Chapter 13 The Peripheral Nervous System ( Q&A )

Match the following nerves with the structures they innervate. _______ Phrenic nerve _______ Median nerve _______ Femoral nerve _______ Tibial nerve _______ Radial nerve _______ Intercostal nerves _______ Common fibular nerve _______ Musculocutaneous nerve A. motor to the triceps brachii muscle and muscles in the forearm that extend to the hand; sensory from the posterior hand B. motor to the muscles in the anterior arm that flex the forearm; sensory from skin over the lateral forearm C. motor the muscles in the anterior and lateral leg that evert and dorsiflex the foot; sensory from the skin of the anteroinferior leg D. motor to the diaphragm muscle E. motor to the muscles in the anterior thigh extend the knee; sensory from the skin over the anterior thigh and leg F. motor to the hamstring muscles that extend the thigh and flex the leg, muscles of the leg that plantar flex the foot, and muscles of the foot; sensory from the skin over the posterior and lateral leg and foot G. motor to the muscles between the ribs and the abdominal muscles; sensory from the skin over the abdomen H. motor to the muscles in the forearm that flex the hand, certain intrinsic hand muscles; sensory from the skin of the anterior hand

( D )Phrenic nerve ( H )Median nerve ( E)Femoral nerve ( F )Tibial nerve ( A )Radial nerve ( G )Intercostal nerves ( C )Common fibular nerve ( B )Musculocutaneous nerve

The lower motor neurons that innervate contractile skeletal muscle fibers are called: A. a-motor neurons B. b-motor neurons C. upper motor neurons D. y-motor neurons

A

Place the following sequence of events for the detection of somatic sensation in the proper order. Place a 1 by the first event, a 2 by the second event, and so on. A. ______ the central process transmits the action potential to a second-order sensory neuron in the CNS B. ______ the action potential is transferred to the central process in the posterior root ganglion C. ______ the stimulus triggers an action potential D. ______ the signal is transferred to other CNS sensory neurons for eventual perception and interpretation E. ______ the action potential is propagated along the peripheral process of the neuron

A. 4 B. 3 C. 1 D. 5 E. 2

First, write the Roman numeral that corresponds to each named cranial nerve (after the abbreviation CN). Second, match the cranial nerve with its correct function from the column on the right. CN _______ __________ Vestibulocochlear nerve CN _______ __________ Trigeminal nerve CN _______ __________ Hypoglossal nerve CN _______ __________ Abducens nerve CN _______ __________ Vagus nerve CN _______ __________ Olfactory nerve CN _______ __________ Accessory nerve CN _______ __________ Oculomotor nerve CN _______ __________ Facial nerve CN _______ __________ Optic nerve CN _______ __________ Glossopharyngeal nerve CN _______ __________ Trochlear nerve A. motor to the lateral rectus muscle B. motor to the muscles of facial expression; lacrimation, salivation, taste to the anterior 2/3 of the tongue C. sense of smell D. motor to the muscles for swallowing; salivation, taste to the posterior 1/3 of the tongue, somatic sensation from the throat E. senses of hearing and equilibrium F. motor to the superior oblique muscle G. motor to the tongue H. motor to the sternocleidomastoid and trapezius muscles I. sense of vision J. motor to muscles of swallowing and speaking; parasympathetic innervation to thoracic and abdominal viscera, sense of taste from the throat K. sensory to the face; motor to the muscles of mastication L. motor to 4 of 6 extrinsic eye muscles; constricts the pupil, changes the shape of the lens, opens the eyelid

A. CN VIII vestibulocochlear nerve e B. CN V trigeminal nerve k C. CN XII hypoglossal nerve g D. CN VI abducens nerve a E. CN X vagus nerve j F. CN I olfactory nerve c G. CN XI accessory nerve h H. CN III oculomotor nerve l I. CN VII facial nerve b J. CN II optic nerve i K. CN IX glossopharyngeal nerve d L. CN IV trochlear nerve f

Mark the following statements as true or false. If a statement is false, correct it to make a true statement. A. The somatic sensory division of the PNS detects sensory stimuli from the organs in the thoracic and abdominopelvic cavities. B. The somatic motor division of the PNS consists of lower motor neurons that directly innervate skeletal muscle fibers. C. The visceral motor division is also known as the autonomic nervous system and maintains homeostasis of many physiological variables. D. The term nerve is the equivalent of the term neuron. E. There are 31 pairs of spinal nerves and 12 pairs of cranial nerves.

A. False - the visceral sensory division of the PNS detects sensory information form the organs in the thoracic and abdominopelvic cavities B. True C. True D. False - the term nerve is not the equivalent of the term neuron (nerves are composed of the axons of many neurons) E. True

Define each of the following terms in your own words, using 20 or fewer words. A. Peripheral nerve B. Nerve plexus C. Posterior root ganglion

A. Peripheral nerve: a collection of axons, connective tissue sheaths, and blood vessels B. Nerve plexus: a network of nerves that innervates a specific body region C. Posterior root ganglion: a collection of cell bodies of sensory neurons located in the posterior root inside the spinal cord

Mark the following statements as true or false. If a statement is false, correct it to make a true statement. A. The simple stretch reflex is monosynaptic reflex with only a single synapse in the spinal cord between the sensory and motor neurons. B. The Golgi tendon organs detect stretch in a simple stretch reflex. C. A flexion reflex is monosynaptic reflex with only one synapse in the spinal cord. D. The crossed-extension reflex occurs simultaneously with the simple stretch reflex.

A. True B. False - muscle spindles detect stretch in a simple stretch reflex C. False - a simple stretch reflex is a monosynaptic reflex with only one synapse in the spinal cord D. False - the crossed-extension reflex occurs simultaneously with the flexion reflex

First - order somatic sensory neurons are ____________ neurons whose cell bodies are located in the _____________. A. multipolar, posterior horn B. pseudounipolar, posterior root ganglion C. bipolar, anterior horn D. pseudounipolar, posterior horn

B

Merkel cell fibers, tactile corpuscles, Ruffini endings, and lamellated corpuscles are all types of: A. nociceptors B. mechanoreceptors C. photoreceptors D. chemoreceptors

B

Which of the following is the correct order of events of a reflex arc? A. stimulus detection and delivery ----> motor response ----> integration in the CNS B. motor response ----> stimulus detection and delivery ----> integration in the CNS C. stimulus detection and delivery ----> integration in the CNS ----> motor response D. integration in the CNS ----> motor response ----> stimulus detection and delivery

C

A receptor potential: A. always leads to an action potential B. never leads to an action potential C. causes hyperpolarization of the neuron D. leads to an action potential if the stimulus is strong enough

D

Why is visceral pain often perceived as cutaneous pain?

Many spinal nerves carry both somatic and visceral neurons, so visceral sensations travel along the same pathways as somatic sensations. This causes referred pain.

Which cranial nerves are sensory only, primarily motor, and mixed?

Sensory Only - I, II, VIII Primarily Motor - III, IV, VI, XI, XII Mixed - V, VII, IX, X

Which two cranial nerves mediate the gag reflex?

The sensory arm is mediated by the glossopharyngeal nerve, and the motor arm is mediated by the vagus nerve.

How do upper and lower motor neurons differ?

Upper motor neurons are located in the motor areas of the cerebral cortex,; they do not directly contact skeletal muscle fibers. They are involved in making the "decision" to move, as well as planning and monitoring movement. Lower motor neurons directly stimulate skeletal muscle fibers to contract, but they are not involved in the planning of movement.

List and describe the basic steps involved in producing movement, beginning with the upper motor neurons in the cerebral cortex.

Upper motor neurons select a motor program. They stimulate the caudate nucleus and putamen, which inhibit the globus pallidus. This allows the thalamus to stimulate the upper motor neurons, which in turn stimulate lower motor neurons. The lower motor neurons then stimulate muscle fibers to contract.

Fill in the Blanks: A spinal nerve divides into a(n) ____________ that serves the anterior side of the body and the limbs and a(n) _____________ that serves the posterior side of the body.

anterior ramus, posterior ramus

Fill in the Blanks: ____________ detect the degree to which a muscle is stretched, whereas ____________ detect the force of a muscle contraction.

muscle spindles, Golgi tendon organs