Ch. 12 Flashcards
aortic semilunar valve
prevents back flow from the blood moving from the left ventricle to the aorta
aorta
branches and carries blood away from the heart to all organs and tissues in the systematic circuit
tricuspid valve
prevents back flow of blood traveling from the right atrium to the right ventricle
pulmonary semilunar valve
prevents back flow of blood traveling from the right ventricle to the pulmonary artery
pulmonary artery
the only artery carrying deoxygenated blood and goes to the lungs to drop off CO2
where is blood oxygenated?
in the lungs
where does the blood go after is it oxygenated?
through the pulmonary vein to the left atrium
pulmonary vein
the only vein in the body carrying oxygenated blood
bicuspid valve
prevents back flow of blood traveling from the left atrium to the left ventricle
where does the blood enter the heart?
through the vena cava (biggest vein)
where does the blood leave the heart
through the aorta (biggest artery)
venules
the small vessels transporting blood to the heart
Cardiac cycle
the atria contracts first which forces blood into the ventricles, then the ventricles contract forcing blood into the arteries
pacemaker cells
sets the rhythm of the heartbeat, produces AP that causes the heart to contract
myogenic
means that our heart contracts because of the cell not because we think about making our heart contract
gap junctions
when one cell gets response it allows for all the cells in the heart to receive the same response allowing the heart to contract together
cardiac conduction fibers
transmits rhythm of heartbeat and carries the AP to every other area on of the heart
where are the pacemaker cells found?
on the SA and AV nodes
where are the cardiac conduction fibers found?
on the intermodal and interatrial pathways and Purkinje fibers
cardiac contractile cells
generate the contractile force
what does the SA node do?
it is where the AP is initiated
what does the AV node do?
slows down the conduction of the AP so that the atria has time to completely contract before the ventricle begins to contract
what causes the funny channels to open?
hyperpolarization of the membrane
what happens when the funny channels open?
more permeable to Na than K; cell becomes more positive; causes depolarization
what happens when funny channels close?
T-type Ca channels open causing the potential to reach threshold (the point of no return)
systole
ventricular contraction
diastole
ventricular relaxation
T type Ca channels
helps the membrane to reach threshold; cell is now more permeable to Ca than Na; closes once it reaches threshold
rapid depolarization
L type Ca channels and Na channels are open causing the cell to become very positive quickly
peak of AP (repolarization)
L type Ca channels and Na channels are closed and K channels are open so the cell returns to a negative potential
L type Ca channels
allow for the cell to have a long duration AP
relaxed muscle fibers
tropomyosin blocks myosin-binding sites
what happens when Ca binds to troponin?
the tropomyosin is moved exposing the myosin binding sites so they muscle can contract
when are the AV valves open?
when the pressure in the atria is higher than the pressure in the ventricles
when are the AV valves closed?
when the pressure in the ventricles is higher than the pressure in the atria
when are both semilunar valves open?
when the pressure in the ventricles is higher than the pressure in the arteries
when are both semilunar valves closed?
when the pressure in the arteries is higher than the pressure in the ventricles
aortic and pulmonary semilunar valves
are found separating the ventricles from the arteries that come out of them
ventricular filling
blood from systemic and pulmonary circuits flow through atria into ventricles; AV valves are open and SL valves are closed; part of diastole because ventricles are relaxed
atrial contraction
at the end of diastole, atria contract, driving more blood into the ventricles; atria begin to relax
isovolumetric contraction
ventricles begin to contract (systole) so the pressure is rising because AV and SL valves are closed
ventricular ejection
ventricles are contracting (systole); AV valves are closed and SL valves are open; opening SL valves allows ventricles to eject their contents into the systemic and pulmonary circuits
isovolumetric relaxtion
ventricles relaxing (diastole); AV and SL valves are closed
