CARDIO 2 Flashcards
where are atrial ventricular valves found
bw atria and ventricles
what is bicuspid / mitral valve
AV valve bw L atrium and L ventricle
what is tricuspid valve
AV valve bw R atrium and R ventricle
where are SL valves found
bw ventricles and arteries which ventricles pump their blood to
what is aortic valve
SL valve bw L ventrice and aorta
what is pulmonary valve
SL valve bw R ventricle and pulmonary trunk / pulmonary artery
what do valves contain
flaps
what is base of valve attached to
valve rings
what do valves allow for
unidirectional flow
what causes valves to open
differences in pressure (passive)
why is opening and closing of valve passive
does not require energy to open / close
what kind of pressure gradient opens valves
- forward pressure gradient
- pressure greater behind valve
what kind of pressure gradient closes valves
- backward pressure gradient
- pressure greater infront of valve
what causes AV valves to open
pressure in atria greater than pressure in ventricles
what causes AV valves to close
pressure in ventricles greater than pressure in atria
what makes up AV valve apparatus (3)
- flaps
- chordae tendinae
- papillary
what is function of papillary muscle
pull on chordae tendinae causing them to become tight
when do papillary muscles contract
when ventricle contracts
why do papillary muscles contract when ventricles contract
- pressure increases in ventricles
- AV valve closes
- chordae tendinae keeps AV valve closed
what makes AV valves diff from SL valves
- AV valves have valve apparatus
- SL valves do not have valve apparatus
what is cardiac skeleton made of
dense CT separating atria and ventricles
what does cardiac skeleton include
- valve rings
2. dense CT bw valve rings
what is result of cardiac skeleton being made of dense CT
not electrically active
what does cardiac skeleton block
direct spread of impulse from atria to ventricles
what is cardiac muscle considered
syncytium
why is cardiac muscle considered syncytium
myocytes act together
what allows for myocytes to act together
- physical coupling (desmosomes)
- electrical coupling (gap junctions
- chemical coupling (gap junctions)
what are 2 functional syncytia in heart
- L and R atrium =1
- L and R ventricle = 1
what kind of property does heart have
all or none
- all myocytes respond + are excited
- no myocytes respond + are excited
how does heart contact in series
- L and R atria depolarize and contract
2. L and R ventricles depolarize and contract
what does and does not generate AP s in hearr
does ==> heart
does not ==> neural stimulation + hormonal stimulation
what is AP origin
myogenic / muscular
what are 2 types of myocytes
- contractile cells
2. conducting cells
what is the function of contractile cells
- squeezing blood
2. propelling blood
where do contractile cells receive AP s from
- adjacent contractile cells
2. conducting cells
what is the function of conducting cells
- initiate AP
- conduct AP
- cause contractile cells to contract
what kind of cells are conducting cells
auto-rhythmic
what do conducting cells make up
conducting system of heart
CONDUCTING SYSTEM what are regions of conducting system
- SA node
- inter nodal pathways
- AV node
- bundle of his
- L and R bundle branches
- purkinje fibres
CONDUCTING SYSTEM what is located in regions of conducting system
conducting myocytes
CONDUCTING SYSTEM where do inter nodal pathways extend from
- SA node to AV node
2. R atrium to L atrium
CONDUCTING SYSTEM what does bundle of his pass through
cardiac skeleton
CONDUCTING SYSTEM what do L and R bundle branches pass through
inter ventricular septum
CONDUCTING SYSTEM where do L and R bundle branches separate
apex
CONDUCTING SYSTEM what do purkinje fibres pass through
ventricular myocardium
CONDUCTING SYSTEM what is only electrical connection bw atria and ventricles
- AV node
2. bundle of his
CONDUCTING SYSTEM how do regions of conducting system differ
rate w which they generate AP s
CONDUCTING SYSTEM what region of conducting system generates AP s at fastest rate
SA node
CONDUCTING SYSTEM what is SA node referred to as
cardiac pace maker
CONDUCTING SYSTEM why is SA node referred to as pace maker
generates AP s that set heart rate
CONDUCTING SYSTEM what happens when SA node generates AP
- AP spreads through inter-nodal pathways to contractile cells in L and R atria
- AP spreads through inter-nodal pathways to AV node
CONDUCTING SYSTEM what happens when AP travels through inter-nodal pathways to AV node
only atria contracts
CONDUCTING SYSTEM what is AV delay
slow propagation of AP s from AV node to bundle of his
CONDUCTING SYSTEM what does AV delay ensure
- ventricles relaxed while atria contracting
2. ventricles have enough time to fill w blood before contracting
CONDUCTING SYSTEM how does excitation travel through conducting system
gap junctions
CONDUCTING SYSTEM how does excitation travel from conducting cell to contractile cell
gap junctions
CONDUCTING SYSTEM what happens at same time that excitation traveling to AV node
excitation travelling from conducting cells to contractile cells
CONDUCTING SYSTEM what happens when excitation spreads to contractile cells in atrial myocardium while excitation spreads to AV node
- atrial myocardium contracts
2. atrial myocardium relaxes
CONDUCTING SYSTEM what happens after atrial myocardium relaxes
- excitation spreads to bundle of his
- excitation spreads to L and R bundle branches
- excitation spreads to purkinje fibres
CONDUCTING SYSTEM what happens when excitation spreads to purkinje fibres
- ventricular myocardium contracts
2. ventricular myocardium relaxes
what are 2 types of AP s in heart
- fast response AP
2. slow response AP
what produces fast response AP s (3)
- contractile myocytes of atrial myocardium
- contractile myocytes of ventricular myocardium
- conducting myocytes
a. bundle of his
b. L and R bundle branches
c. purkinje fibres
what produces slow response AP s (2)
- conducting myocytes
a. SA node
b. AV node
what is fast response AP
rapid rate of depol
what is slow response AP
slow rate of depol
what is concentration of K inside and outside cell
- inside, high
- outside, low
what is concentration of Na inside and outside cell
- inside, low
- outside, high
what is concentration of Ca inside and outside cell
- inside, low
- outside , high
SLOW AP what are phases of slow AP
- pacemaker potential
- depol
- repol
SLOW AP what is pacemaker potential
gradual depol to threshold
SLOW AP what is rate of pacemaker potential
slow
SLOW AP what is function of pacemaker potential
generate AP wout nerves or hormones (external stimuli)
SLOW AP what ion channels are involved in pacemaker potential
- K channel
- F type channel
- T type channel
SLOW AP how do K channels contribute to pacemaker potential
- K out
- makes mem potential neg
SLOW AP how do F type channels contribute to pacemaker potential
- Na in
- depolarizing current
SLOW AP how do T type channels contribute to pacemaker potential
- Ca in
- depolarizing current
(FINAL DEPOLARIZING BOOST)
SLOW AP what channels are involved in depol
- L type channel
SLOW AP what are characteristics of L type channel
- open slowly
- open for long period of time
- depol mem slowly
SLOW AP what channels are involved in repol
- K channel
SLOW AP how to K channels contribute to repol
- K out
- makes mem potential neg
SLOW AP what is happening to K channels during pacemaker potential
- starting to close
- less K out
SLOW AP how long do T type channels remain open
briefly
SLOW AP what happens when mem potential reaches new transiently pos value
- L type channels close
2. K channels open
SLOW AP how does pacemaker potential of AV node differ from pacemaker potential of SA node
rise to threshold more slow