Physiology of the Heart Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Used to describe a collection of mechanisms that influence the active and changing circulation of blood circulation of different volumes of blood per minute at different times is essential for survival

A

hemodynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

the circulation control mechanisms must accomplish 2 function:

A
  • maintain circulation (keep blood flowing) - Vary volume and distribution of the blood circulated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A complete heartbeat, or pumping cycle, consisting of contraction (systole) and relaxation (diastole) of both atria and both ventricles

A

the cardiac cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

contraction of both ventricles of the heart, forcing blood out of these chambers. The atria are in a relaxed state

A

systole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The top number of BP, which is also the higher of the 2 numbers, measures the pressure in the arteries when the heart beats (contracts)

A

systolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The bottom number, which is also the lower of the 2 numbers, measures the pressure in the arteries between heartbeats (when heart muscle is resting between beats and refilling with blood)

A

diastolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

ventricular muscles relax, allowing for blood to fill these chambers. At the end, the atria start contracting to fill the ventricles

A

diastole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

an electrical fluctuation that travels along the surface of a cell’s membrane mediated by the flow of sodium and potassium ions across the membrane; occurs in nerves and muscles.

A

action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • repeatedly generate action potentials that trigger contraction and continue to stimulate heart even after it has been removed from the body
A

autorhythmic cardiac muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

_____, _____, and _____ can alter heartbeat strength and heart rate, but do not change the coordinated contractions of the heart

A

hormones, chemicals, and nerve impulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Conduction system of the heart has 4 structures:

A
  • sinoatrial (SA) node - Atrioventricular (AV) node - AV bundle (bundle of His) - subendocardial branches (purkinjie fibers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • The natural or inherent “pacemaker” of the heart - Initiates each heartbeat and and sets it pace - located high in r atrial wall
A

sinoatrial node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

impulses spread from the ______ to the muscle fibers of both atria causing atrial contraction

A

SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The _____ fires between 60-100 BPM

A

SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • Located at the base of the right atrium - electrically, it acts as the only gateway for electrical impulses from the atria to the ventricles
A

Atrioventricular node (AV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

electrical activity travels very slowly through the _______. The delay allows for contraction of the atria to proceed contraction of the ventricles.

A

AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

AV node stimulation sends impulses to the ________.

A

atrioventricular bundle of His

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

carries electrical impulses (action potentials) into the ventricles. Impulses travel through the right and left bundle branches to the Purkinjie fibers.

A

bundle of His

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

fibers that further spread electrical activity to all parts of the ventricles so that there is a coordinated contraction of each ventricle.

A

subendocardial branched AKA Purkinjie fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

a graphic record of the heart’s electrical activity, specifically the conduction of impulses. It is not a record of the heart’s contractions, but of the electrical events/current that precede them a composite record of action potentials produced by the heart muscle fibers during each heartbeat.

A

electrocardiogram (ECG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In an ECG, changes in voltage are seen as _______ of a line drawn on a paper or traced on a video monitor.

A

deflections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The _______ is composed of deflection waves called the P wave, QRS complex, and T wave.

A

normal ECG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A _______ obtains 12 electrical tracings of the heart from different angles or orientations. Patterns of abnormalities can indicate areas of abnormal conduction.

A

12-lead ECG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

represents depolarization of the atria. Deflection related to passage of an electrical impulse from the SA node through the muscle of both atria.

A

The P wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

larger _______ indicate enlargement of an atria.

A

P waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

represents depolarization of the ventricles and repolarization of the atria

A

the QRS complex

27
Q

represents ventricular repolarization. It is flatter than normal when the heart is not getting enough oxygen.

A

the T wave

28
Q

the length of time for atrial depolarization and conduction from the SA node to the AV node. (Beginning of the P wave to the beginning of the QRS complex)

A

P-R interval

29
Q

The time period from the end of ventricular depolarization through ventricular repolarization. Clinically, unhealthy myocardium can affect the height of this interval (either upward or downward)

A

ST interval/segment

30
Q

The ________ begins at the end of the S wave and ends at the beginning of the T wave.

A

ST interval/segment

31
Q
  • a complete heartbeat consisting of systole and diastole of both atria and ventricles - the 2 atria contract simultaneously filling the ventricles more efficiently - as the atria relax, the two ventricles contract, instead of the entire heart contracting as one unit. Allow for pumping of the heart
A

the cardiac cycle

32
Q

the 5 important events of the cardiac cycle:

A
  • atrial systole - isovolumetric ventricular contraction - ejection - isovolumetric ventricular relaxation - passive ventricular filling
33
Q
  • begins with the P wave of the ECG - atria contract simultaneously completing emptying blood out of the atria into the ventricles - AV valves are open; SL valves are closed - Ventricles are relaxed and filling with blood
A

atrial systole

34
Q
  • onset of ventricular systole coincides with right wave and appearance of the first heart sound (S1), as the AV valves close - between the start of ventricular systole and the opening of the SL valves - volume in the ventricles remains constant as the pressure increases rapidly
A

isovolumetric ventricular contraction

35
Q

pressure increases enough to open the aortic and pulmonary SL valves and blood is ejected from the heart. - blood enters the systemic and pulmonary circulations via the aorta and pulmonary artery - this period coincides with the ST interval

A

ejection

36
Q

the blood that remains in the ventricles at the end of the ejection period (roughly half)

A

residual volume

37
Q

in heart failure the residual volume remaining in the ventricles may greatly exceed that ejected during systole.

A

ejection fraction

38
Q

beings with an isovolumetric period - occurs between closure of the SL valves and opening of the AV valves - closure of the SL valves produce the second heart sound (S2) - corresponds to the T wave and continues until the next P wave

A

isovolumetric ventricular relaxation there is a dramatic fall in intraventricular pressure

39
Q
  • returning venous blood increases intraatrial pressure until the AV valves are forced open and blood rushes into the relaxing ventricles - results in a dramatic increase in ventricular volume before the atria conract - lasts about 0.1 sec
A

passive ventricular filling

40
Q

the amount of blood that flows out of a ventricle of the heart per unit of time

A

cardiac output

41
Q

is measured by the ml of blood pumped out of the left ventricle in one stroke (beat)

A

stroke volume

42
Q

cardiac output (ml/minute) = ______ (ml/beat) x heart rate (beats/minute) = ml/minute

A

stroke volume

43
Q

CO = SV x ___

A

HR

44
Q

____ are created by blood turbulence and vibration as valves close

A

heart sounds

45
Q

the act of listening to sounds within the body

A

auscultation

46
Q

using the bell of a stethoscope is most useful for _____ and may work best with pediatric patients

A

low sounds

47
Q

using the diaphragm is most useful for ______.

A

higher pitch sounds

48
Q

degree of stretch on the heart prior to contraction

A

preload

49
Q

forcefulness on contraction of individual ventricular muscle fibers

A

contractility

50
Q

pressure that must be exceeded before the ejection of blood from the ventricles can occur

A

afterload

51
Q

pathophysiology: - reduction of blood flow to the myocardium - leading cause of death for men and women - atherosclerosis/arteriosclerosis

A

CAD

52
Q

pathophysiology: - physiological: hypertrophy related to fitness training - pathological: related to heart disease

A

cardiomegaly

53
Q

pathophysiology: - loss of pumping efficiency by the heart - caused by CAD, congenital defects, long term high BP, valve disorders

A

CHF

54
Q

heart rate higher than the normal SA node range of 60-100

A

tachycardia

55
Q

a resting heart rate under 50 BPM

A

bradycardia

56
Q
A
57
Q
A
58
Q
A
59
Q
A
60
Q
A
61
Q
A
62
Q
A
63
Q
A