AP 7th edition chapter 7

Regarding muscle fiber elongation,

gravity may help lengthen a muscle fiber after elongation.

Which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur?

incomplete tetanus

The area between Z lines is the

sarcomere.

The insertion of the anterior part of the frontalis muscle is the

skin of the eyebrow and the bridge of the nose.

A person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more ________ in his or her leg muscles.

slow fibers

Nonstriated, involuntary muscle is

smooth.

As a skeletal muscle contraction is initiated, acetylcholine binding alters the motor end plate membrane's permeability to

sodium ions.

Which muscle is not attached in some way to the scapula?

sternocleidomastoid

Structure B

stores calcium

Creatine phosphate serves to

supply energy to synthesize ATP.

Acetylcholinesterase is found within the

synaptic cleft.

The muscle that inserts on the coronoid process of the mandible is the

temporalis

Tropomyosin strands are held in position by which of the following?

troponin molecules

Each myofibril consists of approximately ________ sarcomeres.

10,000

Place these steps of muscle contraction in the correct order. 1. Action potential is generated along the sarcolemma 2. Nerve impulse arrives at synapse 3. Calcium is released into muscle cell cytoplasm 4. Acetylcholine is produced 5. Actin and myosin molecules continuously cross-link, with actin molecules being pulled inward

2, 4, 1, 3, 5

The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of

ATP

Which of the following is one of the steps that ends a contraction?

Acetylcholine is broken down by acetylcholinesterase.

Which muscle is not part of the rotator cuff set of muscles?

biceps brachii

The muscle that would be used to blow air into a trumpet or a clarinet is the

buccinator.

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

calcium ions

Which statement regarding isometric contractions is true?

The tension produced never exceeds the load.

During which phase is the stimulus frequency so high that the relaxation phase is eliminated?

complete tetanus

The striated appearance of skeletal muscle results from

actin and myosin arrangement.

Myofibrils are made primarily of

actin and myosin.

Structure I is composed of

actin and myosin.

Which of the following terms is a descriptive word for a muscle's action?

adductor

A resting muscle generates most of its ATP by

aerobic respiration

Smooth muscle cells

are spindle-shaped.

The ________ contains vesicles filled with acetylcholine

axon terminal

Which muscle would not move the scapula?

erector spinae

Structure J represents a

myofibril.

Structure G is composed of

myosin.

The difference in the action when comparing the biceps brachii to the flexor carpi radialis, is

one muscle flexes the hand at the wrist and the other flexes the entire forearm.

The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called the

oxygen debt.

Which of the following inserts into a tendinous sheet, rather than a bone?

palmaris longus

You are lying on the floor with your feet flat and your knees up practicing your abdominal crunches. You raise your upper body to the ceiling, up and down. What muscles are you using to the greatest extent?

transverse abdominis

Which muscle inserts on the clavicle and the acromion and spine of the scapula?

trapezius

A single stimulus-contraction-relaxation sequence in a muscle fiber is known as a(n)

twitch.

Exhaustion of energy reserves or decline in pH due to production and dissociation of lactic acid causes

muscle fatigue

After death, rigor mortis lasts until

myofilaments are broken down.

Structure E is the

sarcolemma.

Muscle cells

can only contract.

The specialized sarcolemma that contains acetylcholine receptors is the

motor end plate.

Neurotransmitters that cause skeletal muscle contraction are normally stored in

motor neuron axon terminals

Which muscle extends the elbow during the action of push-ups?

triceps brachii

Label A is pointing to

T tubules.

The enzyme acetylcholinesterase causes acetylcholine to

break down.

The active sites on actin molecules are usually covered up by other molecules. What is the critical material required to uncover the active sites on the actin molecules that will then bind to myosin heads?

ATP

Which of the following is characteristic of cardiac muscle?

Cardiac muscle cells are striated.

Which of the following occurs when glycolysis produces pyruvate faster than it can be used by the mitochondria?

Lactic acid is produced.

Why do individual muscle twitches have to be added together, as in summation or tetanus?

Multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle.

Which statement regarding "heat loss" is true?

Muscle contractions play an important role in the maintenance of normal body temperature.

Which of the following is the origin of the pectoralis minor?

anterior surfaces of ribs 3-5

Which of the following is a muscle that originates from the zygomatic arch and functions in elevating the mandible?

masseter

The structures labeled F are the

mitochondria.

The triad, seen as structure D, is composed of

the cisterna of the sarcoplasmic reticulum along with the T tubules.

Structure H is the

thin myofilament.

What is the function of the transverse tubule?

to transmit electrical impulses to the cell's interior

Smooth muscle

uses primarily aerobic metabolism.

Regarding lactic acid regulation, which cells in the body consume extra oxygen and produce ATP for the conversion of excess lactate absorbed from the blood back to glucose?

liver cells

During activities requiring aerobic endurance,

most of the muscle's energy is produced in mitochondria.

The less-movable end of a skeletal muscle is the

origin.

Choose the correct statement regarding motor units.

A motor neuron may control only two or three muscle fibers of the eye muscle(s).

Which statement regarding the relaxation phase of a muscle twitch is true?

Muscle tension falls to resting levels.

Which of the following is true about red muscles?

Red muscles are slower than white muscles.

Which of the following is an accurate characteristic of slow fibers?

Resting slow muscle fibers contain oxygen reserves, bound to myoglobin.

A muscle that inserts on the radial tuberosity or the ulnar tuberosity is most likely involved in

elbow flexion

Which of the following describes the action of the trapezius?

elevates, adducts, depresses, or rotates the scapula

A layer of collagen fibers that surrounds an entire muscle is called

epimysium.

Fast fibers

have high glycogen reserves.

Skeletal muscle fibers differ from "typical cells" in that these muscle fibers

have many nuclei.

The term used to describe muscular growth in response to usage is

hypertrophy.

Glycolysis

is an anaerobic process.

"Anaerobic endurance"

is exemplified by contractions of fast muscle fibers.

Calcium ions are released from the sarcoplasmic reticulum during the ________ phase of contraction.

latent

Which of the following inserts into the intertubercular groove of the humerus and acts to extend, adduct, and rotate the shoulder?

latissimus dorsi

Which of the following originates from the cartilages of ribs 2-6, the sternal body, and the clavicle?

pectoralis major

A sheath of connective tissue surrounding a bundle of striated muscle fibers is called

perimysium

Muscle fascicles are separated by

perimysium.

The muscle that originates from the superior surface of the pubis around the symphysis is the

rectus abdominis.

Botulism

results from a bacterial toxin that prevents the release of acetylcholine at the axon terminals.

The heart has to be able to regulate its contractions. Heart muscle, unlike skeletal muscle, cannot go into a tetanus. This is because

the heart muscle has to be able to consistently contract and pump blood in a controlled fashion.

Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to

the sarcoplasmic reticulum.

During moderate activity, which of the following is true regarding muscle metabolism?

Glucose and fatty acids are catabolized.

The area of the sarcomere that is the light region between two successive A-bands is the

I band.

The region of a sarcomere containing myosin, going from one end of the myosin molecules to the other end of the myosin molecules, is the

I band.

Which of the following statements describes how muscles help maintain homeostasis?

Skeletal muscle contractions help maintain body temperature

Which statement regarding skeletal muscle is true?

Skeletal muscles contain blood vessels.

The deltoid acts to

abduct the arm.

Upon the nerve impulse arriving at the axon terminal,

acetylcholine is released.

Which of the following muscles is named for its shape?

deltoid

Which of the following muscles functions to maintain an erect spinal column and head?

erector spinae

Which muscle(s) would produce a twisting of the upper body?

external and internal oblique muscles

A muscle ________ contains a sarcolemma, sarcoplasm, myofilaments, and myofibrils.

fiber

Which of the following occurs as a result of motor units in a particular muscle being always active, even though their contractions do not produce enough movement to cause contraction?

muscle tone

Looking at the muscle name sternocleidomastoid, you would identify that this muscle is located in the area of the

neck.

In infants, which muscle allows for the mouth to form a tight fit around the nipple during suckling at the breast?

orbicularis oris

The terminal cisternae are structural features of the

sarcoplasmic reticula.

Structure C is the

sarcoplasmic reticulum.

The skeletal muscles store calcium ions in the terminal cisternae of the

sarcoplasmic reticulum.