Chapter 7: The Muscular System

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.

Botulism

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

Upon the nerve impulse arriving at the axon terminal,

acetylcholine is released.

The enlarged areas of the sarcoplasmic reticulum near the T tubules are the

Terminal cisternae

Given these events: 1. The passage of an action potential along a T tubule triggers the release of calcium ions from the sarcoplasmic reticulum 2. When an action potential arrives at the axon terminal, acetylcholine (Ach) is released into the synaptic cleft 3. The binding of ACh to receptors on the motor end plate leads to the generation of an action potential in the sarcolemma 4. Calcium binds to troponin

2,3,1,4

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

Identify the correct sequence of steps in the muscle contraction cycle 1. ATP binds to the myosin head, breaking the link to actin 2. Myosin heads pivot toward the M-line 3. Calcium ions bind to troponin, exposing the active sites 4. Myosin heads bind to the active sites, forming cross-bridges

3,4,2,1

Which of these units contains overlapping actin and myosin myofilaments?

A band

For cross bridge release, it is necessary for __________ to attach to the myosin head.

ATP

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

Calcium ions

Active muscles generate

Carbon dioxide and heat

The end of the muscle that is attached to the more stationary of the two bones is the

The origin

A resting muscle generates most of its ATP by

aerobic metabolism

Which statement regarding isometric contractions is true?

The tension produced is never exceeded

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

Troponin molecules

The connective tissue that covers each muscle fiber

Endomysium

During contraction, muscles shorten __________ , and lengthen __________ .

Forcefully and passively

f the permeability of the motor end plate to Na+ ions increases, the result

Generation of action potential at the sarcolemma

Which of these locations has the ability to break down ATP, which releases energy?

Head of myosin molecule

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

I band

Which of these units contains the Z disk?

I band

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

Incomplete tetanus

A muscle contraction in which the muscle produces an increasing tension, but the length remains constant is a(n)

Isometric contraction

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

Lactic acid is produced

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

Latent

The specialized sarcolemma that contains acetylcholine receptors is the

Motor end plate

Which statement regarding "heat loss" is true?

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

Each muscle cell is called

Muscle fiber

Anaerobic respiration

Produces a oxygen debt

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

Sarcoplamsic reticulum

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

Skeletal muscle contractions help maintain body temperature

Creatine phosphate serves to

Supply energy to synthesize ATP

Acetylcholinesterase is found within the

Synaptic cleft

Muscles that work together to cause a movement are

Synergists