Muscle

Question 1

What are the key properties of muscle?

Answer 1

• Extensibility
• Elasticity
• Force Production

Question 2

How does muscle generate movement?

Answer 2

• Change in shape and pressure

- Changes in length and pulling on levers

Question 3

What percentage of body mass is muscle?

Answer 3

40%

Question 4

What are the types of muscle?

Answer 4

• Smooth
• Cardiac
• Skeletal

Question 5

What are the defining characteristics of a skeletal muscle cell fibre?

Answer 5

• Multinucleated
• Many mitochondria
• T tubules
• Myofibrils and Sarcomeres
• Sarcolemma/plasm/plasmic reticulum

Question 6

What are myofibrils made of?

Answer 6

Thin actin and thick myosin filaments

Question 7

How does the structure of smooth muscle differ to skeletal muscle?

Answer 7

No sarcomeres so no banding pattern. Contraction occurs by change in shape.

Question 8

How does cross bridge activation work in smooth muscle?

Answer 8

Controlled by Caclium ion regulated enzyme (Myosin light chain kinase) that phosphorylates myosin, allowing it to undergo cross-bridge cycling

Question 9

How does smooth muscle relax once contracted?

Answer 9

The myosin is dephosphorylated by myosin light chain phosphatase, making it no longer able to bind to actin