The Cardiac Cycle

Flashcards based on some slides on the cardiac cycle.

Cardiac cycle

One complete heartbeat made of the systole and diastole

Systole

The contraction of a heart chamber

Diastole

The relaxation of a heart chamber

120/80

The normal blood pressure for an adult

Sphygmomanometer

The medical name for a blood pressure cuff

Blood pressure

The force of blood against the walls of arteries

Blood pressure factors

1. Cardiac output

2. Blood volume (about 5 L)

3. Blood viscosity

4. Peripheral resistance

Stethoscope

An instrument to listen to and measure heart sounds

Pulse points

Places where arteries come close to the skin on the body:

• Carotid arteries (on the neck)

• Radial arteries (on the wrists)

• Brachial arteries (opposite of elbow)

Electrocardiogram (ECG)

A recording of the electrical events during a cardiac cycle, notated as letters P through T

P wave

Depolarization of the atria; atrial systole

QRS complex

Depolarization of the ventricles; ventricular systole

T wave

Repolarization of the ventricles

Tachycardia

Fast heart rate

Bradycardia

Slow heart rate

Arrythmia

Irregular heart rate

SA node

The pacemaker and initiator of the heart

AV node

The regulator of electrical signals in the heart

AV bundle (bundle of His)

Fibers that send electrical signals down the septum

Purkinje fibers

Fibers that go around and send electrical signals to the ventricles

Cardiac center

The medulla oblongata

Vessel categories

Arteries, veins, and capillaries

Arteries

Strong elastic vessels that carry blood moving away from the heart

Arterioles

Smaller arteries that connect to capillaries

Veins

Thinner, less muscular vessels carrying blood toward the heart

Venules

Small veins that connect to capillaries

Capillaries

Allows exchange of materials between blood and tissues; contains valves for regulation

Precapillary sphincters

Circular, valve-like muscles at arteriole-capillary junctions

Vasoconstriction

Narrowing a blood vessel

Vasodilation

Expanding a blood vessel

Venous pooling (varicose veins)

The accumulation of blood in the legs; can cause blood clots with a lack of movement

Aorta

The largest artery of the body that leaves the left ventricle

Pulmonary trunk (pulmonary artery)

Deoxygenated artery that splits into left and right segments to lead to the lung

Pulmonary veins

Oxygenated veins that return blood from the lungs to the heart

Superior and inferior vena cava

Veins that return blood from the head and body to the heart, connecting to the right atrium

Branches of the aorta

• Coronary arteries (heart)

• Brachiocephalic artery

  • Right subclavian artery (right arm)

  • Right common carotid artery

• Left common carotid artery (head)

• Left subclavian artery (left arm)

Coronary arteries

Arteries that supply blood to the heart itself

Brachiocephalic artery

Artery that branches into the arms

Right subclavian artery

Supplies blood to the right arm

Left subclavian artery

Supplies blood to the left arm

Left common carotid artery

Supplies blood to the head

Defibrillation

Common treatment for life-threatening cardiac arrhythmia using electricity to re-establish the heart’s normal rhythm

Heart murmur

An unusual sound heard during a heartbeat, usually sounding like a whooshing or swishing noise

Mitral valve prolapse (MVP)

When the valve shifts out of place and creates a clicking sound at the end of a contraction

Regurgitation

The backward flow of blood, causing the heart to work harder to force blood through — this creates damaged or weakened hearts

Valve replacement surgery

Replacing a valve with biological tissue or mechanical valves

Transcatheter aortic valve replacement (TAVR)

The use of a catheter to insert a new valve through an artery in the groin

Myocardial infarction

An obstruction to the coronary artery, commonly called a heart attack — treated with a bypass graft to restore blood flow (double or quadruple refers to how many vessels have been bypassed)

Atherosclerosis

Deposits of fatty materials such as cholesterol in the blood vessels, thus reducing blood flow with a “plaque”

Angioplasty

The treatment of atherosclerosis by inserting a catheter to stretch the walls back open and insert a stent

Hypertension

High blood pressure; can be diagnosed with a blood pressure cuff

Aneurysm

A localized, blood-filled balloon-like bulge in the wall of a blood vessel

Stroke

When blood flow to the brain is cut off; broken into hemorrhagic (broken vessel) or ischemic (blocked vessel) strokes

Aortic stenosis

The narrowing of the valve or aorta, limiting blood flow