Quesmed Cardiac High Yield Flashcards
Which valves are open during diastole?
Only AV valves.
What affects diastolic BP?
Total peripheral resistance, which is the force of blood circulating through the pulmonary vasculature.
Which current is generated by the SA node, AV node and Purkinje fibres?
Funny current, of Na+ and K+ which is activated by hyperpolarisation around -60-70mv which provides automaticity for pacemaker cells.
What is the difference between pacemaker and other cardiac myocytes?
Pacemakers have:
No Phase 1 or 2 action potentials
Depolarisation occurs in phase 0
Slower action potentials
No FAST sodium channels
How does breathing affect venous return?
Inspiration causes greater venous return.
Which ion channels triggger depolarisation?
Voltage gated Na+ channels
Which blood vessels carry the most blood?
Veins
How long does a cardiac cycle last?
200-300 milliseconds.
How do vessels respond to a sudden drop in blood flow?
Transient reduction in blood flow via vasodilation. This is autoregulation, to maintain blood flow to organs.
What do macrophages take up to become foam cells?
LDL
Which vessel has the largest cross sectional area?
Capillaries
Which vessels have the greatest drop in pressure and blood flow velocity?
Arterioles, to prevent damage to blood entering the capillaries. The are known as resistance vessels.
How do activated platelets affect blood flow?
Causes vasodilation to prevent thrombus formation.
What is endothelin
Stimulated by angiotensin II and vasopressin, to cause vasoconstriction, as part of the RAAS effect.
What does the pulsing of the carotid/radial pulse correspond to?
Ventricular systole.
