Skeletal Muscles

Question 1

Structure of a skeletal muscle

Question 2

Myofibrils

Located ? Made up of ?

Answer 2

> Myofibrils are located in the sarcoplasm

> Each myofibril is made up of two types of protein filament:
• Thick filaments made of myosin
• Thin filaments made of actin

Question 3

H band ?

Answer 3

> Only thick myosin filaments

Question 4

I band?

Answer 4

> I band: Only thin actin filaments

> Appear lighter because thick and thin filaments do not overlap

Question 5

A band?

Answer 5

> A band: Contains areas with only myosin filaments

> Appear darker as thick and thin filaments overlap

Question 6

M line?

Answer 6

> M line: attachment for myosin filaments

Question 7

Z line?

Answer 7

> Z line: attachment for actin filaments

Question 8

Sarcomere?

Answer 8

> The section of myofibril between two Z lines

> When a muscle contracts, these sarcomeres shorten and the pattern of light and dark bands changes

Question 9

Tropmyosin

Answer 9

> Am important protein found to n muscle, which forms a fibrous strand around the actin filaments