CARDIO: PHYSIO Flashcards
Completely independent atrial and ventricular beats describe which pathologic condition?
3rd degree (complete) AV block: Atria and ventricles beat independently of each other. Unstable rhythm, requires pacemaker.
Describe the EKG tracing in ventricular fibrillation.
Ventricular fibrillation: no identifiable waves since the rhythm is completely erratic.
Movement of what two ions gives cardiac muscle action potentials a plateau?
1) Cardiac muscle action potentials have a plateau, which is due to Ca2+ influx and K+ efflux.
Which two variables does the Frank-Starling cardiac function curve account for?
The cardiac function curve depicts the Frank-Starling relationship for the ventricle, and shows that cardiac output is a function of end-diastolic volume.
Chronic atrial fibrillation is a risk factor for what sequelae?
Atrial Fibrillation increases risk of emboli from an atrial clot, since the left atrium is dilated and contracting asynchronously.
What is represented by the T wave of an EKG?
The T wave marks ventricular repolarization.
Baroreceptors respond to changes in what?
Baroreceptors respond to changes in blood pressure (BP).
What channels are responsible for the automaticity of cardiac nodal cells?
2) Cardiac nodal cells have automaticity and they spontaneously depolarize. The is due to “funny current” channels (If channels) which are responsible for a slow, mixed Na+/K+ inward current.
What do the chemoreceptors in the carotid and aortic bodies respond to?
The chemoreceptors in the carotid and aortic bodies respond to:
Decreased PO2 (<60 mmHg, primary stimulus)
Increased PCO2
Decreased blood pH
Describe the “x” descent on JVP (jugular venous pulse) tracing in patients with tricuspid regurgitation.
absent “x” descent — tricuspid regurgitation
Backflow of blood into the right atrium during systole prevents relaxation of right atrial pressure. (may see a positive wave)
Which phase of the cardiac nodal cycle is characterized by slow depolarization?
Phase 4 – slow depolarization
