chapter 12-13

Which of the following is NOT correct concerning nerves?

Nerves are collection of axons of either sensory or motor neurons but not both. Nerves can be mixed collections of both sensory and motor axons.

A patient reports that she has become completely deaf; she can't hear anything. Thorough tests on her ears indicate that her ears have not been damaged. Additional tests reveal that her deafness has been caused by damage to her ______.

None of the listed responses is correct.

Which of the following regions of the brain stem carries one-way communications that advise the cerebellum of voluntary motor activities initiated by the motor cortex?

PONS The pons is the point at which all information entering or exiting the cerebellum is collected. Descending motor input and ascending sensory input that feed the cerebellum and all cerebellar output enter or exit the cerebellum through several cerebellar peduncles located in the pons.

Which of these statements is NOT correct regarding our limbic system?

Sights often create strong emotional responses. Your sense of smell is more directly attached to your limbic system and is, therefore, more likely to cause emotional responses.

Which of the following statements is correct concerning the spinal cord?

Spinal nerves have mixed motor and sensory function. The ventral roots carry motor commands out of the spinal cord. The dorsal roots carry sensory information into the spinal cord. The spinal nerves represent a fusion of these two elements.

The letter A in the figure indicates which of the following structures?

Thalamus The letter A indicates the thalamus. Remember that the thalamus is composed of left and right bodies.

Which of the following statements about the cerebellum is NOT correct?

The cerebellum generates conscious motor commands.

Which of the following is true of receptors for dynamic equilibrium?

The receptors for dynamic equilibrium respond to rotational forces. The receptor for rotational (angular) movements of the head, called the crista ampullaris, or simply crista, is a minute elevation in the ampulla of each semicircular canal. Perception of these changes in head rotation is sometimes called our sense of dynamic equilibrium.

Why are the waves represented by the number 3 being sensed closer to the oval window than those represented by 4?

The waves at 3 have a higher frequency than 4. The spiral organ (organ of Corti) sorts waves by frequency. Higher frequencies are detected nearer to the oval window, while lower frequencies are detected further down the basilar membrane.

Identify the function of the structures labeled (2) in this image.

They conduct sound waves and amplify the vibrations within the middle ear.

__________ MOSTLY do NOT exhibit the property of adaptation.

Tonic receptors Tonic receptors provide a sustained response with little or no adaptation. Nociceptors and MOST proprioceptors are tonic receptors because of the protective importance of the information.

Phasic receptors adapt quickly to a stimulus. For that reason, they are good at detecting changes instead of constantly signaling the CNS.

True Phasic receptors adapt rapidly; they are good at detecting changes in stimuli, which is more energetically efficient than constantly sending a signal to the CNS.

As the ciliary muscle relaxes, the suspensory ligaments tighten and stretch the lens, allowing for distance vision.

True Sympathetic innervation relaxes the ciliary body. As the muscle relaxes, it pulls on the suspensory ligaments, which put tension on the lens. This allows images that are farther away to focus on the retina.

In general, a primary sensory cortex breaks down sensory input into component parts, while an association cortex makes sense of sensory inputs.

True The primary sensory cortex receives sensory inputs in their cruder forms, while the association cortex helps you understand what the sensory input means.

The term cerebral dominance designates the hemisphere that is dominant for language.

True One cerebral hemisphere or the other "dominates" each of the brain's tasks, and the term cerebral dominance designates the hemisphere that is dominant for language. In most people (about 90%), the left hemisphere has greater control over language abilities, math, and logic.

Identify the type of tract that communicates between the left prefrontal lobe and the left parietal lobe.

association Association fibers communicate between gyri in the same cerebral hemisphere.

After Joe has a stroke, his doctor asks Joe to touch his right pointer finger to his chin, but Joe is unable to move his right hand. However, when the doctor stimulates Joe's pointer finger with a painful stimulus, Joe's muscles quickly move his hand away from the stimulus. The doctor concludes that ______.

based on the doctor's observations, none of the listed answers are correct conclusions Submit

What is the groove indicated by C?

central sulcus

Which part of the brain is the "executive suite" that controls conscious brain activity?

cerebral cortex The cerebral cortex is the "executive suite" of the nervous system, where most of our higher-level decision making occurs. It enables us to be aware of ourselves and our sensations, communicate, remember, understand, and consciously initiate voluntary movements.

What CNS-associated structure is illustrated in this figure?

choroid plexus Note the specific arrangement of glial cells and capillaries as well as the movements of the fluid.

Which structure is NOT matched with its function?

ciliary body: focus the pupil

Aqueous humor forms during capillary filtration in the __________?

ciliary processes (part of the ciliary body). The ciliary process contains capillaries that filter fluid from blood to form the aqueous humor.

Three main levels of neural integration operate in the somatosensory system. Which level involves the spinal cord?

circuit level Processing at the circuit level includes the transmission of action potentials along ascending spinal pathways. These pathways deliver impulses to the appropriate regions of the cerebral cortex for localization and perception of the stimulus.

Which of the following is a characteristic of a coma but is NOT a characteristic of sleep?

continuously reduced mitochondrial activity in brain neurons Mitochondria are cytoplasmic organelles that produce ATP to provide energy for other cellular activities through the consumption of oxygen and glucose. Brain mitochondrial activity during sleep is similar to activity during the waking state, but mitochondrial activity is reduced during a coma.

What term refers to the eyes moving medially to track items close at hand?

convergence Convergence is the medial rotation of the eyes by the medial rectus muscles; this lets the eyes fixate on a close object.

The fibers indicated by B are most associated with which structure(s)?

corpus callosum

Which pair below is incorrect?

cranial Nerve IV: sensory The trochlear nerve is a motor nerve that innervates the superior oblique of the eye.

Which reflex has a contralateral component?

crossed-extensor The crossed-extensor reflex activates opposing actions in the opposite limb. Return to Assignment

Which type of glial cells are shown in this figure?

ependymal cells Specialized ependymal cells participate in the filtration, absorption, and secretory processes that create cerebrospinal fluid.

At age 79, Mrs. X is diagnosed with a disorder that severely impairs her logical judgment. Medical imaging techniques show that this has been most likely caused by brain damage in a ______.

frontal lobe The frontal lobe has areas that control voluntary motor functions, mood, smell, and social judgment.

Which of the following is NOT a correctly matched pair?

gray matter: myelinated axons Gray matter is indicative of unmyelinated axons and cell bodies in the CNS.

Which of the following carries no sensory information?

hypoglossal nerve The hypoglossal nerve carries motor commands to the tongue.

Where is the illustrated structure located?

in each ventricle Submit

Where are the cell bodies of the sensory neurons at A located?

in the dorsal root ganglion The cell bodies of all sensory neurons that enter the spinal cord, including those of the autonomic nervous system, are found in the dorsal root ganglion.

Where are equilibrium receptors located?

in the semicircular canals and in the vestibule of the ear The equilibrium receptors in the semicircular canals and vestibule are collectively called the vestibular apparatus. The receptors in the vestibule monitor linear acceleration and the position of the head with respect to gravity. Because gravity is constant, this is sometimes called our sense of static equilibrium. The semicircular canals monitor changes in head rotation, sometimes called our sense of dynamic equilibrium.

Name the muscle at D.

inferior rectus The inferior rectus originates from the common tendinous ring at the back of the orbit and inserts into the inferior surface of the eye.

The pathways indicated in the figure pass from the cerebral cortex through the __________ before entering the cerebral peduncles of the midbrain.

internal capsule

Damage to the medial portion of the optic chiasm, cause by a pituitary tumor, would lead to __________.

loss of peripheral vision If you look at the diagram of the visual pathway on page 568, images from your right peripheral visual field land on the left medial retina and vice versa. The ganglion cells from the medial retina of each retina cross over at the optic chiasm. If there were damage at the medial portion of the chiasm, it would block the flow of this peripheral field of view.

Which of the following correctly matches the equilibrium receptor to the type of equilibrium it monitors?

maculae: static equilibrium The maculae ("spots"), one in each saccule wall and one in each utricle wall, are sensory receptor organs that monitor the position of the head in space (with respect to gravity). Because gravity is constant, this is sometimes called our sense of static equilibrium.

In carpal tunnel syndrome, the __________ is compressed.

median nerve The median nerve descends through the arm and forearm before passing through the wrist. Compression of this nerve in the anterior wrist causes carpal tunnel syndrome.

Hiccups could occur if there was irritation or damage to the ______.

motor branches of ventral rami associated with the C3-C5 region of the spinal cord The ventral rami of spinal nerves contain motor fibers that originate from neuron soma found in the spinal cord. These efferent pathways activate the contraction of skeletal muscle. The phrenic nerve branches from this region and innervates the skeletal muscle of the diaphragm.

Which of these is NOT found in the olfactory epithelium?

olfactory tracts The olfactory tracts begin in the olfactory bulb and proceed to the brain. They are not found in the olfactory epithelium.

Most taste buds are located __________.

on the top surface of the fungiform papillae

In order for you to realize there has been a sensory change, it has to reach the __________ level of processing.

perceptual The perceptual level is the third (final) level of neural integration in the somatosensory system. This is when you become aware of a stimulus.

During meningitis, which of the following layers is the most likely to be a direct source of pathogens that may spread to the brain?

pia mater

Which type of white matter fiber tract connects the cerebrum to lower centers, like the spinal cord?

projection fibers Projection fibers either enter the cerebral cortex from lower brain or cord centers or descend from the cortex to lower areas.

Which of the following is NOT a function of the hypothalamus?

regulate the thalamus

You want to look up and to your right. Which extrinsic eye muscles would be the most active in each eye?

right eye: inferior oblique left eye: superior rectus The right eye requires both elevation and lateral movement. The inferior oblique would accomplish both of these. The left eye requires both elevation and medial movement. The superior rectus, because it approaches the eye from the medial side, turns the eye medially as it elevates.

Segmental refers to which level of motor control?

spinal cord The spinal cord represents the segmental level of motor control, which refers to whichever spinal cord segment the nerve originates from.

The brachial plexus can be palpated at the lower lateral border of the sternocleidomastoid muscle. Injury to the brachial plexus could cause weakness or paralysis to all of the following EXCEPT the ______.

sternocleidomastoid muscle The sternocleidomastoid muscle is innervated by the accessory cranial nerve and branches of cervical spinal nerves C2 and C3.

The knee-jerk reflex is an example of a __________.

stretch reflex The most familiar clinical example of a stretch reflex is the knee-jerk reflex. The overall goal of a stretch reflex is to maintain a muscle's length and in turn maintain body position. For example, the knee-jerk reflex, during which the knee extensors contract in response to being stretched, helps keep your knees from buckling when you are standing upright.

Which of the following is NOT a diencephalon component?

superior colliculus Submit

During an epileptic seizure, the triggering of convulsions would not directly involve the uncontrolled activity of neurons located in the ______.

thalamus This area of the diencephalon groups and organizes afferent sensory impulses. Convulsions are directly caused by activation of primary motor and/or motor association areas of the cerebral cortex.

The cortical regions indicated by E are involved in what functions?

the production and interpretation of language Regions indicated by E include Broca's area in the frontal lobe and Wernicke's area in the temporal lobe.

Which of the following characteristics is representative of receptor-level processing, NOT perceptual-level processing?

transduction Transduction is converting a stimulus into a nervous signal; this happens at the receptor level.

Which of the following nerves would you predict is NEVER involved in the development of strabismus?

trigeminal (V) Strabismus is a condition in which the eyes lack normal alignment, usually due to a lack of control of the extraocular muscles. This nerve functions as the major sensory nerve of the face but also controls the blink reflex. It does not control any of the extraocular eye muscles.

Which of the following best describes the hypothalamus?

visceral control center of the body The hypothalamus is the main visceral control center of the body and is vitally important to overall body homeostasis. Its chief homeostatic roles include controlling the autonomic nervous system; controlling endocrine system function; regulating the sleep-wake cycle, body temperature, hunger, and thirst; and initiating physical responses to emotions.

You have a patient experiencing an essential tremor, which makes it hard for him to dress and feed himself. Imaging has detected a lesion in the basal nuclei. How would you best explain the function of these cerebral structures to him?

"This group of cells monitors all of our outgoing motor signals and makes sure there isn't any excessive activity. Your injury is preventing them from doing their job."

Which of the following lists the hierarchy of motor control from lowest to highest level of control?

1) segmental level, 2) projection level, 3) precommand level

Identify the neuron that is last in the transmission pathway of light information, given the cells shown in this image.

A Ganglion cells are last in the transmission pathway seen here. Their role is to transmit the visual signals to the thalamus.

Otosclerosis, which can result in conduction deafness, affects which of these structures?

A Otosclerosis is remodeling or otherwise abnormal bone growth in the auditory ossicles that can lead to loss of hearing.

You realize that many of your geriatric patients have visual problems that impact their care. Which item is NOT a common cause of decreased visual acuity in the elderly?

Abnormal production of vitreous humor Vitreous humor forms during embryonic life and lasts for a lifetime. By contrast, production of aqueous humor is ongoing. If its drainage is blocked, glaucoma results and may cause serious damage to the eye.

Which of these receptor types functions as an exteroceptor?

All of the listed responses are correct. All of the structures illustrated are sensitive to stimuli arising outside the body.

Choose the FALSE statement about nerves.

Axons make up a majority of the matter in a nerve. Axons constitute a small fraction of a nerve's bulk. The balance consists chiefly of myelin, the protective connective tissue wrappings, blood vessels, and lymphatic vessels.

What characteristic does a spinocerebellar tract neuron share with a sensory neuron originating in the quadriceps femoris?

Both neurons carry afferent information.

Your patient's CT scan demonstrates a cerebral vascular accident causing damage to the inferior and posterior portions of her left cerebral hemisphere. Your patient is right-handed. What deficits should you expect?

Broca's area, which controls the production of speech is found in the left frontal lobe in 90% of right-handed people. Her primary motor cortex for the right side of her body is in the posterior portion of her left cerebral hemisphere.

Identify the type of neuronal cell that detects bright light and provides high-resolution color vision.

C The cone cells are photoreceptor cells that require brighter light. By differentiating input from three different types of cones, the brain can differentiate color and high resolution.

Identify the layer that contains both a single-celled pigmented layer and a neural layer.

C The inner layer (retina) contains both the pigmented layer and the neural layer.

What part of the inner ear houses the receptor organ of hearing, the spiral organ (organ of Corti)?

D The cochlea houses the spiral organ (of Corti), which senses hearing.

Which of the receptor types contributes to the sense of touch by responding to light pressure?

E The epithelial tactile complex (Merkel cell and disc) shown in E would be located in the base of the epidermis and would detect light touch.

As light hits the retina, the first structure the light encounters is a rod or a cone.

False Contrary to what might make sense, light has to pass through the ganglion cells, through the bipolar cells, and finally strikes the rods and the cones.

Select the true statement regarding first-order neurons.

First-order neuron cell bodies reside in a ganglion. First-order neurons, whose cell bodies reside in a ganglion (dorsal root or cranial), conduct impulses from the cutaneous receptors of the skin and from proprioceptors to the spinal cord or brain stem, where they synapse with second-order neurons. Return to Assignment