01 Oct Which of the following substances is the neurotransmitter released from motor neurons initiating muscle contraction?
Human Anatomy and Physiology I
Question 1Which of the following substances is the neurotransmitter released from motor neurons initiating muscle contraction?
Acetylcholine
Norepinephrine
Dopamine
Acetylcholinesterase
Question 2Which statement best describes a sarcomere?
It provides an anchor for the thick and thin filament
Store and release calcium ions into the cell interior for muscle contraction
It is the smallest contractile unit of a muscle fiber
It is the plasma membrane of the muscle fiber
Question 3Which of the following is the first phase of muscle contraction?
Excitation-contraction coupling
Relaxation
Contraction
Excitation
Question 4Which of the following is true of muscle contraction?
ATP is converted to ADP during a power stroke.
The Z-disks move farther apart during contraction.
The H-zone lengthens during contraction.
The T-tubules release stored sodium and magnesium to initiate an action potential.
Question 5Which of the following directly covers a skeletal muscle?
Endomysium
Epimysium
Sarcolemma
Perimysium
Question 6ATP is needed to release thick and thin filaments so they can reform another cross-bridge.
True
False
Question 7Which statement is NOT true regarding muscle contraction?
Tropomyosin protein covers the binding sites for the thick filament on the actin protein
The sarcoplasmic reticulum stores the calcium ions that are released within the muscle cell
Acetylcholine is the neurotransmitter that binds to the sarcolemma
ATP is needed for the thick filament to bind to the thin filament
Question 8The motor end plate is the:
End of the motor neuron that looks like a bulb shape and releases acetylcholine
Portion of a neuron that contains vesicles of acetylcholine
Open space where neurotransmitters move freely
Depression on the sarcolemma where the synaptic knob fits
Question 9Which statement is true regarding muscle contraction?
Tropomyosin protein binds to the actin protein
ATP is needed to release the thick filament from the thin filament
The T-tubules store the calcium ions within the internal part of the muscle cell
The power stroke occurs when the thick filament binds to the thin filament
Question 10Which of the following is true of skeletal muscle tissue?
A muscle cell is composed of hundreds of musclefibers.
Each cell has a single nucleus.
Skeletal muscle cells have the same shape as smooth muscle cells.
A skeletal muscle fiber typically contains a sarcolemma, t-tubules, and myofibrils.
Question 11Which statement is NOT true regarding muscle contraction?
Actin is the protein on the thin filament that binds to the thick filament
The sarcoplasmic reticulum stores the calcium ions that is released within the muscle cell during contraction
Calcium ions bind to the tropomyosin protein
The thick filament is composed of the myosin protein
Question 12Which structure separates one fascicle from another in a muscle?
Endomysium
Fascia
Perimysium
Epimysium
Question 13
Which choice best describes the function T-tubules have within muscle contraction?
Transmit the action potential deep into the muscle cell
Store and release calcium ions into the cell interior for muscle contraction
Help align the thick and thin filament for contraction
Store glycogen
Question 14
Within the sarcomere, an A-band contains:
Thick filaments only
Thin and thick filaments
Thin filaments only
Neither thin nor thick filaments.
Question 15
A motor unit is all the nerves that innervate all of the muscle fibers of one muscle.
True
False
Question 16Which choice best describes the function of myoglobin?
Stores glycogen
It is a specialized protein on the thin filament
It provides a reserve supply of oxygen for the muscle cell
Assists in attaching the thick filament to the thin filament
Question 17Which of the following passes through the sarcoplasm, causing the sarcoplasmic reticulum to open its “gates”?
ATP
Calcium
Sodium
Action potential
Question 18
Anaerobic respiration produces lactic acid as a by-product but creates more ATP for muscle contraction when compared to aerobic respiration.
True
False
Question 19
Fast oxidative muscle fibers do not fatigue quickly due to its rich supply of myoglobin.
True
False
Question 20
Which of the following proteins blocks the active site on actin during relaxation?
Tropomyosin
Troponin
Actin
Myosin
Question 21Which choice best describes a fascicle?
Bundle of muscle myofibrils
Connective tissue covering around the entire muscle
Bundle of muscle fibers enclosed by connective tissue
Bundle of myofilaments
Question 22
Which factor is required to allow for muscle contraction?
Actin heads bind to troponin filament
Cross bridging of the thick and thin filament
Sodium ions to be present within the muscle fiber’s cytoplasm
Acetylcholine binds to the motor neuron
Question 23
Which of the following substances binds to troponin, which moves tropomyosin off the “active sites”?
Calcium
Sodium
Acetylcholine
ATP
Question 24Which statement is true regarding slow oxidative muscle fibers?
Appears white in color within a specimen
They don’t contain myoglobin
It is fatigue resistance
They can contract only for short period of times
Question 25What statement is true of smooth muscle?
It is found mainly within internal organs such as the bladder and uterus
It only contracts through conscious control
Its contraction is controlled by the same mechanism as skeletal muscle
It has a striated appearance when viewed under a microscope
