A+P Chapter 6 Muscle

Which of the following is not a function of the muscular system?

Blood cell formation

Why are calcium ions necessary for skeletal muscle contraction?

Calcium ions trigger the binding of myosin heads to actin filaments.

Striated involuntary muscle tissue is classified as ________ muscle.

Cardiac

Striated involuntary muscle tissue found in the heart is ________.

Cardiac muscle

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

Contractility

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

Cross bridges

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract?

Acetylcholine

What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber?

Acetylcholinesterase

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

Action potential

What is covered by the endomysium?

An individual muscle cell

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

Antagonists

Which type of muscle tissue contracts most quickly upon stimulation?

Skeletal

Which one of the following is composed mostly of the protein myosin?

Thick filaments

Jason injured his hamstring muscle group during football practice. He will be unable to perform ________.

Thigh extension and knee flexion

The mechanical force of contraction is generated by _______.

A sliding of thin filaments past thick filaments

During skeletal muscle contraction, to what do myosin heads bind?

Actin filaments

The arrangement of fascicles in orbicularis oris is ________.

Circular

Anaerobic glycolysis requires __________ to make ATP.

Glucose only

Skeletal muscle, as a whole, can generate different amounts of force, and different degrees of shortening, in response to stimuli. What is this concept called?

Graded response.

What organelle wraps and surrounds the myofibril and stores calcium?

Sarcoplasmic reticulum

Which term does NOT describe smooth muscle cells? Visceral, non-striated, skeletal, involuntary

Skeletal

The prime mover of arm abduction is the ________ muscle.

Deltoid

A smooth, sustained contraction, with no evidence of relaxation, is called _________.

Fused, or complete tetanus

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

Isotonic contractions

A motor neuron and all of the skeletal muscle fibers it stimulates are termed a _________.

Motor unit

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

Motor unit

An inherited disease that causes muscles to degenerate and atrophy is known as ________.

Muscular dystrophy

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

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

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

Origin

Which facial muscle is considered the "smiling" muscle since it raises the corners of the mouth?

Zygomaticus