BSC 2086 1st Edition Lecture 6 Outline of Last Lecture I Hormones II Pituitary Gland Outline of Current Lecture I Thyroid Gland II Parathyroid Gland III Adrenal Gland IV Pineal Gland V Pancreas VI Endocrine Tissues of Other Systems VII Hormone Interactions Current Lecture I Thyroid Gland a Location i Anterior to thyroid cartilage of the larynx throat ii Made up of 2 lobes connected by isthmus 1 Thyroid follicles surrounded by capillary network that delivers nutrients and hormones as well as accepts wastes and other products that need to be secreted b Hormones i Thyroxine T4 1 AKA tetraiodothyronine 2 Made of 4 iodide ions ii Triiodothryronine T3 1 Made of 3 iodide ions c Binding molecules i Thyroid binding Globulins TBGs 1 Bind majority of T4 and T3 ii Transthyretin and albumin protein abundant in blood 1 Binds almost all remaining thyroid hormones iii Some remain unbound d Thyroid Stimulating Hormone TSH i Secreted by anterior pituitary gland ii Stimulates the production of thyroid hormone iii Absence of TSH leads to inactivation of thyroid follicles II iv Absence of iodine reduces production since the thyroid hormones are made up of iodide ions The thyroid gland begins to enlarge because its cells are overworking themselves to make the hormones with only a limited supply of iodine e Calorigenic Effect i Heat is generated due to increase energy consumption by the cell ii This causes increased rate in cell metabolism immediately for a short period of time iii Essential to child s normal development f Functions i Rise of body temperature due to elevation in oxygen and energy consumption ii Raises blood pressure by increasing heart rate iii Increases sensitivity to sympathetic stimulation iv Keeps normal sensitivity to respiratory centers v Stimulates red blood cell formation and activity in endocrine tissues vi Speeds up turnover of minerals in bone g Abnormal thyroid hormone production i Congenital hypothyroidism stunted bone growth and mental retardation 1 Cretinism ii Adult hypothyroidism slow heart rate low body temperature sensitive to cold muscle weakness 1 Myxedema iii Hyperthyroidism excessive release of TH 1 Graves disease antibodies mimic TSH causing an autoimmune disease h C cells Calcitonin i Calcitonin CT is used to lower calcium concentrations by inhibiting osteoclasts and stimulating calcium excretion by kidneys Parathyroid Gland a Location i Posterior surface of thyroid gland b Hormones i Parathyroid Hormone PTH 1 Respond to low concentrations of calcium 2 Antagonist of calcitonin 3 4 5 6 III Increases calcium levels Stimulates osteoclasts and stops osteoblasts Reabsorption of calcium in the kidneys Starts formation and secretion of calcitriol by the kidneys a Compliments and enhances PTH Adrenal Gland a Location i Upper border of the kidney b Divided into i Superficial adrenal cortex 1 Controlled by ACTH which is secreted by the anterior pituitary 2 Manufactures corticosteroids 3 Stores lipids and glucose ii Inner adrenal medulla 1 Controlled by sympathetic division of ANS 2 Makes epinephrine and norepinephrine a Increases heart rate and reduces blood flow to stomach and intestines so more blood can reach the brain and the heart c Adrenal Cortex Hormones i Mineralocorticoids Ex Aldosterone 1 Regulate ion levels conserves sodium and eliminates potassium 2 Responds to drop in potassium 3 Aldosteronism excess aldosterone a Increases body weight due to sodium retention ii Glucocorticoids Ex cortisol hydrocortisone with corticosterone 1 Regulate glucose metabolism 2 Some cortisol will be converted to cortisone by liver and some will go back to hypothalamus and receive hormones 3 Regulated by nugatory feedback 4 Inhibits production of a Corticotropin releasing hormone CRH in hypothalamus b ACTH in anterior pituitary c Inhibits its own release 5 Has anti inflammatory effects by stopping activities of white blood cells a Cant be used to treat open wounds iii Androgens 1 Virilization excessive hair growth caused by hypersecretion 2 Amenorrhea loss of menstruation in women caused by hypersecretion iv Abnormal Production 1 Addison s Disease hyposecretion of glucocorticoids and aldosterone IV V a Energy reserves are low causing tiredness and loss of appetite b High potassium low sodium 2 Cushing s Syndrome hypersecretion of cortisol a Released in times of stress b Moon face and buffalo hump c Breakdown of proteins in muscles d Adrenal Medulla Hormones i Epinephrine adrenaline ii Norepinephrine noradrenaline e Functions i Both work to increase metabolic rate for a fight or flight response ii Skeletal muscles 1 Trigger mobilization of glycogen reserves 2 Speeds up break down of glucose to create ATP which increases muscles strength and endurance iii Adipose tissue 1 Break down stored fats into fatty acids 2 Release into blood for other tissues to use to make ATP iv Liver 1 Break down glycogen into glucose which is released into blood 2 Used by neural tissue v Heart 1 Beta 1 receptors stimulated and cause increase in rate and force of cardiac muscle Pineal Gland a Location i In the brain on posterior part of 3rd ventricle b Synthesized melatonin which i Inhibits reproductive functions ii Is an effective antioxidant by protecting against free radicals iii Influences day and nigh cycles as well as other circadian rhythms Pancreas a Location i Inferior to the stomach and proximal to small intestine b Exocrine Pancreas i Roughly 99 of pancreatic volume ii Pancreatic acini clusters of gland cells iii Secrete alkaline enzyme rich fluid 1 Helps with digestion c Endocrine Pancreas i Pancreatic islets cluster of cells ii Alpha cells produce glucagon to break down glycogen when glucose is low iii d Insulin i ii iii iv v VI Beta cells produce insulin after a meal to capture glucose molecules Peptide hormone Accelerates glucose uptake and utilization to increase ATP Stimulates formation of glycogen and triglycerides in adipose tissue Stimulates protein synthesis Diabetes Mellitus 1 Type 1 insulin dependent a Inadequate insulin production by beta cells b Hyperglycemia high glucose levels in the blood i Glycosuria glucose in urine ii Polyuria excessive urine 2 Type 2 non insulin dependent a Most common b Insulin resistance c Associated with obesity 3 Complications a Diabetic nephropathy i Kidney degeneration b Diabetic retinopathy i Retinal damage that can lead to partial or complete blindness c Early heart attacks i Blockages in heart circulation can lead to heart attacks ii 3 5 times more
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