Final Exam 4

Question 1

Which area derives from paraxial mesoderm (parachordal cartilages and occipital somites 1-4) and develops by endochondral ossification?

Answer 1

posterior chondrocranium

Question 2

Expression of which gene characterizes the zone of polarizing activity (ZPA)

Answer 2

sonic hedgehog (Shh)

Question 3

Limb muscles derive from which source?

Answer 3

paraxial (somatic) mesoderm

Question 4

Limb somatic sensory neurons derive from which source?

Answer 4

neural crest cells

Question 5

Expression of which gene is associated with initiation of limb growth?

Answer 5

FGF10

Question 6

Limb bones and cartilages derive from which source?

Answer 6

lateral somatic mesoderm

Question 7

Somatic motor neurons that regulate limb skeletal muscle derive from which source?

Answer 7

neural tube epithelium

Question 8

What is the most sensitive period during development for limb malformations?

Answer 8

weeks 4-5

Question 9

Maternal thalidomide ingestion early in the 4th week of pregnancy would most likely be associated with which limb anomaly?

Answer 9

amelia

Question 10

The pharyngeal pouches derive from which source?

Answer 10

endoderm

Question 11

The posterior one/third of the tongue principally derives from which structure?

Answer 11

posterior hypopharyngeal eminence

Question 12

A cervical sinus fistula would most likely be associated with which structure?

Answer 12

tonsillar sinus

Question 13

Taste sensation for the anterior two/thirds of the tongue is mediated by which cranial nerve?

Answer 13

CN VII

Question 14

The intermaxillary segment that forms the primary palate derives from which structures?

Answer 14

medial nasal prominences

Question 15

The line of fusion between the lateral nasal prominences and the maxillary prominences marks the formation of which adult structure?

Answer 15

lacrimal sac

Question 16

Identify the structures or areas

Answer 16

primary palate

palatal shelves

Question 17

Disruption of which structures would account for bilateral posterior cleft palate?

Answer 17

failed palatine shelf fushion

Question 18

The auricle of the ear derives from the auricular hillocks located where?

Answer 18

1st and 2nd arches

Question 19

Which layers contribute to the tympanic membrane (eardrum)?

Answer 19

ectoderm, mesoderm, and endoderm

Question 20

The middle ear ossicles malleus and incus derive from which source?

Answer 20

1st arch

Question 21

The semicircular canals derive from which structure?

Answer 21

utricular portion of otic vesicle

Question 22

Most axons in the vestibulococlear nerve (CN VIII) represent which type of neuron?

Answer 22

bipolar neurons

Question 23

Identify the germ layer of origin for the lung bud.

Answer 23

endoderm

Question 24

Although the capability for actual gas exchange is limited, the stage of lung development marked by early alveolar development and initiation of surfactant production would be the?

Answer 24

terminal sac

Question 25

What is the origin of the lung Type II cells?

Answer 25

endoderm

Question 26

The pancreas develops from which embryonic layer?

Answer 26

endoderm

Question 27

Which structure does not develop from the original hepatic diverticulum?

Answer 27

dorsal pancreas

Question 28

Which structure derives from or in association with the dorsal mesogastrum?

Answer 28

greater omentum

Question 29

Where does the spleen develop?

Answer 29

dorsal mesogastrum

Question 30

Formation of the midgut primary intestinal loop depends on which major vitelline artery derivative?

Answer 30

superior mesenteric

Question 31

Which adult organ derives from both the foregut and midgut?

Answer 31

duodenum

Question 32

Which structure derives from the caudal limb of the primary intestal loop?

Answer 32

cecum and appendix

Question 33

Failed retraction of the gut following physiological herniation results in?

Answer 33

omphalocele

Question 34

Which characteristic do the lungs, pancreas, appendix and proximal rectum all share in common?

Answer 34

epithelium derives from endoderm

Question 35

The definitive anal canal is composed of which tissues?

Answer 35

endoderm + ectoderm

Question 36

A near-term infant had a light gray shiny mass protruding from the umbilicus. This mass appears to be covered by a thin transparent membrane. Closer inspection showed the mass to consist primarily of intestinal loops. What is the diagnosis?

Answer 36

omphalocele

Question 37

Which structure develops from the ureteric bud?

Answer 37

collecting tubules

Question 38

Which structure will connect directly to the urogenital sinus at some point during embryonic development?

Answer 38

all of the above | allantois, mesonephric duct & metanephric duct

Question 39

What is the origin of the mesonephric ducts?

Answer 39

intermediate mesoderm

Question 40

What is the origin of the metanephric blastemal?

Answer 40

intermediate mesoderm

Question 41

Differentiation of the male gonads and ducts is dependent on a cascade of hormones and growth factors driven by the Y chromosome. Which sequence best describes this cascade in normal males?

Answer 41

TDF- Sertoli cells- MIS- paramesonephric tubule regression

Question 42

What is the origin of the vas deferens?

Answer 42

mesonephric ducts

Question 43

What is the origin of the prostrate gland?

Answer 43

urogenital sinus

Question 44

What is the origin of the oviducts?

Answer 44

paramesonephric ducts

Question 45

What is the origin of the distal vagina?

Answer 45

urogenital sinus

Question 46

What is the origin of the body of the uterus?

Answer 46

paramesonephric ducts

Question 47

Which structure represents the female counterpart of the male scrotum?

Answer 47

labia majora

Question 48

What is the origin of the urogenital sinus?

Answer 48

endoderm

Question 49

An early castrated male embryo supplemented with testosterone will have which duct arrangement?

Answer 49

mesonephric and paramesonephric ducts will be present

Question 50

Bonus- | A child develops a large midline cyst just above the larynx. What is the likely origin of this cyst?

Answer 50

thyroglossal duct remnant

Question 51

What are the basic roles of HOX genes, T-box genes and fibroblast growth factors (FGF) 10 and 8?

Answer 51

HOX - regulates body formation during development. T-box - limb and heart development FGF 10 - limb growth and wound healing FGF 8 - forebrain

Question 52

Explain why the AER (apical ectodermal ridge) is essential to limb development and, how the AER differs from the ZPA (zone of proliferating activity)

Answer 52

it forms ectodermal cells that act as major signaling centers to ensure proper development of a limb; ZPA is essential for maintaining AER

Question 53

What is embryonic limb rotation and why is it important?

Answer 53

it produces normal rotated limbs

Question 54

What is the most sensitive period for limb malformations and why?

Answer 54

4-5 weeks because organogenesis occurs

Question 55

What is thalidomide, what are its effects and when do they occur?

Answer 55

its a sedative, causes limb abnormality (amelia), happens in 4th week

Question 56

What is a cervical sinus fistula and how does it develop?

Answer 56

deep depression on side of neck formed by 2nd-4th pharyngeal grooves merging

Question 57

Outline the process of thyroid gland development and explain how you would distinguish between a cervical cyst and a thyroglossal cyst?

Answer 57

forms as proliferation of endodermal epithelial cells - cervical cyst is in thyroid - thyroglossal cyst is in midline mass

Question 58

Describe the embryonic origins of the adult tongue and its cranial nerve innervation

Answer 58

occipital somites (hypoglossal XII), lateral tongue buds (trigeminal), copula (facial VII), anterior hypopharyngeal eminence (glossopharyngeal IX and vagus X)

Question 59

What is the basis for salivary gland development?

Answer 59

on stomodeum ectoderm the parotid, on endoderm the submandibular and sublingual glands

Question 60

Describe the process of nasal cavity formation.

Answer 60

oronasal breaks apart and causes opening of primitive choana which connects nasal and oral cavity

Question 61

Which structures contribute to primary palate formation and what are their adult derivatives?

Answer 61

1st pharyngeal arch and frontonasal prominence- | nasal and oral cavity

Question 62

Which structures contribute to secondary palate formation

Answer 62

anterior hard palate and posterior soft palate

Question 63

Outline the embryonic origins and development of the external auditory canal and auricle of the ear

Answer 63

external auditory canal-1st groove | auricle of the ear-auricular hillocks

Question 64

What are the embryonic origins of the tympanic membrane and middle ear cavity and ossicles?

Answer 64

tympanic membrane-1st membrane middle ear cavity-1st pouch ossicles-arch1: malleus and incus arch2: stapes

Question 65

What kind of neurons make up most of the axons found in the vestibulocochlear nerve?

Answer 65

bipolar

Question 66

Identify the germ layer of origin for the lung bud, visceral pleura, and parietal pleura

Answer 66

visceral pleura-splanchnic mesoderm | parietal pleura-somatic mesoderm

Question 67

What is a tracheoesophageal fistula and why do they occur?

Answer 67

an abnormal connection between esophagus and trachea

Question 68

List the three primary gut tube regions and outline the major arterial supply and venous drainage routes for each region also adult derivatives

Answer 68

``` foregut -artery: celiac adult: pharynx, esophagus, liver, gallbladder midgut -artery: superior mesenteric adult: jejunum, ileum, cecum hindgut -artery: inferior mesenteric adult: transverse colon, descending colon, sigmoid colon, rectum Venous drainage: Portal venous system ```

Question 69

Describe the location of the omental bursa, greater omentum, lesser omentum, epiploic foramen of Winslow and falciform ligament

Answer 69

falciform ligament-on liver epiploic foramen of Winslow- above stomach below liver lesser omentum-above stomach greater omentum-hangs down from stomach omental bursa-formed by lesser and greater omentum

Question 70

Identify the germ layer origin for each of the following: seminal vesicles, prostate, bulbourethral glands, paramesonephric ducts, paraurethral glands, greater vestibular glands and vagina

Answer 70

seminal vesicles-mesoderm prostate-endoderm paramesonephric ducts-mesoderm

Question 71

Outline the major derivatives of the genital tubercle and urethral and labioscrotal folds in males vs females

Answer 71

genital tubercle becomes penis or clitoris urethral fold becomes labia majora labioscrotal folds become scrotum