Exercise 18 Endocrine System Glucometer Portland Community College

Exercise 18 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

Neuroendocrine effect • The endocrine system operates in conjunction with the nervous system to maintain homeostasis and to ensure that bodily functions are carried out efficiently. • Nerve impulses can affect the release of hormones and hormones can regulate nerve impulses 4

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Endocrine Organs in Head • Pineal gland Secrets: • Melatonin • Involved in circadian rhythms • Day melatonin, Night melatonin • Produces sleepiness 6

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

Endocrine Organs in Head • • Hypophysis 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

Pituitary Histology 10

Endocrine Organs in Neck • 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

Thyroid Histology 12

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

Parathyroid Histology 14

Endocrine organs in thoracic • 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. • The thymus gland produces hormones called thymosins that promote maturation of Tlymphocytes that coordinate the body’s immune response. 15

Endocrine Organs located in abdominopelvic cavity • • • Pancreas secretes: Insulin • Released in response to high blood sugar • Increases cellular absorption of glucose • Increases rate of lipogenesis and formation of glycogen in the liver Glucagon • Released in response to low blood sugar • Elevates blood glucose levels by promoting the breakdown of glycogen. 16

Pancreas • Acinar cells secrete digestive enzymes (exocrine) • Islet cells secrete insulin (beta cells) and glucagon (alpha cells) 17

Adrenal Glands 18

Endocrine Organs located in abdominopelvic cavity • • • 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 19

Endocrine Organs located in abdominopelvic cavity • 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 20

Hormones from the Kidneys • Erythropoietin • Stimulates RBC production • Calcitriol • Stimulates calcium and phosphate absorption • Stimulates calcium release from bone • Inhibits PTH secretion 21

Adrenal Histology 22

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

Gonads • Ovaries in females produce estrogens • Testes in males produce testosterone 24

Ovary • Have an outer cortex that contains ovarian follicles at various stages of development. • Each follicle contains a developing egg cell called an oocyte • Inner medulla is a region of loose connective tissue 25

Testis • Tunica albuginea is a fibrous connective tissue covering. • Connective tissue partitions derived from the tunica albuginea divide the testes into lobules 26

Testes • Each lobule of the testes are three or four seminiferous tubules. • Collectively these cells are called spermatogenic cells. • The interstitial areas contain the interstitial (Leydig) cells. 27

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 28

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) 29

Diagnosing Diabetes Mellitus • Normal blood glucose levels: 70 -100 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 75 gm of glucose • Impaired Glucose Tolerance (Pre-Diabetes) • A fasting glucose level between 100 -126 mg/dl on two separate occasions, or • A blood sugar between 140 -200 mg/dl 2 hours after oral glucose tolerance test with 75 gm of glucose 30

The End 31