chapter 7

Question 1

each muscle contains a collection of _________, arranged into bundles known as ____________.

Answer 1

muscle fibers

fascicles

Question 2

muscle fibers contain bundles of smaller __________

Answer 2

myofibrils

Question 3

the basic functional units of a muscle fibers attached to each end are __________

Answer 3

sacromes

Question 4

the muscle also has proprioceptive (position sense) organs to provide ___________ to the nervous systems about its contraction and load.

Answer 4

sensory feedback

Question 5

muscles that work in opposing pairs are called ___________

Answer 5

antagonistic muscles

Question 6

______, such as triceps, extend a joint,

whereas _____, such as biceps, contract it.

Answer 6

extensors

flexors

Question 7

type I fibers are specialized for _______ at the expense of ______ and _________

type II fibers are specialized for ________ and ________ at the expense of quickly becoming fatigued

Answer 7

endurance, power and speed

power and speed

Question 8

motor neurons make contact with muscle fibers at a specialized structure called the _______________

Answer 8

neuromuscular junction

Question 9

how does the contact at the neuromuscular junction resemble a synapse?

Answer 9

• the axon of a motor neuron ends in a flattened bulb/motor neuron terminal, which is analogous to the presynaptic axon terminal at a connection between two neurons
• the endplate on a muscle fiber is analogous to the postsynaptic cell membrane of a neuron
• the terminal and endplate membranes are separated by a narrow space, much like a neuron-to-neuron synapse

Question 10

what happens when acetylcholine neurotransmission is blocked?

Answer 10

muscles can weaken or paralyze

Question 11

______ and other medicines of its type block the binding of acetylcholine to its receptors on the muscle fiber endplates. They are derived from the ingredient _________.

Answer 11

rocuronium

curare

Question 12

A _______ consists of alpha motor neuron and all of the muscle fibers it innervates.

Answer 12

motor unit

Question 13

____________ detect sudden muscle stretch

Answer 13

proprioceptors

Question 14

the anaerobic bacterium, Clostridium Tentani also produces a potent toxin, ________, which prevents the release of inhibitory neurotransmitter, with similar lethal effects.

Answer 14

tetanospasmin

Question 15

At the level of the medulla, the descending axon bundles of the corticospinal tract are called the _________

the region where the axons cross over to the contralateral sides is called the __________

Answer 15

pyramids

pyramidal decussation

Question 16

the rubrospinal tract sends input from the _________ of the brainstem to control movements of the limbs

Answer 16

red nuclei

Question 17

the ___________ of the brainstem sends input to the spinal cord via the vestibulospinal tract

Answer 17

vestibular nuclei

Question 18

the most elaborate forms of motor control rely on the extensive motor circuitry of the _________, _____________, and ___________.

Answer 18

cerebrum, basal ganglia, and cerebellum

Question 19

what are recognized symptoms of cerebellar injury?

Answer 19

impairments in coordination, rhythm, magnitude, accuracy, and timing of movements in various parts of the body

Question 20

in most species, locomotion requires _____ rather than _______ movements of the left and right sides of the body

Answer 20

alternating

simultaneous

Question 21

_________ are excitatory interneurons that coordinate b/wn ipsi- and contralateral innervation

Answer 21

local circuits

Question 22

type I fibers are specialized for _________ at the expense of ______ and ______

Answer 22

endurance

speed and power

Question 23

type II fibers are specialized for _____ and _______ at the expense of being quickly ______

Answer 23

speed and power

fatigued

Question 24

________ and other medications of its type block the binding of acetylcholine to its receptors on the muscle fiber endplate, preventing muscle contraction even if the motor neurons fire.

Answer 24

Rocuronium

Question 25

At the neuromuscular junction, the released acetylcholine is broken down by an enzyme in the synaptic cleft, called ____________.

Answer 25

acetylcholinesterase

Question 26

the _______ is home to the spinal cord motor neurons/ lower motor neurons

Answer 26

ventral horn

Question 27

Many forms of motor control rely on circuits through the gray matter of the spinal cord. An example is a ___________: if a muscle is stretched suddenly and unexpectedly, it must contract to maintain position.

Answer 27

spinal reflex

Question 28

_______ detect sudden muscle stretch

Answer 28

proprioceptors

Question 29

_________ also produces a potent toxin, tetanospasmin, which prevents the release of inhibitory neurotransmitter, wh

Answer 29

clostridium tetani

Question 30

locomotion requires _______ rather than ______ movements

Answer 30

alternating

simultaneous

Question 31

the most important pathway in humans is the corticospinal tract, which contains axons that travel down from the ________ neurons of the primary motor cortex and connect to the lower motor neurons neurons of the _________

Answer 31

upper motor neurons

spinal cord

Question 32

At the level of the medulla, the descending axon bundles of the corticospinal tract are called the ________.

Answer 32

pyramids

Question 33

The rubrospinal tract sends input from the _______ of the brainstem to control movements of the limbs, particularly of the muscles such as the biceps and quadriceps.

Answer 33

red nuclei

Question 34

the _________ of the brainstem send inputs to the spinal cord via the vestibulospinal tract.

Answer 34

vestibular nuclei

Question 35

the _________ of the brainstem send inputs to the spinal cord via the vestibulospinal tract.

Answer 35

vestibular nuclei

Question 36

what are inputs to the spinal cord via the vestibulospinal tract important for?

Answer 36

coordinating balance movement of the head, neck, trunk, and proximal limbs

Question 37

the tectospinal tract sends inputs from the spatial localizing systems of the midbrain’s _______ to the spinal cord to help coordinate movements for capturing or avoiding moving targets in the surrounding environment.

Answer 37

tectum

Question 38

the _________ is often injured in cerebral palsy

Answer 38

corticospinal tract

Question 39

Several types of interneurons complete the circuitry of the cerebellum. _______ and _______ lie in the molecular layer

Answer 39

basket cells and stellate cells

Question 40

What are the 3 layers of the cerebellar cortex?

Answer 40

1) an inner granule cell layer, packed with tiny neurons that make up most of the cerebellar population
2) a middle Purkinje cell layer, composed of a single thin layer of the large Purkinje cells that integrate information from the other neurons and send output back to the rest of the nervous system
3) an outer molecular cell layer: a communication zone filled with the axons of the granule cells, the dendrites of Purkinje cells, and various forms of small interneurons

Question 41

the __________ nucleus is the cerebellum’s main input nucleus

Answer 41

inferior olivary

Question 42

__________ fibers wrap around the Purkinje cells near the cell body and axon rather than the dendrites, providing powerful excitatory input that varies in time to modulate Purkinje cell activity

Answer 42

climbing fibers

Question 43

_______ cells form connections from the parallel fibers back to the granule cells

Answer 43

Golgi cells