Cardiac Cycle and Heart Rate

Flashcards covering the cardiac cycle, ECG readings, heart rate, and exercise.

Cardiac Cycle

The sequence of events that take place when the heart beats.

Atrial Systole

Contraction of atrial muscle.

Ventricular Systole

Contraction of ventricular muscle.

Joint Diastole

Relaxation of heart muscle.

SA Node (Sinoatrial Node)

Special cardiac muscular tissue that initiates and times heartbeats.

Atrial Systole

The volume of the atria decreases, pressure increases, valves in the vena cava and pulmonary veins close, tricuspid and bicuspid valves open, blood flows into the ventricle.

Ventricular Systole

Volume of the ventricles decreases, pressure increases, tricuspid and bicuspid valves close, semilunar valves in aorta and pulmonary artery open, blood flows into the respective artery.

Joint Diastole

Right atrium receives deoxygenated blood from the body parts via vena cava; left atrium receives oxygenated blood from the lungs via pulmonary veins.

Stethoscope/ECG

Device used to monitor heart activity, measure pulse rate, or listen to the sounds of valves closing.

Heart Rate

Number of times a heart beats in a minute (bpm).

Pacemaker

Group of cells located in the right atrium that controls the natural resting heart rate.

Pulse

Flow of blood through arteries detected as a pulse.

Pulse Rate

Number of pulses per minute.

Systolic Pressure

Pressure when the heart muscle contracts.

Diastolic Pressure

Pressure when the heart muscle relaxes.

Heart Sounds

Noise of the blood when the valves open and close.

"Lub" Heart Sound

When the ventricles contract, blood pushes the cuspid valves to shut.

"Dub" Heart Sound

When the ventricles relax, blood causes the semilunar valves to shut.

Electrocardiogram (ECG)

Device that tests and checks for problems with the electrical activity of the heart.

P-wave

Shows the atria contracting on an ECG.

QRS-wave

Shows the contraction of the ventricles on an ECG.

T-wave

Represents the ventricle relaxing on an ECG.

Heart Function During Exercise

The heart pumps blood to respiring cells to supply oxygen and glucose and remove respiratory waste.

Recovery Time

Time taken for the heart rate to return to the resting rate.

Adrenaline

Increases heart rate as part of a 'fight or flight' response.

Why Heart Rate Increases During Exercise

Sufficient blood is taken to the working muscles to provide them with enough nutrients and oxygen for increased respiration.

Oxygen Debt

Extra oxygen is used to break down the lactic acid that has been built up in cells as a result of anaerobic respiration.