Chap 20 Flashcards
What is Stroke Volume (SV)?
The volume of blood ejected from a ventricle during a contraction.
Formula: SV = End-Diastolic Volume (EDV) - End-Systolic Volume (ESV).
What is End-Diastolic Volume (EDV)?
The amount of blood in the ventricle at the end of diastole (when the heart is relaxed and filling).
What is End-Systolic Volume (ESV)?
The amount of blood remaining in the ventricle at the end of systole (after contraction).
What factors affect Cardiac Output (CO)?
Increased sympathetic stimulation, increased venous return, and increased heart rate.
Formula: CO = Stroke Volume × Heart Rate.
What is Preload?
The stretch of cardiac muscle fibers before contraction (related to EDV).
What is Afterload?
The pressure the ventricles must overcome to eject blood (e.g., arterial pressure).
What is Contractility?
The strength of the heart’s contraction, independent of preload.
What is Cardiac Output (CO)?
The total volume of blood pumped by the heart per minute.
How are the sympathetic nerves related to the heart?
They strongly innervate the ventricles, increasing contraction force and heart rate.
What is the role of the vagus nerve in heart innervation?
Primarily innervates the right atrium and slows the heart rate.
What does the Cardiac Cycle include?
All events during a heartbeat: electrical, mechanical, and pressure changes.
What is the Foramen Ovale?
A hole between the right and left atria, allowing blood to bypass the lungs.
What is the Ductus Arteriosus?
A vessel connecting the pulmonary artery to the aorta, bypassing the lungs.
What are Isovolumetric Diastole and Systole?
Periods during the cardiac cycle when all four valves are closed, and no blood flows in or out of the heart.
How does aging affect atherosclerosis?
Aging increases the risk of atherosclerosis, leading to reduced elasticity and blood flow.
