Ch 15- Structure and Function of the Neurologic System

Which pathway carries sensory information toward the central nervous system (CNS)? a. Ascending b. Descending c. Somatic d. Efferent

A Peripheral nerve pathways can be afferent (ascending) pathways that carry sensory impulses toward the CNS. Efferent, or descending, pathways innervate effector organs. "Somatic" is a branch of the peripheral nervous system and consists of both motor and sensory pathways.

Both oligodendroglia and Schwann cells share the ability to do what? a. Form a myelin sheath b. Remove cellular debris c. Transport nutrients d. Line the ventricles

A The function of oligodendroglia (oligodendrocytes) is to deposit myelin within the central nervous system (CNS). Oligodendroglia are the CNS counterpart of Schwann cells. Microglia remove cellular debris. Astrocytes transport nutrients. Ependymal cells line the ventricles.

What part of the brain mediates the physical expression of emotions? a. Hypothalamus b. Basal ganglia c. Medulla oblongata d. Subthalamus

A The hypothalamus is generally responsible for the physical manifestations of emotions. The nuclei of the basal ganglia are important for coordination of voluntary movement and cognitive and emotional functions. Reflex activities, such as heart rate, respiration, blood pressure, coughing, sneezing, swallowing, and vomiting, are controlled in the medulla oblongata. The subthalamus flanks the hypothalamus laterally and serves as an important basal ganglia center for motor activities.

The nurse recognizes that a patient's diagnosis of a bacterial infection of the brain's meningeal layer is supported by which diagnostic laboratory result? a. Chloride 125 mEq/L b. Leukocytes 110/mm3 c. Protein 32 mg/dL d. Glucose 63 mg/dL

B Viral infections causing meningitis will produce a white blood cell (leukocyte) count greater than 10/mm3. The chloride level and protein levels are normal and the glucose level is observed in patients with acute viral meningitis.

Where is the neurotransmitter, norepinephrine, secreted? a. Somatic nervous system b. Parasympathetic preganglion c. Sympathetic postganglion d. Parasympathetic postganglion

C Most postganglionic sympathetic fibers release norepinephrine (adrenaline). Norepinephrine is not secreted in the somatic nervous system, sympathetic preganglion, or parasympathetic postganglion.

Parkinson disease is associated with defects in which area of the brain? a. Thalamus b. Medulla oblongata c. Cerebellum d. Substantia nigra

D Parkinson disease is a condition associated with defects of the substantia nigra and destruction of dopamine-secreting neurons. No current research supports the role of the thalamus, medulla oblongata, or the cerebellum in Parkinson disease.

What is the membrane that separates the brain's cerebellum from its cerebrum? a. Tentorium cerebelli b. Falx cerebri c. Arachnoid membrane d. Falx cerebelli

A The tentorium cerebelli is a membrane that separates the cerebellum below from the cerebral structures above. The falx cerebri dips between the two cerebral hemispheres along the longitudinal fissure. The arachnoid membrane (or arachnoid mater) is a spongy, weblike structure just underneath the dura mater that loosely follows the contours of the cerebral structures. The tentorium cerebelli (not falx cerebelli), a common landmark, is a membrane that separates the cerebellum from the cerebral structures above.

Which type of axon transmits a nerve impulse at the highest rate? a. Large nonmyelinated b. Large myelinated c. Small nonmyelinated d. Small myelinated

B A myelinated axon has a myelin sheath wrapped around it which functions as an insulating substance that speeds impulse propagation. The diameter of the myelinated axon also affects the speed of nerve impulse transmission with larger diameter axons transmitting at a faster speed than smaller ones.

Where is the region responsible for the motor aspects of speech located? a. Wernicke area in the temporal lobe b. Broca speech area in the frontal lobe c. Wronka area in the parietal lobe d. Barlow area in the occipital lobe

B Broca speech area is the only region responsible for the motor aspects of speech. Wernicke area is responsible for reception and interpretation of speech. Wronka and Barlow areas were not discussed in the text.

A patient is brought to the Emergency Department after being in an explosion. The patient was not seriously injured. Laboratory testing shows an elevated blood glucose (sugar) level, but the patient does not have diabetes. What does the healthcare professional tell the patient about this condition? a. "You should have a physical by your primary care provider." b. "Your blood sugar may be high because of the stress of the situation." c. "You actually may have undiagnosed diabetes mellitus." d. "You should be tested for underlying neurological problems."

B In general, sympathetic stimulation promotes responses that are concerned with the protection of the individual ("fight or flight" response), which include increased blood sugar levels, temperature, and blood pressure. The patient may need a physical and might have undiagnosed diabetes, but these are not the most specific answer to the question and do not give the patient any information. It is not likely that an underlying neurological disorder is the cause of the elevated blood glucose.

During a synapse, what change occurs after the neurotransmitter binds to the receptor? a. The permeability of the presynaptic neuron changes; consequently, its membrane potential is changed as well. b. The permeability of the postsynaptic neuron changes; consequently, its membrane potential is changed as well. c. The postsynaptic cell prevents any change in permeability and destroys the action potential. d. The presynaptic cell synthesizes and secretes additional neurotransmitters.

B The binding of the neurotransmitter at the receptor site changes the permeability of the postsynaptic neuron and, consequently, its membrane potential. The remaining options do not accurately describe the occurrence.

Which area of the brain assumes the responsibility for involuntary muscle control and for maintaining balance and posture? a. Cerebrum b. Cerebellum c. Diencephalon d. Brainstem

B The cerebellum is responsible for reflexive, involuntary fine-tuning of motor control and for maintaining balance and posture through extensive neural connections with the medulla and with the midbrain. The cerebrum is the site of higher brain function. The diencephalon controls vital functions and visceral activities and is closely associated with those of the limbic system. The brainstem contains the reticular formation which is a large network of diffuse nuclei that connect the brainstem to the cortex and control vital reflexes, such as cardiovascular function and respiration. It is essential for maintaining wakefulness and attention.

Where is the cerebrospinal fluid (CSF) produced? a. Arachnoid villi b. Choroid plexuses c. Ependymal cells d. Pia mater

B The choroid plexuses are the structures that produce CSF; they arise from the pia mater. The arachnoid villi reabsorb the CSF. The ependymal cells form sheets that line fluid filled cavities in the brain. The pia mater closely adheres to the surface of the brain and spinal cord. It provides support for blood vessels serving brain tissue.

A healthcare professional is assessing a patient who suffered a head trauma. The patient is not able to sense touch of a sharp pin and cannot distinguish a hot object from a cold one. What part of the patient's brain does the professional suspect is damaged? a. Midbrain b. Pons c. Medulla oblongata d. Lateral colliculi

B The nuclei of cranial nerves V through VIII are located in the pons. An inability to recognize pain from a sharp pin and inability to differentiate hot and cold signify dysfunction of cranial nerve V (trigeminal nerve). The healthcare professional would suspect an injury to the pons.

What name is given to a large network of neurons within the brainstem that is essential for maintaining wakefulness? a. Midbrain b. Reticular activating system c. Medulla oblongata d. Pons

B The reticular activating system is essential for maintaining wakefulness. The midbrain connects the forebrain with the hindbrain. The pons is in the Metencephalon and transmits information from the cerebellum to the brainstem between the two cerebellar hemispheres.

The ability of the eyes to track moving objects through a visual field is primarily a function of which colliculi? a. Inferior b. Superior c. Mid d. Posterior

B The superior colliculi are involved with voluntary and involuntary visual motor movements (e.g., the ability of the eyes to track moving objects in the visual field). The inferior colliculi accomplish similar motor activities but involve movements affecting the auditory system (e.g., positioning the head to improve hearing). The inferior colliculus also is a major relay center along the auditory pathway. There are no mid or posterior colliculi.

A patient has a spinal cord injury that included damage to the upper motor neurons. What assessment finding would the healthcare provider associate with this injury? a. Permanent paralysis below the level of the injury b. Initial paralysis, but gradual partial recovery later c. Hemiplegia on the contralateral side of the body d. Notable increase in the amount of cerebral spinal fluid (CSF)

B Upper motor neurons (i.e., corticospinal tract) are the classification of motor pathways completely contained within the CNS. Their primary roles include directing, influencing, and modifying reflex arcs, lower-level control centers, and motor and some sensory neurons. Damage or destruction to upper motor neurons generally results in partial paralysis that is followed by a gradual and partial recovery. Permanent paralysis is usually the result of lower motor neuron destruction. Hemiplegia is often due to an injury or obstruction of the anterior cerebral artery. Changes in CSF production are a known age-related change and are due to atrophy of epithelial cells and thickening of the basement membrane in the choroid plexus.

Which nerves are capable of regeneration? a. Nerves within the brain and spinal cord b. Peripheral nerves that are cut or severed c. Myelinated nerves in the peripheral nervous system d. Unmyelinated nerves of the peripheral nervous system

C Nerve regeneration is limited to only myelinated fibers and generally occurs only in the peripheral nervous system.

What is the collateral blood flow to the brain provided by? a. Carotid arteries b. Basilar artery c. Circle of Willis d. Vertebral arteries

C The arterial circle (circle of Willis) is a structure credited with the ability to compensate for reduced blood flow from any one of the major contributors (collateral blood flow). The remaining options are not considered sources of collateral blood flow. The brain derives its arterial supply from two systems: the internal carotid arteries (anterior circulation) and the vertebral art eries (posterior circulation) with the carotid arteries supplying the majority of the blood flow. The basilar artery gives rise to three major paired arteries that perfuse the cerebellum and brainstem. The basilar artery also gives rise to small pontine arteries.

The brain receives approximately what percentage of the cardiac output? a. 80% b. 40% c. 20% d. 10%

C The brain receives approximately 20% of the cardiac output, or 800 to 1000 mL of blood flow per minute.

Which of the meninges closely adheres to the surface of the brain and spinal cord and follows the sulci and fissures? a. Dura mater b. Arachnoid c. Pia mater d. Inner dura

C The delicate pia mater closely adheres to the surface of the brain and spinal cord and even follows the sulci and fissures. The dura mater (meaning literally "hard mother") is composed of two layers, with the venous sinuses formed between them. The outermost layer forms the periosteum (endosteal layer) of the skull. The inner dura (meningeal layer) provides rigid membranes that support and separate various brain structures. The arachnoid mater is a spongy, weblike structure just underneath the dura mater that loosely follows the contours of the cerebral structures. The inner dura (meningeal layer) provides rigid membranes that support and separate various brain structures.

A healthcare professional is assessing a patient for dysfunction of cranial nerve VII. What assessment finding would confirm the professional's suspicion? a. Patient is unable to open mouth against resistance. b. Patient does not display intact gag reflex. c. Patient is able to smile only on one side of the face. d. Patient's tongue deviates to the right when sticking out.

C The inability to smile symmetrically is a sign of cranial nerve VII dysfunction (facial nerve). The inability to open the mouth against resistance is related to a dysfunction of cranial nerve V (trigeminal nerve). Loss of a gag reflex correlates with dysfunction of cranial nerve IX (glossopharyngeal nerve). Deviation in tongue position when the patient extends it is a sign of cranial nerve XII (hypoglossal nerve) dysfunction.

Thought and goal-oriented behaviors are functions of which area of the brain? a. Cerebellum b. Limbic system c. Prefrontal lobe d. Occipital lobe

C The prefrontal area is responsible for goal-oriented behavior (i.e., ability to concentrate), short-term or recall memory, and the elaboration of thought and inhibition on the limbic (emotional) areas of the CNS. The cerebellum is responsible for reflexive, involuntary fine-tuning of motor control and for maintaining balance and posture through extensive neural connections with the medulla and with the midbrain. The limbic system mediates emotion and long-term memory through connections in the prefrontal cortex (limbic cortex). Its principal effects are involved in primitive behavioral responses, visceral reaction to emotion, motivation, mood, feeding behaviors, biologic rhythms, and the sense of smell. The occipital lobe lies caudal to the parietooccipital sulci and superior to the cerebellum. The primary visual cortex is located in this region and receives input from the retinas. Much of the remainder of this lobe is involved in visual association.

Norepinephrine produces what primary response? a. Increased contractility of the heart b. Release of renin from the kidney c. Vasoconstriction d. Sleep cycle disturbance

C The primary response from norepinephrine is the stimulation of the α1-adrenergic receptors that cause vasoconstriction. Increased contractility and renin release are the result of β-adrenergic receptors. Dopamine is involved in regulating the sleep cycle.

A patient has a defect in the arachnoid villi. What finding would the healthcare professional expect to note? a. Production of excess cerebrospinal fluid (CSF) b. Ischemia in the choroid plexuses c. Cloudy cerebral spinal fluid on analysis d. Absorption of too little cerebrospinal fluid

D CSF is reabsorbed by means of a pressure gradient between the arachnoid villi and the cerebral venous sinuses. CSF is produced in the choroid plexuses in the lateral, third, and fourth ventricles. The arachnoid villi do not provide perfusion to the choroid plexuses. Cloudy CSF can indicate infection (meningitis).

Maintenance of a constant internal environment and the implementation of behavioral patterns are main functions of which area of the brain? a. Thalamus b. Epithalamus c. Subthalamus d. Hypothalamus

D Hypothalamic function falls into two major areas: (1) maintenance of a constant internal environment and (2) implementation of behavioral patterns. The epithalamus forms the roof of the third ventricle and composes the most superior portion of the diencephalon, which controls vital functions and visceral activities. The subthalamus flanks the hypothalamus laterally and serves as an important basal ganglia center for motor activities.

Reflex activities concerned with heart rate, blood pressure, respirations, sneezing, swallowing, and coughing are controlled by which area of the brain? a. Pons b. Midbrain c. Cerebellum d. Medulla oblongata

D The medulla oblongata makes up the myelencephalon and is the lowest portion of the brainstem. Reflex activities, such as heart rate, respiration, blood pressure, coughing, sneezing, swallowing, and vomiting, are controlled in this area. The pons transmits information from the cerebellum to the brainstem between the two cerebellar hemispheres. The cerebellum is responsible for reflexive, involuntary fine-tuning of motor control and for maintaining balance and posture through extensive neural connections with the medulla (through the inferior cerebellar peduncle) and with the midbrain. The midbrain connects the forebrain to the hindbrain.