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REVIEW: hypovolemia. A Decrease in Blood Pressure:. Heart baroreceptors cause posterior pituitary to secrete VP VP increases vasoconstriction VP increases water pores in the collecting duct, increasing water absorbtion from filtrate Cells in glomerulus secrete renin angiotensin II
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REVIEW: hypovolemia A Decrease in Blood Pressure: • Heart baroreceptors cause posterior pituitary to secrete VP • VP increases vasoconstriction • VP increases water pores in the collecting duct, increasing water absorbtion from filtrate • Cells in glomerulus secrete renin • angiotensin II • Increases aldosterone • Increases vasoconstriction • Increases VP • Stimulates drinking • aldosterone • Increase sodium retention
What about an increase in blood pressure? • Baroreceptors in heart stop sending releasing signals to SON and PVN • Glomerulosa cells produce less renin • Under conditions of excessively high blood pressure: • The atria of the heart secrete Atrial Natriuretic Peptide (ANP) • ANP: • Shuts down secretion of VP, renin, and ALDO • Increases sodium excretion in the urine • Increases diuresis (water loss in urine)
Osmotic Imbalance Review High blood osmolality causes: • Osmoreceptors in the brain to signal SON and PVN nuclei to increase VP secretion • VP increases water retention in the kidney • Glomerular cells decrease secretion of Renin • Decrease Aldosterone secretion • Decrease Angiotensin II levels
INSULIN • Regulation of Secretion • Hyperglycemia stimulates release • Glucose sensors in cells • Gastric Inhibitory Peptide • Released from cells of the small intestine • Potent stimulator of insulin secretion • Somatostatin: inhibits insulin release (paracrine) • Autonomic nervous system • Parasympathetic activation increases insulin release • Sympathetic activation blocks insulin release • Epinephrine (from adrenal) blocks insulin release
INSULIN • Action at Target Tissues • Activation of insulin receptor: • Increases transport of glucose, amino acids, and fatty acids into cells Glucose transporter:
Type 1 DiabetesInsulin Dependent: IDDM • Possibly results from autoimmune reaction • The body’s immune system attacks the cells • Pancreatic markedly reduced • Symptoms only appear after ~80% loss of cells • No insulin……physiological repercussions? • Treatment • Insulin injections • Recent methods
Type 2 Diabetes:Non-Insulin Dependent: NIDDM • Accounts for 90-95% of all Diabetes cases • Usually occurs in overweight individuals over 40 years of age • But ages are getting younger and younger • Associated with abdominal fat in women • Target cells become resistant to insulin • insulin receptor • Fewer receptors • Receptors have lower affinity • Receptor blocked (possibly by antibody) • Post-receptor mechanisms
Diabetes Prevelence in US % Incidence of diagnosed diabetes 1980 1990 2000 2007
2004 % of adults >20 2007
Type 2 Risks 2006 • 7th leading cause of death • With Type 2 diabetes • 2 to 4-fold increase in heart disease related death • 2-fold risk of death • Type 2 associated complications • 2-4 fold risk of stroke • 75% of adults with Type 2 have high blood pressure • leading cause of blindness in adults aged 20-74 • Leading cause of kidney failure