Muscle Flashcards
What are the key properties of muscle?
- Extensibility
- Elasticity
- Force Production
How does muscle generate movement?
- Change in shape and pressure
- Changes in length and pulling on levers
What percentage of body mass is muscle?
40%
What are the types of muscle?
- Smooth
- Cardiac
- Skeletal
What are the defining characteristics of a skeletal muscle cell fibre?
- Multinucleated
- Many mitochondria
- T tubules
- Myofibrils and Sarcomeres
- Sarcolemma/plasm/plasmic reticulum
What are myofibrils made of?
Thin actin and thick myosin filaments
How does the structure of smooth muscle differ to skeletal muscle?
No sarcomeres so no banding pattern. Contraction occurs by change in shape.
How does cross bridge activation work in smooth muscle?
Controlled by Caclium ion regulated enzyme (Myosin light chain kinase) that phosphorylates myosin, allowing it to undergo cross-bridge cycling
How does smooth muscle relax once contracted?
The myosin is dephosphorylated by myosin light chain phosphatase, making it no longer able to bind to actin
