green bits ch 10

Muscular tissue contributes to homeostasis by?

producing body movements, moving substances through the body, and producing heat to maintain normal body temperature.

A skeletal muscle consists of?

individual muscle fibers bundled into muscle fascicles and surrounded by three connective tissue layers that are extensions of the fascia.

The contractile elements of muscle fibers? contain?

myofibrils, overlapping thick and thin filaments.

Myofibrils contain two types of filaments, what are those?

thick filaments and thin filaments

Contractile proteins (------ ------) generate force during -----; regulatory proteins (---- ----) help switch contraction on and off.

(myosin and actin), contraction, troponin and tropomyosin)

During muscle contractions what happens?

thin filaments move toward the M line of each sarcomere.

during the power stroke of contraction what happens?

cross-bridges rotate and move the thin filaments past the thick filaments toward the center of the sarcomere.

what starts the sliding of thin filaments? When the level of Ca2+ in the sarcoplasm declines what happens?

An increase in the Ca2+ level in the sarcoplasm. sliding stops

A muscle fiber develops its greatest tension when there is?

an optimal zone of overlap between thick and thin filaments.

Synaptic end bulbs at the tips of axon terminals contain what?

synaptic vesicles filled with acetylcholine (ACh).

Acetylcholine released at the neuromuscular junction triggers what? which leads to?

a muscle action potential, which leads to muscle contraction.

During a long-term event such as a marathon race, most ATP is produced how?

aerobically

A motor unit consists of what?

a somatic motor neuron plus all of the muscle fibers it stimulates.

A myogram is a record of?

a muscle contraction.

Due to wave summation, the tension produced during a sustained contraction is?

greater than that produced by a single twitch.

In an isotonic contraction, tension remains ----- as muscle length ------or -----; in an ------- -------, tension increases -------without a change in muscle length.

constant, decreases, increases, isometric contraction, greatly

Visceral smooth muscle fibers connect to one another by---- ----and contract as a ---- ----. Multi-unit smooth muscle fibers lack ---- ----- and contract independently.

gap junctions, single unit, gap junctions

Most muscles are derived from?

mesoderm