Ch. 15

A nurse caring for an older adult patient would expect which functional changes to occur? (Select all that apply.) a. Increased risk for falls b. Increased risk for falls c. Loss of muscle in the arms and legs d. Decrease in the need for social interaction e. Increased agitation and frustration levels

ANS: A, B, C Functional changes with aging include skeletal muscle atrophy, progressive deficits in taste and smell, and a decrease in neuromuscular control with changes in gait and posture. Neither increased agitation and frustration nor a decreased need for social interaction is considered an expected change resulting from the aging process.

What evidence does the nurse expect to see when a patient experiences trauma to the hypothalamus? (Select all that apply.) a. Uneven expression of mood b. Unstable blood glucose levels c. Poor regulation of body temperature d. Visual disturbances such as blurred vision e. Nausea, vomiting, and symptoms of gastroesophageal reflux disease

ANS: A, B, C The hypothalamus forms the base of the diencephalon. Hypothalamic function controls autonomic nervous system (ANS) function, regulation of body temperature, endocrine function (e.g., unstable glucose levels), and regulation of emotional expression. Visual and gastrointestinal symptoms would not likely be related to hypothalamus function.

A Schwann cell: (Select all that apply.) a. Can form the myelin sheath. b. Is also referred to as a neurolemmocyte. c. Affects the function of the nodes of Ranvier. d. Is located in the peripheral nervous system. e. Is responsible of decreasing conduction velocity.

ANS: A, B, C, D The Schwann cell, or neurolemmocyte, is a glial cell that wraps around and covers axons in the peripheral nervous system. Schwann cells form and maintain the myelin sheath, and the nodes of Ranvier form the spaces on either side of the Schwann cell. If the myelin layer is tightly wrapped many times around the axon, forming nodes of Ranvier, then it increases conduction velocity and the neuron is referred to as myelinated. Trochlear nerve Fibers emerge from the posterior midbrain and exit from the skull to run to the eye.

The aging process brings about what changes to human cells? (Select all that apply.) a. Increased neurofibrillary tangles b. Imbalance of neurotransmitters c. Increased neuron production d. Decreased myelin presence e. Altered dendrite structure

ANS: A, B, D, E Principal cellular changes associated with aging include a decrease in the number of neurons, decreased myelin, decreased number of dendritic processes and synaptic connections, intracellular neurofibrillary tangles, and an imbalance in the amount and distribution of neurotransmitters. The aging process does not bring about an increase in neuron production.

Which statement is true regarding the blood-brain barrier (BBB)? (Select all that apply.) a. The BBB is dependent on astrocytes. b. It uses the meningeal layers of the brain. c. It restricts the flow of large molecules, such as potassium. d. Naturally occurring inflammatory mediators affect the BBB. e. The BBB appears to play a role in slowing down the onset of degenerative brain disease.

ANS: A, C, D, E The BBB is a term used to describe cellular structures that selectively inhibit certain substances in the blood from entering the interstitial spaces of the brain or CSF. This term emphasizes the impermeability of the nervous system to large and potentially harmful molecules. Astrocytes wrap their foot processes around the epithelial cells of brain capillaries, thereby contributing to the formation of the BBB. Tight junctions between capillary endothelial cells form a barrier that regulates the passage of ions (e.g., sodium, potassium) that could interfere with nerve transmission, prevent toxins from entering the brain, and promote transport of nutrients and the removal of metabolites. Hormones, neurotransmitters, and inflammatory mediators can affect BBB permeability. Inhibiting these endogenous chemicals with drug therapy may reduce brain edema and slow the onset of degenerative brain diseases. The statement regarding the meningeal layers of the brain is incorrect.

The sympathetic nervous system primarily serves to protect an individual by doing which of the following? (Select all that apply.) a. Decreasing mucous production b. Increasing blood sugar levels c. Increasing body temperature d. Decreasing sweat excretion e. Increasing blood pressure

ANS: B, C, E In general, sympathetic stimulation promotes responses that are concerned with the protection of the individual, which include increasing blood sugar levels, temperature, and blood pressure. The remaining options are not protective measures resulting from initiatives made by the sympathetic nervous system.

The function of arachnoid villi is to:

Absorb cerebrospinal fluid into the cerebral venous sinuses-CSF is reabsorbed by means of a pressure gradient between the arachnoid villi and the cerebral venous sinuses. The remaining options do not accurately describe the function of arachnoid villi.

Hypoglossal nerve

Affects control over the motor fibers to the muscles of tongue and sensory impulses from the tongue to the brain.

Which pathway carries sensory information toward the central nervous system (CNS)?

Ascending-Peripheral nerve pathways can be afferent (ascending) pathways that carry sensory impulses toward the CNS. The remaining options do not carry sensory information to the CNS.

The region responsible for the motor aspects of speech is located in the:

Broca area in the frontal lobe-Broca speech area is the only region responsible for the motor aspects of speech.

Spinal accessory nerve

Carries sensory and motor fibers to the pharynx and larynx.

Which area of the brain assumes the responsibility for conscious and unconscious muscle synergy and for maintaining balance and posture?

Cerebellum-The cerebellum is responsible for conscious and unconscious muscle synergy and for maintaining balance and posture. This role is not assumed by any of the remaining options.

The collateral blood flow to the brain is provided by the:

Circle of Willis-The arterial circle (circle of Willis) (see Figure 15-20) 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.

Glossopharyngeal nerve

Controls motor functions to the pharynx and salivary glands and sensory functions from the pharynx and tongue.

Oculomotor nerve

Fibers emerge from the midbrain, exit from the skull, and extend to the eye.

Both oligodendroglia and Schwann cells share the ability to:

Form a myelin sheath-The function of oligodendroglia (oligodendrocytes) is to deposit myelin within the central nervous system (CNS). Oligodendroglia are the CNS counterpart of Schwann cells. The remaining options are not reflective of the common function of these structures.

Maintenance of a constant internal environment and the implementation of behavioral patterns are main functions of which area of the brain?

Hypothalamus-Hypothalamic function falls into two major areas: (1) maintenance of a constant internal environment, and (2) implementation of behavioral patterns. The remaining options do not address these functions.

What is an effect of the sympathetic nervous system?

Increased blood sugar levels -In general, sympathetic stimulation promotes responses that are concerned with the protection of the individual, which include increased blood sugar levels, temperature, and blood pressure. The responses noted in the remaining options are not a result of sympathetic stimulation.

Abducens nerve

Innervates muscles that move the eye laterally.

Vagus nerve

Is made up of parasympathetic motor fibers that supply the smooth muscles of the abdominal organs.

Olfactory nerve

Is purely sensory and carries impulses for the sense of smell.

Which type of axon transmits a nerve impulse at the highest rate?

Large myelinated-If the myelin layer is tightly wrapped many times around the axon and is forming the nodes of Ranvier, then conduction velocity increases and the neuron is referred to as myelinated. The increased diameter of the myelinated axons allows for the transmission of impulses at a faster rate. The other options do not affect nervous impulse transmission rates.

The nurse recognizes that a patient's diagnosis of a viral infection of the brain's meningeal layer is supported by which diagnostic laboratory result?

Leukocytes >10/mm3-Viral infections causing meningitis will produce a white blood cell (leukocyte) count greater than 10/mm 3. The chloride level is observed in tuberculous meningitis, the protein level has little clinical significance, and the glucose level is observed in patients with acute bacterial meningitis.

What parts of the brain mediate the expression of affect, both emotional and behavioral states?

Limbic system and prefrontal cortex-Extensive connections with the limbic system and prefrontal cortex mediate the expression of affect, both emotional and behavioral states. The remaining options are not involved in these expressions.

Reflex activities concerned with heart rate, blood pressure, respirations, sneezing, swallowing, and coughing are controlled by which area of the brain?

Medulla oblongata-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 only in this area.

From which part of the midbrain do cranial nerves IX to XII emerge?

Medulla oblongata-The nuclei of cranial nerves IX through XII (see Table 15-6 for discussion) are located only in the medulla oblongata.

Which nerves are capable of regeneration?

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

Which of the meninges closely adheres to the surface of the brain and spinal cord and follows the sulci and fissures?

Pia mater-The delicate pia mater closely adheres to the surface of the brain and spinal cord and even follows the sulci and fissures. The remaining options are not represented in the description provided in the stem.

From which part of the midbrain do cranial nerves V to VIII emerge?

Pons-The nuclei of cranial nerves V through VIII (see Table 15-6 for discussion) are located only in the pons.

Thought and goal-oriented behaviors are functions of which area of the brain?

Prefrontal lobe-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 remaining options are not involved in these functions.

Trigeminal nerve

Provides motor and sensory functions to the face, mouth, nose, and eyes.

What name is given to a large network of neurons within the brainstem that is essential for maintaining wakefulness?

Reticular activating system-The reticular activating system is essential for maintaining wakefulness. The remaining options are not essential to this function.

The ability of the eyes to track moving objects through a visual field is primarily a function of which colliculi?

Superior-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). Tracking moving objects is not the primary function of the remaining options.

The neurotransmitter, norepinephrine, is secreted in the:

Sympathetic postganglion-Most postganglionic sympathetic fibers release norepinephrine (adrenaline). The remaining options do not reflect the correct site of norepinephrine secretion.

The membrane that separates the brain's cerebellum from its cerebrum is the:

Tentorium cerebelli-The tentorium cerebelli is a membrane that separates the cerebellum below from the cerebral structures above. The remaining options do not perform the function described in the stem.

During a synapse, what change occurs after the neurotransmitter binds to the receptor?

The permeability of the postsynaptic neuron changes; consequently, its membrane potential is changed as well.-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 statement is true regarding upper motor neurons?

They modify spinal reflex arcs.-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. The remaining options do not accurately describe the characteristic functions of upper motor neurons.

Norepinephrine produces what primary response?

Vasoconstriction-The primary response from norepinephrine is the stimulation of the 1-adrenergic receptors that cause vasoconstriction. The remaining options do not accurately reflect the primary response of norepinephrine.

Vestibulocochlear nerve

Transmits impulses for the sense of hearing.

The brain receives approximately what percentage of the cardiac output?

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

Parkinson and Huntington diseases are associated with defects in which area of the brain?

Basal ganglia-Parkinson and Huntington diseases are conditions associated with defects of the basal ganglia. No current research supports the role of any of the other options in these diseases.

Which cranial nerves contain parasympathetic nerves? (Select all that apply.) a. I (olfactory) b. III (oculomotor) c. VII (facial) d. IX (glossopharyngeal) e. X (vagus)

ANS: B, C, D, E All but cranial nerve I (olfactory) contain parasympathetic nerves.

Where is the cerebrospinal fluid produced?

Choroid plexuses-The choroid plexuses are the structures that produce CSF; they arise from the pia mater. The remaining options do not have a role in CSF production.