The sarcomere

Question 1

Structure

• Organisation
• Elements

Answer 1

• Basic contractile element of CMs
• Highly organised, gives striated appearance of muscle

Thin filaments

Thick Filaments

Crossbridges

Question 2

M-Band

Answer 2

• Line in centre

- Bridges connecting the thick filaments

Question 3

A-Band

Answer 3

• The thick filaments (arranged in a hexagonal lattice)

- 1.6 um

Question 4

I-Band

Answer 4

• Area of thin filaments either side of Z-line not sliding against thick filament

Question 5

Contraction

Answer 5

• Filaments don’t change length

- I-band and H-zone shorten

Question 6

H-zone

Answer 6

• Area of thick filament in centre (near M-band) that isn’t interacting with thin filament