A&P Chapter 10 HW

Cross bridge detachment is caused by ________ binding to the myosin head.

ATP

The area in the center of the A band that contains no thin filaments is the

H band

The region of the sarcomere that always contains thin filaments is the

I band

Which of the following is not true of acetylcholine?

It enters the muscle fiber to release calcium form the sarcoplasmic reticulum.

How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?

It would cause muscles to stay contracted.

The soleus muscle is very red in color. Which of these statements about soleus muscle fibers is FALSE?

They are large in diameter

The most important factor in decreasing the intracellular concentration of calcium ion after contraction is

active transport of calcium into the sarcoplasmic reticulum.

A(n) ________ can be described as a broad tendinous sheet.

aponeurosis

Smooth muscle contracts when calcium binds to __________ and activates __________.

calmodulin; myosin light chain kinase

A muscle producing its maximum tension for a prolonged period is in __________.

complete tetanus

Fatigued muscles signify

decreased pH

At what point during excitation contraction coupling does exocytosis play a role?

during acetylcholine release from the synaptic terminal

Titin is an

elastic protein

The dense layer of connective tissue that surrounds an entire skeletal muscle is the

epimysium

Muscle fibers differ from "typical cells" in that muscle fibers

have many nuclei

What can the nervous system do to increase muscle tension?

increase stimulation frequency recruit larger motor units increase the number of active motor units

Heat energy gained from muscle contraction is released by the ________ system.

integumentary

The type of contraction in which the muscle fibers do not shorten is called

isometric

Muscle fatigue occurs because of a buildup of __________ and a(n) __________ in pH.

lactic acid; decrease

In an isotonic contraction,

muscle tension exceeds the load and the muscle lifts the load.

The advantage of having many nuclei in a skeletal muscle fiber is the ability to

produce large amounts of muscle proteins.

Which of these is NOT a function of smooth muscle?

pushing blood into the great vessels of the heart

The increase in muscle tension that is produced by increasing the number of active motor units is called

recruitment

A patient takes a medication that blocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction?

reduces the muscle's ability for contraction

After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as

rigor mortis

What happens to sarcomere length if the zone of overlap is decreased?

sarcomere length increases

Which type of muscle tissue has the greatest effect on the body's heat production?

skeletal

The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n)

tendon

Increased muscle fiber endurance can be produced by __________.

the type of activity performed

The muscle action potential penetrates deep into a fiber along the __________.

transverse tubules

The protein that regulates muscle contraction by controlling the availability of active sites on actin is called

tropomyosin

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called

wave summation