BIO 311D 2nd Edition Lecture 24 Outline of Last Lecture I Homeostasis and negative feedback control II How do hormone systems work III Homeostasis of blood glucose level Outline of Current Lecture I Diabetes Mellitus II Hypothalamus and pituitary control III Feedback control of thyroid function IV The adrenal glands two part response to stress Current Lecture I II Diabetes Mellitus A Type I insufficient insulin B Type II can t respond to insulin C IClicker Questions When blood glucose levels drop below the set level which of these is triggered Glucagon is secreted One cause of juvenile onset diabetes results from autoimmune attack and destruction of the beta cells of the pancreas Which type of diabetes would result Type I Treated Insulin injections Type II Diabetes is treated by exercise diet Hypothalamus and pituitary control A The hypothalamus is part of the brain that monitors body conditions Part of the hypothalamus consists of neuro secretory cells secrete directly into blood Neurosecretory cell secretes releasing factor B The pituitary is an endocrine gland in the center of the head The anterior pituitary gland secretes tropic hormones C Hypothalamus release hormones such as TRH thyrotropin releasing hormone D Neurohormones from hypothalamus travel in the blood and affect the pituitary gland E Anterior pituitary Tropins TSH ACTH Gonadotropins affect other glands III Feedback Control of Thyroid Function A Thyroxin travels in blood complexes with glucose B In order for the negative feedback to work the anterior pituitary would need to have receptors for T3 T4 C Cool body temperature stimulates hypothalamus to release more TRH How Hypothalamus sensors detect changes in temperature in the blood in the capillaries in the brain activates the thyroid to release thyroxin D High Levels of TSH cause hypothalamus to release less TRH How A classic negative feedback TSH can be monitored by hypothalamus E High T3 T4 stimulate metabolism and produce more body heat How could the heat activate negative feedback control F A hyperactive thyroid can lead to slightly elevated body temperature G Goiter enlarged thyroid gland Iodine is required for making thyroxin T3 and T4 People with iodine deficient diet can develop goiter Can t produce thyroxin so just grow bigger IV The Adrenal Glands attach on kidney stress responses A The adrenal cortex produces steroid hormones glucocorticoids mineralocorticoids and sex steroids respond to hormones pituitary gland Corticosteroid steroid target cell receptor locates inside the cell receptor Long response B The adrenal medulla produces epinephrine and norepinephrine gets it signals from the nervous system Epinephrine peptide target cell receptor in plasma membrane triggers signal transduction Short response
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