Week 1: Musculoskeletal System (Muscle)

Question 1

Structure of skeletal muscle

Answer 1

• muscle fiber (muscle cell)
• connective tissue
• blood vessel, nerve

Question 2

Muscle fibers

Answer 2

• surrounded by 3 connective tissue membrane
  1) endomysium - individual muscle fiber
  2) perimysium - bundle of muscle fiber
  3) epimysium - entire skeletal muscle

Question 3

Myofibrils

Answer 3

• extend muscle fiber

- composed of sacromere

Question 4

Sacromere

Answer 4

composed of thick and thin myofilaments

Question 5

Thick, Thin myofilament

Answer 5

• thick: composed of myosin

- thin: composed of actin

Question 6

Skeletal muscle contraction

Answer 6

• innervated by lower motor neuron

- axon terminal of lower motor form synapse called neuromuscular junction with muscle fiber

Question 7

Muscle contraction steps

Answer 7

1) AP arrive neuromuscular junction
2) ACh released, bind to chemically-gated ion channel on sarcolemma
3) Na+ depolarise sarcolemma
4) GP generated, stimulate AP in sarcolemma
5) AP travel through sarrcolemma
6) AP travel T tubules
7) AP trigger Sarcoplasmic Reticulum to release Ca2+
8) Ca2+ bind to troponin
9) Active site exposed on actin
10) Myosin head bind to active site
11) Thin myofilament pulled toward M-line