Cardiovascular Flashcards
Angiotensin system
Liver creates angiotensinogen
Kidney produces renin
Renin breaks angiotensinogen to angiotensin I
Endothelial cells produce angiotensin converting enzyme which converts angiotensin I to angiotensin II
What does angiotensin ii do
Binds at angiotensin i and angiotensin ii receptors
Vasoconstriction in blood vessel sites
Sodium reabsorption in kidney sites (more fluid reabsorption)
Releases ADH in pituitary gland sites increasing water reabsorption
Releases aldosterone in adrenal gland sites increasing sodium reabsorption
Action of NO
Inhibits angiotensin II
Vasodilation & prevention of vasoconstriction
Inhibits platelet adhesion
Anti-inflammatory
Action potential system
Phase 0 - Sodium enters cell causing rapid depolarisation
Phase 1 - Potassium leaves cell causing slight repolarisation
Phase 2 - Calcium enters cell slowing repolarisation
Phase 3 - Calcium channels close so rapid repolarisation
Phase 4 - Resting phase as sodium (and calcium) and potassium switch places ready for next depolarisation
Action of Calcium channel blockers (Amlodipine)
Bind to calcium channels on heart and blood vessels
Vasodilation
Reduces rate, force and conduction of heart
Action of Beta blockers (Bisopralol)
Bind to beta i and beta ii sites on heart and blood vessels
Decreases heart rate and force prolonging action potential by inhibiting potassium channels
Slight vasoconstriction
Blood clotting system
Injury to blood vessel
Thromboxane released
Vasoconstriction
Platelets activate and send signals to bring more platelets to area
Von Willebrand Factor protein binds platelets forming plug
Clotting factor proteins stimulate production of fibrin from fibrinogen which forms fibrin clot
Fibrinolysis
Plasmin breaks down fibrin and fibrinogen
Plasminogen is always available in blood to prevent clotting and activated by T-PA into plasmin
Action of aspirin
COX inhibitor
Reduces pain and inflammation
Lowers temperature
Increases stomach acidity
Inhibits thromboxane synthesis
Action of clopidogrel
Binds to platelets (forever)
Prevents platelet adhesion
Action of Ticagrelor
Binds to platelets (not forever)
Prevents platelet adhesion
Action of Warfarin
Inhibits enzyme that activates vitamin K
Vitamin K synthesises clotting factors
Action of heparin
Counters clotting cascade by binding to thrombin and antithrombin preventing the formation of clotting factors
Action of TXA
Competitive antagonist to plasminogen so that TPA does not bind and produce plasmin which breaks fibrin clot
Actions of statins
Inhibit enzyme involved in the synthesis of cholesterol
Causes liver to increase LDL receptors which then clears LDL which reduces plaqu buildup