Chapter 20 Flashcards
The neural groove closes dorsally during which week of gestational life?
a. Second.
b. Fourth
c. Eight
d. Twelfth
b. Fourth.
During the fourth gestational week, the neural groove deepens, its folds develop laterally, and it closes dorsally to form the neural tube, epithelial tissue that ultimately becomes the central nervous system (CNS). The second week is too early, and the other options represent times periods after the groove closes.
Which nutritional deficiency in a pregnant woman is associated with neural tube defect (NTD)?
a. Iron
b. Vitamin C.
c. Zinc
d. Folate
d. Folate
Maternal folate deficiency is associated with NTDs, but the specific mechanism that relates to how folate supplements prevent these anomalies is unknown. The other options are not thought to cause such a defect.
Which defect of neural tube closure is most common?
a. Anterior
b. Posterior
c. Lateral
d. Midline
b. Posterior
Posterior defects are most common
What is the anomaly in which the soft bony component of the skull and much of the brain is missing?
a. Anencephaly
b. Myelodysplasia
c. Cranial meningocele
d. Hydrocephaly
a. Anencephaly
Anencephaly is an anomaly in which the soft, bony component of the skull and much of the brain are missing
The most common cause of obstructive hydrocephalus in infants is:
a. Obstructed arachnoid villi
b. Stenosis of the aqueduct of Sylvius
c. Excessive production of cerebrospinal fluid
d. Impaired cerebrospinal fluid circulation in the subarachnoid space
b. Stenosis of the aqueduct of Sylvius
Congenital aqueduct stenosis most commonly causes obstructive hydrocephalus.
What is the term for a herniation or protrusion of brain and meninges through a defect in the skull?
a. Encephalocele
b. Meningocele
c. Arachnoidocele
d. Cephacephalocele
a. Encephalocele
Encephalocele refers to a herniation or protrusion of brain and meninges through a defect in the skull, resulting in a saclike structure.
What is the result of a Chiari type II malformation associated with a myelomeningocele?
a. Upward displacement of the cerebellum into the diencephalon
b. Motor and sensory lesions below the level of the myelomeningocele
c. Downward displacement of the cerebellum, brainstem, and fourth ventricle
d. Generalized cerebral edema and hydrocephalus
c. Downward displacement of the cerebellum, brainstem, and fourth ventricle
One serious, potentially life-threatening problem associated with myelomeningocele is the Chiari type II malformation. This deformity involves the downward displacement of the cerebellum, cerebellar tonsils, brainstem, and fourth ventricle
Prompt surgical repair of a myelomeningocele is critical to best prevent:
a. Infection
b. Paralysis
c. Mental retardation
d. Additional nervous system damage
d. Additional nervous system damage
Until the myelomeningocele is surgically closed, cerebrospinal fluid (CSF) may accumulate, resulting in further dilation and enlargement of the sac, which may risk more damage to the nervous system
Which body system is the largest site for human immunodeficiency virus (HIV) infection in infants and children?
a. Central nervous system
b. Gastrointestinal system
c. Integumentary system
d. Musculoskeletal system
a. Central nervous system
A particularly vulnerable site of HIV-1 infection in infants and children is the CNS.
An infant diagnosed with hydrocephalus is observed to demonstrate:
a. Shrunken ventricles
b. Bulging fontanels
c. Retarded head growth
d. Decreased production of cerebrospinal fluid
b. Bulging fontanels
During the early weeks of life, the head begins to grow at an abnormal rate. Significant dilation of the ventricles may occur before an abnormal increase in head growth develops. The fontanels enlarge and become full and bulging
Gait disturbances and instability are characteristic of which form of cerebral palsy?
a. Spastic
b. Dyskinetic
c. Ataxic
d. Biochemical
c. Ataxic
Ataxic cerebral palsy causes damage to the cerebellum and exhibits gait disturbances and
instability
Children with phenylketonuria (PKU) are unable to synthesize:
a. Essential amino acid, phenylalanine, to tyrosine
b. Renin, erythropoietin, and antidiuretic hormone
c. Aldosterone, cortisol, and androgens
d. Neurotransmitters gamma-aminobutyric acid (GABA) and acetylcholine
a. Essential amino acid, phenylalanine, to tyrosine
PKU is an inborn error of metabolism characterized by the inability of the body to convert the essential amino acid, phenylalanine, to tyrosine
Benign febrile seizures are characterized by:
a. A temperature lower than 39° C
b. Respiratory or ear infections
c. Onset after the fifth year of life
d. Episodes lasting 30 minutes or longer
b. Respiratory or ear infections
An acute respiratory or ear infection is usually present. Simple febrile seizures are rare in infants before 9 months of age or in children older than 5 years of age. The convulsion occurs with a rise in temperature higher than 39° C (102.2 °F). The convulsion is short (15 minutes or less).
What is the most common general symptom of a localized childhood brain tumor?
a. Poor bonding
b. Increased intracranial pressure
c. Delayed extinction of newborn reflexes
d. Failure to thrive
b. Increased intracranial pressure
Symptoms of brain tumors may be generalized or localized. The most common general symptom is increased intracranial pressure, which may cause headaches, irritability, vomiting, somnolence, and bulging of fontanels
The tonic neck reflex observed in a newborn should no longer be obtainable by:
a. 2 years
b. 1 year
c. 10 months
d. 5 months
d. 5 months
The tonic neck reflex should be unobtainable by 5 months of age.
