A&P II Lab: Cardiac Cycle

the first heart sound is a result of closure of the

AV valves

at what point in the cardiac cycle is the pressure in the heart lowest?

diastole

when are AV valves open?

diastole

when are the semilunar valves closed?

diastole

atrial systole

-atria contract -AV valves open -semilunar valves vlosed

early ventricular systole

-atria relax -ventricles contract -AV valves forced closed -semilunar valves closed

early ventricular diastole

-atria relax -ventricles relax -AV valves closed -semilunar valves closed -atria begin passively filling with blood

late ventricular diastole

-atria relax -ventricles relax -atria passively fill with blood -AV valves open -semilunar valves closed

late ventricular systole

-atria relax -ventricules contract -AV valves remain closed -semilunar valves open

sounds of korotkoff

-characteristic sounds heard when measuring BP --Systolic pressure: pressure in cuff equals arterial pressure, begin to hear sounds. --Diastolic pressure: pressure in cuff drops below minimal pressure in ventricular relaxation, sounds disappear

vasoconstriction

-decreases luminal space -increases resistance -decreases blood flow --Controlled by sympathetic nervous system

blood pressure

-force per unit area exerted on vessel wall by the blood -cardiac output x peripheral resistance (BP=COxPR)

peripheral resistance

-frictional force that opposes blood flow (flow=p/r) -3 main factors affect resistance: --blood vessel length -adults vs children --diameter (and flexibility) -atherosclerosis, arteriosclerosis, medications --viscosity(and volume) -pregnancy, medications, diet

hypertension

-high BP -sustained elevated arterial pressure of 140/90 or higher -primary: due to several risk factors including heredity, diet, obesity, age, stress, diabetes mellitus, and smoking

shock

-hypoperfusion -inadequate circulation of blood (oxygen) to the cells

vasodilation

-increases luminal space -decreases resistance -increases blood flow --Controlled by sympathetic nervous system

hypotension

-low BP -orthostatic: temporary low BP and dizziness when suddenly rising from a sitting or reclining position -acute: important sign of circulatory shock

factors affecting BP

-posture -exercise -cardiovascular disease -diet (salt intake) -medications

congestive heart failure (CHF)

-progressive condition where the CO is so low that blood circulation is inadequate to meet tissue needs -caused by: -coronary atherosclerosis -persistent high blood pressure -multiple myocardial infarcts

vital signs

-pulse points -blood pressure -response to exercise

pulse points

-pulse results from alternating surges of pressure in artery occurring with each beat of left ventricle -average adult between 60-100 -apical pulse counted from heart -pulse deficit - lag time between apical and distal pulse

circulatory signs

-skin color: cyanosis (lips, nail beds). -capillary refill: perfusion, often measured at nail beds. -diaphoresis: clammy, sweaty skin

PR and vessel diameter

-smaller diameter means more blood cells in contact with vessel walls, creating more friction -results in greater resistance and thus greater pressure

systole

-ventricular contraction -pressure in ventricles rises -AV valves close (lub) -ventricular pressure > arterial (aortic) pressure -semilunar valves open -ventricles contract -blood pumped out forcefully -late systole: ventricles relax, semilunar valves shut (dub)

diastole

-ventricular relaxation -low pressure in heart -blood flows passively into chambers -AV valves open -semilunar valves closed -late diastole.atrial systole (atria contract)

cardiac output

-volume of blood pumped out by left ventricle each minute (stoke volume x heart rate)

regulation of cardiac output

HR and SV often change in opposite directions as compensatory mechanisms try to maintain constant cardiac output. Ex: Bleeding

cardiac cycle

all events in 1 heart beat

chambers that just emptied

atrium

after the second heart sound, what are filling with blood? what are empty?

atrium,ventricles

sphygmomanometer

blood pressure cuff

dicrotic notch

brief backflow resulting in closing of semilunar valves

arteriosclerosis

calcified and rigid artery cannon expand; artery walls experience higher pressures

pressure point at side of neck

carotid

what event causes the semilunar valves to close?

dicrotic notch (brief backflow)

pressure point at dorsum of foot

dorsalis pedis

pressure point at front of ear

facial

Tachycardia

fast pulse rate

pressure point at groin

femoral

systolic pressure

highest pressure in artery at peak ventricular contraction

diastolic pressure

lowest pressure during ventricular relaxtion

monosyllables describing the heart sounds are

lub and dup

pressure point at medial malleolus

post. tibial

pressure point at wrist

radial

second heart sound is a result of closure of the

semilunar valves

Bradycardia

slow pulse rate

at what point in the cardiac cycle is the pressure in the heart highest?

systole

when are AV valves closed?

systole

when are the semilunar valves open?

systole

pulse pressure

systolic-distolic

the heart chamber that have just been filled when you hear the first heart sound are the

ventricles

what event causes the semilunar valves to open?

ventricular pressure is higher than atrial pressure

what event within the heart causes the AV valves to open?

when ventricular pressure is lower than atrial pressure