Term
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Definition
| epicardium, myocardium, endocardium |
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Term
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Definition
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Definition
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Term
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Definition
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Term
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Definition
thin-walled
reservoir for systemic venous blood |
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Term
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Definition
propels blood into pulmonary circulation
low pressure
1/3 thickness of left ventricle |
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Term
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Definition
| receives oxygenated blood from lungs |
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Term
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Definition
high pressure
thick muscles
pressure exceeds right by five fold
forces blood into aorta |
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Term
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Definition
| cusps attached to thin strands of fibrous tissue called chordae tendinea |
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Term
| Where do chordae tendinea extend to? |
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Definition
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Term
| semilunter valves (3 symmetrical cuplike cusps) |
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Definition
secured to fibrous ring
above cusps of aortic vavle are three outpouchings of the aortic wall called the sinuses of Valsalva |
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Term
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Definition
| opening to coronary arteries located within these outpouchings |
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Term
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Definition
| ability to spontaneously generate impulses |
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Term
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Definition
| regularity of impulse generation |
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Term
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Definition
| ability to transmit impulses |
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Term
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Definition
| ability to response to stimulation |
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Term
| sympathetic nervous system |
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Definition
increases both heart rate and force of cardiac contraction
sympathetic receptors are beta receptors |
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Term
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Definition
| electrical excitation of heart |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
-90 mV
sodium outside cell and potassium inside
negative cell inside and positive cell outside |
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Term
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Definition
+30 mV
increased membrane permeability to sodium so inside becomes positive and outside becomes negative |
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Term
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Definition
small, abrupt change in ionic concentration and relative electrical change occurs
due to influx of chloride ions which reduces positive influence a little |
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Term
| mid diastole phase of cardiac cycle |
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Definition
slow ventricular filling or "diastasis"
atrial and ventricular chambers are relaxed |
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Term
| Late diastole phase of cardiac cycle |
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Definition
| depolarization spreads through atria causing atria to contract, forcing blood into ventricles |
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Term
| Early systole phase of cardiac cycle |
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Definition
depolarization spreads through ventricles causing AV valves to close which generated first heart sound
semilunar valves remain closed |
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Term
| late systole phase of cardiac cycle |
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Definition
| ventricular pressure exceeds pressures within vessels causing semilunar valves to open and ventricular ejection |
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Term
| early diastole phase of cardiac cycle |
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Definition
repolarization spreads through ventricle and chambers relax
prsesure drops blow arterial pressures, causing semilunar valves to close which produces heart sound
pressure continues to drop causing AV valves to open allowing filling of ventricles |
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Term
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Definition
| represents atrial depolarization |
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Term
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Definition
time from onset of atrial activation to onset of ventricular activation
0.12 to 0.20 seconds |
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Term
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Definition
represents ventricular depolarization
0.06 - 0.10 seconds |
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Term
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Definition
represents time between end of spread of the impulse through the ventricles and repolarization of ventricles
0.12 seconds |
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Term
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Definition
| represents ventricular repolarization |
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Term
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Definition
"electrical systole" of the ventricles
0.4 seconds |
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Term
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Definition
quantity of blood ejected by each ventricle per minute
normally equals around 5 liters |
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Term
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Definition
| Cardiac Output(CO)= cardiac rate X stroke volume |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
ventricles fill during relaxation to an end diastocilic volume of 100 ml of blood
contraction typically forces about 2/3 of this volume into arterial blood vessels, leaving 30 ml in the ventricles at end of systole (end systolic volume or ESV) |
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Term
| What are the 3 factors that infleuence ESV or SV? |
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Definition
| preload, contractility, and afterload |
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Term
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Definition
refers to stretch of myocardial muscle initiated by return of venous blood to the heart
as increasing quanities of blood enter the atria, an associated rise in intra-atrial and intraventricular pressures should cause an increase in cardiac output |
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Term
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Definition
| alterations in strength of caridac muscle contraction caused by factors other than preload stretch |
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Term
| What causes contractility to increase? |
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Definition
| exposure to calcium, norepinephrine, or epinephrine and stiumalation by sympathetic nervous system |
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Term
| What causes contractility to decrease? |
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Definition
| acidosis, hypocalcemia, hyperkalemia, and parasympathetic neural stimualtion |
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Term
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Definition
amount of force that must be gerenated during systole to eject blood into aterial vessels
varies primarily as function of arterial blood pressure and ventricular radium
explains why myocardial work must increase under certain conditions if stroke volume is to be maintained (if rising arterial blood pressure poses resistance to exit if blood from heart, the cardiac muscle will have to exer great effort to sustain output) |
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Term
| What are the three layers of the blood vessels? |
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Definition
| tunic intima (innermost), tunica media (middle), and tunica externa or adventitia (outermost) |
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Term
| What are arterial walls composed of? |
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Definition
| elastic connective tissue, fibrous connective tissue, and smooth muscle |
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Term
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Definition
have thick tunica media with more elastic fibers than smooth muscle
ex: aorta and pulmonary trunk |
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Term
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Definition
| contain more muscle fibers than elastic thus affected more by vasoconstriction/vasodilation |
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Term
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Definition
| lumen diameteres of less than 0.5 mm and are composed almost entirely of smooth muscle |
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Term
| What do the capillary walls contain? |
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Definition
| simple squamous epithelium---only tunica intima |
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Term
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Definition
force exerted on liquid (blood) per unit area
expressed as dynes per square centimeter, mm Hg, or torr |
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Term
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Definition
opposition to force
in blood most resistance provided by diameter and length of blood vessels
resistance is inversely related to blood floow
flow varies inversely to viscosity of fluid |
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Term
| neural control of total peripheral resistance |
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Definition
| autonomic nervous system can regulate cardiac output and peripheral resistance |
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Term
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Definition
increase in volume a vessel can accommodate for a given increase in pressure
depends on ratio of elastic fibers to muscle fibers |
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