Etsey Exam #2 Flashcards
Which of the following structures propagates action potentials from the surface of a muscle fiber to its interior?
The sarcomeres
The sarcoplasmic reticulum
The endomysium
The myofibrils
The T tubules
The T tubules
All muscle types will respond to an electrical stimulus because all muscle cells are _________.
excitable
contractile
striated
involuntary
isometric
excitable
Skeletal muscle is called ___________ because it is usually subject to conscious control.
excitable
contractile
striated
voluntary
isometric
voluntary
Which of the following is considered to be a myofibril regulatory protein?
G actin
Titin
Troponin
Myosin
Calcium
Troponin
Which of the following structures store calcium ions that trigger skeletal muscle contraction?
Mitochondria
Myofibrils
T tubules
Sarcoplasmic reticulum
Synaptic vesicles
Sarcoplasmic reticulum
Which of the following contains overlapping thick and thin myofilaments?
A band
H band
I band
M line
Z discs
A band
In a relaxed muscle fiber, what blocks the active sites on actin?
Tropomyosin
Troponin
Calcium ions
Myosin heads
Elastic fibers
Tropomyosin
Which of the following is predominantly made up of myosin?
G actin
F actin
The thin myofilament
The thick myofilament
The elastic filament
The thick myofilament
Which protein acts as a calcium receptor in skeletal muscle?
F actin
Tropomyosin
Troponin
Titin
Dystrophin
Troponin
If a person is injected with a toxin that blocks acetylcholine receptors, which of the following will occur?
The sarcolemma will be constantly stimulated, and muscles will continually contract.
Spastic paralysis will result.
The toxin will have no effect on muscle action.
Stimulation of the sarcolemma will not be possible, and muscles will be paralyzed.
The person will develop myasthenia gravis.
Stimulation of the sarcolemma will not be possible, and muscles will be paralyzed.
The absence or inhibition of acetylcholinesterase at a synapse would lead to __________.
flaccid paralysis
continued muscle contraction
atrophy
numbness
muscle wasting
continued muscle contraction
Which of the following is considered to be the “functional unit” of skeletal muscle fibers?
The sarcomere
The Z disc
The myofilaments
The sarcoplasmic reticulum
The neuromuscular junction
The sarcomere
Which of the following structures is found at each end of a sarcomere?
A sarcoplasmic reticulum
An I band
An H band
An A band
A Z disc
A Z disc
What comprises a motor unit?
One neuromuscular junction
The distance from one Z disc to the next
One thick myofilament and all thin myofilaments with which it forms cross-bridges
One nerve fiber and all the muscle fibers innervated by it
One myofibril of a muscle fiber
One nerve fiber and all the muscle fibers innervated by it
To stimulate muscle contraction, acetylcholine is released from the ___________ into the synaptic cleft.
synaptic vesicles
postsynaptic membrane folds
sarcoplasmic reticulum
sarcolemma
terminal cistern
synaptic vesicles
What is a loss of muscle mass from a lack of activity called?
Myopathy
Dystrophy
Apathy
Atrophy
Tetanus
Atrophy
Slow oxidative fibers have more __________ and less __________ than fast glycolytic fibers.
glycogen; myoglobin
ATP; mitochondria
lactic acid; ATP
myoglobin; lactic acid
capillaries; mitochondria
myoglobin; lactic acid
Which of the following is a connective tissue sheath that surrounds an individual muscle fiber?
Epimysium
Fascia
Tendon
Endomysium
Perimysium
Endomysium
What is the longest muscle in the human body?
Sartorius
Rectus abdominis
Gastrocnemius
Rectus femoris
Triceps brachii
Sartorius
What is the Latin term for “short”?
Brevis
Punctum
Minimus
Minor
Brevis
After taking their wedding vows, a bride and groom often ceremonially use which of the following muscles before walking away from the altar?
Depressor anguli oris
Orbicularis oris
Levator labii superioris
Platysma
Quadriceps femoris
Orbicularis oris
Based on its name, how would you describe the rectus femoris?
Triangular and in the thigh
Diagonal and in the calf
Straight and in the thigh
Straight and in the calf
Diagonal and in the thigh
Straight and in the thigh
Which cells would you expect to increase in number during an infection of the CNS?
Oligodendrocytes
Astrocytes
Microglia
Ependymal cells
Schwann cells
Microglia
Which of the following is/are found only in the PNS?
Nerves
Astrocytes
Myelin
Lipofuscin
Unmyelinated axons
Nerves