Question

question 24
1 pts
visceral effectors are innervated by sympathetic fibers.
true
false
question 25
1 pts
which of the following is not true?
the spinal cord does not completely fill the spinal cavity.
the spinal cord extends from the foramen magnum to the first lumbar vertebra.
one bundle of nerve fibers (nerve roots) projects from each side of the spinal cord.
the spinal cord has anterior and posterior grooves that almost divide the cord into symmetrical halves.
question 26
1 pts
spinal nerves are _____ fibers.
only sensory
only motor
completely autonomic
motor and sensory

Explanation:

• Question 24: Visceral effectors (smooth muscle, cardiac muscle, glands) are innervated by both sympathetic and parasympathetic fibers (autonomic nervous system). So the statement "Visceral effectors are innervated by sympathetic fibers" is too narrow as it ignores the parasympathetic innervation.
• Question 25:
• The spinal cord does not completely fill the spinal cavity (there is space for cerebro - spinal fluid).
• The spinal cord extends from the foramen magnum to the first or second lumbar vertebra.
• There are two bundles (anterior and posterior nerve roots) that project from each side of the spinal cord (not one).
• The spinal cord has anterior and posterior grooves (anterior median fissure and posterior median sulcus) that almost divide it into symmetrical halves.
• Question 26: Spinal nerves are mixed nerves. They contain both sensory (afferent) fibers that bring information to the spinal cord and motor (efferent) fibers that carry information away from the spinal cord. They are not only sensory, only motor, or completely autonomic (autonomic is a part of the motor function but not the whole story for spinal nerves).

Answer:

• Question 24: False
• Question 25: One bundle of nerve fibers (nerve roots) projects from each side of the spinal cord.
• Question 26: motor and sensory