A&P Chapter 10 & 11

Each skeletal muscle fiber is controlled by a motor neuron at a single

neuromuscular junction

Muscles with fibers that run at an angle to the long axis of the body are called

oblique

Which of these muscles produces lateral rotation at the hip?

obturator internus, piriformis, gluteus maximus

Put the following events of the contraction cycle in the order in which they occur. 1. Cross-bridge detachment 2. Cross-bridge formation 3. Active site exposure 4. Myosin reactivation 5. Calcium ions bind troponin 6. Myosin head pivoting

5,3,2,6,1,4

Put the following structures in order from superficial to deep. 1. muscle fiber 2. perimysium 3. myofibril 4. fascicle 5. endomysium 6. epimysium

6,2,4,5,1,3

The region of the sarcomere containing the thick filaments is the

A band

At rest, the tropomyosin molecule is held in place by

troponin molecules

Each thin filament consists of

two actin protein strands coiled helically around each other

The following is a list of the events that occur during a muscle contraction. What is the correct sequence of these events? 1. Myosin cross-bridges bind to the actin. 2. The free myosin head splits ATP. 3. Calcium ion is released from the sarcoplasmic reticulum. 4. The myosin head pivots toward the center of the sarcomere. 5. Calcium ion binds to troponin. 6. The myosin head binds an ATP molecule and detaches from the actin.

3,5,1,4,6,2

Put the following events of excitation-contraction coupling in the order in which they occur. 1. Excitation 2. Sarcomere shortening 3. Generation of muscle tension 4. Neural control 5. Contraction cycle begins 6. Release of calcium ions

4,1,6,5,2,3

Put the following events of the neuromuscular junction in the order in which they occur. 1. Action potential is propagated in the sarcolemma. 2. Acetylcholine binds to ligand gated sodium channels. 3. Action potential arrives at the neuromuscular junction. 4. Vesicles full of acetylcholine are stored at the axon terminal. 5. Acetylcholine is released into the synaptic cleft.

4,3,5,2,1

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

ATP

The skeletal muscle complex known as the triad consists of

a transverse tubule and two terminal cisternae

Triggering of the muscle action potential occurs after

acetylcholine binds to chemically-gated channels in the motor end plate

A resting muscle generates most of its ATP by

aerobic metabolism of fatty acids

A type of muscle whose action opposes that of another muscle is called a(n)

antagonist

Which of the following are members of the hamstring group?

biceps femoris, semitendinosus, amd semimembranosus

The role of acetylcholinesterase is to

break down acetylcholine into acetate and choline components

Active sites on the actin become available for binding after

calcium binds to troponin.

In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases

calcium ions

Which of the following is true about the difference between cardiac muscle cells and skeletal muscle cells?

cardiac muscle cells have intercalated discs where skeletal muscle cells do not

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

epimysium

When the fulcrum is located between the load and the force, it is called a ________ lever.

first-class

A fascicle is a

group of muscle fibers that are encased in the perimysium

The ________ muscle allows you to look down.

inferior rectus

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

it would cause muscles to stay contracted

Which of the following is not primarily a muscle of facial expression?

masseter

A single motor neuron together with all the muscle fibers it innervates is called a(n)

motor unit

Thick filaments are made of the protein

myosin

Each of the following muscles is involved in the process of chewing or manipulating food in the mouth except the

omohyoid

The "kissing muscle" that purses the lips is the

orbicularis oris

The end of a muscle that remains stationary when the muscle contracts is called the

origin

The muscle that elevates the tongue is the

palatogossus

Most of the skeletal muscles in the body are ________ muscles.

parallel

In a ________ muscle, the muscle fibers and fascicles lie in a slanted or oblique position to the tendon.

pennate

A(n) ________ is a muscle whose contraction is chiefly responsible for producing a particular movement.

prime mover

Which of the following is not an extrinsic eye muscle?

rectus abdominus

Muscles of the rotator cuff include all of the following except

rhomboid

The plasma membrane of a skeletal muscle fiber is called the

sarcolemma

The long strap-like muscle on the anterior thigh is the ________ muscle.

sartorius

The type of muscle fiber that is most resistant to fatigue is the ________ fiber.

slow

Muscles visible at the body surface are often called

superficialis

A muscle that assists the muscle that is primarily responsible for a given action is a(n)

synergist

At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium, come together to form a

tendon

The most common lever systems in the body are those that have the applied force between the fulcrum and the load. These are called ________ levers.

third-class

A muscle that dorsiflexes the foot is the

tibialis anterior

In the sarcomere which elastic protein attaches the thick filament to the Z line?

titin

A muscle whose name ends in the suffix -glossus would be found within or attached to the

tongue

The action potential is conducted into a skeletal muscle fiber by

transverse tubules

Which of these muscles is a member of the quadriceps group?

vastus medialis, vastus intermedius, rectus femoris

The muscle that raises the corners of the mouth as when smiling is the ________ muscle.

zygomaticus major

Which of the following controls adduction at the shoulder?

teres major

Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass?

testosterone

A lever consists of

a rigid structure and a fulcrum

The powerful abductor muscle of the upper arm is the

deltoid

Which of the following best describes the term Z line?

thin filaments are anchored here