits the release of prolactin

b. Hormones Anterior Lobe: human growth hormone (HGH or Somatotropin) – promotes growth in bones and muscles Disorders: Gigantism (person becomes extremely tall, but body proportions are normal) Acromegaly (leads to the growth of some bones such as the eyebrow ridge, lower jaw, nose, hands and feet) ACTH (Corticotropin adrenal steroid) – targets adrenal cortex, stimulates the release of hormones involved in stress response (cortisol and aldosterone) TSH (Thyroid Stimulating Hormone) – targets the thyroid, stimulates the release of thyroxin which regulates cellular metabolism (stimulated by thyroid releasing factor from nerve cells)

Gigantism Acromegaly e.com/watch?v=u TrRM9C6K20&fe ature=related

The Science of Gigantism on the National Geographic Channel (25 min) National Geographic - Science of Dwarfism (45 min) om/watch?v=jXyfXfq Vmis or om/watch?v=jXyfXfq Vmis earch.com/mywebsea rch/video.jhtml?searc hfor=the+science+of+ dwarfism&p2=%5EH J%5Exdm019%5EY Y%5Eca&n=77DE88 57&ss=sub&st=hp&p tb=C5D6CFF4-D EFA57EB3FA9&tpr =sbt&si=pconverter earch.com/mywebsea rch/video.jhtml?searc hfor=the+science+of+ dwarfism&p2=%5EH J%5Exdm019%5EY Y%5Eca&n=77DE88 57&ss=sub&st=hp&p tb=C5D6CFF4-D EFA57EB3FA9&tpr =sbt&si=pconverter

Growth Hormone Use com/watch?v=Xhw8 GLIVKPY com/watch?v=Xhw8 GLIVKPY

b. Hormones Anterior Lobe: Prolactin (PRL) – targets mammary glands, stimulates milk production (inhibited by an inhibitory hormone produced in the hypothalamus - dopamine ) Follicle Stimulating Hormone (FSH) – targets ovaries and testes, stimulates follicle development in female ovaries and stimulates the development of sperm cells in testes Luteinizing hormone (LH) – targets ovaries and testes, in females, LH stimulates ovulation and formation of the corpus luteum (progesterone production). In males, LH stimulates the production of the male sex hormone testosterone (called ICSH)

b. Hormones Posterior Lobe: antidiruetic hormone (ADH) – increases water reabsorption into the blood resulting in decreased urine production, regulates water in the body oxytocin – causes the muscles of the uterus walls to contract and makes birth easier, involved in the discharge of afterbirth, stimulates the release of milk

2. Thyroid Gland Located at the base of the neck in front of the trachea

a.Hormones N_8 N_8 Thyroid Gland: Thyroxine (T4) – hormone secreted by the thyroid gland, which regulates the rate of body metabolism, by the oxidation of sugars and other nutrients. An increase in thyroxin increases metabolism, thus decreasing body weight Calcitonin – hormone secreted in the thyroid gland which lowers calcium and phosphate levels of blood by inhibiting bone breakdown and accelerating Ca 2+ absorption into bones

b. Thyroid disorders Y Y goiter – enlargement of the thyroid gland, occurs when inadequate amounts of iodine are not obtained in the diet hypothyroidism – inactivity of the thyroid resulting in a decrease in thyroxine secretion hyperthyroidism – over activity of the thyroid resulting in an increase in thyroxine secretion thyroid cancer – cancer of the thyroid

Cretinism.html es.com/image/endocrinology%5Cmetabolism.htm Cretinism – thyroid doesn’t develop properly people are shorter and stockier (hypothyroidism) Grave’s disease – overactive thyroid often results in swelling of muscles around the eyes Goiter

c. Parathyroid Glands The parathyroid glands produce parathyroid hormone Blood Ca 2+ levels are raised by increasing the absorption from the GI tract and from the release of Ca 2+ from the bones

3. Adrenal Glands

Stress response aJC-Km5U&feature=related Science of Stress response science/health-human-body-sci/human- body/science-stress-sci/ science/health-human-body-sci/human- body/science-stress-sci/

a. Hormones Adrenal Cortex (outer portion): cortisol – associated with blood glucose levels. An increase in cortisol increases amino acid levels in the blood to relieve stress, amino acids are converted to glucose in the liver, thus raising blood sugar levels aldosterone – increase sodium retention and water reabsorption in kidneys and helps maintain body fluid levels small amounts of sex hormones

a. Hormones Adrenal Medulla (inner portion): epinephrine (adrenaline) – initiates the fight or flight response norepinephrine (nor-adrenaline) – initiates the fight or flight response in stress – hormones released increase blood sugar levels thus increasing energy levels, also increasing heart rate, blood pressure, metabolic rate, urine production, blood glucose

4. Pancreas Islet Cells

Insulin, Glucose and you

a. Hormones Insulin – produced in the beta cells of the Islets of Langerhans, it is released when blood sugars are high, it increases glucose utilization by make cells more permeable to glucose Glucagon – causes an increase in blood sugar levels, it is released when blood sugar levels are too low, promotes glycogen to convert to glucose which is absorbed into the blood Somatotropin (hGH)

Blood Glucose Regulation Glucagon – raises blood glucose Insulin – lowers blood glucose Adrenaline – raises blood glucose Thyroxine – decreases blood glucose levels by increasing metabolism (more glucose used due to increased cellular respiration)

Blood Glucose Disorders Hypoglycemia – low blood sugar caused by an increase in insulin and a decrease in glucagon production Hyperglycemia (diabetes mellitus)– high blood sugar caused by decreased insulin production Juvenile Diabetes (Type 1) – onset before age 20, usually caused by degeneration of beta cells Mature Onset diabetes (Type 2) – insulin is produced but the body cannot use it, is regulated by diet Type 2 Diabetes

Other Glands and Hormones Pineal Gland – secretes melatonin (regulates sleep) Thymus – produces T-cells (immunity)

Feedback Diagrams

C.Feedback Diagrams htm htm 1. Testosterone and LH (494) 2. Cortisol (453)

3. Insulin and Glucagon (457)

4. TSH and Thyroxin (448) m/watch?v=zf_n2 mmp3vM Thyroid Hormone 2 -

5. Parathyroid Hormone and calcium (449)

D.Control of Hormone Release homeostasis animation body/systems/endocrine/adam htm body/systems/endocrine/adam htm negative feedback Hormone A causes a release of hormone B, which inhibits hormone A negative feedback based on need for hormone eg. Insulin responds to increasing blood glucose nervous system Epinephrine from adrenal medulla antagonistic hormones eg. Insulin vs. glucagon