Cardio overview -better(?) Flashcards
(30 cards)
Define stroke volume (SV).
The volume of blood ejected by a ventricle in a single contraction, typically measured in milliliters (mL).
How is cardiac output (CO) calculated?
Cardiac output is the volume of blood the heart pumps per minute. CO = Stroke Volume × Heart Rate.
Name the four chambers of the heart.
Right atrium, right ventricle, left atrium, left ventricle.
What are the valves of the heart?
Mitral (bicuspid), tricuspid, aortic, and pulmonary valves.
Describe the flow of blood through the heart and body.
Body → Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body.
What is the primary function of capillaries?
Exchange of gases, nutrients, and waste between blood and tissues.
What is the difference between arteries and veins?
Arteries carry blood away from the heart; veins carry blood toward the heart.
What initiates the cardiac action potential?
The sinoatrial (SA) node spontaneously depolarizes to initiate the heartbeat.
What does the P wave on an ECG represent?
Atrial depolarization.
What does the QRS complex represent?
Ventricular depolarization.
What does the T wave represent?
Ventricular repolarization.
What is the PR interval?
The time from the onset of the P wave to the start of the QRS complex; reflects AV node conduction.
What causes the S1 heart sound?
Closure of the mitral and tricuspid valves.
What causes the S2 heart sound?
Closure of the aortic and pulmonary valves.
What is isovolumetric contraction?
Phase of the cardiac cycle when ventricles contract with both valves closed, increasing pressure.
When does ventricular ejection occur?
When left ventricular pressure exceeds aortic pressure, opening the aortic valve.
What is isovolumetric relaxation?
Phase after ejection when both valves are closed and ventricular pressure decreases.
When does the mitral valve open?
When ventricular pressure drops below atrial pressure.
What ions are involved in ventricular action potentials?
Na⁺ (influx during depolarization), Ca²⁺ (plateau), and K⁺ (efflux during repolarization).
What role does calcium play in cardiomyocyte contraction?
Calcium binds to troponin, allowing actin-myosin cross-bridging and contraction.
What is the plateau phase in cardiac action potentials?
A sustained depolarization caused by Ca²⁺ influx balancing K⁺ efflux.
What is intrinsic regulation of cardiac output?
Regulation by internal heart mechanisms such as preload and contractility.
What is extrinsic regulation of the heart?
Control by external mechanisms like the autonomic nervous system.
What effect does sympathetic stimulation have on the heart?
Increases heart rate and contractility via β1 receptors.
