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

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