Chap015_Cardiovascular_Function

Cardiac Cycle

The series of events in the heart during one complete heartbeat, including contraction (systole) and relaxation (diastole).

Systole

Phase of the cardiac cycle when the heart muscle contracts, rising blood pressure and ejecting blood into arteries.

Diastole

Phase of the cardiac cycle when the heart muscle relaxes, blood pressure falls, and the heart fills with blood.

Preload

The degree of stretch of the heart muscle before contraction, affecting stroke volume.

Afterload

The resistance the heart must overcome to eject blood during systole.

Frank-Starling Law

The principle that the strength of the heart's contraction is directly related to its initial length or end-diastolic volume.

Isovolumetric contraction

The phase of the cardiac cycle in which the ventricles contract with no change in volume because all valves are closed.

Atrioventricular Valves

Valves located between the atria and ventricles, preventing backflow during contraction.

Semilunar Valves

Valves located at the exit of the ventricles, allowing blood to flow into the arteries and preventing backflow.

Ejection Fraction

The percentage of the end-diastolic volume that is ejected from the ventricle during systole.

Cardiac Output (CO)

The total volume of blood pumped by the heart per minute, calculated as stroke volume times heart rate.

Mean Arterial Pressure

The average blood pressure in a patient's arteries during one cardiac cycle.

Electrocardiogram (ECG)

A recording of the electrical activity of the heart over time, used to assess its health.

P Wave

The graphical representation of atrial depolarization in an ECG.

QRS Complex

The graphical representation of ventricular depolarization in an ECG.

T Wave

The graphical representation of ventricular repolarization in an ECG.

Pacemaker Cells

Specialized cardiac muscle cells that generate action potentials to initiate heartbeats.

Action Potential

A temporary reversal of the electrical potential across a cell membrane, leading to muscle contraction.

Myocardial Infarction (MI)

A heart attack caused by the obstruction of blood flow to the heart muscle.

Coronary Circulation

The flow of blood to and from the tissues of the heart.

Atherosclerosis

A cardiovascular disease characterized by the hardening and narrowing of the arteries due to plaque buildup.

Bradycardia

A slower than normal heart rate, typically fewer than 60 beats per minute.

Tachycardia

A faster than normal heart rate, typically more than 100 beats per minute.

Pericardium

A double-walled sac that encloses the heart, providing protection and allowing free movement.

Stroke Volume

The amount of blood pumped by the left ventricle in one contraction.

Hypertension

High blood pressure, a condition that can lead to severe health issues including heart attack and stroke.

Cardiac Catheterization

A medical procedure used to diagnose and treat cardiovascular conditions through the insertion of a catheter into heart chambers.

Sinoatrial Node (SA Node)

The heart's natural pacemaker located in the right atrium; it generates electrical impulses that set the rhythm for the heart.

Ventricular Hypertrophy

Thickening of the ventricular walls due to increased workload on the heart, often a result of hypertension.

Calcium Ions (Ca++)

Essential for the contraction of cardiac muscle, entering cells during the action potential.

Secured Valves

Heart valves that prevent backflow of blood, ensuring one-way flow.

Aortas

The largest artery in the body, carrying oxygenated blood from the heart to the rest of the body.

Pulmonary Veins

Blood vessels that carry oxygenated blood from the lungs to the left atrium of the heart.

Pulmonary Arteries

Blood vessels that carry deoxygenated blood from the right ventricle to the lungs.

Heart Rate

The number of times the heart beats in one minute.

Left Ventricle

The chamber of the heart that pumps oxygenated blood to the body.

Right Ventricle

The chamber of the heart that pumps deoxygenated blood to the lungs.

Chamber Dilatation

The enlargement of the heart chamber which can affect its pumping efficiency.

Atrial Fibrillation

An irregular and often rapid heart rate that can increase the risk of strokes.

Myocytes

Muscle cells in the heart that facilitate contraction.

Coronary Sinus

A vessel that collects deoxygenated blood from the heart muscle and returns it to the right atrium.

Cardiac Performance

The efficiency of the heart in pumping blood, influenced by various factors like preload and afterload.

Hypotension

Abnormally low blood pressure, potentially leading to insufficient blood supply to organs.

Echocardiography

Ultrasound imaging of the heart used to visualize its structure and function.

Metabolic Control

Regulation of blood flow and oxygen delivery to tissues based on metabolic needs.