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Flashcards in chapter 18 Deck (60)
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1

where are cardiac centers in the brain located?

medulla oblongata

2

What is an electrocardiogram?

a composite of all the action potentials generated by nodal and contractile cells at a given time

3

what is a P wave caused by?

depolarization of SA node

4

what causes a T wave?

ventricular repolarization

5

what occurs during the first sound of a heart beat?

AV valves close and signifies beginning of systole

6

what occurs during the second sound of a heart beat?

SL valves close at the beginning of ventricular diastole

7

What is End-systolic volume (ESV)?

Volume of blood remaining in each ventricle after the ejection phase

8

What are murmurs?

abnormal heart sounds

9

What is end-diastolic volume?

Volume of blood in a ventricle at the end of a filling cycle

10

Which ECG wave would appear after the 2nd sound?

T wave

11

What is SV or stroke volume?

Volume of blood pumped out by a ventricle with each beat

12

what is the cardiac output?

Volume of blood pumped by each ventricle in one minute

13

what is the cardiac reserve?

difference between resting and maximal Cardiac Output

14

what is preload in relation to heart physiology?

the degree of stretch of cardiac muscle cells during diastole

15

what do positive inotropic agents do to stroke volume and contractility?

they increase both

16

what is afterload in regards to cardiac physiology?

the pressure that must be overcome for ventricles to eject blood

17

Mitral stenosis would have what effect on the preload and stroke volume of the left ventricle?

decrease preload and stroke volume

18

positive chronotropic factors

increase heart rate

19

negative chronotropic factors

decrease heart rate

20

Another word for the Atrial reflex

Bainbridge reflex

21

what is an Atrial reflex?

Sympathetic reflex initiated by increased venous return that increases the heart rate

22

effect of epinephrine on heart rate?

increases it

23

effect of thyroxine on heart rate?

increases heart rate and enhances the effects of norepinephrine and epinephrine

24

abnormally fast heart rate

Tachycardia

25

abnormally slow heart rate

Bradycardia

26

what is the physiological pacemaker of the heart?

the sinoatrial node (SA node)

27

another word for unstable potential

pacemaker potential or prepotential

28

what is the sinus rhythm?

the rhythm of the contraction of the heart set by the SA node

29

how many action potential (heart beats) dones the SA node produce per minute?

90-95

30

how many action potentials does the AV node produce per minute?

40-60