Lecture 1 Flashcards
What are the basic units of muscle structure?
Muscles are made of bundles of fibers known as fascicles. Each of these fibers contains many myofibrils.
What is the function of the Z line of muscles?
Z line is a zigzag which connects to actin and the space between z lines narrows during muscle contraction.
What volume of the muscle fiber consists of myofibrils?
Myofibrils occupy 80% of the fibre volume.
100s to 1000s of myofibrils exist in each fiber and each myofibril is 1 - 2 micrometers in diameter.
What is a sarcomere?
sarcomere is one contractile unit
Where is the sarcoplasmic reticulum located in muscle fibers.
Sarcoplasmic reticulum surrounds the muscle fiber bundles.
Where are nuclei located in muscle fibers?
Nuclei are located in the periphery and damaged muscle fibers contain the nuclei in the middle.
What is the function of titin?
Titin stretches from one z line to another. It provides the muscle with elasticity by acting like a spring.
What does myosin contain that makes it perform its function?
Myosin contains an actin binding site, a hinge region, and an ATP hydrolysing site.
What is the function of calcium in muscles?
tropomyosin covers myosin binding sites and when calcium binds to troponin the tropomyosin moves out of the way to allow for crossbridge cycling to occur.
Why is pennation a good shape for muscle structure?
pennation allows more muscle fibers to insert into the tendon.
What is a fusiform muscle fiber?
fusiform = muscle fibers run full length.
How is force produced related to the cross sectional area?
force production is proportional to muscle CSA
What is a miometric contraction and a pliometric contraction?
Miometric contraction is a concentric contraction
Pliometric contraction is eccentric
What is the Length - Tension Relationship?
Maximum is too short or long the force produced is sub optimal.
What is the force velocity relationship?
With an increase in load the muscle shortening time is much slower and vice versa.
