Deck 3: Muscle Physiology and Motor Control

Question 1

Inhibitory synapses result in a ________________ of the postsynaptic membrane.

A) depolarization
B) repolarization
C) hypopolarization
D) hyperpolarization

Answer 1

hyperpolarization

Question 2

________________ function as a neural bridge between the upper and lower motor neurons.

A) Alpha motor neurons
B) Interneurons
C) Gamma motor neurons
D) Afferent neurons

Answer 2

Interneurons

Question 3

Motor neurons receive synaptic connections from __________ of other neurons.

A) a couple
B) tens
C) hundreds
D) thousands

Answer 3

thousands

Question 4

Upper motor neurons are best described as being located in:

A) the ventral horn gray matter
B) the ventral horn white matter
C) the cerebral cortex and spinal cord
D) only in the lateral and medial corticospinal tracts

Question 5

At rest, potential reactive sites on actin filaments are inhibited from coupling with myosin filaments due to:

A) acetylcholine
B) tropomyosin
C) troponin
D) calcium

Question 6

During a concentric contraction of a muscle fiber, the I-band:

A) becomes smaller
B) becomes larger
C) does not change
D) response is variable

Question 7

Golgi tendon organs transmit __________ information via ______ fibers.

A) afferent; Ia
B) afferent; Ib
C) efferent; Ia
D) efferent; Ib

Question 8

Alpha motor neurons innervate:

A) extrafusal muscle fibers
B) intrafusal muscle fibers
C) muscle spindles
D) Golgi tendon organs

Question 9

Type I muscle fibers are characterized as _________ twitch and _________ in appearance.

A) slow; light
B) fast; light
C) slow; dark
D) fast; dark

Question 10

Within a sarcomere, the H-band contains:

A) actin filaments
B) myosin filaments
C) both actin and myosin filaments
D) tropomyosin

Question 11

Intracellular ions are predominantly negative inside the cell.

Question 12

The thin connective tissue surrounding the muscle is known as the:

A) endomysium
B) perimysium
C) epimysium
D) fasciculi

Question 13

Under resting conditions when no action is occurring, the resting membrane potential is best described as:

A) negative
B) positive
C) neutral-neither negative or positive
D) in a constant state of flux

Question 14

Efferent receptors provide accurate and timely information about the status of each body part and the state of the environmental surroundings.

Question 15

To increase the amount of tension/force a muscle can generate:

A) It is advantageous to recruit solely the small motor units.
B) The body responds by recruiting a greater number of motor units.
C) The frequency of stimulation of individual motor units is decreased.
D) The body responds by recruiting a few number of motor units.

Question 16

_____________ is a syndrome dominated by sustained muscle contractions.

A) Atonia
B) Dystonia
C) Hypotonia
D) Hypertonia

Question 17

The entire process from afferent stimulation to motor response occurs within:

A) nanoseconds
B) microseconds
C) milliseconds
D) seconds

Question 18

Type II muscle fibers are ___________ in diameter and generate _________ force when compared with type I muscle fibers.

A) small; less
B) small; more
C) large; more
D) large; less

Question 19

A sarcomere lies between two:

A) A-bands
B) Z-discs
C) H-bands
D) I-bands

Question 20

The arrival of a nerve impulse at the myoneural junction initially causes a release of _____________ from the presynaptic ending.

A) acetylcholine
B) calcium
C) cholinesterase
D) curare

Question 21

Actin filaments are thicker than myosin filaments.

Question 22

Motor control utilizes the hierarchical contributions from many systems to orchestrate coordinated movement.

Question 23

Muscles that are responsible for fine motor control exhibit small muscle to nerve fiber ratios.

Question 24

The cell body and axon of a lower motor neuron originate in the ventral horn of the spinal cord.

Question 25

After a lower motor neuron injury, hypertonicity is likely to be evident.

Question 26

In a neurologically intact adult, co-activation of muscle groups is infrequent, particularly when learning a new task.

Question 27

Within the nervous system, white matter is associated with a high concentration of myelin.

Question 28

When a cell's membrane depolarizes, it becomes more negative.

Question 29

Neural connections at the spinal cord level are associated with automatic control and rapid responses.

Question 30

The sarcoplasmic reticulum runs perpendicular to the myofibril.

Question 31

Muscle spindles provide afferent information to the nervous system related to muscle length.

Question 32

Golgi tendon organs are thought to provide information directly related to the position of a joint.

Question 33

Muscle tone is influenced by both the intrinsic mechanical properties of the muscle as well as the level of excitability of the entire pool of motor neurons that control the respective muscle.

Question 34

Postural muscles contain a high proportion of type I muscle fibers.

Question 35

The peripheral nervous system is composed of the brain and spinal cord.

Question 36

Maintaining one's equilibrium is an exclusive function of the vestibular system.