Transcript endocrine1
Wednesday, 14 September Chapter 11 The Endocrine System • • • • • • • • Classes of hormones The adrenal gland Fates of hormones Control of hormone secretion Hormone interactions (permissive effects) Hypothalamus & Pituitary The story of Aunt Dot Endocrine disorders (lab next week) 1QQ # 4 8:30 am 1. What changes in hepatocyte metabolism are produced by glucagon? 2. A) What advise would you give to a person who is a reactive hypoglycemic and B) provide the reasons for your advise. 3. Your patients plasma glucose level is 45 mg/dl. A) What hormone is responsible for her rapid heart rate, pale clammy skin, and irritability? B) Why does she have a headache? 1QQ # 4 9:30 am 1. Explain in some detail how beta cells of the Islets of Langerhans are affected by anticipating an excellent meal. 2. A) Describe a situation that would lead to the activation of the sympathetic nervous system. B) How does sympathetic stimulation affect the secretion from beta cells in the Islets of Langerhans? C) Why is this beneficial for the person in terms of fuel supply? 3. After an overnight fast, a patient arrives for an Oral Glucose Tolerance Test. The first blood sample (even before ingestion of the Tru-Glu cola shows a plasma glucose concentration of 150 mg/dl. A) Do you have the patient drink the Tru-Glu? Why or why not? B) What might you do next to determine what is “wrong” with your patient? Class activity • 24 students were hormones and we classified these hormones as amines, peptides or steroids, considered how they are synthesized and stored (or not) in secretory cells, transported in the plasma, the locations of their receptors in/on target cells, the nature of the response in target cells (latency & duration), 24 Hormones, 24 Students • • • • • • • • • • • • Corticosterone Testosterone Estriol Cortisol Aldosterone Estrone TSH ADH CRH TRH PTH LH • • • • • • • • • • • • Glucagon DA EPI NE T3 Insulin T4 GH ACTH FSH EPO CCK Endocrine Organs (Table 11-1) • • • • • • • • • • Hormone Pituitary Gland Paracrine agent Thyroid Gland Autocrine agent Pancreas Neurotransmitter Gonads Neuromodulator Gastrointestinal Tract Heart Hormone: chemical messengers carried by blood to target cells Kidney upon which they act. Hypothalamus Liver Only those cells having receptors Etc. Can respond to a given hormone 3 Chemical Classes of Hormones • 1: – – • 2: • 3: Amine hormones (from amino acid tyrosine) Thyroid hormones Adrenal medullary hormones (catecholamines) Peptide hormones (peptides & proteins) Steroid Hormones (derivatives of cholesterol) Amine Hormones Fig. 11.01 Thyroid Hormones Not soluble in plasma, bound & free Adrenal medulla NT Catecholamines soluble in plasma NT Steroid hormones Fig. 11.03 not soluble in plasma, not storable in vesicles Bound & Free Target cells have intracellular receptors. Changes is gene expression. Timecourse: longer latency, longer lasting Peptide Hormones Fig. 11.02 Soluble in plasma e.g. Beta cell Guess peptide! Cell surface receptors on target cells Examples of Peptide Hormones: Insulin, glucagon prolactin, erythropoietin, parathyroid hormone, gastrin, leptin, growth hormone, oxytocin, vasopressin, FSH, LH, GHRH, and many more! Know Table 11-2 p 319 • • • • • Hormone class Major form in plasma Location of receptors Signal transduction mechanisms Rate of excretion / metabolism Fig. 11.05 Steroids Catecholamines Adrenal Gland Part of Sympathetic Nervous System Hormones of the Adrenal Cortex Androgens DHEA “Andro” Glucocorticoids Mineralicorticoid What regulates the secretion of cortisol and aldosterone? Fig. Gonadal Steroids 11.06 (not adrenal cortex) Estrogens King DS, Sharp RL, Vukovich MD, Brown GA, Reifenrath TA, Uhl NL, Parsons KA . Effect of oral androstenedione on serum testosterone and adaptations to resistance training in young men: a randomized controlled trial. JAMA 1999; 281(21):2020-8 What happens to hormones once released? Be able to give Examples. Ex: Renin Fast if free Slow if bound T4 to T3 and Testosterone to Estradiol Factors that affect hormone secretion Na+, K+, Ca++, etc. NE, ACh, etc. TRH, TSH, DA, etc. Integrator! Recall example: beta cells of Islets of Langerhans Secretion is usually pulsative, may be diurnal. Fig. 11.08 Permissive effect Thyroid hormone stimulates production of beta-adrenergic receptors, which increases the target cell’s responsiveness to EPI.