Kaplan Anatomy 2 Flashcards
221. To anesthetize an area under the nailbed of the index finger, which nerve should be injected? A. Axillary B. Median C. Musculocutaneous D. Radial E. Ulnar
The correct answer is B. The tumor in question is probably a benign glomus tumor, which is
notorious for producing pain far out of proportion to its small size. The question is a little tricky
because the most distal aspect of the dorsal skin of the fingers, including the nail beds, is
innervated by the palmar digital nerves rather than the dorsal digital nerves. Specifically, the
median nerve, through its palmar digital nerves, supplies the nail beds of the thumb, index
finger, middle finger, and half the ring finger.
The axillary nerve (choice A), musculocutaneous nerve (choice C), and radial nerve (choice
D) do not supply the nail beds. The radial nerve does supply the more proximal skin of the
back of the index finger.
The ulnar nerve (choice E) supplies the nail beds of the small finger and half of the ring
finger.
- An individual has an eye that is persistently directed toward his nose. A lesion of which
of the following nerves could produce this finding?
A. CN III
B. CN IV
C. CN V
D. CN VI
E. CN VII
The correct answer is D. Cranial nerve VI is the abducens nerve, which supplies the
abductor of the eye, the lateral rectus. A paralysis of the lateral rectus leads to unopposed
adduction, causing the eye to point toward the nose.
Cranial nerve III (choice A) is the oculomotor nerve, which supplies all of the muscles of the
eye, except the superior oblique and lateral rectus. Paralysis of III would impair adduction, not
abduction, of the eye. The eye would tend to rotate downward and outward.
Cranial nerve IV (choice B) is the trochlear nerve, which supplies the superior oblique
muscle. This muscle serves to depress and abduct (down and out) the eyeball. Paralysis of IV
tends to produce double vision but does not cause an obvious deficit in conjugate gaze
without careful testing.
Cranial nerve V (choice C) is the trigeminal nerve, which is a mixed sensory and motor nerve
that supplies the face. It provides sensory innervation to the face and innervates the muscles
of mastication. It does not innervate the eye muscles.
Cranial nerve VII (choice E) is the facial nerve, which innervates the muscles of facial
expression but not the muscles of the orbit. CN VII is additionally involved in salivation,
lacrimation, taste, and general sensation from the external ear.
223. The patient closes both of his eyelids in response to the left eye being touched with a thin wisp of cotton as he looks to the right. Which of the following cranial nerves is responsible for the motor limb of this reflex? A. Abducens B. Facial C. Optic D. Trigeminal E. Trochlear
The correct answer is B. The corneal reflex is tested by touching the cornea of one eye with
a cotton wisp; this causes both eyes to close. The afferent, or sensory, component of the
corneal reflex is mediated by the ophthalmic division of the ipsilateral trigeminal nerve (V-1).
The efferent, or motor, component is mediated by the facial nerve (CN VII), bilaterally.
The abducens nerve (CN VI; choice A) innervates the lateral rectus muscles, which abduct
the eyes.
The optic nerve (CN II; choice C) is responsible for vision, providing the afferent limb of the
pupillary light reflex. The Edinger Westphal nucleus mediates part of this reflex.
The trigeminal nerve (CN V; choice D) is responsible for the afferent limb of the corneal
reflex. It also innervates the muscles of mastication and provides sensory innervation to the
face.
The trochlear nerve (CN IV; choice E) innervates the superior oblique muscles, which
depress, intort, and abduct the eyes.
- Which of the following veins may be anastomosed to accomplish a porto-caval shunt?
A. Left renal vein and left testicular vein
B. Right renal vein and right suprarenal vein
C. Splenic vein and left renal vein
D. Superior mesenteric vein and inferior mesenteric vein
E. Superior mesenteric vein and splenic vein
The correct answer is C. The splenic vein drains directly into the portal vein. The left renal
vein drains directly into the inferior vena cava. Anastomosis of these veins would allow blood
from the portal vein to drain retrograde though the splenic vein into the renal vein and then
into the inferior vena cava.
The left renal vein (choice A) drains directly into the inferior vena cava. The left testicular vein
drains directly into the left renal vein. Thus, these veins are already in communication, and
neither vein is part of the portal venous system.
The right renal vein (choice B) drains directly into the inferior vena cava. The right suprarenal
vein also drains directly into the inferior vena cava. Thus, neither vein is part of the portal
venous system.
The superior mesenteric vein (choice D) drains directly into the portal vein. The inferior
mesenteric vein drains into the splenic vein, which then drains into the portal vein. Thus,
neither vein is part of the caval venous system. The superior mesenteric vein (choice E)
drains directly into the portal vein. The splenic vein also drains directly into the portal vein.
Thus, neither vein is part of the caval venous system.
- In a histological section of a normal ovary, an oocyte is surrounded by several layers of
follicular cells. A small antrum is present. Which of the following is the correct term for the
entire structure, composed of the oocyte, follicular cells, and antrum?
A. Corpus luteum
B. Graafian follicle
C. Primary follicle
D. Primordial follicle
E. Secondary follicle
The correct answer is E. Follicles in different stages of maturation have different
appearances. The most primitive follicles, primordial follicles (choice D), are inactive reserve
follicles that contain primary oocytes (arrested in prophase of the first meiotic division)
surrounded by a single layer of flattened follicular cells. Primary follicles (choice C), the next
stage, are slightly larger and contain a central oocyte surrounded by one or several cuboidal
follicular cells. When several small spaces in the follicular mass fuse to form the antrum
(follicular cavity), the follicle is termed a secondary follicle (choice E). The secondary follicles
continue to enlarge and develop a more complex structure that includes cumulus oophorus,
corona radiata, theca interna, theca externa, and zona pellucida. The Graafian follicle (choice
B) is the mature form of the follicle, which extends through the entire cortex and bulges out at
the ovarian surface. After it ruptures and releases the ovum, the corpus luteum (choice
A)develops and secretes progesterone as the cells of the follicle and the theca interna cells
enlarge, become epithelioid, and secrete estrogen. If pregnancy occurs, it is maintained
throughout the pregnancy; if pregnancy does not occur, the corpus luteum eventually
degenerates.
226. Within which of the following peritoneal structures is the cystic artery located? A. Falciform ligament B. Gastrocolic ligament C. Gastrohepatic ligament D. Hepatoduodenal ligament E. Splenorenal ligamen
The correct answer is D. The hepatoduodenal ligament is the portion of the lesser omentum
that connects the liver to the first part of the duodenum. Within the hepatoduodenal ligament
are found the proper hepatic artery and its branches, the common bile duct and its branches,
and the portal vein. The cystic artery is usually a branch of the right hepatic artery, which is a
branch of the proper hepatic artery.
The falciform ligament (choice A) is a mesentery that connects the liver to the anterior
abdominal wall. Within the free edge of the falciform ligament is found the round ligament of
the liver (ligamentum teres hepatis), the adult remnant of the umbilical vein.
The gastrocolic ligament (choice B) is the portion of the greater omentum between the
greater curvature of the stomach and the transverse colon. The gastroepiploic arteries lie
within the gastrocolic ligament along the greater curvature of the stomach.
The gastrohepatic ligament (choice C) is the portion of the lesser omentum between the liver
and the lesser curvature of the stomach. The right and left gastric arteries are within the
gastrohepatic ligament along the lesser curvature of the stomach. The splenorenal ligament
(choice E) is the mesentery that connects the spleen to the posterior abdominal wall. The
splenic artery and splenic vein are within the splenorenal ligament.
- While performing a tonsillectomy, the surgeon accidentally damages the
glossopharyngeal nerve. Which of the following functional losses is likely to result from this
injury?
A. Loss of sensation on the posterior 1/3 of the tongue
B. Loss of taste on the anterior 2/3 of the tongue
C. Paralysis of the constrictor muscles of the palate
D. Paralysis of the muscles of the soft palate
E. Paralysis of the muscles of the tongue
The correct answer is A.The glossopharyngeal nerve, or cranial nerve IX, lies in the tonsillar
fossa. This nerve provides general sensory innervation to the mucosa of the pharynx, and
general sensory and taste sensation to the mucosa of the posterior 1/3 of the tongue. The
nerve also innervates the stylopharyngeus muscle, but this innervation occurs proximal to the
point at which the nerve crosses the tonsillar fossa. The full anatomical picture of the
glossopharyngeal nerve is as follows: It originates from the posterior 1/3 of the tongue, part of
the pharynx and palate, as well as the carotid arteries of the neck (sensory). It passes through
the jugular foramen of the temporal bone to foramen lacerum between the occipital and
temporal bones. The destination is to the sensory nuclei of the medulla oblongata, pharyngeal
muscles involved in swallowing, as well as the parotid.
Taste sensation to the anterior 2/3 of the tongue (choice B) is provided by the facial nerve.
The chordae tympani branch of the facial nerve travels with the lingual nerve to reach the
tongue.
The constrictor muscles of the pharynx (choice C) are innervated by the vagus nerve. The
vagus nerve fibers contribute to the pharyngeal plexus.
The muscles of the soft palate (choice D) are mostly innervated by the vagus nerve. The
tensor palati is innervated by the trigeminal nerve (V3).
The muscles of the tongue (choice E) are innervated by the hypoglossal nerve.
228. If the lateral wall of the left ventricle receives insufficient blood supply, which artery is most likely involved? A. Left anterior descending B. Left circumflex C. Left main coronary D. Right coronary
The correct answer is B. In some patients with coronary artery disease, thallium stress tests
may be performed instead of cardiac catheterization to determine the vessels involved and
the extent of occlusion. The left circumflex (LCx) branch supplies the lateral wall of the left
ventricle; in 10% of the population, it also supplies the posterior wall and AV node.
The left anterior descending (LAD) branch of the left coronary artery (choice A) supplies the
anterior wall of the left ventricle and the anterior portion of the interventricular septum.
The left main coronary artery (choice C) gives rise to both LCx and the LAD.
The right coronary artery (RCA; choice D) supplies the right ventricle; in 90% of the
population, it supplies the AV node and posterior and inferior walls of the left ventricle.
229. Which of the following products would mast cells be most likely to secrete? A. Bradykinin B. Complement factor 3a C. Histamine D. Interleukin-2 E. Nitric oxide
The correct answer is C. The cells in question are mast cells, which play an important role in
IgE-mediated allergic responses. It is also important to note that histamine is found in
basophils. They are a normal (minor) constituent of dermal skin and are most definitely
identified with stains, such as the Giemsa stain, that highlight the granularity of their
cytoplasm (mast cells are closely related to blood basophils). Mast cells secrete histamine,
serotonin, many leukotrienes, and platelet-aggregating factor (PAF). Their histamine secretion
after IgE stimulation helps to trigger the acute inflammatory part of the allergic response.
Bradykinin (choice A) is a nonapeptide found in the plasma. It is a potent vasodilator and
stimulates pain receptors.
Complement factor 3a (choice B) is a plasma protein that induces vascular leakage as part of
the acute inflammatory response.
Interleukin-2 (choice D) is secreted by lymphocytes and augments the immune response.
Nitric oxide (choice E) is released by macrophages and endothelium. It causes vasodilation
and cytotoxicity.
230. Which of the following gastrointestinal hormones is structurally related to secretin? A. Cholecystokinin B. Gastrin C. Glucagon D. Somatostatin E. Substance P
The correct answer is C. Glucagon, secretin, and vasoactive intestinal polypeptide (VIP) are
all structurally related.
Cholecystokinin (choice A) and gastrin (choice B) form another family of related hormones.
Neither somatostatin (choice D) nor substance P (choice E) are structurally related to
secretin. In addition to their role in the gastrointestinal system, both hormones are also
present in the brain.
231. In which of the following regions of the liver is the oxidase P450 system located? A. Bile ducts B. Intermediate zone C. "Ito" cells D. Pericentral vein zone E. Periportal zone
The correct answer is D. The liver can be divided into three zones. Zone 1 is periportal,
zone 2 is intermediate (between 1 and 3), and zone 3 is associated with the central vein.
Zone 3 contains the P450 oxidase enzyme system and is most sensitive to injury. The CP450
system is very important to be familiar with because it is the major site of drug interaction. For
example, the macrolides, which are commonly used in dentistry in penicillin-allergic patients
are potent hepatic enzyme inhibitors, as are antifungals like ketoconazole and fluconazole.
The P450 system is not located in the bile ducts (choice A).
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The intermediate zone (choice B), or zone 2, is the second area most sensitive to ischemic
injury.
“Ito” cells (choice C) are the fat-containing mesenchymal cells located in the space of Disse.
This is the site of vitamin A storage.
The periportal zone (choice E), or zone 1, is the area most sensitive to toxic injury. This is the
area that shows infiltration with hepatitis.
232. Which part of the hypothalamus controls satiety, and would lead to obesity if destroyed? A. Lateral nucleus B. Septal nucleus C. Suprachiasmatic nucleus D. Supraoptic nucleus E. Ventromedial nucleus
The correct answer is E. The ventromedial nucleus is thought to be the satiety center of the
brain. Bilateral destruction leads to hyperphagia, obesity, and savage behavior. Stimulation
inhibits the urge to eat.
Destruction of the lateral nucleus (choice A) results in starvation, whereas stimulation of this
nucleus induces eating.
Destruction of the septal nucleus (choice B) produces aggressive behavior.
The suprachiasmatic nucleus (choice C) receives direct input from the retina and plays a role
in controlling circadian rhythms.
The supraoptic nucleus (choice D), along with the periventricular nucleus, regulates water
balance and produces antidiuretic hormone (ADH) and oxytocin.
233. A premature infant develops a progressive difficulty with breathing over the first few days of life. Deficient surfactant synthesis by which of the following cell types may have contributed to the infant's respiratory problems? A. Alveolar capillary endothelial cells B. Bronchial mucous cells C. Bronchial respiratory epithelium D. Type I pneumocytes E. Type II pneumocytes
The correct answer is E. This child has neonatal respiratory distress syndrome (hyaline
membrane disease), which is caused by the inability of the immature lungs to synthesize
adequate amounts of surfactant. Surfactant, which reduces surface tension, helps keep
alveoli dry, and aids in expansion of the lungs, is synthesized by type II pneumocytes.
Alveolar capillary endothelial cells (choice A) are important in maintaining the capillary
structure and permitting flow of gases into and out of the blood stream.
Bronchial mucous cells (choice B) produce the usually thin (in healthy individuals) coat of
mucus that lines the bronchi.
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The ciliated bronchial respiratory epithelium (choice C) is responsible for moving the dustcoated
mucus layer out of the bronchi.
Type I pneumocytes (choice D) are the squamous cells that line alveoli and permit easy gas
exchange. These cells tend to be immature (and thick) in premature infants but do not
produce surfactant.
- Inability to extend the hand at the wrist is often accompanied by loss of sensation to
which area?
A. Lower part of the back of the little finger
B. Lower part of the back of the thumb
C. Palmar aspect of the forefinger
D. Palmar aspect of the little finger
E. Thumbnail bed
The correct answer is B. Associate “wrist drop” with a radial nerve lesion. The radial nerve
also provides sensation to the dorsal aspect of the radial side of the hand, including the lower
part of the dorsal aspect of the thumb and all the fingers, except for the little finger and half of
the ring finger.
The lower part of the back of the little finger (choice A) is supplied by the ulnar nerve.
The palmar aspects of all of the fingers (choices C and D) are supplied by the median nerve,
as are the nailbeds, including the thumbnail bed (choice E).
235. At which of the following locations might a penetrating wound to the heart damage the AV node? A. Apex of the heart B. Interatrial septum C. Interventricular septum D. Wall of the right atrium E. Wall of the left atrium
The correct answer is B. This question is essentially asking “where is the AV node located
on the heart?” The atrioventricular (AV) node is in the subendocardium of the interatrial
septum. The AV node can also be described as being within the floor of the right atrium near
the opening of the coronary sinus. From the AV node, the Purkinje fibers of the
atrioventricular bundle enter the interventricular septum to carry impulses to the ventricle. The
function of the AV node is to retard the conduction of the cardiac impulses so that ventricular
systole occurs after atrial systole.
The apex of the heart (choice A) is composed of ventricular wall musculature of the left
ventricle. There is no nodal tissue in this region.
The interventricular septum (choice C) contains the common bundle (AV bundle) and the
right and left bundle branches of the cardiac conduction system. These bundles are
composed of Purkinje fibers, which are specialized cardiac muscle cells.
The sinoatrial (SA) node is located in the right atrial wall (choice D), near the entrance of the
superior vena cava. The SA node contains specialized cardiac muscle cells that depolarize
more rapidly than do typical cardiac muscle cells, thereby serving as the pacemaker of the
heart. The wall of the left atrium (choice E) does not contain any nodal cells.
