Calcium-induced calcium release

Question 1

The structure of _____ ______ ______ is crucial to excitation contraction coupling

Answer 1

cardiac muscle fibres

Question 2

The Ca2+ release channels of the junctional SR are positioned just under ____ of the T tubule surface membrane

Answer 2

LTCC

Question 3

The Ca2+ release channels of the junctional SR are positioned just under the LTCC of the ______ surface membrane

Answer 3

T-Tubule

Question 4

The Ca2+ release channels of the ________ ______ are positioned just under the LTCC of the T-Tubule surface membrane

Answer 4

junctional SR

Question 5

The Ca2+ release channels of the junctional SR are positioned just under the LTCC of the T-Tubule surface membrane
organised as release units - _____

Answer 5

dyad

Question 6

The Ca2+ release channels of the junctional SR are positioned just under the LTCC of the T-Tubule surface membrane
each dyad consists if:
10-25 _____
100-200 _________

Answer 6

10-25 LTCC
100-200 “foot proteins”`

Question 7

The Ca2+ release channels of the junctional SR are positioned just under the LTCC of the T-Tubule surface membrane
Dyadic organisation ensures what

Answer 7

LTCC and RyR are very close together to maximise the efficiency of the CICR

Question 8

The Ca2+ release channels of the junctional SR are positioned just under the LTCC of the T-Tubule surface membrane
Dyadic organisation ensures that LTCC and RYR are very close together, why?

Answer 8

to maximise the efficiency of CICR

Question 9

Ca2+ release from the SR is in the form of sparks
“sparks” occur spontaneously or can be evoked by what

Answer 9

depolarisation of cell patches, single isolated cells

Question 10

Ca2+ release from the SR is in the form of sparks
“sparks” occur spontaneously or can be evoked by depolarisation of cell patches, single isolated cells. They occur in where

Answer 10

intact cardiac muscle

Question 11

Ca2+ release from the SR is in the form of sparks
Evoked at ‘Z lines’ (SR junctional contact with transverse tubules, RyR clusters/LTCC dyad

Question 12

Ca2+ release from the SR is in the form of sparks
Evoked by single L-type Ca channel current
vgoltage and time-dependant of Ca spark propbability is similar to that of what

Answer 12

L type Ca channels

Question 13

Normal CICR is a global summation of

Answer 13

sparks

Question 14

Ca2+ removal from the cytoplasm allows what

Answer 14

relaxation

Question 15

Ca2+ removal from the cytoplasm allows relaxation
3 means:
Back into the SR -

Answer 15

SarcoEndoplasmic Reticulum Ca2+ ATP-ase (SERCA)

Question 16

Ca2+ removal from the cytoplasm allows relaxation
3 means:
Back into the SR - SarcoEndoplasmic Reticulum Ca2+ ATP-ase (SERCA)
Out of the cardiomyocyte -

Answer 16

sodium calcium exchanger (NCX)

Question 17

Ca2+ removal from the cytoplasm allows relaxation
3 means:
Back into the SR - SarcoEndoplasmic Reticulum Ca2+ ATP-ase (SERCA)
Out of the cardiomyocyte - sodium calcium exchanger (NCX)
Out of the cardiomyocyte -

Answer 17

PlasmaleMmal Ca2+ ATP-ase (PMCA)

Question 18

SERCA2a, regulated by what

Answer 18

endogenous inhibitor (phospholamban

Question 19

SERCA2a phosphorylation of PLB by _____ and or _____ relieves endogenous inhibition

Answer 19

PKS and/or CamKII

Question 20

NCX is an electrogenic __________

Answer 20

transporter

Question 21

NCX is an electrogenic transporter
Normal mode Ca2+ = ______
how many Na in

Answer 21

Ca2+ exits
3Na in

Question 22

NX is an electrogenic transporter
Reverse mode
Ca2+ ______
how many Na in

Answer 22

Ca2+ entry
3Na out

Question 23

The amount of Ca2+ in the SR is very sensitive to whether the cardiomyocyte _____ or _____ Ca2+

Answer 23

gains or loses

Question 24

SERCA is a pump and it will move Ca2+ in the _____ regardless of the concentration gradient

Answer 24

SR

Question 25

SERCA is a pump and it will move Ca2+ into the SR regardless of what

Answer 25

of the concentration gradient

Question 26

Any gain or loss of Ca2+ from the cardiomyocyte is reflected in the SR ______ ______

Answer 26

CA2+ content

Question 27

CA2+ entry via LTCC and exit via ___ acts to maintain SR Ca2+ content

Answer 27

NCX

Question 28

Spontaneous Ca2+ release occurs during what

Answer 28

SR overload

Question 29

Spontaneous Ca2+ release are propagating sparks

Increased SR Ca2+ content increases:
Spark ______
Spark_______

Answer 29

frequency and amplitude

Question 30

Spark frequency and Spark Amplitude increase when what

Answer 30

increased SR Ca2+ content

Question 31

Spontaneous Ca2+ release are propagating sparks

Increased SR Ca2+ content increases:
Spark Frequency
Spark Amplitude
When these sparks overcome local CA2+ buffering capacity, they can activate neighbouring ______ clusters

Answer 31

RyR2

Question 32

Spontaneous Ca2+ release are propagating sparks

Increased SR Ca2+ content increases:
Spark Frequency
Spark Amplitude
When these sparks overcome local CA2+ buffering capacity, they can activate neighbouring RyR2 clusters and set up a _______ ____ of CA2+ release

Answer 32

propagating wave

Question 33

Spontaneous Ca2+ release are propagating sparks

Increased SR Ca2+ content increases:
Spark Frequency
Spark Amplitude
When these sparks overcome local CA2+ buffering capacity, they can activate neighbouring RyR2 clusters and set up a propagating wave of CA2+ release, this can cause ______ _____ _______ and set up re entrant arrhythmias

Answer 33

delayed after depolarisations