Muscular System

Striated involuntary muscle tissue is classified as ________ muscle.

• skeletal

• cardiac

• smooth

• either smooth or skeletal

Which term does NOT describe smooth muscle cells?

• visceral

• nonstriated

• skeletal

• involuntary

Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________.

• elasticity

• irritability

• contractility

• extensibility

One neuron and all the skeletal muscles it stimulates is known as a ________.

• sarcoplasmic reticulum

• motor unit

• synaptic cleft

• neuromuscular junction

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.

• neuromuscular junctions

• synapses

• cross bridges

• motor units

What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma?

• neuromuscular junction

• action potential

• neurotransmitter

• acetylcholine

According to the sliding filament theory, how does muscle contraction occur?

• Myosin heads form cross bridges and pull thin filaments, causing them to slide.

• Both thick and thin filaments shorten as the muscle contracts.

• A bands bunch up and shorten as myosin heads attach to thin filaments.

• Myosin heads attach and detach from thin filaments, causing thin filaments to shorten.

Contractions in which muscles shorten and produce movement are known as ________.

• isotonic contractions

• twitches

• isometric contractions

• resistance exercises

The point of muscle attachment to an immovable or less movable bone is known as the ________.

• innervation

• action

• insertion

• origin

Muscles that perform opposite actions to one another are termed ________.

• synergists

• prime movers

• antagonists

• fixators