BSCI202: Blood Pressure and Pulse

The cycle of contraction and relaxation of both atria and ventricles

Cardiac cycle

Contraction of the atria (atrial systole) or the ventricles (ventricular systole)

Systole

Relaxation of the atria (atrial diastole) or the ventricle (ventricular diastole)

Diastole

Blood delivered into atria via veins; 80% of blood flows passively into the ventricles (also in diastole)

Atrial diastole

Last 20% of blood left in atria delivered to the ventricles by atrial systole

Atrial systole

What begins shortly after atrial systole or when ventricular contraction begins?

Pressure rises

Cycle repeats

Ventricular diastole

1st heart sound; closure of the AV valves

Lub

2nd heart sound; closure of the SL valves

Dub

An abnormal heart sound; indicates a defect in one of the valves

Heart murmur

Surges of pressure in arteries (as heart pushes blood out during the cardiac cycle); equivalent to the heart rate

Pulse

Number of beats per minute (bpm)

Heart rate

Normal range for resting heart rate

60-100 bpm

Average resting heart rate

70-76 bpm

How long does the average heart beat lasts?

0.8 seconds

This formula determines what?

Heart Rate

Pressure exerted against walls of the arteries

Blood pressure

Pressure exerted against the walls of the arteries during ventricular systole

Systolic blood pressure (SBP)

Pressure exerted against the arterial wall during ventricular diastole

Diastolic blood pressure (DBP)

Blood pressure is measured using a what?

Sphygmonanometer

What is the unit used in blood pressure?

mmHg

What is the normal blood pressure?

120/80

What is 120 in 120/80 mmHg?

Systolic blood pressure (SBP)

What is 80 in 120/80 mmHg?

Diastolic blood pressure (DBP)

The first sound heard in the stethoscope (crackling or knocking sound) when taking blood pressure; indicates the systolic pressure

Sounds of Korotkoff

The amount of force exerted on circulating blood by the vasculature

Total peripheral resistance (TPR)

The amount of blood pumped by the left ventricle during the contraction

Stroke volume (SV)

Average SV

70mL

The amount of blood pumped by the heart in one minute

Cardiac output (CO)

How to calculate cardiac output?

SV x HR

How to calculate for blood pressure?

CO x TPR

The difference between systolic and diastolic blood pressure (SBP - DBP)

Pulse pressure

The average pressure in a patient’s arteries during one cardiac cycle; represents the force generated by the heart during contraction; considered a better indicator of perfusion to vital organs than SBP

Mean arterial pressure (MAP)

How to calculate MAP?

DBP + pulse pressure/3