Anatomy and Physiology

1. Anatomy and Physiology The Endocrine System

2. The endocrine systemincludesanything that secretes hormones directly into body fluids. • Endocrine glands include: the thyroid, parathyroid, adrenal, kidney, hypothalamus, pituitary, pineal, pancreas, ovaries, testes, and thymus glands. • The function of the endocrine systems is to regulate metabolic pathways (chemical rxns, electrolyte balance, membrane transport, reproduction, & digestion) by secreting hormones.

3. http://www.worsleyschool.net/science/files/hormones/mainpic.gifhttp://www.worsleyschool.net/science/files/hormones/mainpic.gif

4. Some terms: • Hormone: a biochemical that affects a specific metabolic pathway in another cell. • These are secreted into body fluids & blood. • These are mostly steroids and made from cholesterol but some are amines, peptides, proteins, and glycoproteins. • Target cells (or organs): cells or organs that receive the hormone (cell that is affected). These cells have binding sites (a.k.a. receptors) for specific hormones.

5. Hormones are placed in 2 groups: Steroid hormones and Nonsteroid hormones. • Steroid Hormones: lipid soluble, meaning they easily pass (diffuse) thru membranes. These are formed from cholesterol usually. • Nonsteroid hormonesmust bind to receptors of target cells (do not diffuse thru membranes). These are amines, peptides, proteins, and glycoproteins.

6. Hormonal Secretion Control: • This is done by negative feedback control. • Mechanism that regulates the production of hormones based on the accumulation of another substance along a metabolic pathway. For example: • The adrenal gland produces chemical A which continues a pathway: A BC D E • When E is accumulated, it prevents (or inhibits) the adrenal gland from producing A. This is a negative feedback mechanism.

7. http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/endocrine%20system/cortisol.gifhttp://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/endocrine%20system/cortisol.gif http://www.google.com/imgres

8. The Endocrine Glands and Their Hormones

9. The Pituitary Gland: • found in the base of the brain • has 2 parts: anterior and posterior (based on the lobe of the brain in which it is found). • controlled by the hypothalamus (by releasing hormones) http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T012393A.gif

10. The Pituitary Hormones: Anterior Pituitary Hormones: • Growth Hormone (GH):stimulates growth of cells (increase in size & cell division). • Prolactin (PRL):stimulates and sustains the milk production in new mothers. • Thyroid-Stimulating Hormone (TSH):controls thyroid gland secretions and is partially regulated by the hypothalamus.

11. Anterior Pituitary Hormones (cont’d): • Adrenocorticotropic hormone (ACTH):controls the hormone production of the adrenal cortex. Stress may increase ACTH. • Follicle-stimulating hormone (FSH) and luteinizing hormone (LH): are released in the gonads (testes and ovaries).These are called gonadotropins.

12. The Posterior Hormones: • Antidiuretic hormone (ADH):decreases urine production by regulating the amount of water the kidneys excrete; therefore, regulating [water] in body fluids. • Oxytocin (OT): considered an antidiuretic; it stimulates the uterine muscles to contract (causing contractions & birth), lactationb/c it stimulates milk-producing glands, and milk ejection.

13. The Thyroid Gland and its hormones: • This is located on both sides of the larynx and in front of the trachea. • Thyroxine (a.k.a. T4or tetraiodothyronine) has 4 atoms of iodine and Triiodothyronine (a.k.a. T3) has 3 atoms of iodine (is 5 times stronger). Both regulate the metabolism of carbs (stimulate their use), proteins (stimulate their production), & lipids (stimulate their breakdown). • Calcitonin: not technically a thyroid hormone (b/c of the location of production). This regulates the [Ca] and [phosphate ions] in the blood.

14. Thyroid http://stb.msn.com/i/D8/DF6013611CDFDC22A8FB8E28C1DFF.jpg

15. The Parathyroid Glands and their hormones: • These 4 are found on the thyroid gland. • These secreteparathyroid hormone (PTH):increases blood [Ca++] and decreases blood [phosphate ion], affecting the kidneys, bones & intestines. This works with calcitonin and is regulated by the [ ] of these ions in the blood. http://stb.msn.com/i/BD/F8BC26E3251ABD2F3FEA4607A1D47.jpg

16. The Adrenal Glands and their hormones: • This is located on top of the kidneysand contains 2 portions: • adrenal medulla (central portion) • adrenal cortex (outer portion). http://www.massgeneral.org/cancer/crr/types/endocrine/images/adrenal_gland.jpg

17. The Adrenal Cortical Hormones: • Aldosterone: regulates the [mineral] in the blood, stimulating water retention and sustaining b.p. and volume. • Cortisol: a.ka. hydrocortisone, affects glucose, protein & fat metabolism. • Adrenal Sex Hormones: in males, a.k.a.adrenal androgens; in females, a.k.a. estrogens. These supplement sex hormones & stimulate gonad development.

18. The Adrenal Medulla Hormones: • Epinephrine (a.k.a.adrenaline) and norepinephrine (a.k.a.noradrenaline) are released simultaneously. These increase the heart rate, increase heart contractions, increase breathing rate, increase b.p., increase blood glucose levels, & decrease digestion causing the typical “fight or flight reaction”

19. The Pancreas and its Hormones: • This is found by the stomach and has 2 functions:exocrine gland (secretes digestive juices) and endocrine (releasing hormones). • The endocrine section contains groups of cells known as theIslets of Langerhans which contain alpha cells (secrete glucagon) and beta cells (secrete insulin). http://www.pancreatic.org/atf/cf/%7BA69EE367-5C5C-4B26-A094-64E9EA47D990%7D/image001.jpg

20. The Pancreatic Hormones: • Glucagon: produced by alpha cells; stimulates the breakdown of glycogen and amino acids. It raises [blood sugar] and is regulated by a low blood sugar (hypoglycemia). • Insulin: produced by beta cells; stimulates the liver to make glycogen, promotes the transport of glucose into cells, stimulates protein synthesis and stimulates fat storage; thus,it decreases [blood sugar] and is regulated by a high blood sugar(hyperglycemia).

21. Blood Sugar Regulation: http://www.endocrineweb.com/images/sugar.gif

22. Other Endocrine Glands

23. Pineal Glands: • This is found in the brain on the upper portion of the thalamus. • This secretes melatonin which regulatescircadian rhythms (response to light and dark conditions of the environment. These rhythms dictate sleep patterns & seasonal cycles of fertility in some mammals. http://training.seer.cancer.gov/module_anatomy/images/illu_pituitary_pineal_glands.jpg

24. Thymus Gland: • This is found between the lungs (shrinks with age). • This secretesthymosins which regulate the production & differentiation of white blood cells, specifically T cells (T lymphocytes) http://www.besthealth.com/besthealth/bodyguide/reftext/images/Thymus_spleen.jpg

25. Reproductive Glands: • Ovaries: produceestrogens & progesterone • Testes: producetestosterone • Placenta: producesestrogens, progesterone & gonadotropin http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/17122.jpg http://www.actionhealthinc.org/teenzone/images/female.jpg http://www.malecontraceptives.org/methods/images/heat.jpg

26. Heart: producesatrial natriuretic peptide (stimulates urinary Na secretion). • Kidneys:produceerythropoietin (stimulates the production of rbc’s). http://www.nhlbi.nih.gov/health/dci/images/heart_interior.gif http://www.healthline.com/blogs/health_observances/uploaded_images/kidney-713543.jpg

27. Stress and Health: • Stress is defined as a condition that causes change in the internal environment (a physiological response that alters homeostasis). • A stressor is a factor that causes stress. http://www.google.com/imgres

28. Stress and Health: There are types of stressors: • physical which can be temperature changes internally or externally, [O2] changes, injury, illness (infections), exercise, noise, etc. • psychologicalfactors which include emotions, feelings (anger, joy, fear, grief, anxiety, depression, etc.), thoughts, losses, unpleasant and pleasant encounters, and sexual arousals/encounters. http://www.google.com/imgres

29. Response to stress: These are physiological responses, calledgeneral stress syndrome, which is an adaptation to general stress. • This is controlled by the hypothalamuswhich activates fight or flight rxns (increases epinephrine output). The physical responses include: • Increased [blood glucose] levels • increased heart rate • increased rate of breathing • increased b.p. • air passage dilation http://www.google.com/imgres

30. Other hormones are increased in output as well:glucagons, GH (both increase use of energy sources) and ADH (decrease urine output, conserving water, & maintaining blood volume). • In addition, cortisol is increased which decreases the # of lymphocytes (increasing risk of infection/illness by lowering resistance and increasing the risk of high b.p., GI ulcers and atherosclerosis).

31. Look up online or in text! • Know the following: dwarfism, gigantism, acromegaly, diabetes insipidus, goiters, Grave’s disease, cretinism, exophthalmos, tetany, Addison’s disease, Cushing’s syndrome, diabetes mellitus, ketosis, polyuria, polydipsia, polyphagia, insulin resistance, and menopause.