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28 Cards in this Set
- Front
- Back
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Where is the SA node located?
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What is its composition/connections?
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Located anteriolaterally
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Collection of nodal tissue
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cardiac muscle fibers and fibroelastic connective tissue. P- cells or pacemaker cells- round T-cells or transitional cells
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What are the 3 Myogenic conduction/tracts
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Anterior- Bachmans - to L atrium
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Middle internodal- Wekebach
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Posterior internodal - Thorels
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Where is the AV node located?
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It's blood supply is from where?
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Located posterioinferior region near coronary sinus
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AV nodal Artery- largest and usually first IV septal branch of the posterior IV artery- from the RCA in 80%
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What is the purpose of the AV bundle?
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Where is its location?
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Electrical isolation of the atria and ventricle
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Act as the bridge between atrial and ventricular myocardium.
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Passes through the opening in the insulating fibrous skeleton along the IV septum.
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Where are the bundle branches located?
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What do they stimulate?
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Bundle divides at the junction of the membranous and muscular parts of the septum-into the Right and Left Bundle branches and proceeds down either side of the intraventricular septum.
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Right- Stimulate IVS
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anterior papillary muscle
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Left -6 smaller tracts-IVS
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anterior & posterior papillary muscles & wall of L ventricle
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Disruption in LAD or RCA would give rise to conduction difficulties where?
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Where are the cardiac plexuses located?
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LAD gives rises to most of the anterior septal supply so blockage here would result in conduction difficulties at the bundle branch level.
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RCA supplies SA &AV nodes- disruption here may result in complete heart block and leave only the ventricular intrinsic rate of 25-30 BPM
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Located in front of the trachea at the the level of the bifurcation behind the ascending aorta and above the bifurcation of the pulmonary trunk.
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Describe the action of the sympathetic supply
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what where the pre and post synaptic fibers lie
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Presynaptic fibers- whose cell bodies lie in the the lateral horn of superior 5 & 6 thoracic segments of the spinal cord.
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Postsynaptic fibers- cell bodies in the cervical and thoracic paravertebral ganglia of sympathetic trunks.
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Describe the parasympathetic supply actions and location of its pre and post synaptic fibers
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Action- decreases heart rate & force of contract and constricts coronary arteries
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Presynaptic fiber of the vagus nerves
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Postsynaptic fibers end in the SA & AV nodes- their cell bodies constitute intrinsic ganglia
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