Chapter 21: Neurologic Anatomy and Physiology Flashcards
Which structure(s) form(s) the blood–brain barrier?
a. Postsynaptic terminals
b. Pia mater
c. Vascular endothelial cells
d. Myelin sheath
ANS: C
The blood–brain barrier operates on the concept of tight junctions between adjacent cells and actually consists of three separate barriers: the endothelial cells of cerebral blood vessels, the epithelial cells of the choroid plexus, and the cells that form the outermost layer of the arachnoid.
Which neurologic structure carries nerve impulses from the central nervous system (CNS) to the periphery to produce a response such as contraction of the skeletal muscles?
a. Efferent fibers
b. Afferent fibers
c. Sensory fibers
d. Neurotransmitters
ANS: A
Efferent fibers (motor fibers) transmit the central nervous system (CNS) response to the periphery to produce a motor response such as contraction of skeletal muscles, contraction of the smooth muscles of organs, or secretion by endocrine glands. This sensory information is transmitted to the CNS by afferent fibers (sensory fibers). Fibers enclosed in the sheath are called myelinated fibers. Neurotransmitters help with nerve transmission from one neuron to the next.
Which type of hematoma results from traumatic injury involving the middle meningeal artery?
a. Subdural
b. Epidural
c. Subarachnoid
d. Intercerebral
ANS: B
The main blood supply for the dura mater is the middle meningeal artery. This artery lies on the surface of the dura in the epidural space within grooves formed on the inside of the parietal bone. Traumatic disruption of the parietal bone may result in tearing of the middle meningeal artery and development of an epidural hematoma.
A patient has neurologic damage to the limbic system. Which assessment finding is specific
to this type of deficit?
a. Flat affect with periods of emotional lability
b. Unable to recall early events
c. Disorientation to place and time
d. Unable to interpret written words
ANS: A
The limbic lobe’s primary functions are related to self-preservation and include functions such as recall of pleasurable as well as unpleasant or potentially dangerous events, modification of mood and emotional responses in relation to perceived events, interpretation of smell, and augmentation of visceral processes (e.g., heart rate, respiration) associated
with emotion.
Which area of the ventricular system is usually cannulated for intracranial pressure monitoring?
a. Frontal horn of the lateral ventricle
b. Aqueduct of Sylvius
c. Foramen of Monro
d. Fourth ventricle
ANS: A
When cannulation of the ventricular system is required for intracranial pressure monitoring,
cerebrospinal fluid (CSF) drainage, or placement of a CSF shunt, the frontal horn of the lateral ventricle on the nondominant side of the brain is most often selected.
What percentage of the body’s total resting cardiac output is used by the brain?
a. 5%
b. 10%
c. 20%
d. 40%
ANS: C
The brain constitutes 2% of the body’s weight but uses 20% of the body’s total resting cardiac output. It requires approximately 750 mL of blood flow per minute and can extract as much as 45% of arterial oxygen to meet normal metabolic needs.
Which areas of the spinal cord have tenuous blood supply and are especially vulnerable to circulatory embarrassment?
a. C2 to C3
b. C5 to C6
c. T8 to T10
d. L4 to L5
ANS: A
Arterial supply to the spinal cord is segmented at best, making portions of the spinal cord that receive blood supply from two separate sources vulnerable to low flow states. The most vulnerable of these areas are C2 to C3, T1 to T4, and L1 to L2
Damage to the upper portion of the reticular activating system results in which condition?
a. Seizures
b. Diabetes insipidus
c. Apnea
d. Impaired consciousness
ANS: D
The reticular activating system (RAS) works through activation of the hypothalamus, which results in diffuse cortical stimulation and autonomic stimulation. Damage to the thalamic or hypothalamic RAS pathways results in impaired consciousness.
A person with a cerebellar lesion will have difficulty with which physiologic mechanism?
a. Breathing
b. Equilibrium
c. Memory
d. Speech
ANS: B
Cerebellar impulses are communicated to descending motor pathways to integrate spatial orientation and equilibrium with posture and muscle tone, ensuring synchronized adjustments in movement that maintain overall balance and motor coordination. Cerebellar
monitoring and adjustment of motor activity occurs simultaneously with movement, enabling significant control of fine motor function.
What is the large opening at the base of the cranium called?
a. Cisterna magna
b. Median foramen
c. Foramen magnum
d. Lateral foramen
ANS: C
The cranium is a solid, nonexpanding bony vault with only one large opening at the base called the foramen magnum, through which the brainstem projects and connects to the spinal cord.
Which statement best describes the role of neuroglial cells?
a. They are fewer in number than neurons.
b. They provide support to the neuron in nutrients and structural formation.
c. They protect the central nervous system (CNS) from nonmetabolic primary
neoplasms.
d. They produce a steady supply of neurotransmitters.
ANS: B
These cells provide the neuron with structural support, nourishment, and protection. They also retain their ability to replicate but can replicate abnormally and hence are the primary source of central nervous system neoplasms.
What is the tissue that adheres directly to the brain called?
a. Dura mater
b. Arachnoid mater
c. Pia mater
d. Blood–brain barrier
ANS: C
The outermost layer of meninges directly beneath the skull is the dura mater. The arachnoid membrane is a delicate, fragile membrane that loosely surrounds the brain. Cerebrospinal fluid (CSF) circulates freely in the subarachnoid space fragile membrane that loosely surrounds the brain. The pia mater adheres directly to brain tissue. Rich in small blood vessels that supply a large volume of arterial blood to the central nervous system, this membrane closely follows all folds and convolutions of the brain’s surface.
Obstructive hydrocephalus can occur in the presence of what abnormality?
a. Blockage in the arachnoid villi
b. Malformation of the falx cerebelli
c. Blockage of cerebrospinal fluid (CSF) flow in the ventricular system
d. Increased production of CSF
ANS: C
Blockage of cerebrospinal fluid (CSF) flow occurring within the ventricular system obstructs the normal circulation of CSF, causing dilation of the ventricles, a condition called obstructive hydrocephalus.
Substances most likely to pass across the blood–brain barrier have what characteristics?
a. Low pH compared with body fluids
b. Lipid solubility
c. Large particle size
d. A close relation to toxic metabolites
ANS: B
Passage of substances across the blood–brain barrier is a function of particle size, lipid solubility, and protein-binding potential. Most drugs or compounds that are lipid soluble and stable at body pH rapidly cross the blood–brain barrier. The blood–brain barrier is also very permeable to water, oxygen, carbon dioxide, and glucose.
Control of the rate of respirations occurs in the in which brain center?
a. Apneustic center
b. Pneumotaxic center
c. Reticular activating system
d. Midbrain
ANS: B
Two respiratory control centers are located in the pons, namely the apneustic and pneumotaxic centers. Whereas the apneustic center controls the length of inspiration and expiration, the pneumotaxic center controls respiratory rate.
