Friday, 12 September Chapter 11 The Endocrine System Classes of hormones The adrenal gland Fates of hormones RAA system Hypothalamus-Pituitary System Hormone interactions Control of hormone secretion Categories of endocrine disorders

Endocrine Organs (Table 11-1) Pituitary Gland Thyroid Gland Pancreas Gonads Gastrointestinal Tract Heart Kidney Hypothalamus Liver Etc. Hormone: chemical messengers carried by blood to target cells upon which they act. Only those cells having receptors Can respond to a given hormone Hormone Paracrine agent Autocrine agent Neurotransmitter Neuromodulator

3 Chemical Classes of Hormones 1: Amine hormones (from amino acid tyrosine) –Thyroid hormones –Adrenal medullary hormones (catecholamines) 2: Peptide hormones (peptides & proteins) 3: Steroid Hormones (derivatives of cholesterol)

Fig Catecholamines soluble in plasma Thyroid Hormones Not soluble in plasma, bound & free Amine Hormones Adrenal medulla NT

Fig Peptide Hormones Examples: Insulin, glucagon prolactin, erythropoietin, parathyroid hormone, gastrin, leptin, growth hormone, oxytocin, vasopressin, FSH, LH, GHRH, and many more! Cell surface receptors on target cells Guess peptide! Soluble in plasma e.g. Beta cell

Fig Steroid hormones not soluble in plasma, not storable in vesicles Target cells have intracellular receptors, Commonly changes is gene expression Timecourse? Bound & Free

Questions so far?

Know Table 11-2 p 323 Hormone class Major form in plasma Location of receptors Signal transduction mechanisms Rate of excretion / metabolism

Fig Adrenal Gland Part of Sympathetic Nervous System

Adrenal Medullary Hormones Adrenal medulla is modified sympathetic ganglion Catecholamines: EPI (80-85%), NE (15-20%) Short half-life in plasma (soluble) Receptors on surface of target cells (adrenergic) Effects response to stress Effects generally prepare for “Fight or Flight”

Hormones of the Adrenal Cortex Glucocorticoids Mineralicorticoid Androgens DHEA

Fig Gonadal Steroids (not adrenal cortex)