Chapter 7

Which of the following is characteristic of cardiac muscles?

Cardiac muscle cells are striated

Single stimulus contraction-relaxation sequence in a muscle fiber is known as

A twitch

Rigor mortis occurs after death due to lack of

ATP

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

Acetylcholine

Myofibrils are made primarily of

Actin and myosin

Striated appearance of skeletal muscle results from

Actin and myosin arrangement

A resting muscle generates most of its ATP by

Aerobic respiration

Smooth muscle cells

Are spindle shared

The contains vesicles filled with acetylcholine

Axon terminal

The enzyme acetylcholinesterase causes acetylcholine to

Break down

During which phase is the stimulus frequency so high that the relaxation phase is eliminated?

Complete tetanus

Layer of collagen fibers that surrounds the entire muscle

Epimysium

Regarding muscle fiber elongation

Gravity may help lengthen a muscle fiber after elongation

Fast fibers

Have high glycogen reserves

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

Have many nuclei

Area of sarcomere that is a light region between two successive n-bands

I band

Which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur?

Incomplete tetanus

Neurotransmitters that cause skeletal muscle contraction are normally stored in

Motor neuron axon terminals

The skeletal muscle structure that actively shorten and are responsible for muscle fiber contraction are normally stored in

Motor neuron axon terminals

Which statement regarding "heat loss" is true?

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

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

Muscle fatigue

Which statement regarding the relaxation phase of a muscle twitch is true?

Muscle tension falls to resting levels

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

Muscle tone

Pre-exertion labels is called

Oxygen debt

The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called

Oxygen debt

Muscle Fascicles are separated by

Perimysium

Sheath of connective tissue surrounding bundle of striated muscle fibers

Perimysium

Which of the following is true about red blood cells?

Red muscles are slower than white muscles

Area between Z line

Sarcomere

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

Skeletal muscle contractions help maintain body temperature

Which of the following is an effect of aging on the muscular system?

Skeletal muscle fibers become smaller in diameter

Which statement regarding skeletal muscles is true?

Skeletal muscles contain blood cells

Nonstriated, involuntary muscle is

Smooth

Creatine phosphate serves to

Supply energy to synthesize ATP

Acetylcholinesterase is found within the

Synaptic cleft

Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to

The sarcoplasmic reticulum

What is the function of the transverse tubule?

To transmit electrical impulses to the cells interior

Muscle cells

Can only contract

Muscle ___ contains sarcolemma, sarcoplasm, myofilaments, and myofibrils.

Fiber