Card Set Information
cardiovascular system composed of
subdivisions of cardiovascular system (3)
components of conduction pathway
sinoatrial node (SA)
atrioventricular node (AV)
bundle of his
fast response action potentials (3)
slow response action potentials (2)
slow action potentials are associated with
T/F slow action potentials never rest
SA node is affected, the sympathetic nerve activites are
increased rate of diastolic depolarization
when the AV node is affected, the sympathetic nerve activites are
increased conduction rate
when the artial muscle is affected, what is the sympathetic nerve activites
increased strength of contraction
an increase in HR under sympathetic activity causes a release of
an increase in HR under parasympathetic activity causes a release of
when ACH binds to its receptors what 2 things happen?
permeability and decreases Ca
what is the oxygen level of the cardiac muscle?
cardiac muscle is innervated by
neurons of the autonomic branch of the peripheral nervous system
T/F cardiac muscle has muscle fibers in a chamber to essentially contract in unison
communication site between cells or with different regions within a cell
how is the electrical synapses message carried?
T/F electrical synapses have neurotransmitters
electrical synapses in the heart
what 2 ways do intercalated disks enhance conductivity?
allows action potentials to spread from:
- one cardiac muscle fiber to an adjacent one
- within a cardiac fiber
where do all myofibers contract in unison?
atria or ventricles
what is the contraction of cardiac muscle dependent on?
how does the extra-cellular Ca
enter the cell? (2)
via voltage regulated channels on the plasma membrane
by having the extra-cellular Ca
in the cardiac muscle fiber, what does it extend?
duration of action potential- ensures enough time for emptying the artia/ventricles
absolute refractory period- cardiac muscle needs to fully relax before it can contract
which valve is from the atria to ventricles?
which valve is from the right ventricle to the pulmonary artery?
which valve is from the left ventricle to the aorta?
when blood flows from the right atrium to the right ventricle, which valve needs to open?
right AV valve
when blood goes from the right ventricle to the pulmonary artery, which valve has to open?
when blood goes from the left atrium to the left ventricle, which valve has to open?
left AV valve
contraction of the heart
relaxation of the heart
when atria are in systole, ventricles are in diastole
what is phase 1 of the cardiac cycle called?
isovolumetric ventricular contraction
what is phase 2 of the cardiac cycle called?
ventricular ejection which the aortic and pulmonary vavles are opened
what is phase 3 and 4 of the cardiac cycle called?
isovolumetric ventricular relaxation
what is phase 5 and 6 of the cardiac cycle called?
atrial contraction in which the AV valve is opened
in what phase is the ventricular volume isnt changing?
in what phase is the having rapid ejection?
in what phase is the blood volume the same?
3 and 4
in what phase the heart filling actively?
in what phase can the heart have passive or active filling?
the volume of blood ejected from the ventricles per minute
what is the resting CO?
what is the max CO?
equation of SV
EDV - ESV
starting volume - final volume
fraction of blood ejected from the ventricles during ventricular stage
equation for ejection fraction
3 things EDV can be influenced by
time of ventricular diastole
volume of blood the returns to the right atrium
ventricular filling is influenced by
time of ventricular diastole is
what is circulating blood volume proportional to (2)
tissue fluid volume
what is venous pressure around?
veins have greater _____ compared to arteries? (2)
diameter of blood vessels is influenced by (2)
skeletal and respiratory muscle contraction
dense bodies are connected by
what does calcium bind to for smooth muscle contraction?
for smooth muscle contraction, the increase in sympathetic activity causes what? (2)
increase in frequency and strength of contraction
reduces the diameter of vessel
when VP is increases, what else is also?
right atrial pressure
when venous pressure is equal to right atrail pressure, what happens to venous return?
there is no VR
frank starling law
the volume of blood that enters the ventricles is proportional to the volume of blood that is ejected from the ventricles
increase in blood does what to sarcomeres?
increases the length
an increase in sympathetic activity does what to ESV?
when MAP increases, what happens to the ESV?
increases which then decreases SV
what is normal range for MAP?
an increase of sympthetic activity does what for smooth muscle contractions? (everything)
: HR, EDV, CO, VP, VR, SV
: time of diastole, ESV, diameter of veins
at rest, where is most of the blood distributed?
GI tract and renal
left atrium and ventricle compose what artery?
left coronary artery
when is there no blood flow to the heart?
what does the meta-arterioles connect?
arterioles to venules
what does the meta-arterioles do?
opens new "capillaries" during relaxation
an increase in metabolic activity increases blood flow how?
when the precapillary sphincters are sensed with oxygen during an increase of metabolic activity, what happens?
they contracted which decreases blood flow
an increase of CO
does what to capillaries?
vasodilation which allows more blood flow
why does blood pressure oscillate in arteries?
in systole, the aortic valve opens letting blood in which expands in pressure and volume
in diastole, the blood leaves and then there is an elastic recoil
why does blood pressure drop as blood travels from the arteries to veins?
capillaries are between them which have more surface area and veins are more compliant
equation of MAP
(CO)(total peripheral resistance)
resistance to friction forces as blood travels over the walls of vessels
an increase in radius does what to PR
what is MAP regulated by?
: nervous system
: endocrine and renal
what 2 things regulate short-term regulation of MAP?
where are the baroreceptors found?
where does the medulla send signals to?
cardiac control center
: regulates HR
: regulates PR