Chapter 18 - Endocrine System- lecture 3.pdf

Part 1: Thyroid Gland, Histology, Hormones, and Regulation. Part 2: Thyroid Hormone Production, the Parathyroid Glands, and Calcium Regulation. Part 3: The Adrenal Gland, Its Histology and Hormones, and Adrenal Gland Imbalances. Part 1:  Describe the anatomy and histology of the thyroid gland, iden...

Part 1: Thyroid Gland, Histology, Hormones, and Regulation. Part 2: Thyroid Hormone Production, the Parathyroid Glands, and Calcium Regulation. Part 3: The Adrenal Gland, Its Histology and Hormones, and Adrenal Gland Imbalances. Part 1:  Describe the anatomy and histology of the thyroid gland, identify hormones secreted by thyroid & functions, & know which region each is secreted from. Part 2:  Explain the formation process for T3 and T4, and identify the imbalances related to hyper- and hypo secretion.  Describe the parathyroid gland, and differentiate the functions of calcitonin and PTH. Part 3:  Explain the function and anatomy of adrenal glands, the different functional section, and the various hormones secreted by the gland w/functions.  Identify and describe the hormone via pineal gland.    Inferior to thyroid cart. (Adam’s apple) of larynx. 2 lobes connected via isthmus. Composed of thyroid follicles. ◦ Hollow spheres lined by simple cuboidal epithelium.   colloid – viscous fluid w/in follicle filled w/Thyroglobulin [TGB], a protein precursor to thyroid hormone produced by follicle cells. Cells surrounded by capillaries delivers/receives nutrients, horm., & wastes.  Can you identify this as the “Thyroid gland”, spot the “C- vs follicle-cells”, know the hormones released, identify the colloid, know what’s stored in the colloid    Pituitary, peptide hormone – stimulates iodine absorption + T3 & T4 production & secretion. Released when levels of T3 and T4 are below normal range. Low levels of T3 & T4 or of TSH results in mental & physical sluggishness  In children, essential for normal development: ◦ Skeletal, muscular, and nervous systems.  If TSH in the blood were high but levels of T3 & T4 were low, what does this indicate?  TSH receptor issue   Most cells; binds intracellular receptors (lipid-sol.) Functions related to? ◦ A) Energy usage/metabolism in some tissue  Processing of lipids, carbs, and proteins ◦ B) Regulation of body temperature ◦ C) Growth & development, esp. for children!  Bone, hair, teeth, connective tissue, and neural tissue.  Important element for its formation? ◦ Iodine;   lack of iodine can lead to? Goiter TH formed w/3 iodine ions=T3or Triiodothyronine. TH formed w/4 iodine ions = T4 or Thyroxine.   Increases metabolic activity by: 1) Elevate oxygen + energy consumption ◦ raises body temperature.  2) Increase heart rate + force of contractions. ◦ raises blood pressure – quicker distribution.   3) Increase sensitivity to sympathetic stimulation. 4) Stimulates RBC formation ◦ Enhances oxygen delivery.    5) Stimulates other endocrine tissues. 6) Accelerates turnover of minerals in bone. Has a calorigenic effect – consumes energy and releases heat! Part 1: Thyroid Gland, Histology, Hormones, and Regulation. Part 2: Thyroid Hormone Production, the Parathyroid Glands, and Calcium Regulation. Part 3: The Adrenal Gland, Its Histology and Hormones, and Adrenal Gland Imbalances. Part 1:  Describe the anatomy of the thyroid, identify the hormones secreted and their functions, and know which region each is secreted from. Part 2:  Explain the formation process for T3 and T4, and identify the imbalances related to hyper- and hypo secretion.  Describe the parathyroid gland, and differentiate the functions of calcitonin and PTH. Part 3:  Explain the function and anatomy of adrenal glands, the different functional section, and the various hormones secreted by the gland w/functions.  Identify and describe the hormone via pineal gland.   1) Iodine Ions actively transported into follicle cells 2) Follicle cells synthesize thyroglobulin - Tyrosine containing globular protein + TH precursor. 18.11 ◦ Fig.18.11 3) TGB + iodine diffuse to apical surface of follicle cells; tyrosines of TGB gets iodinated      4) Iodinated TGB is exocytosed into follicle lumen (2-4 months). 5) w/in colloid, TGB undergoes chemical reactions resulting in globular T3 and T4 6) Globular T3 + T4 w/in TGB are endocytosed 7) w/in follicle cell, TGB broken down into individual T3 & T4 hormones via lysosomes. 8) T3 & T4 diffuse into blood bind to Thyroxine-binding globulin and transported appropriately.  1) Get Iodine, 2) Form TGB, 3) Combine iodine and TGB  4) Transport iodinated TGB into colloid, 5) enzymes convert TGB to globular T3 and T4 w/in colloid.  6) Globular T3 and T4 and endocytosed, 7) lysosomes break globular T3 and T4 into individual T3 and T4 hormones.  8) T3 and T4 diffuse into blood, 9) T3 and T4 bind thyroxine-binding globulin or a transport protein.     Hyperthyroidism – high levels of thyroid secretions Symptoms: increase metabolic rate, high body temp., weight loss, increased appetite, copious sweating, rapid heart rate, high BP, abnormal EKG, weak muscles, hyperactivity, insomnia, + others. Hypothyroidism – low levels of thyroid secretions Symptoms: decrease metabolic rate, low body temp., weight gain, reduce appetite, low sweat and oil secretions causing dry skin, reduced heart rate and BP, enlarged heart, sluggish movement w/weak, untoned muscles, apathetic, always fatiqued, + others.   Produce and secrete calcitonin (CT)? Regulates Ca2+ levels in blood & body fluids by? ◦ Inhibits osteoclasts – slows release from bone. ◦ Stimulates osteoblasts – increase uptake from blood. ◦ Increases excretion of Ca2+ at kidneys.  Net affect of calcium in blood? ◦ Decrease in available calcium in blood.   Glands embedded in posterior surface of thyroid. Chief cells secrete parathyroid hormone. (18.12) ◦ When blood Ca2+ levels are low. What does it do?  1) Stimulates osteoclasts/inhibits osteoblasts. ◦ Accelerates mineral turnover; releasing Ca2+ off bone ◦ Considered calcitonin’s Antagonist?   2) Enhances Ca2+ reabsorption. at kidney 3) Stimulates formation and secretion of Calcitriol by kidneys. ◦ Compliments PTH ◦ Increase uptake of Ca2+ via digestion.    Calcitonin increases bone absorption + calcium secretion, which decreases blood Ca2+ concentration. PTH breaks bone down releasing Ca2+ + reabsorb @ kidney = increases blood Ca2+ concentration. Calcitriol is similar to PTH but increases Ca2+ conc. via absorption at intestines! Part 1: Thyroid Gland, Histology, Hormones, and Regulation. Part 2: Thyroid Hormone Production, the Parathyroid Glands, and Calcium Regulation. Part 3: The Adrenal Gland, Its Histology and Hormones, and Adrenal Gland Imbalances. Part 1:  Describe the anatomy of the thyroid, identify the hormones secreted and their functions, and know which region each is secreted from. Part 2:  Explain the formation process for T3 and T4, and identify the imbalances related to hyper- and hypo secretion.  Describe the parathyroid gland, and differentiate the functions of calcitonin and PTH. Part 3:  Explain the function and anatomy of adrenal glands, the different functional section, and the various hormones secreted by the gland w/functions.  Identify and describe the hormone via pineal gland.    Located superiorly to each kidney. (fig. 18.14) 2 regions: 1) Adrenal cortex (superficial) ◦ Stores lipids (high cholesterol and fatty acids) ◦ Manufactures steroid hormones (3 types).  2) Adrenal medulla (inner region) ◦ Produces epi and norepinephrine (catecholamines). ◦ Controlled via sympathetic division of ANS  1) Identify as adrenal gland? 2) Identify each region? 3) Identify a hormone released at each region? 4) know the function of each hormone?    Hyposecretions = low level of secretions cause by removal of gland or loss of function. A) Mineralocorticoids – hyponatremia (low Na+ levels), hyperkalemia (high K+ levels), acidosis, low BP, tremors of skeletal muscle, and polyuria. B) Cortisol – removal of gland or loss of function ◦ Hypoglycemia (low blood glucose levels), depressed immune system, loss of appetite, nausea, vomiting, weight loss.  Addison’s Disease – low levels of both – ie: major issues with the adrenal cortex. ◦ Weight loss, muscle weakness, low BP, constant fatigue   Hypersecretion = high level of secretions A) Mineralocorticoids – caused by tumor in gland or aldosteronism. ◦ Slight hypernatremia, hypokalemia, alkalosis, high BP, weakness in muscles, and acidic urine.  B) Cortisol – tumor in gland or Cushing Syndrome (includes hypersecretion of androgens) ◦ Hyperglycemia – leads to diabetes mellitus, depressed immune system, tissue protein destruction leading to muscle weakness & atrophy, impaired wound healing, re-distribution of adipose (to face, neck, and abdominal region). ◦ Emotional effects of euphoria & depression.    Pinealocytes (cells) secrete? Melatonin, which? Influences circadian rhythms? ◦ (sleep/wake cycles)   In humans, peak levels @ night ➔ drowsy lowest levels @ noon (day) ➔ awake 1. 2. 3. 4. 5. 6. What is the function of thyroid hormones, what leads to it being secreted, and how would someone feel if they didn’t produce enough T3 and T4? What are the steps involved in the formation of T3 and T4? Where is TGB iodinated? Where is globular T3 and T4 formed? Where is individual T3 and T4 formed? What's the other hormone produced by the thyroid gland, which cells produce this hormone, and what’s the hormones function? How are PTH and calcitriol similar yet different? What are the functions of aldosterone, glucocorticoids (cortisone), Epi- & norepinephrine and which regions are each secreted? What is Cushions Syndrome vs Addison’s Disease?