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Cardiovascular Physiology > L5/6 > Flashcards

L5/6 Flashcards

(71 cards)

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1
Q

autorhythmicity

A

built-in rhythm of action potentials -> heart contractions

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2
Q

autorhymic fibers function

A

non-contracting pace maker cells (inititate action potentials)

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3
Q

autorhymic fibers location

A
  • SA node
  • AV node
  • AV bundle
  • right/left bundle branches
  • Purkinje fibers
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4
Q

contractile fibers

A
  • delivers action potential via contractions but cannot initiate action potential
  • acts as pacemaker conduction system
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5
Q

propagation of cardiac action potential

A

depolarized SA node -(ap)-> both atria -> atria contraction -(ap)-> AV node -(ap)->AV bundle -(ap)->right & left bundle branches -(ap)-> Purkinje fibers -(ap)-> heart apex -(ap)-> ventircular myocardium -(ap)-> ventricle contraction -(blood)->semilunar valves

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6
Q

peacemaker potential is _mV

A

-60mV

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7
Q

peacemaker potential reaching threshold

A
  1. closed K+ channels & open F-type channels (Na+ permeable) -> almost at threshold
  2. F-type channels close & T-type voltage-gated Cas2+ channels open -> threshold reached
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8
Q

generation of action potentials in contractile fibers

A

opening L-type voltage-gated Ca2+ channels -> generates action potential -> causes contractile fibers to enter depolarizing phase

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9
Q

contractile fibers have a potential of _mV

A

-90mV

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10
Q

contractile fibers depolarizing phase

A

open fast voltage-gated Na+ channels -> +20mV

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11
Q

contractile fibers initial repolarizing phase

A

close fast voltage-gated Na+ channel and open fast voltage-gated K+ channels -> decreased from 20mV

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12
Q

contractile fibers plateau phase

A

close fast voltage-gated K+ channels and partially open slow voltage-gated K+ channels ->constant 10mV

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13
Q

contractile fibers final repolarizing phase

A

fully open slow voltage-gated K+ channels -> -90mV -> close channels

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14
Q

L-type voltage-gated Ca2+ channels close when

A

the final repolarizing phase of contractile fibers has been completed (-90mV)

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15
Q

Excitation-Contraction coupling in cardiac muscle

A

links cardiac action potential to cardiac contraction

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16
Q

calcium-induced calcium release

A

L-type voltage-gated Ca2+ -> increase extracellular calcium concentration (10% required) -> Ca2+ rleased from SR (other 90% required) -> contraction

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17
Q

graded contractions cardiac muscle

A

increase or decreasing contraction of syncytium muslce fibers by manipulating how much Ca2+ is in the sarcoplasm

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18
Q

relaxing cardiac muscle after contraction

A

decrease calcium concentration in the extracellular fluid with Ca2+-ATPase pump

> Ca2+ goes to SR

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19
Q

Cardiac muscle refractory period

A

-very long because of plateau phase

>helps with proper pumping (heart needs to relax and fill with blood)

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20
Q

ATP production

A

aerobic respiration

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21
Q

ECG P

A

atrial depolarization

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22
Q

ECG QRS

A

ventricular depolarizaiton

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23
Q

ECG T

A

ventricular repolairzation

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24
Q

ECG P-Q/P-R

A

atrial ventricular excitation conduction time

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25
ECG S-T
Ventricular contractile fibers depolarize/pleateau phase
26
ECG Q-T
Ventricular depolarization to repolarization time
27
increase Q wave
myocardial infraction
28
increase R wave
enlarged ventricules
29
flat T wave
decreased O2 (ex: coronory artery disease)
30
increased T wave
hyperkalemia (high K+ in blood)
31
systole
phase of contraction
32
diastole
phase of relaxation
33
passive ventricular filling
1. atria/ventricule(diastole)-(atria fills with blood from veins)-> atrial pressure > ventricular pressure 2. AV valves open: atria -(blood)-> ventricules (80% capacity) 3. SL valves close * no muscle contractions * 4. SA node -(ap)-> atria -> depolaries
34
atrial contraction
1. atrial depolarization -> atrial systole -> contraction -> increased atrial pressure -> opens AV valves 2. AV valves add remaining 20% of blood to ventricule
35
isovolumetric ventricular contraction
1. ventricules depolarized -> systole (atrial in diastole)-> increased ventricle pressure -> AV vavles close 2. isovolumetric ventricular contraction when AV and SL vavles are closed
36
ventricular ejection
1. left ventricule > aortic pressure/right ventricle>pulmonary trunk -> SL valves open 2a. left ventricle -(70mL blood) -> aorta 2b. right ventricle-(70mL blood) ->pulmonary trunk
37
EDV
the filled volume of the ventricle prior to contraction
38
ESV
is the residual volume of blood remaining in the ventricle after ejection
39
stroke volume
stroke volume = EDV-ESV | volume of blood ejected from each ventricle/contraction
40
ejection fraction
ejection fraction = SV/EDV x 100% | percentage of the end-diastolic volume that is ejected with each stroke volume
41
isovolumetric ventricular relaxation
1. ventricular repolarization -> diastole -> relexation -> decreased pressure 2. vavle cusps collect backflow -> close SL valves 3. ventricule pressure < atrial pressure -> A.V valves open -> repeat
42
Heart beat steps
- passive ventricular filling - atrial contraction - ventricular ejection - isovolumetric ventricular relaxation
43
lubb & dupp
lubb: AV valves closing (louder) dupp: SL valves closing
44
cardiac output
volume of blood ejected from each ventricle/minute
45
heart rate definition
number of beats per minute
46
cardiac reserve
maximum cardiac output-cardiac output at rest
47
stroke volume preload
degree of stretch on heart before it contracts
48
frank-starling law
increased stretch leads to increased contraction
49
increased EDV causes
increased filling time and increased venous return
50
stroke volume contractility definition
forcefulness of contraction of individual ventricular msucle fibers
51
inotropic effects
alter contractility >postivie: increases >negative: decreases
52
positive inotropic effect mechanisms
1. NE + B1-adrenergiic receptor (sarcolemma) 2. Gs activates -(stimulates)-> adenylyl cyclase -(produces)-> cAMP 3. cAMP + protein kinase -> phosphorylates: - L-type voltage gated Ca2+ channels -> increased Ca2+ in sacroplasm - Ca2+ release channels -> release Ca2+ from SR lumen into sacroplasm - phospholamban -> reuptake Ca2+ to SR lumen after contraction to preserve Ca2+ supply - myosin heads -> increases rate of crossbridge cycling 4. increases contractivity
53
negative inotropic effect mechanisms
decreases Ca2+ in sarcoplasm to decrease contractility
54
stroke volumme afterload definition
pressure that must be exceed before ejection of blood from ventricles >must open SL vavles
55
increased afterload causes
decreased velocity of ventricular muscle fiber shortening
56
chronotropic effects
+ -> increases heart rate | - -> decreases heart rat
57
cardiac accelerator nerves and heart rate regulation (ANS)
cardiac accelerator nerves: connect sympathetic NS with SA node, AV node and ventricular myocardium
58
Vagus X nerves and heart rate regulation (ANS)
connect parasympathetic and heart wall (AV and SA nodes)
59
NE and increased heart rate via SA node increased ap mechanism
NE + B1-adrenergic receptors in sarcolemma -> Gs -> increased adenyly cyclase -> increased cAMP + F-type NA+ channels -> Na+ enters cell -> depolarziation -> SA node generate action potentials
60
NE and increased heart rate sympathetic or parasympathetic?
sympathetic
61
increasing heart rate via increasing action potential conduction (atria->ventricules) mechanism
F-type Na+ channels -> Na+ influx -> depolarize AV node -> fires AP
62
increasing heart rate via increasing action potential conduction (atria->ventricules) sympathetic or parasympathetic?
sympathetic
63
increasing heart rate by increasing contractility mechanism
NE + B1-adrenergic receptors -> G protein -> increased Ca2+ -> increased contractility
64
increasing heart rate by increasing contractility mechanism sympathetic or parasympathetic?
sympathetic
65
decreasing heart rate via Ach mechanism
Ach + Gi -> decreased cAMP | Ach + Gi -> opens K+Ach channels -> K+ outflux -> hyperpolarizes -> SA node decreases Ap
66
decreasing heart rate via Ach sympathetic or parasympathetic?
parasympathetic
67
decreasing heart rate via decreasing conduction (atria -> ventricles) mechanism
K+Ach open -> K+outflow -> hyperpolarizes AV node -> decreases action potentials
68
decreasing heart rate via decreasing conduction (atria -> ventricles) mechanism sympathetic or parasympathetic?
parasympathetic
69
heart rate chemical regulation via hormones
E and NE
70
heart rate chemical regulation via ions
Na+, K+ and Ca2+
71
heart rate chemical regulation via no ions and no hormones
age, gender, physical fitness and body temperature

Cardiovascular Physiology (14 decks)

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