Conduction Review Flashcards
Craniosacral is innervated by
PNSNS
Thoracolumbar is innervated by
SNS
What are the cardioaccelerator fibers
T1-T4
Which nerve depresses cardiac function?
Vagus Nerve
What substances bind catecholamines
Adrenergic receptors
SNS postganglions attach to
cardiac and thoracic nerves
PSNS and some SNS postgang attach to the cardiac plexus leading to
SA & AV nodes and the atrial myocardium
what receptors are at the end of PSNS and what substances bind these receptors
Muscarinic (M1)
ACh
Inotropy means
contractility
Chronotropy means
Heart Rate
Dromatropy means
AV conduction
Lusitrophy means
myocyte relaxation
SA node refers to
Nodal (pacemaker)
Atrial and ventricular myocytes refers to
non-nodal
Troponin activates ______of actin & myosin
contraction
Phase 0 of the cardiac non nodal (ventrical) must reach a threshold level of _______and causes ______ _____ channels to open
This ion causes the cells membrane to ___________
-70; Fast Na+; depolarize
Phase 1 of the cardiac non-nodal (ventrical) is when the fast Na+ channels are _______and the ______channels open
This ion leaving causes an initial ___________(______)
(this ion leaks)
inactivated;K+
repolarization (hyperpolarization)
Phase 2 of the cardiac non nodal (ventricle) is called a ________and is when K+ continues to slowly move outward and_____ ______ _______channels open. This phase helps prolong depolarization
plateau; L-type slow Ca+ channels open
Phase 3 of the cardiac non nodal (ventricle), Ca+ channels become________ and slow ______channels remain open in addition to more ______channels opening. More of this ion leaving causes rapid_________/___________ (more dramatic process)
inactivated; K+; K+; repolarization/hyperpolarization
Phase 4 of the cardiac non nodal (ventricle) resting membrane potential is ______
This ion predominates here
-90mV; K+
What is the absolute/Effective Refractory period
period where once Na+ channels open, the heart shouldnt be able to respond to another action potential
Is the beginning of phase 0 and end of phase 2
What is the relative refractory period?
We want the heart in refractory to limit frequency of depolarization and heart rate
Happens at the end of absolute refractory to the beginning of phase 3 & 4
This period may generate another action potential
This period allows for adequate ventricular filling and preservation of EF
The nodal action potential (SA/AV node) threshold is
-40 to -30mV
Phase 0 of the nodal action potential (SA/AV node) is when the ___ ____ ____ channels open and cause the cell to ____________
L-type Ca+ channels; depolarize
Phase 3 of the nodal action potential (SA/AV node) is when the ____ ____ ____channels become _______ and the ______channels open
This ion leaving causes the cell membrane to ______/_______
L-type Ca+channels; inactivated; K+; repolaraize/hyperpolarize
Phase 4 of the nodal action potential (SA/AV node) is when the cell membrane________ to ________mV
________channels open and _____slowly comes in
The slow movement of this ion causes the cell membrane to ________ ________
hyperpolarizes; -60mV; Ca+; Na+; Spontaneously depolarize
NE binding to Beta 1 ________the slope of phase ______, decreasing the time it takes to reach threshold
This increases slow Na+ and Ca+ inward currents
increases; 4
ACh binding to M ______slope of phase ____, increasing time to reach threshold, increasing K+ currents out and decreasing Na+ and Ca+ currents in
This hyperpolarizes membrane during phase 4
decreases; 4
Hyperkalemia effects on the heart
bradycardia, may stop SA nodal firing
depolarizes the membrane
decreases degree of hyperpolarization at the end of
phase 3
Hypokalemia effects on the heart
tachycardia
increases rate of phase 4 depolarization
increases phase 3 repolarization
Loss of O2 at the cellular level causes
depolarization leading to bradycardia
decreases slope of phase 4
When using leads, depolarizinig towards will give
positive deflection
depolarizing perpendicular with produce a
biphasic deflection
A positive deflection with show ip as what on an EKG
P wave
What are the augmented limb leads
aVR,aVL, and aVF (shows frontal plane)
What are the precordial leads
V1-V6
Current flows from
base to apex
3 lead monitoring are adequate when monitoring _________arrhythmias, especially in lead ___
atrial; 2
How is monitoring in 3 lead limiting
limits ability to detect ischemia
Which 2 leads are better together with monitoring
2 and 5 (80%)
V5 is unipolar
What is the most common arrhythmia
Afib
Nodal cells have __________
automaticity
triggered rhythms happen by either these two mechanisms
early or delayed afterpolarization
both due too problems with Ca+ regulation
What is reentry
AP travels back to already depolarized tissue
The more distal we are in the heart
the slower the heart rate
bradycardia decreases
Co and arterial blood pressure
tachycardia can cause a
decrease in preload, SV and CO
abnormal ventricular conduction
impaired contraction
reduced EF
increased myocardial O2 demand
angina
Afib can cause
risk of thrombus and embolism
lost contraction and perfusion
lost fill
Vfib can cause
zero CO
