Pathomedicine Module 3.3 Blood Pressure Regulation PDF

Pathomedicine Module 3.3 Blood Pressure Regulation Aaron E. Yancoskie, D.D.S. Diplomate, American Board of Oral and Maxillofacial Pathology Blood Pressure (BP) Regulation Narrow range corresponds to health Hypotension results in inadequate perfus...

Pathomedicine Module 3.3 Blood Pressure Regulation Aaron E. Yancoskie, D.D.S. Diplomate, American Board of Oral and Maxillofacial Pathology Blood Pressure (BP) Regulation Narrow range corresponds to health Hypotension results in inadequate perfusion Hypertension damages vasculature and organs Determinants Cardiac output Vascular resistance BP Regulation Cardiac output Function of Stroke volume Filling pressure Regulated by sodium homeostasis which impacts blood volume Myocardial contractility Regulated by alpha and beta aderenergics Heart rate Regulated by alpha and beta aderenergics Peripheral resistance Regulated mostly at arterioles Neural inputs Robbins Basic Pathology, 9th Edition. PP Alpha and beta adrenergics 332. Fig 9-3. Hormonal inputs Angiotensin II Catecholamines Endothelin Vasodilators Kinins Prostaglandins Nitric oxide Fine tuning by tissue pH and hypoxia for local metabolic needs Selected Regulators The kidneys and heart contain cells that sense changes in blood pressure or volume When changes are perceived the following regulators are released Renin Cleaves plasma angiotensinogen Vascular relaxing substances Adrenal aldosterone Myocardial natriuretic peptides Renin Proteolytic enzyme produced by renal juxtaglomerular (JXG) cells Myoepithelial cells located at glomerular afferent arterioles JXG cells release renin in response to the following: Low blood pressure Elevated levels of catecholamines Low sodium levels in the distal convoluted tubules Occurs when cardiac output is low, leading to increased sodium resorption in the proximal tubules and lower sodium more distally Function of renin Cleaves plasma angiotensinogen to angiotensin I Angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II in the peripheral tissues Angiotensin II Elevates blood pressure by Contraction of vascular smooth muscle Increasing aldosterone release by the adrenal glands Increasing sodium resorption by the renal tubules Aldosterone Elevates blood volume by Increasing sodium resorption With water --- volume Drives urinary excretion of potassium Myocardial Natriuretic Peptide (MNP) Increased blood volume induces secretion of MNP by Myocardium of atrium and ventricle Results in sodium excretion and diuresis (urinary water excretion) Robbins Basic Pathology, 9th Edition. PP 331. Fig 9-4.  Self-Study Pages 330-332 Robbins Basic Pathology, 9th Edition.