Question 1
Question
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
Answer
-
sliding filament
-
actin
-
myosin
-
Z
-
force
Question 2
Question
Fill in the blanks
Question 3
Question
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)
Answer
-
contractile
-
length
-
stroke volume
Question 4
Question
If the muscle is overstretched (ie, during dilation of the heart), its ability to produce an active tension is reduced
Question 5
Question
Fill in the blanks
Question 6
Question
What is this curve an example of?
Question 7
Question
Label the graph with the following; increased, normal, decreased
Answer
-
increased
-
increased
-
normal
-
decreased
Question 8
Question
Increased contractility means
Answer
-
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
Question 9
Question
A rise to a higher starling curve means decreased contractility
Question 10
Question
dP/dtmax is a good measure of
Answer
-
myocardial contractility
-
myocardial reponse
-
myocardial dilation
-
myocardial pressure
Question 11
Question
Label the following curves A, B and C
Question 12
Question
Agents that cause an increase in contractility are said to have a positive [blank_start]inotropic[blank_end] effect
Question 13
Question
Which of the following are examples of positive inotropic agents?
Answer
-
noradrenaline
-
adrenaline
-
digoxin
-
verapamil
Question 14
Question
Positive inotropic agents have the general effect of increasing
Question 15
Question
Which of the following are negative inotropic agents?
Answer
-
calcium channel blockers
-
beta adrenergic blockers
-
hypoxia
-
epinephrine
Question 16
Question
Fill in the blanks
Answer
-
actin
-
tropomyosin
-
troponin complex
-
myosin body
-
myosin head
-
z line
Question 17
Question
CICR stands for [blank_start]calcium induced calcium release[blank_end]
Question 18
Question
SERCA stands for [blank_start]sarcoplasmic endoplasmic reticulum[blank_end] calcium ATPase
Question 19
Question
Which of the following statements are true?
Answer
-
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)
Question 20
Question
Fill in the blanks
Answer
-
2
-
3
-
3
-
phospholamban
-
junctional SR
-
ryanodine receptor
-
transverse tubule
-
CICR
-
extracellular fluid
Question 21
Question
What is SERCA regulated by?
Answer
-
phospholamban
-
ryanodine
-
CICR
-
noradrenaline
Question 22
Question
What happens at the end of contraction?
Answer
-
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
Question 23
Question
What does sympathetic stimulation of the cardiac muscle produce?
Answer
-
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
Question 24
Question
Fill in the blanks
Question 25
Question
Label the pink rectangles 1-12( step 2 is there twice). Label the blue ovals cardiac glycosides, catecholamine, troponin I, troponin C and phospolamban
Answer
-
1
-
2
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
troponin c
-
troponin I
-
phospholamban
-
catecholamine
-
cardiac glycosides
Question 26
Question
cAMP activates [blank_start]protein kinase A[blank_end]
Question 27
Question
Protein Kinase A [blank_start]phosphorylates[blank_end] the L-type calcium channel
Question 28
Question
Which of the following are true?
Answer
-
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