lab practical 2: bp and pulse

cardiac cycle

the cycle of contraction and relaxation of both atria and ventricles

systole

contraction of atria or ventricles

diastole

relaxation of atria or ventricles

Blood is _____ during systole

Pumped out

blood is ___ during diastole

filling

atrial diastole

blood delivered into atria via veins

atrial systole

last 20% of blood left in the atria delivered to the ventricle by atrial systole

ventricular systole

ventricular contraction begins, pressure rises, AV valves close

ejection phase

as pressure begins to rise in the ventrciles, blood is pumped into the great arteries

ventricular diastole

cycle repeats

phase 1 of cardiac cycle

ventricular filling

what happens during ventricular filling

atrial pressure > ventricular pressure, the AV valves are forced open, blood flows passively into the atria and on through the ventricles

What is ventricular filling + atrial contraction

the atria contract to complete the filling of ventricles. ventricular diastole ends, and so the end diastolic volume of the ventricles is achieved

what is phase 2 of the cardiac cycle

isovolumetric contraction

what happens during isovolumetric contraction

The contraction of the ventricles begins, and ventricular pressure increases, closing the AV valves

what is phase 3 of the cardiac cycle

Ventricular ejection

what happens during Ventricular ejection

Ventricular pressure continues to rise; when the pressure in the ventricles exceeds the pressure in the great vessels exiting the heart, the SL valves open, and blood is ejected 

what is phase 4 of the cardiac cycle

Isovolumetric relaxation

what happens during Isovolumetric relaxation

the ventricles relax, decreasing the pressure in the ventricles, the decrease in pressure causes the SL valves to close.

what is the dicrotic notch

the result of a pressure fluctuation that occurs when the aortic valves snap shut

what causes AV to valves open

Blood returning to the heart fills the atria, putting pressure against atrioventricular valves

what causes AV to valves close

ventricular contraction

how do AV valves prevent backflow

Papillary muscles and chord tendineae tighten, preventing valve flaps from everting into atria.

what causes SL valves to open

as ventricles contract, blood pushes against SL valves

what causes SL valves to close

ventricular relaxation

the tool used to accurate heart sounds

stethoscope

1st heart sound indicates..

closure of the AV Valves

2nd heart sound indicated

closure of the SL valves

heart murmur

an abnormal heart sound that indicates a defect in one of the valves

pulse

surges of pressure in arteries as heart pushes blood out during cardiac cycle

heart rate

number of beats per minute

normal range for resting HR

60-100bpm

average heart beat lasts

0.8 seconds

average resting HR

70-76bpm

how to calculate HR from Heart beat length

60 seconds/ heart beat duration = HR

blood pressure

pressure exerted against walls of arteries

systolic bp

pressure exerted against the walls of the arteries during ventricular systole

diastolic bp

pressure exerted against the atrial wall during ventricular diastole

tool to measure bp

sphygmomanometer

units to measure bp

mmHg

normal bp

< 120 and <80

elevated bp

120-129 and <80

hypertension stage 1

130-139 or 80-89

hypertension stage 2

≥140 or ≥ 90

hypertensive crisis

≥180 and/or ≥120

Total peripheral resistance (TPR)

the amount of force exerted on circulating blood by the vasculature

stroke volume SV

The amount of blood pumped by left ventricle during one contraction

cardiac output CO

The amount of blood pumped by the heart in one minute

Calculate CO

CO= SV * HR

Calculate BP

BP= CO * TPR

Calculate pulse pressure

pulse pressure = SBP - DBP

Mean atrial pressure MAP

average pressure in a patients arteries during one cardiac cycle

Calculate MAP

MAP= DBP + Pulse pressure / 3