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Mammalian Physiology > Exam 3 Info - Ch. 18B slides > Flashcards

Exam 3 Info - Ch. 18B slides Flashcards

1
Q

(cardiac muscle contraction) depolarization of the heart is … and …

A

rhythmic; spontaneous

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2
Q

(cardiac muscle contraction) about 1% of cardiac cells have … - are …

A

automaticity; self-excitable

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3
Q

(cardiac muscle contraction) … ensure the heart contracts as a unit
long … period (250 ms)

A

gap junctions; absolute refractory

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4
Q

(cardiac muscle contraction) depolarization opens … in the sarcolemma
reversal of membrane potential from -90 mV to … mV

A

voltage-gated fast na+ channels; +30 mV

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5
Q

(cardiac muscle contraction) depolarization wave in T tubules causes the SR to release …
depolarization wave also opens … in the sarcolemma

A

Ca2+;

slow Ca2+ channels

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6
Q

(cardiac muscle contraction) Ca2+ surge prolongs the … phase (…)

A

depolarization; plateau

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7
Q

(cardiac muscle contraction) repolarization is due to calcium channels inactivating and … channels opening. this allows …, which brings the membrane potential back to its resting voltage

A

potassium; K+ efflux

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8
Q

(cardiac muscle contraction) calcium influx triggers opening of … in the SR, which liberates bursts of calcium
…. occurs as calcium binds to troponin and sliding of the filaments begins

A

calcium sensitive channels;

E-C coupling

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9
Q

(cardiac muscle contraction) durationof the AP and the contractile phase is much … in cardiac than skeletal muscle
repolarization results from inactivaton of calcium channels and opening of … channels

A

greater; voltage gated K+ channels

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10
Q

(heart physiology-electrical events) intrinsic cardiac conduction system: a network of .. (…) cells that initiate and distribute impulses to coordinate the … and … of the heart

A

noncontractile; autorhythmic; depolarization; contraction

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11
Q

(autorhythmic cells) have … resting potentials (… potentials or …) due to open …

A

unstable; pacemaker; prepotentials; slow sodium channels

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12
Q

(autorhythmic cells) at threshold, … open
explosive …. influx produces the rising phase of the action potential
repolarization results from inactivation of … channels and opening of voltage gated K+ channels

A

Ca2+ channels;
Ca2+;
Ca2+

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13
Q

(heart physiology: sequence of excitation) 1. … (pacemaker): generates impulses about 75 times/ min (… rhythm(
depolarizes faster than any other part of the myocardium

A

sinoatrial node; sinus;

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14
Q

(heart physiology: sequence of excitation) 2. … node;

… diameter fibers; fewer …

A

atrioventricular;
smaller;
gap junctions

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15
Q

(heart physiology: sequence of excitation) 2. AV node:
… impulses about 0.1 s
depolarizes … times/min in absence of SA node input

A

delays;

50

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16
Q

(heart physiology: sequence of excitation) 3. … (…):

only electrical connection between the atria and ventricles

A

atrioventricular (AV) bundle; bundle of His

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17
Q

(heart physiology: sequence of excitation) 4. … and …: two pathways in the interventriuclar septum that carry the impulses toward the … of the heart

A

right and left bundle branches; apex

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18
Q

(heart physiology: sequence of excitation) 5. …:
complete the pathway into the apex and ventricular walls
AV bundle and these depolarize only … times per minute in absence of AV node input

A

purkinje fibers; 30

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19
Q

(homeostatic imbalances) defects in the intrinsic conduction system may result in:
…: irregular heart rhythms
… atrial and ventricular contractions
…: rapid, irregular contractions; useless for pumping blood

A

arrhythmias;
uncoordinated;
fibrillation

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20
Q

(homeostatic imbalances) defective SA node may result in:
…: abnormal pacemaker takes over
if AV node takes over, there will be a … rhythm (40-60 bpm)

A

ectopic focus;

junctional

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21
Q

(homeostatic imbalances) defective AV node may result in:
partial or total …
few or no impulses from … reach the …

A

heart block;
SA node;
ventricles

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22
Q

(extrinsic innervation of the heart) heartbeat is modified by the …

A

ANS

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23
Q

(extrinsic innervation of the heart) cardiac centers are located in the …
… innervates SA and AV nodes, heart muscle, and coronary arteries through sympathetic neurons
… center inhibits SA and AV nodes through parasympathetic fibers in the … nerves

A

medulla oblongata;
cardioacceleratory center;
cardioinhibitory; vagus nerves

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24
Q

(extrinsic innervation of the heart) the vagus nerve (para) … heart rate
sympathetic cardiac nerves … heart rate and …

A

decreases;

heart rate; force of contraction

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25
Q

(electrocardiography) electrocardiogram (ECG or EKG): a composite of all the … generated by nodal and contractile cells at a given time

A

action potentials

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26
Q

(electrocardiography) three waves:
… wave: depolarization of …
2. … complex: …
3. … wave: …

A

P; SA node;
QRS; ventricular depolarization;
T; ventricular repolarization

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27
Q

(electrocardiography) 1. …, initiated by the SA node, causes the P wave
2. with this complete, the impulse is … at the AV node

A

Atrial depolarization;

delayed

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28
Q

(electrocardiography) 3. … begins at apex, causing the QRS complex. … occurs

A

ventricular depolarization; atrial repolarization

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29
Q

(electrocardiography) 4. … is complete
5. … begins at apex, causing the T wave
6. … is complete

A

ventricular depolarization;
ventricular repolarization;
ventricular repolarization

30
Q

(electrocardiography) … rhythm: The SA node is nonfunctional, P waves are absent, and heart is paced by the AV node at 40 - 60 beats/min.

A

junctional

31
Q

(electrocardiography) …: some P waves are not conducted through the AV node; hence more P than QRS waves are seen. in this tracing, the ratio of P waves to QRS waves is mostly …

A

second degree heart block; 2: 1

32
Q

(electrocardiography) …: these chaotic grossly irregular ECG deflections are seen in acute heart attack and electrical shock

A

ventricular fibrillation

33
Q

(Heart Sounds) two sounds (lub-dup) associated with ….
first sound occurs as … close and signifies beginning of …
second sound occurs when … close at the beginning of …

A

closing of heart valves;
AV valves; systole;
SL valves; ventricular diastole

34
Q

(Heart Sounds) ….: abnormal heart sounds most often indicative of valve problems

A

heart murmurs

35
Q

aortic valve sounds heard in … intercostal space at …

A

2nd intercostal space; right sternal margin

36
Q

pulmonary valve sounds heard in … intercostal space at …

A

2nd intercostal space; left sternal margin

37
Q

mitral valve sounds heard over … (in … intercostal space) in line with …

A

heart apex; 5th; middle of clavicle

38
Q

tricuspid valve sounds typically heard in … of … intercostal space

A

right sternal margin; 5th

39
Q

….: all events associated with blood flow through the heart during one complete …

A

cardiac cycle; heartbeat

40
Q

(cardiac cycle) systole: …

diastole: …

A

contraction; relaxation

41
Q

(phases of the cardiac cycle) ventricular filling: takes place in …

A

mid-to-late diastole

42
Q

(phases of the cardiac cycle) … are open
80% of blood … flows into ventricles
… occurs, delivering the remaining 20%

A

AV valves;
passively;
atrial systole

43
Q

(phases of the cardiac cycle) … (…): volume of blood in each ventricle at the end of ventricular diastole

A

end diastolic volume; EDV

44
Q

(phases of the cardiac cycle)

ventricular systole: atria .. and ventricles begin to …

A

relax; contract

45
Q

(phases of the cardiac cycle)
rising … results in … of AV valves
…. phase (all valves are closed)

A

ventricular pressure; closing;

isovolumetric contraction

46
Q

(phases of the cardiac cycle) in ejection phase, … exceeds pressure in the …, forcing the … open

A

ventricular pressure; large arteries; SL valves

47
Q

(phases of the cardiac cycle) …: volume of blood remaining in each ventricle

A

end systolic volume (ESV)

48
Q

(phases of the cardiac cycle) isovolumetric relaxation occurs during …
… relax
backflow of blood in … and … closes … valves

A

early diastole;
ventricles;
aorta; pulmonary trunk; SL

49
Q

(cardiac output) volume of blood pumped by each … in one minute

A

ventricle

50
Q

(cardiac output) CO = … x …

A

heart rate (HR); stroke volume (SV)

51
Q

(cardiac output) HR = number of … per minute

SV = … pumped out by a … with each beat

A

beats;

volume of blood; ventricle

52
Q

… will increase heart force and rate

A

norepinephrine

53
Q

norepinephrine binds to … receptor such that G protein activates adenylate cyclase to make cAMP and activate protein kinase A
protein kinase A then phosphorylates plasma membrane ..,. increasing …

A

beta-1 adrenergic receptor;

calcium channels; extracellular calcium entry

54
Q

norepinephrine pathway:

protein kinase A also phosphorylates …, speeding … and ….

A

SR calcium pumps; calcium removal and relaxation

55
Q

norepinpehrine pathway: calcium from SR binds to … and enhances … interaction which increases cardiac muscle … and …

A

troponin; actin-myosin; force; velocity

56
Q

norephinephrine pathway:

… disrupt this system

A

beta-blockers

57
Q

(regulation of stroke volume) …: pressure that must be overcome for ventricles to eject blood

A

afterload

58
Q

(regulation of stroke volume) … increases afterload, resulting in increased … and reduced …

A

hyptertension; ESV; SV

59
Q

(regulation of heart rate) … factors increase heart rate

… factors decrease heart rate

A

positive chronotropic;

negative chronotropic

60
Q

(autonomic nervous system regulation) sympathetic nervous system is activated by … or …

A

emotional or physical stressors

61
Q

(autonomic nervous system regulation) sympathetic NS:

norepinephrine causes the pacemaker to … (and at the same time …)

A

fire more rapidly; increases contractility

62
Q

(autonomic nervous system regulation) parasympathetic nervous system opposes sympathetic effects:
… hyperpolarizes pacemaker cells by opening …

A

acetylcholine; K+ channels

63
Q

(autonomic nervous system regulation) parasympathetic:

the heart at rest exhibits … (parasymp)

A

vagal tone

64
Q

(autonomic nervous system regulation) … (…) reflex: a sympathetic reflex initiated by increased venous return
stretch of the atrial walls stimulates the …
also stimulates … activating … reflexes

A

Atrial; Bainbridge;
SA node;
atrial stretch receptors; sympathetic

65
Q

(chemical regulation of heart rate) hormones:

epinephrine from adrenal medulla enhances … and …

A

heart rate; contractility

66
Q

(chemical regulation of heart rate) thyroxine increases … and enhances the effects of … and …

A

heart rate; norepinephrine; epinephrine

67
Q

(chemical regulation of heart rate) intra- and extracellular … must be maintained for normal heart function

A

ion concentrations

68
Q 
other factors that influence heart rate: 
... 
... 
... 
...
A

age;
gender;
exercise;
body temps

69
Q

(homeostatic imbalances) …: abnormally fast heart rate (> … bpm) –> if persistent, may lead to …

A

tachycardia; 100; fibrillation

70
Q

(homeostatic imbalances) ….: heart rate slower than … bpm
may result in grossly inadequate …
may be desirable result of …

A

bradycardia; 60; blood circulation; endurance training

71
Q

(congestive heart failure) progressive condition where the … is so low that blood circulation is inadequate to meet tissue needs

A

CO

72
Q 
(congestive heart failure) caused by: 
... 
persistent ... 
multiple ... 
... - ...
A

coronary atherosclerosis;
high blood pressure;
myocardial infarcts;
dilated cardiomyopathy (DCM); enlarged heart

Mammalian Physiology (31 decks)

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