Chapter 7 Physiology

Which of the following is a stimulus for contraction in skeletal muscle?

Acetylcholine

Muscle cells

can only contract

Exhaustion of energy reserves or decline in pH due to production and dissociation of lactic acid causes

muscle fatigue

Which of the following occurs as a result of motor units in a particular muscle being always active, even though contractions do not produce enough movement to cause contraction?

muscle tone

Muscles whose names contain the root cervi- would be found in the

neck

A single stimulus-contraction-relaxation sequence in a muscle fiber is known as a(n)

twitch

In response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases

calcium ions

Which of the following muscles functions to maintain an erect spinal column and head?

erector spinae

A muscle ______ contains a sacrolemma, sarcoplasm, myofilaments, and myofibrils.

fiber

The skeletal muscle structures that actively shorten and are responsible for muscle fiber contraction are called

myofibrils

Tropomyosin strands are held in position by which of the following?

troponin molecules

Rigor mortis occurs at death due to a lack of

ATP

Myofibrils are made primarily of

actin and myosin

The striated appearance of skeletal muscle results from

actin and myosin arrangement

When calcium ion binds to troponin

active sites on actin are exposed

A resting muscle generates most of its ATP by

aerobic respiration

The less-movable end of a skeletal muscle is the

Origin

Fast fibers

have high glycogen reserves

Skeletal muscle fibers differ from "typical cells" in that these muscle fibers

have many nuclei

The term used to describe muscular growth in response to usage is

hypertrophy

Botulism

results from a bacterial toxin that prevents the release of acetylcholine at the axon terminals

The area between Z lines is the

sacromere

A person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more ______ in his or her leg muscles

slow fibers

Nonstriated =, involuntary muscle is

smooth

Which statement regarding "heat loss" is true?

Muscle contractions play an important role in the maintenance of normal body temperature

The skeletal muscles store calcium ions in the terminal cisternae of the

Sarcoplasmic reticulum

Which statement regarding skeletal muscle is true?

Skeletal muscles contain blood vessels.

Which of the following statements describes how mucles help maintain homeostasis?

Skeletal muscles contractions help maintain body temperature.

Which type of scenario is most likely?

Small motor units are recruited first

Which of the following is characteristic of cardiac muscle?

Cardiac muscle cells are striated