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