exap #3 A&P

Most parts of the sarcomere shorten during contraction, but what part of the sarcomere stays the same size during contraction?

A Band

What is the I band of the sarcomere?

Actin filaments, Z discs, and connectin - but no overlap with thick fila

Of the three systems that make energy for muscle cells, which one uses oxygen and makes the most ATP?

Aerobic cellular respiration

Put the steps of cross-bridge cycling in the order they occur, starting with the formation of cross-bridges between myosin and actin.

Cross-bridge formation (myosin binds to actin) Myosin head pulls and slides actin filament, myosin releases ADP and Pi Myosin head binds ATP and releases from actin. Myosin head resets as it breaks down ATP into ADP and Pi.

What is the 'neuro' part of the neuromuscular junction?

It's the axon terminal of a motor neuron that contacts the muscle cell

Why is skeletal muscle rich in blood vessels and innervation?

Skeletal muscles need to bring in a lot of oxygen and nutrients and quickly remove wastes to function properly. Nerves allow us to control contraction consciously

What does the sarcoplasmic reticulum do in muscle cells?

Stores calcium and releases it when the action potential travels into the T tubule.

The muscle fibers arranged in the orbicularis oculi have a circular arrangement -- what does this mean?

They are arranged in a ring around an opening.

What do you know to be true for "slow oxidative fibers"?

They use aerobic respiration to make ATP, are a darker red color because they have myoglobin, and usually have slower contractions than fast fibers.

The occipitofrontalis muscle has its origin on the occipital bone and inserts into the skin of the eyebrows and nose. What would you expect its action to be?

To wrinkle the forehead, as it moves the scalp and eyebrows.

The muscle whose action is opposite that to the action of the agonist is the _____.

antagonist

Where is the rectus abdominus located?

anterior-most part of the abdominal wall, under the rectus sheath.

The erector spinae muscles (spinalis, longissimus, and iliocostalis)

are the superficial trunk muscles that maintain posture and keep the spine erect.

Which one of the following muscles is most likely to be involved in a frown?

depressor anguli oris

The following muscles are all used in breathing. Which one is the prime mover?

diaphragm

As part of the posterior compartment muscles of the thigh, the hamstrings

extend the hip

Generally speaking, the anterior arm muscles (ie, biceps brachii)

flex the elbow

Which set of muscles moves the tongue?

genioglossus, palatoglossus, styloglossus

The _____ is the more mobile end of the muscle.

insertion

Due to its size and locations of its origin and insertion, the trapezius muscle has multiple actions. One of those actions is

moves/stabilizes the scapula.

What protein will you find in thick filaments?

myosin

Muscles in the posterior compartment of the leg, like the gastrocnemius muscle,

plantar flex (push down) the foot.

The masseter is the prime mover of the muscles involved in chewing (mastication). It

pulls the jaw up and forward.

The sternocleidomastoid has its origins on the manubrium and clavicle and inserts onto the mastoid process. When both contract equally,

the neck flexes.