Muscular Study Guide

A sarcomere is best described as ______

• a part of the sarcoplasmic reticulum

• a group of fascicles

• a group of myofibrils

• a unit within a myofibril

Myofibrils are composed primarily of

• actin and myosin

• ATP and ADP

• troponin and tropomyosin

• fascia and tendons

Endomysium separates individual muscle fibers from each other.

• True

• False

A motor neuron and the muscle fibers that it controls constitute a motor unit.

• True

• False

The electrical impulse that triggers a contraction travels deep into a skeletal muscle fiber by means of

• sarcoplasmic reticulum

• transverse tubules

• mitochondria

• motor end plates

Binding sites on the surface of actin allow the formation of cross bridges with molecules of

• ATP

• myosin

• troponin

• tropomyosin

In the initiation of muscle contraction, calcium ions bind to tropomyosin, exposing active sites on actin for cross-bridge formation.

• True

• False

Rigor mortis that occurs in skeletal muscles a few hours after death is due to

• lack of ATP

• increased membrane permeability to calcium ions

• None of the choices are correct.

• persistent stimulation by motor neuron

ATP is necessary for muscle relaxation.

• True

• False

Tags

NGSS.HS-LS1-7

Anaerobic muscle fatigue is most likely due to an accumulation of ____________.

• lactic acid

• carbon dioxide

• glycogen

• creatine phosphate

Tags

NGSS.HS-LS2-3