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

Exam 3 Info - Ch. 18B slides Flashcards

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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
(electrocardiography) electrocardiogram (ECG or EKG): a composite of all the ... generated by nodal and contractile cells at a given time
action potentials
26
(electrocardiography) three waves: ... wave: depolarization of ... 2. ... complex: ... 3. ... wave: ...
P; SA node; QRS; ventricular depolarization; T; ventricular repolarization
27
(electrocardiography) 1. ..., initiated by the SA node, causes the P wave 2. with this complete, the impulse is ... at the AV node
Atrial depolarization; | delayed
28
(electrocardiography) 3. ... begins at apex, causing the QRS complex. ... occurs
ventricular depolarization; atrial repolarization
29
(electrocardiography) 4. ... is complete 5. ... begins at apex, causing the T wave 6. ... is complete
ventricular depolarization; ventricular repolarization; ventricular repolarization
30
(electrocardiography) ... rhythm: The SA node is nonfunctional, P waves are absent, and heart is paced by the AV node at 40 - 60 beats/min.
junctional
31
(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 ...
second degree heart block; 2: 1
32
(electrocardiography) ...: these chaotic grossly irregular ECG deflections are seen in acute heart attack and electrical shock
ventricular fibrillation
33
(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 ...
closing of heart valves; AV valves; systole; SL valves; ventricular diastole
34
(Heart Sounds) ....: abnormal heart sounds most often indicative of valve problems
heart murmurs
35
aortic valve sounds heard in ... intercostal space at ...
2nd intercostal space; right sternal margin
36
pulmonary valve sounds heard in ... intercostal space at ...
2nd intercostal space; left sternal margin
37
mitral valve sounds heard over ... (in ... intercostal space) in line with ...
heart apex; 5th; middle of clavicle
38
tricuspid valve sounds typically heard in ... of ... intercostal space
right sternal margin; 5th
39
....: all events associated with blood flow through the heart during one complete ...
cardiac cycle; heartbeat
40
(cardiac cycle) systole: ... | diastole: ...
contraction; relaxation
41
(phases of the cardiac cycle) ventricular filling: takes place in ...
mid-to-late diastole
42
(phases of the cardiac cycle) ... are open 80% of blood ... flows into ventricles ... occurs, delivering the remaining 20%
AV valves; passively; atrial systole
43
(phases of the cardiac cycle) ... (...): volume of blood in each ventricle at the end of ventricular diastole
end diastolic volume; EDV
44
(phases of the cardiac cycle) | ventricular systole: atria .. and ventricles begin to ...
relax; contract
45
(phases of the cardiac cycle) rising ... results in ... of AV valves .... phase (all valves are closed)
ventricular pressure; closing; | isovolumetric contraction
46
(phases of the cardiac cycle) in ejection phase, ... exceeds pressure in the ..., forcing the ... open
ventricular pressure; large arteries; SL valves
47
(phases of the cardiac cycle) ...: volume of blood remaining in each ventricle
end systolic volume (ESV)
48
(phases of the cardiac cycle) isovolumetric relaxation occurs during ... ... relax backflow of blood in ... and ... closes ... valves
early diastole; ventricles; aorta; pulmonary trunk; SL
49
(cardiac output) volume of blood pumped by each ... in one minute
ventricle
50
(cardiac output) CO = ... x ...
heart rate (HR); stroke volume (SV)
51
(cardiac output) HR = number of ... per minute | SV = ... pumped out by a ... with each beat
beats; | volume of blood; ventricle
52
... will increase heart force and rate
norepinephrine
53
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 ...
beta-1 adrenergic receptor; | calcium channels; extracellular calcium entry
54
norepinephrine pathway: | protein kinase A also phosphorylates ..., speeding ... and ....
SR calcium pumps; calcium removal and relaxation
55
norepinpehrine pathway: calcium from SR binds to ... and enhances ... interaction which increases cardiac muscle ... and ...
troponin; actin-myosin; force; velocity
56
norephinephrine pathway: | ... disrupt this system
beta-blockers
57
(regulation of stroke volume) ...: pressure that must be overcome for ventricles to eject blood
afterload
58
(regulation of stroke volume) ... increases afterload, resulting in increased ... and reduced ...
hyptertension; ESV; SV
59
(regulation of heart rate) ... factors increase heart rate | ... factors decrease heart rate
positive chronotropic; | negative chronotropic
60
(autonomic nervous system regulation) sympathetic nervous system is activated by ... or ...
emotional or physical stressors
61
(autonomic nervous system regulation) sympathetic NS: | norepinephrine causes the pacemaker to ... (and at the same time ...)
fire more rapidly; increases contractility
62
(autonomic nervous system regulation) parasympathetic nervous system opposes sympathetic effects: ... hyperpolarizes pacemaker cells by opening ...
acetylcholine; K+ channels
63
(autonomic nervous system regulation) parasympathetic: | the heart at rest exhibits ... (parasymp)
vagal tone
64
(autonomic nervous system regulation) ... (...) reflex: a sympathetic reflex initiated by increased venous return stretch of the atrial walls stimulates the ... also stimulates ... activating ... reflexes
Atrial; Bainbridge; SA node; atrial stretch receptors; sympathetic
65
(chemical regulation of heart rate) hormones: | epinephrine from adrenal medulla enhances ... and ...
heart rate; contractility
66
(chemical regulation of heart rate) thyroxine increases ... and enhances the effects of ... and ...
heart rate; norepinephrine; epinephrine
67
(chemical regulation of heart rate) intra- and extracellular ... must be maintained for normal heart function
ion concentrations
68
``` other factors that influence heart rate: ... ... ... ... ```
age; gender; exercise; body temps
69
(homeostatic imbalances) ...: abnormally fast heart rate (> ... bpm) --> if persistent, may lead to ...
tachycardia; 100; fibrillation
70
(homeostatic imbalances) ....: heart rate slower than ... bpm may result in grossly inadequate ... may be desirable result of ...
bradycardia; 60; blood circulation; endurance training
71
(congestive heart failure) progressive condition where the ... is so low that blood circulation is inadequate to meet tissue needs
CO
72
``` (congestive heart failure) caused by: ... persistent ... multiple ... ... - ... ```
coronary atherosclerosis; high blood pressure; myocardial infarcts; dilated cardiomyopathy (DCM); enlarged heart

Mammalian Physiology (31 decks)

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