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COB Embryo Exam 3 book questions > exam 3 book questions > Flashcards

exam 3 book questions Flashcards

1
Q

Which of the following molecules plays an important role in the determination of the dorsoventral axis of the developing limb?

a. Msx-1
b. Wnt-7a
c. Hoxd-13
d. Pax-1
e. FGF-8

A

b. Wnt-7a

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2
Q

What molecule is associated with myogenic cells migrating into the limb bud from the somites?

a. shh
b. BMP-7
c. FGF-4
d. Pax-3
e. En-1

A

d. Pax-3

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3
Q

What is the principal function of the AER?

a. stimulating outgrowth of the limb bud
b. setting up the anteroposterior axis of the limb bud
c. determining the specific characteristics of the ectodermal appendages of the limb
d. determining the pattern of neural ingrowth into the limb
e. attracting the subcutaneous plexus of capillaries in the limb bud

A

a. stimulating outgrowth of the limb bud

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4
Q

In the developing limb the sonic hedgehog (shh) gene product is produced in the :

a. progress zone
b. region of interdigital cell death
c. ZPA
d. AER
e. common muscle mass

A

c. ZPA

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5
Q

The connective tissue of the limb arises from the:

a. paraxial mesoderm
b. neural crest
c. intermediate mesoderm
d. somitic mesoderm
e. lateral mesoderm

A

e. lateral mesoderm

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6
Q

The formation of clubfoot (talipes equinovarus) is associated with:

a. a misplaced ZPA
b. defective cellular migration from somites
c. thalidomide
d. oligohydramnios
e. a neural crest defect

A

d. oligohydramnios

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7
Q

An infant whose mother underwent chorionic villus sampling during pregnancy was born with the tips of two digits missing. What is a possible cause?

A

A tear of the amnion during the chorionic villus sampling procedure could have resulted in an amniotic band wrapping around the digits and strangulating their blood supply, thereby causing the tips to degenerate and fall off.

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8
Q

A woman who underwent amniocentesis during pregnancy gave birth to a child with a duplicated thumb. What is a possible cause?

A

This defect is unlikely to be related to the amniocentesis procedure because the morphology of the digits is well established by the time this procedure is done ( usually around 15 to 16 weeks). The most likely cause is a genetic mutation.

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9
Q

If the somites close to a limb-forming region are experimentally removed, the limbs form without muscles. Why?

A

Muscle-forming cells arise from the somites

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10
Q

A child is born with webbed fingers (syndactyly). What is the reason for this anomaly?

A

The immediate cause is likely the absence of programmed cell death in the interdigital mesoderm. The cause of the disturbance in cell death is currently not understood.

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11
Q

Rathke’s pouch arises from the:

a. diencephalon
b. stomodeal ectoderm
c. mesencephalon
d. pharyngeal endoderm
e. infundibulum

A

b. stomodeal ectoderm

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12
Q

Which of these cell and tissue types arises from cranial, but not trunk, neural crest cells?

a. sensory ganglia
b. adrenal medulla
c. melanocytes
d. schwann cells
e. none of the above

A

e. none of the above

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13
Q

Which molecule is a poor substrate for migrating neural crest cells?

a. laminin
b. chondroitin sulfate
c. fibronectin
d. type IV collagen
e. hyaluronic acid

A

b. chondroitin sulfate

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14
Q

Neural crest cells arise from the:

a. somite
b. dorsal non-neural ectoderm
c. neural tube
d. splanchnic mesoderm
e. yolk sac endoderm

A

c. neural tube

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15
Q

A 6-month old infant exhibits multiple congenital defects, including a cleft palate, deafness, ocular hypertelorism, and a white forelock but otherwise dark hair on his head. The probable diagnosis is:

a. CHARGE association
b. von Recklingausen’s disease
c. Hirschsprung’s disease
d. Waardenburg’s syndrome
e. none of the above

A

d. Waardenburg’s syndrome

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16
Q

What molecule is involved in the migration of neural crest cells from the neural tube?

a. slug
b. BMP-2
c. mash 1
d. norepinephrine
e. glial growth factor

A

a. slug

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17
Q

Which is not a derivative of the neural crest?

a. sensory neurons
b. motoneurons
c. schwann cells
d. adrenal medulla
e. dental papilla

A

b. motoneurons

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18
Q

What maintains the competence of neural crest cells to differentiate into autonomic neurons?

a. sonic hedgehog
b. acetylcholine
c. mash 1
d. glial growth factor
e. transforming growth factor-beta

A

c. mash 1

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19
Q

If trunk neural crest cells are transplanted into the cranial region, they can form all of the following types of cells except:

a. pigment cells
b. schwann cells
c. sensory neurons
d. cartilage
e. autonomic neurons

A

d. cartilage

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20
Q

How does the segmental distribution of the spinal ganglia occur?

A

Along the length of the spinal cord, migrating neural crest cells are funneled into the anterior sclerotomal region of the somites and are excluded from the posterior half. This results in the formation of a pair of ganglia for each vertebral segment and space between ganglia in the craniocaudal direction.

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21
Q

What are the three major differences between cranial and trunk neural crests?

A
  1. cranial crest cells can form skeletal elements, while trunk crest cells cannot.
  2. migrating cranial neural crest cells have more morphogenetic information encoded in them than trunk cells do. (for ex. craniocaudal levels are specified in cranial crest cells)
  3. cranial crest cells from large amounts of dermis and other connective tissues, whereas trunk crest cells do not.
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22
Q

Neural crest-derived cells constitute a significant component of which tissue of the eye?

a. neural retina
b. lens
c. optic nerve
d. cornea
e. none of the above

A

d. cornea

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23
Q

The otic placode arises through an inductive message given off by the:

a. telencephalon
b. rhombencephalon
c. infundibulum
d. diencephalon
e. mesencephalon

A

b. rhombencephalon

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24
Q

What molecule plays a role in guidance of advancing retinal axons through the optic nerve?

a. Pax-2
b. FGF-3
c. BMP-4
d. Pax-6
e. BMP-7

A

a. Pax-2

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25
Q

Surface ectoderm is induced to become corneal epithelium by an inductive event originating in the:

a. optic cup
b. chordamesoderm
c. optic vesicle
d. lens vesicle
e. neural retina

A

d. lens vesicle

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26
Q

The second pharyngeal arch contributes to the:

a. cochlea and earlobe
b. auditory tube and incus
c. stapes and earlobe
d. auditory tube and stapes
e. otic vesicle and stapes

A

c. stapes and earlobe

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27
Q

During a routine physical examination, an infant was found to have a small segment missing from the lower part of one iris. What is the diagnosis, what is the basis for the condition, and why may the infant be sensitive to bright light?

A

Coloboma of the iris is caused by failure of the choroid fissure to close during the sixth week of pregnancy. Because the area of the defect remains open when the rest of the iris constricts in bright light, excessive unwanted light can enter the eye through the defect.

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28
Q

why does a person sometimes get a runny nose while crying?

A

Some of the secretions of the lacrimal glands enter the nasolacrimal ducts, which carry the lacrimal fluid into the nasal cavity.

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29
Q

What extracellular matrix molecule is often associated with migration of mesenchymal cells, and where does such an event occur in the developing eye?

A

Hyaluronic acid. Migration of neural crest cells into the developing cornea occurs during a period when large amounts of hyaluronic acid have been secreted into the primary corneal stroma.

30
Q

Why is the hearing of a newborn often not as acute as it is a few months later?

A

During the fetal period, the middle ear cavity is filled with a loose connective tissue that dampens the action of the middle ear ossicles. After birth, the connective tissue is resorbed.

31
Q

Why are malformations or hypoplasia of the lower jaw commonly associated with abnormalities in the shape or position of the ears?

A

Similar to the lower jaw, much of the external ear arises from tissue of the first arch bordering the first pharyngeal cleft.

32
Q

An early induction in tooth development consists of the ectoderm of the dental epithelium acting on the underlying neural crest mesenchyme. which of the following molecules is an important mediator of the inductive stimulus?

a. BMP-4
b. Tenascin
c. Hoxb-13
d. Msx-1
e. syndecan

A

a. BMP-4

33
Q

The facial nerve (cranial nerve VII) supplies muscles derived from which pharyngeal arch?

a. first
b. second
c. third
d. fourth
e. sixth

A

b. second

34
Q

Cleft lip results from lack of fusion of the:

a. nasomedial and nasolateral processes
b. nasomedial and maxillary processes
c. nasolateral and maxillary processes
d. nasolateral and mandibular processes
e. nasomedial and mandibular processes

A

b. nasomedial and maxillary processes

35
Q

In cases of holoprosencephaly, defects of facial structures are typically secondary to defects of the:

a. pharynx
b. oral cavity
c. forebrain
d. eyes
e. hindbrain

A

c. forebrain

36
Q

Meckel’s cartilage is a prominent structure in the early formation of the:

a. upper jaw
b. hard palate
c. nasal septum
d. soft palate
e. lower jaw

A

e. lower jaw

37
Q

A 15-year old boy with mild acne developed a tender boil along the anterior border of the sternocleidomastoid muscle. What embryological condition would be included in a differential diagnosis?

A

One option is simply acne. Another more significant possibility is a branchial cyst. Branchial cysts are typically located along the anterior border of the sternocleidomastoid muscle. One possible reason for its late manifestation is that the same conditions that resulted in the boy’s acne caused a simultaneous reaction in the epidermis lining the cyst.

38
Q

The physician of the 15 year old boy described in the previous question determined that the boy had a congenital cyst that needed to be removed surgically. What should the surgeon consider during removal of the cyst?

A

First, all epithelium lining the cyst must be removed, or the remnants could reform into a new cyst, and the symptoms could recur. The surgeon also must determine that the cyst is isolated and not connected to the pharynx via a sinus, which would result from an accompanying persistence of the corresponding pharyngeal pouch.

39
Q

Why does a person sometimes get a runny nose when crying?

A

Some of the secretions of the lacrimal glands enter the nasolacrimal ducts, which carry the lacrimal fluid into the nasal cavity.

40
Q

A woman who took an anticonvulsant drug during the 10th week of pregnancy gave birth to an infant with bilateral cleft lip and cleft palate. she sued the physician, blaming the facial malformations on the drug,and you are called in as an expert witness for the defense. what would be the basis for your case?

A

By 10 weeks, all the processes of fusion of facial primordial have already been completed. The cause of the defects could almost certainly be attributed to something that influenced the embryo before the time when the anticonvulsant therapy was initiated, probably before the 7th week of pregnancy.

41
Q

A woman who averaged 3 mixed drinks a day during pregnancy gave birth to an infant who was mildly retarded and who had a small notch in an upturned upper lip and a reduced olfactory sensitivity. What is the basis for this constellation of defects?

A

These defects could be a manifestaton of fetal alcohol syndrome. They could represent a mild form of holoprosencephaly, which in this case would relate to defective formation of the forebrain (prosencephalon). The defects in olfaction and in the structure of the upper lip could be secondary effects of a primary defect in early formation of the prosencephalon.

42
Q

Which condition is most closely associated with a disturbance of neural crest?

a. anal atresia
b. meckel’s diverticulum
c. omphalocele
d. volvulus
e. aganglionic megacolon

A

e. aganglionic megacolon

43
Q

Meckel’s diverticulum is most commonly located in the:

a. IIeum
b. ascending colon
c. jejunum
d. transverse colon
e. duodenum

A

a. IIeum

44
Q

The primordium of which structure is located in the septum transversum?

a. dorsal pancreas
b. lung
c. liver
d. thymus
e. spleen

A

c. liver

45
Q

The yolk stalk is most closely associated with which artery?

a. celiac
b. umbilical
c. superior mesenteric
d. aorta
e. inferior mesenteric

A

c. superior mesenteric

46
Q

The dorsal pancreatic bud is initially induced from the gut endoderm by the:

a. liver
b. notochord
c. lung bud
d. yolk sac
e. none of the above

A

b. notochord

47
Q

Splanchnic mesoderm acts as an inducer of all of the following tissues or organs except:

a. teeth
b. trachea
c. liver
d. lungs
e. pancreas

A

a. teeth

48
Q

During the first feeding, a newborn begins to choke. What congenital anomalies should be included in the differential diagnosis?

A

Esophagela atresia or a tracheosophageal fistula

in esophagela atresia-the milk fills the blind esophageal pouch and then spills into the trachea via the laryngeal opening.

Tracheoesophageal fistula–milk may pass directly from the esophagus int othe trachea depending on the type of fistula

49
Q

A newborn took the first feeding of milk without incident, but an hour later was crying in pain and vomited the milk with considerable force. Examination revealed a hard mass near the midline in the upper region of the abdomen. What was the diagnosis?

A

Congenital pyloric stenosis- projectile vomiting is common, and palpation of the knotted pyloric opening of the stomach confirmed the diagnosis.

50
Q

An infant was noted to extrude a small amount of mucus and fluid from the umbilicus when crying or straining. This should make the physician think of what congenital anomaly in the differential diagnosis?

A

vitelline duct fistula connecting the midgut with the umbilicus.——This allows some contents of the SI to escape through the umbilicus. Or could be urachal fistula—which connects the urinary bladder to the umbilicus through a persistent allantoic duct. In this case, however, the escaping fluid would be urine and would likely not be accompanied by mucus.

51
Q

A newborn was given a cursory physical examination and was taken home by the mother 1 day after delivery. Several days later, the mother brought the infant to the clinic. The infant was in obvious severe discomfort with a swollen abdomen. Physical examination revealed that an important congenital anomaly had been overlooked at the original examination. What was that anomaly?

A

Imperforate anus. When examining a newborn, clinicians must ensure that there is an anal opening.

52
Q

Which of the following does not connect directly with the primary nephric (mesonephric) duct?

a. metanephros
b. cloaca
c. nephrotomes
d. mesonephric tubules
e. ureteric bud

A

a. metanephros

53
Q

Which association is correct?

a. Potter’s facies and hydramnios
b. urachal fistula and hydramnios
c. Horseshoe kidney and superior mesenteric artery
d. GDNF and metanephrogenic blastema
e. bilateral renal agenesis and compensatory hypertrophy

A

d. GDNF and metanephrogenic blastema

54
Q

Which defect is strongly associated with oligohydramnios?

a. pelvic kidney
b. renal agenesis
c. horeshoe kidney
d. crossed ectopia
e. polycystic kidney

A

b. renal agenesis

55
Q

Which anomaly is most closely associated with exstrophy of the bladder?

a. epispadias
b. renal agenesis
c. anal atresia
d. pelvic kidney
e. ectopic ureteral orifice

A

a. epispadias

56
Q

The uterus arises from the:

a. paramesonephric ducts
b. urogenital sinus
c. mesonephric tubules
d. pronephric ducts
e. mesonphric ducts

A

a. paramesonephric ducts

57
Q

the floor of the penile urethra in the male is homologous to what structure in the female?

a. clitoris
b. trigone of the bladder
c. labia majora
d. labia minora
e. perineum

A

d. labia minora

58
Q

The metanephrogenic blastema is induced by the:

a. prnephric duct
b. ureteric bud
c. mesonephric tubules
d. allantois
e. mesonephric duct

A

b. ureteric bud

59
Q

Drops of a yellowish fluid were observed around the umbilicus of a young infant. What is a likely diagnosis, and what is the embryological basis?

A

urachal fistula connecting the urinary bladder to the umbilicus and allowing the leakage of urine. This is caused by the persistence of the lumen in the distal part of the allantois.

60
Q

A woman who gained relatively little weight during pregnancy gives birth to an infant with large, low set ears, a flattened nose, and a wide interpupillary space. Within hours after birth, the infant is obviosly in great distress and dies after 2 days. What is the diagnosis?

A

Bilateral renal agenesis. The first clue was the mother’s low weight gain, which could have been the result of oligohydramnios ( although this is not the only cause for low weight gain during pregnancy). The infant’s appearance showed many of the characteristics of Potter’s syndrome—which is caused by intrauterine pressures on the fetus when the amount of amniotic fluid is very low

61
Q

A seemingly normal woman experiences pelvic pain during the later stages of pregnancy. An ultrasound examination reveals that she has a bicarnuate uterus. What is the embryological basis for this condition?

A

In normal development, the caudal ends of the paramesonephric ducts swing toward the mid-line and fuse. In this patient’s case, the point of fusion probably occurred more caudally than normal. This condition is compatible with a normal pregnancy and delivery, although in some cases, pain or problems with delivery can occur.

62
Q

Nucleated erythrocytes found circulating in the embryo are produced in the:

a. yolk sac
b. para-aortic clusters
c. liver
d. bone marrow
e. none of the above

A

a. yolk sac

63
Q

in a 7-month fetus, blood draining the left temporalis muscle enters the heart via the:

a. left anterior cardinal vein
b. coronary sinus
c. left common cardinal vein
d. superior vena cava
e. none of the above

A

d. superior vena cava

64
Q

Adherons are inductive particles released by what structure in the endocardial cushion area?

a. endocardium
b. cardiac jelly
c. myocardium
d. epicardium
e. none of the above

A

c. myocardium

65
Q

Neural crest contributes to the structure of which of the following?

a. truncus arteriosus
b. ascending aorta
c. pulmonary trunk
d. all of the above
e. none of the above

A

d. all of the above

66
Q

For which of these cardiovascular malformations is a patent ductus arteriosus necessary for survival of the individual?

a. atrial septal defect
b. ventricular septal defect
c. double aortic arch
d. right subclavian artery from arch of aorta
e. none of the above

A

e. none of the above

67
Q

Five days after birth, an infant becomes cyanotic during a prolonged crying spell. The cyanosis is most likely caused by venous blood entering the systemic circulation through the:

a. interatrial septum
b. ductus arteriosus
c. ductus venosus
d. umbilical vein
e. interventricular septum

A

a. interatrial septum

68
Q

The internal carotid artery arises from aortic arch number:

a. 1
b. 2
c. 3
d. 4
e. 5

A

c. 3

69
Q

A 12-year old boy tells his physician that over the past few months he has noticed some difficulty in swallowing when eating meat. The physician performs a physical examination and orders an upper gastrointestinal x-ray series. After examining the films, the physician refers the boy for some vascular studies. What is the reasoning behind this decision?

A

The physician suspected that the boy had a double aortic arch or a right aortic arch, either of which can cause difficulty in swallowing (dysphagia) during childhood, especially when growth spurts are occurring.

Another possibility for an embryo-logically based dysphagia is esophageal stenosis.

70
Q

An individual with atresia of the mitral valve could not survive after birth without other defects of the cardiovascular system that could compensate for the primary defect, in this case a complete blockage between the LA and Ventricle. Construct at least one set of associated defects that could compensate for the disruption caused by the mitral atresia.

A

To survive, an individual with this defect would have to have a means for draining blood entering the LA and a means of transporting blood into the LV or the systemic circulation. One combination that would compensate is an atrial septal defect, which allows incoming blood to escape from the LA, and an associated ventricular septal defect, which allows blood from the RV to pass into the LV.

A patent ductus arteriosus added to the first 2 compensatory defects could also help to balance the circulation by adding blood to the systemic side of the circulation. This would not be very helpful in the physiological sense, however, because the added blood would be unoxygenated blood entering the aorta from the pulmonary artery.

71
Q

What is the embryological basis for a duplication of the inferior vena cava caudal to the kidneys?

A

Persistence of the caudal segment of the left supracardinal vein.

normally, the caudal segment of the right supracardinal vein persists and becomes incorporated into the inferior vena cava, and the corresponding segment of the left supracardinal vein disappears. A wide variety of anomalous patterns of the abdominal veins exist.

COB Embryo Exam 3 book questions (1 decks)

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