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Flashcards in Rhythmical Excitation of the heart Deck (14)
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1
Q

system of heart does what things in order to produce rthymical self excitation and repetitive conduction

A
  1. Generates electrical impulse to initiate the rhythmically contraction of the heart
  2. Conducts these impulses repeatedly through the heart
2
Q

What features are shown because of this system of rhythmical contraction and repetitive impulses

A
  1. The atria contracts 1/6th of second ahead of ventricle this allows filling of ventricle before they pump blood from lungs and peripheral circulation
  2. Both the atria contacts together
3
Q

WHat happens in ischemia and why ischemia happens

A

Happen because of inadequate amount of coronary blood flow and causes bizarre rhythmical contractions of heart, the pumping effectiveness of the heart is affected

4
Q

SA node

A

normal rhythmical impulses are generated in SA node

5
Q

internodal pathways

A

that take the impulse from the SA node to AV node

6
Q

AV node

A

the node in which the impulses are delayed from the atrial to ventricle

7
Q

AV bundle

A

the bundle which conducts impulses from atrium to ventricle

8
Q

Purkinje fibers

A

purkinje bundle branches of right and left conducts impulses to all parts of the ventricles

9
Q

Describe SA node

A

it is a small, flattened, ellipsoid specialized cardiac muscle. 15mm long, 3mm wide and 1mm thick

10
Q

location of SA node

A

Present in superior posterolateral wall of right atrium below and slightly lateral to where the superior vena cave enters

11
Q

Function of SA node

A

SA node fibers are connected directly to Muscle fibers of atrium so the action potential can be spread immediately

12
Q

Resting membrane potential of SA node between discharge is

A

-55 to -60

13
Q

Resting membrane potential of ventricles between discharge is

A

-85 to -90

14
Q

Why resting membrane potential Of SA node is less than ventricle

A

due to the natural leakage of Na and calcium ions.