76. Force Generation by the Heart

Question 1

the cardiac muscle is……….

Answer 1

striated

Question 2

what causes striation in cardiac muscle

Answer 2

the regular arrangement of contractile proteins

Question 3

The cardiac myocytes are electrically coupled by what

Answer 3

gap junctions

Question 4

gap junctions form what kind of communication between neighbouring myocytes

Answer 4

low resistance electrical communication pathways

Question 5

in histograms of cardiac muscle what can be seen

Answer 5

intercalated discs
branching cardiac muscle fibres

Question 6

what kind of junctions are within intercalated discs

Answer 6

desmosomes

Question 7

The Desmosomes within the intercalated discs provide …………between adjacent cardiac cells

Answer 7

mechanical adhesion

Question 8

Each muscle fibre (cell) contains many………..

Answer 8

Myofibrils

Question 9

what are myofibrils

Answer 9

contractile units of muscle

Question 10

myofibrils contain tick and thin protein filaments called……… ………..

Answer 10

Actin (thin) lighter appearance
Myocyin (thick) darker appearance

Question 11

within each myofibril, Myocyin and actin are arranged into ………

Answer 11

scaromeres

Question 12

sliding of actin filaments on myocyin filaments causes what?

Answer 12

muscle tension aka how the muscle shortens and produces force

Question 13

Force generation depends upon ……………………..between thick (myosin) and thin (actin) filaments

Answer 13

ATP-dependent interaction

Question 14

is ATP required for contraction or relaxation

Answer 14

Both

Question 15

the interaction between myosin and actin is a process is known as the

Answer 15

cross-bridge formation

Question 16

what is required to switch on cross bridge formation. And what does that bind to

Answer 16

Ca2+ which binds to Tropomyosin