The Peripheral Nervous System - Chapter 13
How many of the pairs of cranial nerves originate from the brain stem?
All but two of the twelve pairs of cranial nerves arise from the brain stem. The other two pairs arise from the forebrain.
The brachial plexus can contain fibers from
The brachial plexus is formed from the intermixing of the ventral rami of the inferior four cervical nerves (C5-C8) and most of T1 ramus. Additionally, it often receives fibers from C4, T2, or both.
Which branch of a spinal nerve contain autonomic fibers?
The rami communicantes
The rami communicantes are joined to the base of the ventral rami of spinal nerves in the thoracic region and contain autonomic nerve fibers.
Which cranial nerve is NOT involved with the eye?
The oculomotor, trochlear, and abducens innervate the extrinsic muscles of the eye. The optic is the sensory nerve of vision and is actually a brain tract.
Which cranial nerve is purely sensory?
The cranial nerves associated with sensory organs are considered purely sensory.
Which cranial nerve has a name that means "the wanderer"?
The vagus nerve is the only cranial nerve to extend beyond the head and neck to the thorax and abdomen.
Which fiber in the skeletal muscle are stimulated only by the degree of stretch?
Type II fibers are stimulated only by the degree of stretch, whereas type Ia fibers are stimulated both by the rate and degree of stretch. Gamma fibers maintain the sensitivity of the spindle, and alpha fibers stimulate extrafusal muscle fibers.
Which region is NOT a nerve plexus?
The thoracic rami
Except for T1-T12, all ventral rami branch and join one another lateral to the vertebral column forming complicated nerve plexuses.
Which nerve does NOT arise from the brachial plexus?
The phrenic nerve
The phrenic nerve arises from cervical plexus and receives its major input from C3 and C4.
Which receptor is considered a free dendritic ending?
Tactile (Merkel's) discs
Tactile (Merkel's) discs are composed of free dendritic endings associated with Merkel cells and are classified as free dendritic endings.
Which reflex is particularly important in maintaining balance?
Crossed extensor reflexes
Crossed extensor reflexes are particularly important in maintaining balance.
Which reflex would test the integrity of L4 to S2?
Drawing a blunt object downward along the lateral aspect of the foot causes downward curling of the toes
The reflex known as the plantar reflex and used to test the integrity of the spinal cord from L4 to S2 and determines whether the corticospinal tracts are functioning properly.
Collections of neuron cell bodies associated with nerves in the peripheral nervous system are known as:
Ganglia are collections of neuron cell bodies associated with nerves in the PNS.
The lowest level of the motor hierarchy is the:
The lowest level of motor hierarchy is the segmental level.
Reflexes that result from practice or repetition are known as:
In addition to basic, inborn types of reflexes, there are learned, or acquired, reflexes that result from practice or repetition.
The muscle fiber or gland cell that responds to the efferent impulses is known as the:
he muscle fiber or gland that responds by contracting or secreting is known as the effector.
Which cranial nerve controls chewing food?
The trigeminal nerve controls muscles of mastication.
Which nerve controls the quadriceps muscle group?
The femoral nerve serves the muscles of the anterior thigh.
Which is a pain transmitter?
If pain continues for a long time, what develops?
Which receptor is also known as lamellated corpuscles?
Which receptor is stimulated by a substance known as capsaicin?
The two-point discrimination test tests the patient's _______________ ability of sensory perception.
Wallerian degeneration is the:
degeneration of the axon and myelin sheath distal to the injury site caused by the lack of nutrients.
Hilton's law states that:
any nerve serving a muscle that produces a movement at a joint does innervate the joint and the skin over the joint.
Which is an example of an intrinsic reflex?
Pulling the hand away from a hot object
What area of the brain is responsible for precisely starting or stopping movement?
The cerebellum controls precisely starting or stopping movement.
If a patient has difficulty using the "pincher grasp" to pick up small objects, which nerve is injured?
The patient had difficulty using the "pincher gasp" to pick up small objects would have damage to the median nerve.