Inn of heart

Question 1

Where is the SA node located, what is its firing rate and what is it supplied by

Answer 1

location- Deep to epicardium @ junction bw sup vena cava and r atrium

Firing- 70 impulses/min (signals travel to AV node)

Supply- SA artery (branch of r coronary)

Question 2

Where is AV node located, what is its firing rate (if acting alone), what supplies it

Answer 2

location- interatrial septum near opening of coronary sinus

Firing- 40-60 impulses/min (signals travel to av bundle)

Supply- AV nodal aa (branch of r coronary)

Question 3

where is AV bundle located, what is its firing rate (if acting alone), blood supply

Answer 3

location- passes thru fibro skeleton of heart (subendocardial)

Firing- 40-55 impulses/min

supply- AV nodal branch

Question 4

where are the right + left bundles located and what does it end with

Answer 4

distributes nerve signal towards contractile myocardium

• right bundle goes to ant wall of r ventricle thru septomarginal trabeculea
• left goes to left ventrical
• both branch into purkinje fibres

Question 5

what is the impulse rate of purkinje fibres if acting alone

Answer 5

20 impulses a min (uneven tho)

Question 6

sympathetic contribution to heart from

Answer 6

T1-5 cardiopulmonary splanchnic nerves

Question 7

function of sympathetic contribution to heart

Answer 7

cardiac accelerator, increased myocardial contraction, increasese blood and oxygen (dialation)

Question 8

parasympathetic contribution to heart from

Answer 8

vagus n (upper/inf cervical cardiac n and sup/inf thoracic cardiac n)

Question 9

function of parasympathetic contribution to heart

Answer 9

-Cardiac depressor, HR decreased, decreases contraction, constriction of vessels

Question 10

sites of coronary artery occlusion (mc-> least)

Answer 10

Ant interventriucular branch
Right coronary artery
circuferential branch (x2)
left coronary arter
post interventricular branch

Question 11

what is a percutaneous transluminal angioplasty

Answer 11

enters thru femoral aa and is for less extreme/earlier stages of atherosclerosis. Balloon clears the lumen