2. Structure and Function of Endocrine System 1

3. 2 Name the parts of the endocrine system and discuss the function of each part Discriminate the functions of each endocrine hormone secreted by same endocrine glands Analyze the action of each hormone and demonstrate its contribution in maintaining homeostasis Classify hormones according to its molecular structure and actions Identify and describe the structure and function of important biochemical compounds, including protein and steroid hormones (314-3) Analyze homeostatic phenomena to identify the feedback mechanisms involved (317-2)

4. 3 Regulates many bodily functions Maintains homeostasis by regulating the production of chemicals that affect most functions of the body Secretes substances that aid the nervous system Important regulator of growth and development Endocrine glands are ductless glands, unlike exocrine glands that secrete substances into ducts. The Endocrine System

5. Maintaining homeostasis high low hormone 1 lowers body condition hormone 2 gland specific body condition raises body condition gland Feedback

6. Negative Feedback Response to changed body condition ◦ if body is high or low from normal level  signal tells body to make changes that will bring body back to normal level ◦ once body is back to normal level, signal is turned off high hormone 1 lowers body condition gland specific body condition

7. Regulation How we maintain homeostasis ◦ nervous system  nerve signals control body functions ◦ endocrine system  hormones  chemical signals control body functions

8. Hormones Why are hormones needed? ◦ chemical messages from one body part to cells in other parts of body ◦ communication needed to coordinate whole body ◦ maintaining homeostasis growth hormones

9. Endocrine System Endocrine system releases hormones ◦ glands which secrete (release) chemical signals into blood  chemicals cause changes in other parts of body  growth hormones  sex hormones  response hormones  metabolism hormones  and more….

10. Responding to hormones Lock and key system ◦ hormone fits receptor on “target” cell target cell non- target cells secreting cell can’t read signal

11. II. Endocrine System vs Neuronal System 1. Neural & Hormonal communication a. Similarities i. Chemicals are stored and released ii. Release of chemicals is due to stimulation iii. Many different hormones & neurotransmitters iv. Both systems react w/specific receptors

12. v. Second messenger involved in both (The first messenger reacts to the initial signal - like an ionotropic receptor, found in CNS only) 2. Second messenger reacts to a signal from a first messenger (like a metabotropic receptor) and affects intracellular functioning; it is a complex intracellular response that affects functioning.

13. b. Differences i. In nervous system, neurons communicate with adjacent neurons; in hormones messages are sent long distances ii. Neural messages induce rapid response compared to hormones which have slower messages iii. Neural messages follow the all or none principle; hormonal messages are graded in strength iv. Neural messages can be directed as observed in behavior; hormonal messages are primarily involuntary (cannot be directed)

14. 2. Three types of hormones a. Protein hormones – effect is on receptors within the membrane, binds to the receptors on the outside of membrane; its effects are the most rapid of all the hormones i. Oxytocin – involved in development of relationships ii. Adrenocorticotrophin – protein hormone; chains of amino acids

15. b. Amine hormones – same relatively fast receptor response as protein hormones i. Epinepherine ii. Norepinepherine iii. Thyroid hormones iv. Melatonin c. Steroid hormones – binds to the intercellular receptors; slow actions i. Gonadal hormones 1. Estrogen, progesterone, androgens ii. Adrenal hormones 1. Glucocorticoids, mineralocorticoids

19. Major Glands of the Endocrine System Hypothalamus Pituitary Thyroid Adrenal Gonads: Ovaries & Testes

22. 21 Consists of: glands secrete hormones into bloodstream to target tissues The Endocrine System

23. 22 Homeostasis exists when there is a balance of substances. Endocrine conditions are due to either hypo (too little) or hyper (too much) secretions of substances (hormones). hyper hypo

24. 23 Hypothalamus Part of the nervous system. Also serves as an endocrine gland because it releases hormones that regulate pituitary hormones Hormones released have either a releasing or an inhibiting factor

26. 25 Pineal Gland Located superior and posterior to the pituitary gland Releases melatonin, a hormone believed to affect sleep and gonad functioning

27. Pituitary Anterior Pituitary - derived during embryological development from the roof of the mouth - connected to the hypothalamus by a portal system (hypothalamic-pituitary portal system) - most of the hormones are released from the anterior pituitary

28. Posterior Pituitary - derived from nervous tissue - two protein hormones released: oxytocin & vasopressin _________________________________ Two Important Points: Hormones released from the posterior pituitary are synthesized in the hypothalamus. Hormones released from the anterior pituitary are dormant unless directed to be released by the hypothalamus via Releasing Factors.

31. Hypothalamus Anterior Pituitary Posterior Pituitary Target Organs RF SH Hormone RF = Releasing Factor SH = Stimulating Hormone Pituitary & all Hormones are Under the Control of the Hypothalamus

32. Hypothalamic Hormones: Gondotropin RF Corticotropin RF (CRF) Thyrotropin RF Growth Hor RF Prolactin RF Pituitary Hormones: Follicle SH & Luteinizing Hor. Thyrotropin SH Adrenocorticoptropin Hormone (ACTH) Prolactin Growth Hormone Target Gland or Structure: Ovaries & Testes (androgens, estrogen) Adrenal Gland (cortisol) Cells of body Thyroid Gland (thyroxine) Bones, breasts & cells of body

34. Adrenal Gland i. Adrenal cortex (outer) produces about 50 different chemicals including… 1. Mineralocorticoids (outer layer) 2. Glucocorticoids, cortisol (middle layer) 3. Sex hormones (inner most layer) a. Estrogen, progesterone androgens note: Congenital adrenal hyperplasia – too much testosterone produced by mother. This comes from dysfunction in adrenal gland. ii. Adrenal medulla (inner) 1. Dopamine  Norepinepherine/Epinepherine

37. Thyroid Gland 1. Too little thyroxin – hypothyroidism a. Depression (clinical or subclinical), attention & memory problems 2. Too much thyroxin – hyperthyroidism a. Agitation, irritability, & weight loss *Goiters – Growths on thyroid gland

39. Gonads & Hormones LH & FSH

40. Growth Hormone Cells of body in response to growth hormone i. During childhood GH is at maximum 1. Too little and we have a small person 2. Too much and we have gigantism, often accompanied by acromegaly (continued growth of extremities of bones) a. Makes hands, feet, jaw, nose, and eye sockets (orbits) enlarged

41. Oxytocin The hormone involved in inducing labor during childbirth Hormone involved in bonding Hormone involved in relationships Might be deficient in Autism

43. All hormones utilize feedback loops: Autocrine response – Same as the autoreceptors, both communicate and terminate release Note similarity to the CNS: Autoreceptors – in the CNS the receptors on presynaptic cell that are sensitive to its own NT

44. 43 Parathyroid Gland Four oval shaped glands located on the dorsal side of the thyroid Regulates calcium and phosphate levels Thymus Gland Also part of the immune system The hormones secreted stimulate the production of T and B cells Adrenal Glands A pair of glands, each one situated on top of a kidney Each gland has an outer portion (adrenal cortex) and inner portion (adrenal medulla) Regulates electrolytes Adrenal medulla secretes catecholamines (epinephrine and norepinephrine) in response to stress

47. 46 Helps maintain proper blood glucose levels Is both an endocrine and exocrine gland. The islets of Langerhans serve its endocrine functions Two types of cells, alpha and beta are produced by the islets of Langerhans Insulin is released by the beta cells which stimulate the glucose to be sent to the body’s cells and convert unused glucose to glycogen Low Blood sugar Glucagon is released by the alpha cells which stimulate stored glycogen to be transformed into glucose again Blood sugar Elevated Pancreas

48. 47 Insulin and Glucagon Insulin Glucagon Artery Drop in blood glucose stimulates glucagon secretion Rise in blood glucose stimulates insulin secretion Promotes movement of glucose into certain cells Stimulates formation of glycogen from glucose In response to insulin, blood glucose drops toward normal (and inhibits insulin secretion) In response to glucagon, blood glucose rises toward normal (and inhibits insulin secretion) Stimulates cells to break down glycogen into glucose Stimulates cells to convert non-carbohydrates into glucose Pancreas

50. Ultimately,what controls the endocrine system? Our emotions Our perceptions Our cognitions Our experiences Our behavior Our response to the environment Higher Brain Areas Hypothalamus Pituitary Endocrine Glands

51. 50 OvariesTestes Located in the female pelvic region one attached to the top of each fallopian tube Produce the female hormones: -estrogen -progesterone Located in the scrotum, a sac outside the body Produce spermatozoa which fertilizes the female ova Produce male sex hormones: -testosterone

52. 51 Combining FormMeaning aden(o) adren(o) gluc(o) glyc(o) gonad(o) pancreat(o) parathyroid(o) thyr(o) gland adrenal glands glucose glycogen sex glands pancreas parathyroid thyroid gland

53. 52 Abbreviation Meaning ACTH ADH CRH DM FSH GH GTT HCG adrenocorticotropic hormone antidiuretic hormone corticotropin-releasing hormone diabetes mellitus follicle-stimulating hormone growth hormone glucose tolerance test human chorionic gonadotropin

54. 53 Abbreviation Meaning IDDM LH MSH NIDDM PRL PTH STH TSH insulin-dependent diabetes mellitus luteinizing hormone melanocyte-stimulating hormone noninsulin dependent diabetes mellitus prolactin parathyroid hormone, parathormone somatotropin hormone thyroid-stimulating hormone