Monday, 21 September Chapter 11 The Endocrine System Classes of hormones The adrenal gland Fates of hormones Renin-Angiotensin-Aldosterone System Control of hormone secretion Hormone interactions (permissive effects) Hypothalamus & Pituitary The story of Aunt Dot Endocrine disorders (lab)
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
Renin-angiotensin-aldosterone Renin is released from kidney cells into bloodstream, its “target” in a plasma protein. Renin Angiotensinogen from liver, a plasma protein Angiotensin I Angiotensin converting enzyme (ACE) Angiotensin II Thirst Zona Glomerulosa of Adrenal Cortex Arterial smooth muscle … vasoconstriction…increase blood pressure Aldosterone Promotes Na+ retention in Kidney
Renin from Juxtaglomerular cells in Kidney (-) Don’t fret over this [Na+] in distal tubule of nephron detected by Macula Densa Sympathetic activity Renin from Juxtaglomerular cells in Kidney (-) Multi-step process involving Angiotensin I and II Angiotensin II Aldosterone K+ in plasma _______ Na+ reabsorption in kidney thirst Plasma volume Drink Blood pressure vasoconstriction
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 Integrator! 11.09.jpg Recall example: beta cells of Islets of Langerhans Secretion is usually pulsative, may be diurnal.
Adrenergic Cholinergic 16.08.jpg
Fig. 11.08 Permissive effect Thyroid hormone stimulates production of beta-adrenergic receptors 11.08.jpg
Questions so far?
Fig. 11.12a 11.12a.jpg
Fig. 11.12b Neurohypophysis Adenohypophysis 11.12b.jpg Vasopressin (= Antidiuretic hormone) Oxytocin
Typical Blood Flow Portal System Artery – arteriole- capillary –venule- vein –heart Portal System Artery – arteriole- capillary –portal vessel –capillary –venule- vein –heart Hypothalamo-hypophyseal portal system Hepatic portal system Vasculature of nephrons
Release-inhibiting Hormone Tropic hormones control the function Trophic hormones promote survival and growth of targets A S P Long Loop Negative Feedback Long Loop Negative Feedback Hypothalamo-hypophyseal portal system 11.17.jpg Releasing Hormone Release-inhibiting Hormone
Who Cares?
Menopause Widmaier text p. 694 Onset ~ age 50 Irregular menstrual cycles Breasts and genital organs gradually atrophy Decrease in bone mass & strength (osteoporosis) (bone resorption greater than bone deposition) Hot flashes…sweating, etiology unknown Increased incidence of coronary artery disease