A motor unit refers to
a. a single motor neuron plus all of the muscle fibers it innervates
b. a single muscle fiber plus all of the motor neurons that innervate it
c. all of the motor neurons supplying a single muscle
d. a pair of antagonistic muscles
e. a sheet of smooth muscle cells connected by gap junctions
A
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On axial sectional images of the wrist, the flexor tendons, carpal tunnel, and median nerve are all seen anteriorly.
Answer the following statement true (T) or false (F)
Which panel in the figure shows an example of the movement termed inversion?
a) B b) D c) E d) F e) G
Which of the following is incorrect pertaining to the thoracic part of the vertebral column?
A) includes the most frequently fractured vertebra B) presence of costal facets C) Most vertebrae have horizontal spinous processes. D) articular facets that are most effective at limiting flexion E) Inferior vertebrae have mammillary processes.
Four species of salamanders in the genus Desmognathus form a streamside salamander guild in the mountains of North Carolina. The four species are found at different distances from the stream, as listed in the table
Suggest one or more hypotheses to explain the relationship between the body sizes of these species and the distance each is found from the water. What prediction can you make for each hypothesis, and how could you test that prediction? Species D. quadramaculatus D. monticola D. ochrophaeus D. anaeus Adult body length 100-175 mm 83-125 mm 70-100 mm 44-57 mm Distance from stream Less than 10 cm Less than 1 m 1-4 m 4-7 m