Create an account
Name the heart valves and describe their location, function, and mechanism of operation.
Heart valves open and close in response to pressure changes as the chambers contract and relax. Two types of valves:
atrioventricular valves (tricuspid, bicuspid)
semilunar valves (pulmonary, aortic)
Atrioventricular valves are forced OPEN as pressure increases in the atria. Blood returning to atria forces heart places pressure on atrioventricular valves! As atria fills, A flaps hang loose into ventricles. Atria contract, forcing blood flow into ventricles. AV valves are then forced closed by ventrical pressure.
Semilunar Valves: (Pulmonary and aortic) Forced open as pressure grows in ventricles! Blood is pressing against them... so they open. Pressure from blood in the arteries makes it close.
Describe the normal heart sounds and the events in the heart they correspond to.
Auscultation: act of listening to sounds within the body
. Lub DUB!
Describe the events that occur during cardiac muscle contraction.
Three major phases during contraction:
Depolarization: Rapid depolarization due to Na+ inflow when voltage gated fast Na channels open.
Plateau : Maintained depolarization due to Ca2 inflow when voltage gated slow Ca2+ channels open and K+ outflow when some K+ channels emerge.
Repolarization: Dulse to close of Ca+ channels and K+ outflow when additional voltage gated K+ channels open.
Name the components of the cardiac conduction system.
Specialized cardiac muscle fibers called autorhythmic fibers make your heart beat!! Autorhythmic fibers act as:
Pacemaker: initiates the signal
Conduction system: propagates the signal throughout the heart
Trace the pathway of conduction in the heart.
Sinoatrial (SA) node (pacemaker): generates impulses.
Atrioventricular (AV) node: impulse pauses here
Atrioventricular (AV) bundle: Connects atria to ventricles
Right/left bundle branches: conducts impulses through interventricular septum
Purkinje fibers (in walls of ventricles): Depolarize!
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together