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Flashcards in conducting system Deck (11):
1

Sinoatrial (SA) node

initiation of heartbeat
pacemaker (controls pace for cardiac activity)
SA node signal travels to AV node

2

Atrioventricular node

slows downs contraction and activation of ventricles
from AV node, signal travels to AV bundles

3

AV bundles

signal travels from AV bundle to ventricle via purkinje fibres
= contraction of ventricular muscle cells

4

systole

contraction
chamber ejects blood

5

diastole

dilation/relaxation - chamber fills with blood

6

1. relaxation period

all 4 chambers are diastole and low pressure in ventricles
2nd heart beat - blood flows from atria to ventricles
ventricles fill passively approx. 75%

7

2. atrial systole

atria contract and push last 25% of blood into ventricles

8

3. ventricular systole

ventricular contraction forces AV valves shut
1st heart beat = pressure builds and forces semilunar valves open = blood ejected

9

innervation - parasympathetic

vagus nerve
decrease heart rate
no effect on contraction

10

innervation - sympathetic

sympathetic trunk
increase HR
increase strength of cardiac contraction

11

innervation

receives visceral motor innervation