Pregunta 1
Pregunta
Shortening of the muscle occurs by the [blank_start]sliding filament[blank_end] mechanism
- [blank_start]actin[blank_end] filaments slide along adjacent [blank_start]myosin[blank_end] filaments by cycling of cross-bridges with myosin
• The [blank_start]Z[blank_end] lines come closer together and the muscle cell shortens
• The cardiac muscle thus produces [blank_start]force[blank_end] or tension
Respuesta
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sliding filament
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actin
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myosin
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Z
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force
Pregunta 2
Pregunta
Fill in the blanks
Pregunta 3
Pregunta
This ability of cardiac muscle to increase its [blank_start]contractile[blank_end] force with a slight increase in its [blank_start]length[blank_end] underlies its ability to control [blank_start]stroke volume[blank_end] (the volume of blood ejected from the heart during a single beat)
Respuesta
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contractile
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length
-
stroke volume
Pregunta 4
Pregunta
If the muscle is overstretched (ie, during dilation of the heart), its ability to produce an active tension is reduced
Pregunta 5
Pregunta
Fill in the blanks
Pregunta 6
Pregunta
What is this curve an example of?
Pregunta 7
Pregunta
Label the graph with the following; increased, normal, decreased
Respuesta
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increased
-
increased
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normal
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decreased
Pregunta 8
Pregunta
Increased contractility means
Respuesta
-
higher stroke volume for the same end diastolic volume
-
lower stroke volume for the same end diastolic volume
-
higher stroke volume for the higer end diastolic volume
-
higher stroke volume for the lower end diastolic volume
Pregunta 9
Pregunta
A rise to a higher starling curve means decreased contractility
Pregunta 10
Pregunta
dP/dtmax is a good measure of
Respuesta
-
myocardial contractility
-
myocardial reponse
-
myocardial dilation
-
myocardial pressure
Pregunta 11
Pregunta
Label the following curves A, B and C
Pregunta 12
Pregunta
Agents that cause an increase in contractility are said to have a positive [blank_start]inotropic[blank_end] effect
Pregunta 13
Pregunta
Which of the following are examples of positive inotropic agents?
Respuesta
-
noradrenaline
-
adrenaline
-
digoxin
-
verapamil
Pregunta 14
Pregunta
Positive inotropic agents have the general effect of increasing
Pregunta 15
Pregunta
Which of the following are negative inotropic agents?
Respuesta
-
calcium channel blockers
-
beta adrenergic blockers
-
hypoxia
-
epinephrine
Pregunta 16
Pregunta
Fill in the blanks
Respuesta
-
actin
-
tropomyosin
-
troponin complex
-
myosin body
-
myosin head
-
z line
Pregunta 17
Pregunta
CICR stands for [blank_start]calcium induced calcium release[blank_end]
Pregunta 18
Pregunta
SERCA stands for [blank_start]sarcoplasmic endoplasmic reticulum[blank_end] calcium ATPase
Pregunta 19
Pregunta
Which of the following statements are true?
Respuesta
-
Junctional SR is studded with Ca2+ release channels
-
RYR is a giant protein with a terminal foot with a T-shaped tube in its centre through which Ca2+ ions are releases
-
The density of RYR is low near L-type Ca channels
-
The distance between the Ca channels and the RYR is very short (nm)
Pregunta 20
Pregunta
Fill in the blanks
Respuesta
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2
-
3
-
3
-
phospholamban
-
junctional SR
-
ryanodine receptor
-
transverse tubule
-
CICR
-
extracellular fluid
Pregunta 21
Pregunta
What is SERCA regulated by?
Respuesta
-
phospholamban
-
ryanodine
-
CICR
-
noradrenaline
Pregunta 22
Pregunta
What happens at the end of contraction?
Respuesta
-
Ca2+ influx ceases and the SR is no longer stimulated to release Ca2+
-
the intracellular concentration of Ca2+ must be rapidly reduced
-
most of the cytoplasmic Ca2+ is pumped back into the SR by SERCA
-
a small amount of calcium is pumped out of the cell by the cell membrane Ca pump
Pregunta 23
Pregunta
What does sympathetic stimulation of the cardiac muscle produce?
Respuesta
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Increase in active tension
-
Increase in the rate of active tension development
-
Increase in the rate of tension relaxation
-
Increase in passive tension
-
Increase in the rate of passive relaxation
-
decrease in active tension
-
decrease in passive tension
Pregunta 24
Pregunta
Fill in the blanks
Pregunta 25
Pregunta
Label the pink rectangles 1-12( step 2 is there twice). Label the blue ovals cardiac glycosides, catecholamine, troponin I, troponin C and phospolamban
Respuesta
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1
-
2
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
troponin c
-
troponin I
-
phospholamban
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catecholamine
-
cardiac glycosides
Pregunta 26
Pregunta
cAMP activates [blank_start]protein kinase A[blank_end]
Pregunta 27
Pregunta
Protein Kinase A [blank_start]phosphorylates[blank_end] the L-type calcium channel
Pregunta 28
Pregunta
Which of the following are true?
Respuesta
-
Increased intracellular Ca2+ concentration increases the force of contraction (positive inotropic effect)
-
Protein kinase A phosphorylates Phospholamban and Troponin I
-
phosphorylation of troponin I leads to inhibition of binding of
calcium to troponin C and relaxation occurs
-
phosphorylation of phospholamban leads to reduced inhibition of SERCA which leads to increased uptake of calcium into the SR and relaxation occurs
-
Phospholamban phosphorylation promotes the rate of contraction