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Flashcards in Heart 2 Deck (25)
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1
Q

cardiac muscle has more what

A

mitochondria and electrical connections

2
Q

what is the pace maker of the heart

A

sinoatrial node (SA)

3
Q

the heart has what type of rythmn

A

intrinsic

4
Q

where is the back up pacemaker

A

in the ventricles (AV node)

5
Q

describe the backup pacemaker

A

slower paced; gets overriden by SA node signal

6
Q

what is the heart’s nervous system

A

cardiac conduction system

7
Q

what are the 6 steps of the cardiac conduction system

A
  1. SA node fires 2. atria contract 3. atrioventricular node delays signal about .1 sec 4. atrioventricular bundle conducts rapidly 5. bundle branches take signal to apex 6. purkinje fibers
8
Q

in what order does pumping occur

A

first is the atria then ventricles(inferior to superior)

9
Q

what maximizes efficiency of the heart

A

the timing of action potentials and pumping

10
Q

what is the heart’s intrinsic rhythm usually slowed by

A

parasympathetic

11
Q

what is a typical heart rate

A

75 beats per minute

12
Q

what is the SA node pace slowed by

A

parasympathetic(specifically acetolcholine)

13
Q

where does sympathetic stimulation flow

A

brain stem-spinal cord-rib-either SA node, AV node, or left ventricle

14
Q

what cause an increase of heart rate

A

SA and AV nodes

15
Q

what cause the heart to beat more strongly

A

left ventricle

16
Q

aka adrenaline

A

epinephrine

17
Q

this records the composite electrical impulses of the heart (noninvasive)

A

electrocardiography (ECG)

18
Q

how do ECGs work

A

they measure thoracic electrical signals(patient must lie still)

19
Q

what is atrial contraction

A

P wave

20
Q

what is atrial relaxation and ventricular contraction

A

QRS complex

21
Q

ventricular relaxation/repolarization

A

T wave

22
Q

what happens when depolarized

A

atria contract

23
Q

how long does the atria stay contracted

A

1.5 sec then it relaxes

24
Q

what happens during the ST segment

A

emptying, squeezed shut and squeezes blood out

25
Q

what happens during ventricular filling

A

blood flow back into the ventricle; fills it up