Module 3.2 Skeletal Muscle Contraction

Review Questions from end of chapter

The main role of skeletal muscles is to?

contract and relax to move bones

Each skeletal muscle fiber is best described as?

a cell with multiple nuclei and myofibrils

what is the thin filament protein in skeletal muscle

actin

which structure gives skeletal muscle its characteristic striated appearance?

sarcomeres

the smallest contractile unit of skeletal muscle is the?

sarcomere

what structure serves as the attachment point for thin filaments?

Z-line

What structure serves as the attachment point for thick filaments?

M-line

According to the sliding filament model, what happens as a muscle contracts?

thin and thick filaments slide past each other without changing length

during full contraction, the actin filaments appear to?

disappear as they overlap one another

which statement best describes what happens to the sarcomere during contraction?

the z-lines move closer together as actin slides inward

ONE: ach/muscle contraction

Acetylcholine released; binds ligand-gated channels; action potential generated.

TWO: ach/muscle contraction

action potential travels along muscle fiber and T-tubules.

THREE: ach/muscle contraction

action potential reaches SR; calcium released.

FOUR: ach/muscle contraction

calcium binds troponin, exposing myosin-binding sites

FIVE: ach/muscle contraction

ATP binding, cross-bridge cycling, and power strokes pull actin filaments.

SIX: ach/muscle contraction

calcium actively transported back into SR

SEVEN: ach/muscle contraction

troponin blocks myosin-binding sites; contraction ends.