Cardiac Cycle and Blood Pressure

cardiac cycle

one complete heart beat

aortic pressure

pressure within the aorta; reflects systemic blood pressure

atrial contraction (atrial systole)

Atria contract, delivering the last of the required blood to the ventricles.

atrial depolarization

P wave on ECG

atrial relaxation (atrial diastole)

atria relax and fill with blood from veins

atrial pressure

increases during atrial contraction

atrial repolarization

QRS complex

cardiac output (CO)

amount of blood pumped per minute

CO = HR x SV

dicrotic notch

small dip in the aortic pressure curve caused by closure of the aortic valve

electrocardiogram

recording of the heart's electrical activity

heart rate

number of heartbeats per minute

heart sounds

first heart sound: "lub" when AV snaps shut

second heart sound:"dub" when semilunar snap shut

isovolumetric contraction

starts ventricular contraction, where pressure builds in the ventricles; all valves closed, no movement of blood

isovolumetric relaxation

beginning of ventricular relaxation, pressure falls in ventricles; no blood moves, all valves closed

passive ventricular filling

ventricular volume increases, atria are in diastole

phonocardiogram

graphic record of heart sound

stroke volume (SV)

amount of blood ejected from a ventricle per beat

SV = EDV - ESV

ventricular contraction (systole)

the ventricle contract (ventricular systole) forcing blood out of the ventricles into the aorta and pulmonary artery

ventricular depolarization

QRS complex

ventricular volume

the amount of blood within the ventricle throughout different stages of the cardiac cycle

ventricular ejection

blood leaves ventricles through semilunar valves

ventricular filling

ventricular volume increases from blood flowing from atria to ventricles

ventricular repolarization

T wave

auscultation

listening to internal body sounds with a stethoscope

diastole

Relaxation of the heart

diastolic blood pressure

Pressure in the arteries when the heart relaxes and ventricles fill with blood, the bottom or second number

hypertension

high blood pressure

hypotension

low blood pressure

korotkoff sounds

sounds heard while taking the blood pressure

Mean Arterial Pressure (MAP)

average pressure present in arteries

diastolic pressure + 1/3 (systolic pressure - diastolic pressure)

OR

diastolic

pulse pressure

the difference in pressure between the systolic and diastolic pressures (systolic-disatolic)

sphygmomanometer

measures blood pressure (cuff and guage)

stethoscope

used to listen to the sounds in our case of blood pressure

systole

heart contracting and pumping blood

systolic blood pressure

top number on blood pressure reading, measures the force of blood pushing against artery walls as heart beats

total peripheral resistance

the amount of resistance the blood encounters as it flows

brachial pulse

• pulse on brachial artery

carotid pulse

• pulse on common carotid artery

facial pulse

• pulse on facial artery

palpate

using fingers to feel a pulse

radial pulse

• pulse on radial artery

ulnar pulse

• pulse on ulnar artery

anastomosis

surgery between two blood vessels allowing blood to bypass blocked pathway

autonomic nervous system

controls timing, speed, and strength of cardiac cycle through dual innervation

parasympathetic nervous system

slows heart rate, decreases contraction force, and lengthens time of rest or diastole

sympathetic nervous system

speeds up heart rate, increases contraction force, accelerated relaxation