07 Muscular System Flashcards
What are the three types of muscle tissue?
Skeletal, Cardiac, and smooth.
Name the two myofilaments and describe their basic shape
Myosin- more complex, double-headed protein, called a thick filament.
Actin- a more basic protein strand called a thin filament. Support proteins attach to actin play an important role in regulating muscle contraction.
what bundles make up skeletal muscle?
Fascicles, fibers, myofibrils, myofilaments.
What is a sarcomere?
The main contractile unit of muscle fiber
What are striations?
Alternating light & dark crossbands visible in muscle
What are the dark and light bands called in striations?
A-Band & I-Band
What are the light and dark bands in striations made of?
A-band- Myosin blocks light from reaching your eye causing a dark appearance.
I-Band- Actin is thin and allows light to pass through.
briefly describe what happens when skeletal muscle contracts
when signaled by a motor neuron from the brain, the myosin “heads” grab onto the actin and begin to pull. This does not cause the myosin or actin to get shorter - instead, the actin “slides” past the myosin, effectively causing the muscle to shorten.
What role does troponin play in muscle contraction?
Troponin holds tropomyosin in place like a nail or glue.
what role does tropomyosin play in muscle contraction?
The protein tropomyosin is like a rope or a snake, winding around and around actin, blocking myosin from attaching.
what role does calcium play in muscle contraction?
Calcium attaches to a binding site on the troponin support protein to “facilitate the movement of your muscles.”
What does the term “excitation-contraction coupling” mean?
the term used to describe the series of events that allows an electrical signal to cause a muscle contraction.
Describe what happens at the neuromuscular junction.
Where the action potential will “jump” from the neuron to the muscle fiber.
What role do T-tubules and sarcoplasmic reticulum play in muscle contraction?
Action potential travels through T-Tubules and triggers the release of calcium from the sarcoplasmic reticulum.
