Exercise 28 Endocrine System Glucometer Portland Community College BI 232

The endocrine system Diverse collection of organs and tissues that contain endocrine glands. Glands secrete chemicals called hormones into blood capillaries Hormones are transported to target cells at a distant location Hormone binds to a specific receptor and the cell responds to message. 2

Endocrine and Exocrine Exocrine glands secrete substances into ducts, which transport the secretions internal cavities of organs or to surface of the skin. 3

Effects of Hormones Areas receptive to hormones are called target cells and may be tissues or organs. Can have many effects such as growth, development, metabolism, etc. Many organs produce hormones such as heart, stomach and kidneys. 4

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Pineal Gland Secretes: Melatonin Involved in circadian rhythms Day  melatonin, Night  melatonin Produces sleepiness 6

Hypothalamus and Pituitary Gland (Hypophysis) Hypothalamus produces a number of releasing hormones and inhibiting hormones. Stored in posterior pituitary (neurohypophysis) ADH (antidiuretic hormone) Reduces urine output by increasing water reabsorption in the kidney Plays small role in blood pressure regulation Also called vasopressin Oxytocin Causes uterine contractions in labor Causes milk let down in lactating mothers 7

Anterior lobe (Adenohypophysis) ACTH (adrenocorticotropic hormone) Regulates the activity of the cortex of the adrenal gland TSH (thyroid stimulating hormone) Stimulates production and release of thyroid hormone GH (growth hormone) Stimulates growth of bones, cartilage, muscle Timing and amount released determines body size 8

Endocrine Organs in Head PRL (prolactin) Stimulates breast development Promotes and maintains lactation after childbirth FSH (follicle stimulating hormone) Causes formation of ovarian follicles and stimulates them to produce estrogen Stimulates sperm development in men LH (luteinizing hormone) Initiates ovulation, maintains corpus luteum Regulates testosterone production in males 9

10 Pituitary Histology Intermediate lobe (part of the anterior lobe) produces melanocyte stimulating hormone

Thyroid Gland Secretes: Thyroid Hormone Regulates metabolic rate of the entire body Important in development of the nervous system Calcitonin Decreases bone reabsorption, lowering serum calcium levels PTH (parathyroid hormone) Increases serum calcium Decreases serum phosphorus 11

12 Thyroid Histology

13 Thyroid Histology Follicular cells produce the colloid (contains precursors to thyroid hormone) Parafollicular cells secrete calcitonin

14 Parathyroid Histology

Thymus Active in young individuals and plays a part in immunocompetency. Produces thymosin which causes maturation of T cells. T cells start out in bone marrow and migrate to thymus 15 The T cells migrate to lymph nodes and spleen to carry out their functions.

Hormones secreted by heart Heart: If blood volume is elevated above normal, cardiac muscle cells in the heart was secrete natriuretic peptides. Act on the kidneys to promote the loss of sodium ions and water. 16

Pancreas Secretes: Insulin (beta cells) Released in response to high blood sugar Increases cellular absorption of glucose Increases rate of lipogenesis and formation of glycogen in the liver Glucagon (alpha cells) Released in response to low blood sugar Elevates blood glucose levels by promoting the breakdown of glycogen. Somatostatin (delta cells) inhibit both Insulin and glucagon and may increase efficiency in digestion. 17

18 Pancreas Acinar cells secrete digestive enzymes (exocrine) Islet cells secrete insulin (beta cells) and glucagon (alpha cells)

19 Adrenal Glands

Secrete: Glucocorticoids (Cortisone) Released in response to stress Increases formation of glucose from protein and fat breakdown Decreases inflammation Aldosterone Increases blood volume by causing kidneys to retain sodium (where sodium goes water goes too) in exchange for potassium Increased blood volume will increase blood pressure 20

Adrenal Glands Androgens Are male sex hormones that are produced in small quantities and converted to estrogens (female sex hormones) when they enter the blood Epinephrine & Norepinephrine Fight or flight response Increase heart rate, increase skeletal muscle blood flow, decrease skin blood flow 21

22 Adrenal Histology

23 Adrenal Cortex Zona Glomerulosa: Aldosterone Zona Fasiculata: Glucocorticoids (Cortisone) Zona Reticularis: Androgens

Hormones from the Kidneys 24 Erythropoietin Stimulates RBC production Calcitriol Stimulates calcium and phosphate absorption Stimulates calcium release from bone Inhibits PTH secretion

Gonads Ovaries in females produce estrogens Testes in males produce testosterone Both are stimulated by FSH from anterior pituitary Influenced by LH which increases the level of hormone produced 25

Testis Produce testosterone responsible for secondary sex characteristics such as facial hair and expansion of larynx. Inhibin involved in negative feedback providing regulation of testosterone production 26

Testes seminiferous tubules where the sperm are produced The interstitial areas contain interstitial (Leydig) cells where the testosterone is produced. 27

Ovary Produce oocytes (eggs) and have an endocrine function by producing estrogen and progesterone Responsible for secondary sex characteristics in women. 28

29 Diabetes Type 1: Insulin Dependent Diabetes AKA: juvenile diabetes Caused by a lack of insulin Autoimmune disorder Immune system destroys beta cells in the pancreas

30 Diabetes Type 2: Non-Insulin Dependent Caused by an insensitivity of cells to insulin. Diabetes mellitus marked by hyperglycemia  urine production (polyuria)  thirst (polydipsia)  eating (polyphagia)

31 Diagnosing Diabetes Mellitus Normal blood glucose levels: mg/dl Diabetes mellitus: A fasting glucose level above 140 mg/dl on two separate occasions, or A blood sugar over 200 mg/dl 2 hours after oral glucose tolerance test with 75gm of glucose Impaired Glucose Tolerance (Pre-Diabetes) A fasting glucose level between mg/dl on two separate occasions, or A blood sugar between mg/dl 2 hours after oral glucose tolerance test with 75gm of glucose

Glucometer Exercise We need 4 volunteers to let us test their blood glucose levels at 30 minute intervals. Measure glucose level Drink soda or juice After 30 min test again 1 hour after drinking test again If levels haven’t gone down after test again after 2 hours 32

Endocrine physiology experiment LH stimulates the final maturation of the oocyte and causes ovulation. About hours prior to ovulation there is a spike. Are there any students in the middle of your ovarian cycle like to volunteer to test for the presence of LH? If a woman has significant amounts of LH then the test strip produces a color (usually blue) 33

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41 The End