L6 muscle structure & contraction

Question 1

what important organelle do skeletal muscles contain for energy?

Answer 1

mitochondria

Question 2

what are the 3 main muscle types?

Answer 2

1. skeletal muscle
2. smooth muscle
3. cardiac muscle

Question 3

describe the connective tissue stucture of skeletal muscle cells

Answer 3

• skeletal cells are surrounded by a connective tissue sheath called the endomysium
• cells are grouped in fascicles surronded by perimysium
• fascicles are grouped together to form the muscle which is surrounded by the epimysium

Question 4

are skeletal cells multinucleate?

Answer 4

yes

Question 5

what are myofibrils?

Answer 5

each skeletal muscle fibre contains bundles of filaments, called myofibrils running along the axis of the cell

Question 6

what is the plasma membrane of a skeletal muscle cell called?

Answer 6

the sarcolemma

Question 7

what are important ‘landmarks’ or features of the sarcomere?

Answer 7

• H zone - where overlap takes place - only contains the thick filaments
• I band - thin filaments - its a light colour
• z lines - define the boundary of each sarcomere

Question 8

what is a sarcomere?

Answer 8

• a unit of a myofibril contained between 2 z lines
• the functional unit of skeletal muscle - ie for contraction