Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Anatomy > circulation part two > Flashcards

circulation part two Flashcards

1
Q

Depolarization of the heart is

A

rhythmic and spontaneous

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

what ensures the heart contracts as a unit

A

gap junctions

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

cardiac muscle contraction graph parts

A

beginning; Na+ influx shoots to top (depolarization)
plateau where Ca2+ leaks slowly
rushes down where Ca2+ closes and k+ opens (repolarization)

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

E-C coupling occurs as

A

Ca2+ binds to troponin and sliding of the filaments begins

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

Duration of the Action Potential and the contractile phase is what in comparison to skeletal muscle

A

Duration of the Action Potential and the contractile phase is much greater in cardiac muscle than in skeletal muscle

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

Intrinsic cardiac conduction system

A

A network of noncontractile (autorhythmic) cells that initiate and distribute impulses to coordinate the depolarization and contraction of the heart

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

the self excitable myocytes act as

A

nerves

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

the self excitable myocytes have two important roles

A

forming the conduction system of the heart and acting as pacemakers within the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

autorhythmicity

A

spontaneously depolarize at a given rate. once one group of A cells start an action potential, all the cells around it also depolarize

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

SA node fires how often

A

every .8 seconds, or 75 action potentials per minute

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

autorhythmic cells reasoning with graph

A

Have unstable resting potentials (pacemaker potentials or prepotentials) due to open slow Na+ channels
At threshold, Ca2+ channels open
Explosive Ca2+ influx produces the rising phase of the action potential
Repolarization results from inactivation of Ca2+ channels and opening of voltage-gated K+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Heart Physiology: Sequence of Excitation

A 
SA node 
AV node
AV bundle 
right and left bundle branches 
perkinje fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what Depolarizes faster than any other part of the myocardium

A

SA node

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

whatDelays impulses approximately 0.1 second

A

AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how often does AV node fire

A

Depolarizes 50 times per minute in absence of SAnode input

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

what is the Only electrical connection between the atria and ventricles

A

AV bundle

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

how often do AV bundle and purkinje fibers depolarize

A

AV bundle and Purkinje fibers depolarize only 30times per minute in absence of AV node input

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

Defects in the intrinsic conduction system may result in

A

Arrhythmias
Uncoordinated atrial and ventricular contractions
Fibrillation

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

Arrhythmias

A

irregular heart rhythms

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

Fibrillation

A

rapid, irregular contractions; useless for pumping blood

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

Defective SA node may result in

A

Ectopic focus: abnormal pacemaker takes over

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

Defective AV node may result in

A

Partial or total heart block

Few or no impulses from SA node reach the ventricles

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

Heartbeat is modified by the

A

autonomic nervous system

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

Cardiac centers are located in the

A

medulla oblongata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what does Cardioacceleratory center do
innervates SA and AV nodes, heart muscle, and coronary arteries through sympathetic neurons
26
what does Cardioinhibitory center do
inhibits SA and AV nodes through parasympathetic fibers in the vagus nerves
27
The vagus nerve | (parasympathetic does what
decreases heart rate
28
Sympathetic cardiac | nerves does what
increase heart rate | and force of contraction
29
Electrocardiogram (ECG or EKG
a composite of all the action potentials
30
EKG three waves
P wave: depolarization of SA node QRS complex: ventricular depolarization T wave: ventricular repolarization (go over pictures on powerpoint)
31
EKG six steps
``` Depolarization of the Atria Repolarization of the Atria Septal Depolarization Apical Depolarization Late Left Ventricular Depolarization Repolarization of the Ventricle ```
32
Junctional rhythm.
p waves absent, weird t waves, look at pictures
33
Second-degree heart block.
Some P waves are not conducted through the AV node; more P than QRS waves are seen
34
Ventricular fibrillation
These chaotic, grossly irregular ECG | deflections are seen in acute heart attack and electrical shock.
35
lub
First sound occurs as AV valves close and signifies beginning of systole
36
dub
Second sound occurs when SL valves close at the beginning of ventricular diastole
37
Heart murmurs
abnormal heart sounds most often indicative of valve problems
38
Cardiac cycle
all events associated with blood flow through the heart during one complete heartbeat
39
Systole
contraction
40
diastole
relaxtion
41
Phases of the Cardiac Cycle
Ventricular filling Ventricular systole Isovolumetric relaxation occurs in early diastole
42
Ventricular filling
takes place in mid-to-late diastole AV valves are open 80% of blood passively flows into ventricles Atrial systole occurs, delivering the remaining 20%
43
End diastolic volume (EDV
volume of blood in each ventricle at the end of ventricular diastole
44
Ventricular systole
Atria relax and ventricles begin to contract Rising ventricular pressure results in closing of AV valves Isovolumetric contraction phase (all valves are closed) In ejection phase, ventricular pressure exceeds pressure in the large arteries, forcing the SL valves open
45
End systolic volume (ESV
volume of blood remaining in each ventricle
46
Isovolumetric relaxation occurs in early diastole
Ventricles relax Backflow of blood in aorta and pulmonary trunk closes SL valves and causes dicrotic notch (brief rise in aortic pressure)
47
dont forget!!!
go over graphs
48
Cardiac Output (CO
Volume of blood pumped by each ventricle in one minute
49
CO =
heart rate (HR) x stroke volume (SV)
50
heart rate
number of beats per minute
51
stroke volume
volume of blood pumped out by a ventricle with each beat
52
At rest | CO (ml/min)
HR (75 beats/min) × SV (70 ml/beat) | = 5.25 L/min
53
Maximal CO
is 4–5 times higher than resting CO in nonathletic people
54
Maximal CO may reach --- in athletic people
35 L/min in trained athletes
55
Cardiac reserve:
difference between resting and maximal CO
56
SV = formula
EDV – ESV
57
Three main factors affect SV
Preload Contractility Afterload
58
starlings law of the heart
the more the heart muscle is stretched before contraction (preload), the more forcefully the heart will contract
59
Preload
degree of stretch of cardiac muscle cells before they contract
60
cardiac muscle cells stretching
At rest, cardiac muscle cells are shorter than optimal length Slow heartbeat and exercise increase venous return Increased venous return distends (stretches) the ventricles and increases contraction force
61
Contractility
contractile strength at a given muscle length, independent of muscle stretch and EDV
62
Positive inotropic agents increase contractility
Increased Ca2+ influx due to sympathetic stimulation | Hormones (thyroxine, glucagon, and epinephrine)
63
Negative inotropic agents decrease contractility
Acidosis Increased extracellular K+ Calcium channel blockers
64
Afterload
pressure that must be overcome for ventricles to eject blood
65
what does hypertension increased afterload result in
resulting in increased ESV and reduced SV
66
how do Positive and negative chronotropic factors affect heart rate
Positive chronotropic factors increase heart rate | Negative chronotropic factors decrease heart rate
67
sympathetic nervous system is activated by
emotional or physical stressors
68
what does Norepinephrine do
causes the pacemaker to fire more rapidly (and at the same time increases contractility)
69
what does Acetylcholine do
Acetylcholine hyperpolarizes pacemaker cells by opening K+ channels
70
at rest is the heart parasympathetic or sympathetic
The heart at rest exhibits vagal tone (parasympathetic)
71
Atrial (Bainbridge) reflex:
a sympathetic reflex initiated by increased venous return
72
Stretch of the atrial walls stimulates
the SA node | Also stimulates atrial stretch receptors activating sympathetic reflexes
73
what does Epinephrine do
enhances heart rate and contractility
74
what does Thyroxine do
increases heart rate and enhances the effects of norepinephrine and epinephrine
75
Other Factors that Influence Heart Rate
``` Age Gender Exercise Body temperature hormones ions ```
76
Tachycardia
abnormally fast heart rate (>100 bpm)
77
tachycardia can lead to
may lead to fibrillation if persistent
78
Bradycardia
heart rate slower than 60 bpm
79
Bradycardia can lead to
May result in grossly inadequate blood circulation | May be desirable result of endurance training
80
Congestive Heart Failure (CHF)
Progressive condition where the CO is so low that blood circulation is inadequate to meet tissue needs
81
Congestive Heart Failure (CHF) caused by
Coronary atherosclerosis Persistent high blood pressure Multiple myocardial infarcts Dilated cardiomyopathy (DCM)
82
Age-Related Changes Affecting the Heart
Sclerosis and thickening of valve flaps Decline in cardiac reserve Fibrosis of cardiac muscle Atherosclerosis
83
systolic blood pressure
higher pressure measured during left ventricular systole when the aortic valve is open
84
diastolic blood pressure
lower pressure measured during left ventricular diastole when the valve is closed
85
normal blood pressure
about 120mm Hg systolic over 80 mmHg diastolic in healthy adult. females normally 10mmHg less `

Anatomy (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions