HBS

Cardiovascular System

The system comprising the heart and blood vessels, responsible for circulating blood, oxygen, and nutrients throughout the body.

Artery

A blood vessel that carries oxygenated blood away from the heart to the body (except pulmonary artery, which carries deoxygenated blood to the lungs).

Vein

A blood vessel that carries deoxygenated blood back to the heart (except pulmonary vein, which carries oxygenated blood from the lungs to the heart).

Capillary

The smallest blood vessels that connect arteries and veins; they facilitate the exchange of oxygen, carbon dioxide, and nutrients between blood and tissues.

Heart Rate

The number of times the heart beats per minute (bpm).

Pulse

The rhythmic expansion and recoil of arteries due to the beating of the heart; commonly felt at the wrist or neck.

Cardiac Output

The amount of blood pumped by the heart per minute; calculated as Heart Rate × Stroke Volume.

Stroke Volume

The amount of blood ejected by the left ventricle per beat.

Blood Pressure

The force exerted by circulating blood on the walls of blood vessels, measured in mmHg (systolic/diastolic).

Sphygmomanometer

A device used to measure blood pressure.

Systolic Pressure

The pressure in the arteries when the heart contracts (top number in BP readings).

Diastolic Pressure

The pressure in the arteries when the heart relaxes between beats (bottom number in BP readings).

EKG (Electrocardiogram)

A test that records the electrical activity of the heart.

SA Node (Sinoatrial Node)

The heart’s natural pacemaker, which initiates the electrical impulses that regulate heartbeats.

AV Node (Atrioventricular Node)

A part of the heart’s electrical system that delays the impulse before sending it to the ventricles.

Bundle of His

A pathway of fibers that transmits electrical impulses from the AV node to the ventricles.

Purkinje Fibers

Fibers that distribute electrical impulses through the ventricles, causing contraction.

Arrhythmia

An irregular heart rhythm, which can be too fast, too slow, or erratic.

Left Side of the Heart

Thicker and more muscular because it pumps oxygenated blood to the entire body (systemic circulation).

Right Side of the Heart

Thinner because it only pumps deoxygenated blood to the lungs (pulmonary circulation).

Blood Flow Pathway

Deoxygenated blood enters the right atrium, flows to right ventricle, through pulmonary valve to lungs, oxygenated blood returns to left atrium, flows to left ventricle, pumped through aortic valve to body.

Aorta

Largest artery, carries oxygenated blood to the body.

Pulmonary Artery

Carries deoxygenated blood to the lungs.

Coronary Arteries

Supply blood to the heart itself.

Carotid Arteries

Supply blood to the brain.

Femoral Arteries

Supply blood to the legs.

Superior and Inferior Vena Cava

Return deoxygenated blood to the heart.

Pulmonary Veins

Carry oxygenated blood from lungs to the heart.

Jugular Veins

Drain blood from the brain.

Femoral Vein

Returns blood from the legs.

Cardiac Output Calculation

Calculated as Heart Rate multiplied by Stroke Volume.

High Blood Pressure (Hypertension)

Increased risk of stroke, heart attack, kidney damage, and aneurysms.

Low Blood Pressure (Hypotension)

Can cause dizziness, fainting, and shock (dangerously low blood flow to organs).

Ankle-Brachial Index (ABI)

Compares blood pressure in the ankles and arms; used to diagnose Peripheral Artery Disease (PAD).

Normal ABI Range

1.0 - 1.4; indicates normal blood flow.

Mild PAD ABI

0.9 - 0.7; indicates mild peripheral artery disease.

Severe PAD ABI

Below 0.4; indicates severe peripheral artery disease.

Peripheral Artery Disease (PAD)

A condition where narrowed arteries reduce blood flow to the limbs, often caused by atherosclerosis.

Symptoms of PAD

Leg pain while walking (claudication), cold feet, slow-healing wounds.

P Wave

Atrial depolarization (atria contracting).

QRS Complex

Ventricular depolarization (ventricles contracting).

T Wave

Ventricular repolarization (ventricles relaxing).

Key Study Tip 1

Memorize key terms and their functions.

Key Study Tip 2

Practice tracing blood flow through the heart.

Key Study Tip 3

Understand blood pressure readings and their implications.

Key Study Tip 4

Learn how to calculate cardiac output.

Key Study Tip 5

Familiarize yourself with EKG waveforms and their meanings.