Ch 20A_ Blood Pressure.pdf

Terminology Blood flow – volume of blood flowing through a vessel/organ/circulation in a given time period (ml/min) – Perfusion – blood flow per unit of mass Blood pressure – force per unit area exerted on a cell wall by the contained blood (mm Hg) Resistance – opposition to flow, amount of friction...

Terminology Blood flow – volume of blood flowing through a vessel/organ/circulation in a given time period (ml/min) – Perfusion – blood flow per unit of mass Blood pressure – force per unit area exerted on a cell wall by the contained blood (mm Hg) Resistance – opposition to flow, amount of friction the blood encounters in the peripheral system cells water through straw US milkshake through straw-thicker bloomer – Blood viscosity – Blood vessel diameter ceisattreee ConstrateTheVessel tamount OfSistance ager – Blood vessel length c e : thicker the blood 4 resistance Thicknes S / requires m o re force red blood cells to plasma variable -. fastest smaller ↑ height ↑ blood more the the tube variable tube smaller to more change resistance resistence resistance pressure -- arteries verus Co needs : ↓ c at b SV - EDV ↑ Preloade (stretching) >↑ ↑ Afterload - > - &HR SVe - ESV 2 ↓ SV & : Not &HR Vol -4 ↑ ALD - 4 Blood sein veeng 1004 1 3 ANP : Stretch that get > - EDV-ESV calcium As , lood 3 volume (H2O) & SV & SVH ↑ Blood - Nervous stem Blood volume , ↑PR ANS Autonomic Blood always help ↓ HR &: doesn't : ALD ADH ↑ > - ↑BP Cardiac tamponade > - ↓ BP 6 PR of contraction blc prevents I D IL pilation volume and ACE 3 - preload from bCa-USV transitioning > &HR - blu oration ALD ↑ > - ADH ↑ ANG I - 4 hypothalmus H ~ ↑ thirst Inhibitors Theproductionof dec. Inhibit angiotensina vasoconstriction decrease PR4 BP which madebrain ↑ - constriction AND Ace angiotensin const - 46 - - easiest viscosity variable vasoactivity & HR Inhibitors - the SV ↑ SV EP I After load Preload goes ↑ Afterload goes & ↑ ventricle : of 4 stretch volume ACE S&the changes reabsorptions Sodiure · content Crea &- SVXHR HPR Preload of > - Kidneys EPS BP CO XPR M & att ( Vasoactivity ↑ PR ↑ L Peripheral resistance cell visco blood L Y ↓ Force ANG2 - - - released = RAAS ↓ CO IS response of to the & BP : > ALD volume - ↓ Blood stay stable to ased post. by Pituitary Neural Controls -Sympathetic nervouS - p re s u re ors system Neural Controls Chemoreceptors – Carotid & aortic bodies detect increases in CO2 or decreases in pH and increase CO and cause vasoconstriction – More active in the respiratory system Medullary ischemic reflex – Decreased perfusion to the brain causes increased CO and vasoconstriction Hormonal Controls runsar co ↑ sympathetic > - nervous Vaso const > - ↑PR > - ↑ BP ↳ posterior pituitary Reabsorbsocon Adren" e ↳ reabsorb Sodium then H20 Hypertension Killyoulateiel : Renal Controls Homeostatic Imbalances Hypertension – Systolic above 140 mm Hg or diastolic above 90 mm Hg – Primary Heredity, age, diet, obesity, Type 2 diabetes mellitus, stress, smoking – Secondary Identifiable cause, ex: kidney disease Hypotension – Less than 90/60 mm Hg – Acute – circulatory shock Circulatory Shock Circulatory shock – blood vessels are inadequately filled and blood cannot circulate normally – Hypovolemic – large scale blood or fluid loss – Vascular – blood volume is normal but widespread vasodilation decreases peripheral resistance Anaphylaxis, septic shock – Cardiogenic – pump (heart) failure Circulatory Shock