NGRTCI Endocrine System Anatomy Lecture


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Endocrine System Anatomy Lecture

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NGRTCI Endocrine System Anatomy Lecture

  2. 2. God the Father Creator of all things living and no-living true source of light and wisdom enlighten our heart and mind to follow your will today help us to avoid confusions and lead us to clarification let your sublime wisdom penetrate our humanity…
  3. 3. and your light shine our dark parts give us the source of inspiration that we may become also an inspiration to others. we ask this through Christ our Lord AMEN.
  4. 4. The cells, tissues, and organs are called endocrine glands • They are ductless • They use the bloodstream • They secrete hormones • There are also similar glands called paracrine and autocrine glands that are quasi-endocrine Glands that secrete substances are the exocrine glands • They have ducts • They deliver their products directly to a specific site Hormone secretion (a) (b) Blood flow Skin Duct Thyroid gland Endocrine gland Endocrine cell Exocrine gland (sweat gland) Exocrine cells
  5. 5. Nerve impulse Bloodstream Neuron transmits nerve impulse Glandular cells secrete hormone into bloodstream Neurotransmitter released into synapse Post- synaptic cell responds Target cells (cells with hormone receptors) respond to hormone Hormones have no effect on other cells
  6. 6. Hypothalamus Pituitary gland Thyroid gland Thymus Adrenal gland Pancreas Parathyroid gland Pineal gland Kidney Testis (in male) Ovary (in female) Chemically, hormones are either: • Lipid-soluble Hormones  Steroid hormones  Thyroid hormones  Nitric oxide (NO) • Water-soluble Hormones  Amine hormones  Peptide hormones and protein hormones  Eicosanoid hormones
  7. 7. 1. Hormonal mechanism: for example, the hypothalamus secretes hormones that stimulate the anterior pituitary gland to secrete hormones that stimulate other endocrine glands to secrete hormones. 2. Humoral mechanism: for example, capillary blood contains a low concentration of calcium that stimulates secretion of parathyroid hormone. Parathyroid hormone makes serum calcium go up. 3. Neural mechanism: preganglionic SNS fiber stimulates the adrenal medulla cells to secrete catecholamines.
  8. 8. Nervous system Target cells Action Target cells Action – – – – Anterior pituitary gland Action Hypothalamus Peripheral endocrine gland Target cells Endocrine gland Changing level of substance in plasma Endocrine gland
  10. 10. Optic nerve Sphenoid bone Hypothalamus Optic chiasma Sella turcica Third ventricle Trochlear nerve Basilar artery Anterior cerebral artery Pituitary stalk (Infundibulum) Anterior lobe of pituitary gland Sphenoidal sinus Posterior lobe of pituitary gland Oculomotor nerve
  12. 12. • Growth hormone (GH): controls growth and protein, carbohydrate, and lipid metabolism. Production of growth hormone is controlled by two other hormones: 1. Somatostatin: inhibits growth hormone. 2. Somatotropin: stimulates secretion of growth hormone. • The majority of growth hormone is secreted during sleep. Other factors that increase secretion of growth hormone are exercise, stress, hypoglycemia, starvation, and hypothyroidism.
  13. 13. 1. Prolactin: stimulates breast growth and production of milk. 2. FSH: stimulates development of egg and sperm and secretion of sex hormones. 3. LH: stimulates the production of progesterone and regulates ovulation in women, and regulates testicular growth, testosterone production, and androgen production in men. To stimulate the release of these gonadotropic hormones, gonadotropin-releasing hormone (GnRH) must be present.
  14. 14. Important for cervical dilatation prior to birth, and helps the uterus to contract during labor and delivery, especially during the second and third stages. In breast-feeding (lactating) mothers, oxytocin causes milk to be “let down” into area of breast where baby can suckle and receive milk. When ADH is secreted, WATER is retained in the vascular space.
  15. 15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Follicular cells Colloid Extrafollicular cells © Fred Hossler/Visuals Unlimited Larynx Colloid Isthmus (a) (b) Thyroid gland Follicular cell Extrafollicular cell Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  16. 16. When thinking about thyroid hormones think energy and metabolism!
  17. 17. 1. Increases the metabolism of protein, fat, and glucose. 2. Increases body temperature in response to an elevated metabolism, which produces body heat. 3. Increases the use of oxygen as metabolism increases. 4. Aids in the development of the neural and skeletal systems in fetuses. 5. Helps regulate secretion of growth hormone. 6. Aids in production of red blood cells. 7. Affects respiratory rate: too much thyroid hormone increases respiratory rate, and too little decreases respiratory rate. 8. Aids in normal growth and development.
  18. 18. • Both T3 and T4 increase metabolic rate of cells and tissues. • T4 is the precursor to T3. • T3 regulates the metabolic rate of all cells and all processes of cell growth and tissue differentiation. • T3 and T4 indirectly increase blood glucose levels. • Being cold increases the conversion of T4 to T3. • Things such as stress, starvation, certain dyes, and certain drugs like steroids, beta-blockers, PTU (propylthiouracil), and amiodarone decrease the conversion of T4 to T3.
  19. 19. • Targets the bones, kidneys, and epithelial cells of the intestines. • Decreases blood/serum calcium in three ways: 1. Decreases intestines’ ability to absorb calcium. 2. Decreases osteoclast activity in the bones. 3. Decreases calcium resorption from the kidney tubules. Bone resorption occurs when osteoclasts break down bone and release calcium from the bone into the blood.
  20. 20. Posterior view Esophagus Pharynx Thyroid gland Parathyroid glands Trachea Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Secretory cells Capillaries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © R. Calentine/Visuals Unlimited
  21. 21. Liver Intestinal enzymes Ultraviolet light in skin Kidney Stimulated by PTH Hydroxycholecalciferol Foods Ca+2 Ca+2 Ca+2 Cholesterol Provitamin D Vitamin D (Cholecalciferol) Also obtained directly from foods Dihydroxycholecalciferol (active form of vitamin D) Controls absorption of calcium in intestine • Parathyroid hormone (PTH) makes the serum calcium level go up! • Too much PTH hyperparathyroidism hypercalcemia, hypophosphatemia, bone damage, and renal damage. • Too little PTH hypoparathyroidism, hypocalcemia, hyperphosphatemia, hyperreflexia, and cognitive changes (altered sensorium).
  22. 22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PTH Ca+2 + PTH PTH Ca+2 + Ca+2 Bloodstream –Stimulation Inhibition Release into bloodstream Parathyroid glands (on posterior of thyroid gland) Decreased blood calcium stimulates parathyroid hormone secretion Increased blood calcium inhibits PTH secretion Kidneys conserve Ca+2 and activate Vitamin D Bone releases Ca+2 Intestine absorbs Ca+2 Active Vitamin D
  23. 23. CortexMedulla Capsule Zona glomerulosa Zona fasciculata Zona reticularis Chromaffin cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke Adrenal gland Kidney Adrenal cortex (a) Zona lomerulosa Connective tissue capsule (b) Zona fasciculata Zona reticularis Adrenal medulla Adrenal cortex Adrenal medulla Surface of adrenal gland Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  24. 24. Many heart attacks occur during the early morning hours when people are coming out of REM sleep, as this is a very stressful time for the body.
  25. 25. 1. Stimulate gluconeogenesis (the formation of carbohydrates from proteins and other substances by the liver). 2. Provide amino acids and glucose during times of stress. 3. Suppress the immune system due to powerful immunosuppressive and anti-inflammatory properties. 4. Stimulate fat breakdown.
  26. 26. An increase in aldosterone secretion is also caused by: • Low fluid volume levels in the vascular space as in shock or hypovolemia. • High blood levels of potassium. The illnesses associated with aldosterone are: • Hyperaldosteronism (Conn’s syndrome) • Hypoaldosteronism
  27. 27. Sex hormones are usually broken down into three categories: 1. Androgens, testosterone being the main one. 2. Estrogens, estradiol being the main one. 3. Progestagens, progesterone being the main one. Synthetic androgens (sex hormones) are referred to as anabolic steroids.
  28. 28. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pancreatic islet (Islet of Langerhans) From Kent M. Van De Graaff and Stuart Ira Fox, Concepts of Human Anatomy and Physiology, 2nd ed. ©1989 Wm. C. Brown Publishers, Dubuque, Iowa. All Rights Reserved. Reprinted with permission Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gallbladder Common bile duct Pancreatic duct PancreasDuct Capillary Small intestine Digestive enzyme- secreting cells Pancreatic islet (Islet of Langerhans) Hormone-secreting islet cells
  29. 29. too high too low Control center Beta cells secrete insulin Receptors Beta cells detect a rise in blood glucose Effectors Insulin • Promotes movement of glucose into certain cells • Stimulates formation of glycogen from glucose Stimulus Rise in blood glucose Response Blood glucose drops toward normal (and inhibits insulin secretion) Normal blood glucose concentration Stimulus Drop in blood glucose Response Blood glucose rises toward normal (and inhibits glucagon secretion) Receptors Alpha cells detect a drop in blood glucose Effectors Glucagon • Stimulates cells to break down glycogen into glucose • Stimulates cells to convert noncarbohydrates into glucose Control center Alpha cells secrete glucagon
  30. 30. Pineal Gland • Secretes melatonin • Regulates circadian rhythms Thymus Gland • Secretes thymosins • Promotes development of certain lymphocytes • Important in role of immunity Reproductive Organs • Ovaries produce estrogens and progesterone • Testes produce testosterone • Placenta produces estrogens, progesterone, and gonadotropin Other organs: digestive glands, heart, and kidney
  31. 31. Sympathetic impulses CRH released ACTH released Cortisol released Long-term adjustment or resistance stage • Increase in blood concentration of amino acids. • Increased release of fatty acids. • Blood glucose increases. • Blood glycerol and fatty acids increase. • Heart rate increases. • Blood pressure rises. • Breathing rate increases. • Air passages dilate. • Pupils dilate. Anterior pituitary Hypothalamus Adrenal cortex Adrenal medulla Neural signals Hormonal signals Stress results from changes in the external environment Signals from sensory receptors Epinephrine and norepinephrine released Norepinephrine released Short-term “fight or flight” or alarm stage. • Blood flow redistributes. • Increased glucose formed from noncarbohydrates—amino acids (from proteins) and glycerol (from fats).
  32. 32. • Endocrine glands decrease in size • Muscular strength decreases as GH levels decrease • ADH levels increase due to slower break down in liver and kidneys • Calcitonin levels decrease; increase risk of osteoporosis • PTH level changes contribute to risk of osteoporosis • Insulin resistance may develop • Changes in melatonin secretion affect the body clock • Thymosin production declines increasing risk of infections
  33. 33. test Normal values significance Thyroid-stimulating hormone 0.5–5.0 U/mL ↑ in primary hypothyroidism ↓in primary hyperthyroidism Triiodothyronine (T3) 80–200 ng/100 mL ↓ in hypothyroidism ↑ in hyperthyroidism Thyroxine (T4 ) 4–12 g/100 mL ↓ in hypothyroidism ↑ in hyperthyroidism
  34. 34. test Normal values significance Parathyroid hormone 25 pg/mL ↑ in primary hyperparathyroidism ↓ in primary hypoparathyroidism, parathyroid trauma during thyroid surgery Calcium 8.5–10.5 mg/100 mL ↑ in some cancers, hyperparathyroidism ↓ in hypothyroidism Phosphorus 2.4–4.7 mg/dL ↑ in hypoparathyroidism ↓ in hyperparathyroidism
  35. 35. test Normal values significance Growth hormone 5 ng/mL ↑ in acromegaly ↓ in small stature Antidiuretic hormone 2.3–3.1 pg/mL ↑ in SIADH ↓ in diabetes insipidus Urine specific gravity 1.010–1.025 ↓ in diabetes insipidus Adrenocorticotropic hormone 120 pg/mL at 6–8 a.m. ↑ in Addison’s disease ↓ in Cushing’s syndrome, long- term corticosteroid therapy
  36. 36. test Normal values significance Cortisol 5–25 g/100 mL ↑ in Cushing’s syndrome, stress ↓ in Addison’s disease, steroid withdrawal Vanillylmandelic acid (VMA) 0.7–6.8 mg/24 h ↑ in pheochromocytoma
  37. 37. test Normal values significance Fasting plasma glucose (FPG) 70–100 mg/dL in stress, Cushing’s syndrome FPG 101–125 pre-diabetes FPG 126 diabetes mellitus ↓ in hypoglycemia, Addison’s disease Oral glucose tolerance test Blood glucose less than 140 mg/dL at 2 hours BG 140–199 at 2 hours pre- diabetes; BG 200 at 2 hours diabetes mellitus Glycosylated hemoglobin 4%–7% ↑ in poor diabetes control
  38. 38. • A thyroid scan may be done to determine the presence of tumors or nodules. • A computed tomographic (CT) scan or magnetic resonance imaging (MRI) may be done to locate a tumor or identify hypertrophy of a gland. • Ultrasound may be done of the thyroid or parathyroid glands to determine if they are enlarged or to find masses. • Biopsy is done to obtain tissue to examine for possible cancerous cells.