Structure of skeletal muscle

Question 1

WHat are sacrolemma?

Answer 1

• skeletal muscles are made up of bundles of muscle fibres
• these are enclosed within a plasma memrabne known as the sacrolemma

Question 2

How do muscles fibres compare to normal cells?

Answer 2

the muscle fibres contain a number of nuclei and they are mushc longer than normal cells

Question 3

How are muscle fibres formed?

Answer 3

• formed as a result of many individual embryonic muscle cells fusing together

Question 4

Why are the muscle cells fused together?

Answer 4

• this makes the muscle stronger
• as the junction between adjacent cells would act as a cyotplasm

Question 5

What is the sacroplasm?

Answer 5

the shared cytoplasm within a muscle fibre

Question 6

What are transvers (T) tubules?

Answer 6

• parts of the sarcolemma that fold inwards

Question 7

What is the purpose of transverse tubules?

Answer 7

• help electrical impulses spread throughout the sacroplasm
• this ensure that the whole fibre receives the impulse to contract at the same time

Question 8

What are the adaptations of muscle fibres?

Answer 8

• muscle fibres have lots of mitochondria to provide the ATP that is needed for muscle contraction
• they also have a modified version of the endoplasmic reticulum, known as the sacroplasmic reticulum
  
  • this extends throughout the muscle fibre and contain calcium ion required for muscle contraction