Development of Bodily Coelom

Question 1

The coelom is formed by the splitting of the lateral mesoderm extending to the ____ and ____ but does not reach the level of the pharynx

Answer 1

thoracic and abdominal region

Question 2

____ closes the coelom ventrally, except at the level of the ____

Answer 2

Lateral body folds

umbilicus

Question 3

In the embryo, all regions of the intraembryonic coelom are continuous, the only partition is the ____ lying in a transverse plane between the sinus venosus and the liver

Answer 3

septum transversum

Question 4

Dorsal to the septum transversum is the common ____ continuous with the peritoneal coelom

Answer 4

pleuropericardial cavity

Question 5

Caudal growth of the ____ brings the lungs into the dorsal part of the pleuropericardial cavity near the level of the septum transversum and into cranial mediastinum

Answer 5

laryngotracheal groove

Question 6

refers to any median partition commonly used in reference to the thoracic cavity

Answer 6

Mediastinum

Question 7

Formation of the pericardial cavity and its separation from the pleural cavity is iniated by the ____ which grow medially and fuse
with the mediastinum ventral to the esophagus forming the pleuropericardial septum Pleural and pericardial cavities then formed

Answer 7

pleuropericardial folds

Question 8

The diaphragm is composed of
two components:

Answer 8

septum transversum

caudal mediastinum sometimes called
dorsal mesentery

Question 9

*DIAPHRAGM

(forms early during heart formation) that forms the central tendinous part of the diaphragm

Answer 9

septum transversum

Question 10

*DIAPHRAGM

____ thru which the esophagus and caudal vena cava pass

Answer 10

caudal mediastinum (dorsal mesentery)

Question 11

*DIAPHRAGM

Expansion of the ____ dorsoventrally causes
the roof of the pleural cavities to elevate on either side

Answer 11

caudal medistinum

Question 12

*DIAPHRAGM

Final closure of the cavities is thru the growth of the ____ projecting the peritoneal cavity

Answer 12

pleuroperitoneal folds

Question 13

*CLOACA

The ____ portion of the hindgut gives rise to the aboral portion of the transverse colon and the descending colon.

Answer 13

oral

Question 14

*CLOACA

The more ____ portion of the hindgut gives rise to the rectum, and to the allantois and its derivatives.

Answer 14

aboral

Question 15

The hindgut terminates in the ____, a caudal cavity lined by endoderm and sealed from the amniotic cavity by the ____ which is lined by endoderm and covered by ectoderm on the outside.

Answer 15

cloaca

cloacal membrane

Question 16

*CLOACA

A layer of mesoderm that separates the allantoic duct and the hindgut.

Answer 16

URORECTAL SEPTUM

Question 17

*URORECTAL SEPTUM

Divides the cloacal membrane into an ____ dorsally and a ____ ventrally.

Answer 17

anal membrane

urogenital membrane

Question 18

• Continuous with the hindgut
• Becomes the rectum and most of the anal canal.

Answer 18

Dorsal chamber (of urorectal septum)

Question 19

• The urogenital sinus
• Continuous with the allantois.
• Develops into the perineal body.

Answer 19

Ventral chamber (of urorectal septum)

Question 20

Tissue surrounding the anal membrane grows caudally creating a depression called the ____.

Answer 20

proctodeum

Question 21

• When the anal membrane degenerates, the proctodeum becomes incorporated into the anal canal.
• In carnivores, lateral diverticula of proctodeum ectoderm become ____.

Answer 21

anal sacs

Question 22

Which mesentery?

fates: Greater omentum,
mesoduodenum,
mesentery (mesojejunum mesoileum),
mesocolon,
mesorectum

Answer 22

Dorsal mesentery

Question 23

Which mesentery?

fates: Lesser omentum,
coronary,
falciform ligaments of the liver,
median ligament of the urinary bladder

Answer 23

ventral mesentery

Question 24

Results from the lack of fusion of the
maxillary and medial nasal prominences
during embryonic development.

Answer 24

CHEILOSCHESIS (CLEFT LIP)

Question 25

Result from partial or complete failure of apposition and fusion of the palate processes resulting in an open connection between oral and nasal cavities.

Answer 25

PALATOSCHISIS (CLEFT PALATE)

Question 26

Complete absence of the lower jaw

Answer 26

MANDIBULAR AGNATHIA

Question 27

* Short lower jaw or overshot or parrot mouth in horses * The mandible is shorter than the maxilla.

Answer 27

MANDIBULAR BRACHYGNATHIA

Question 28

* Prognathia or undershot in horses * The mandible is longer than the maxilla.

Answer 28

MAXILLARY BRACHYGNATHIA

Question 29

* The tongue is incomplete or abnormally developed. * ‘Bird tongue’ in dogs and may be a component of the fading puppy syndrome.

Answer 29

ANKYLOGLOSSIA

Question 30

* Enlargement of the tongue * Seen in Belted Galloway cattle but is rarely clinically significant

Answer 30

MACROGLOSSIA

Question 31

Abnormally small tongue

Answer 31

MICROGLOSSIA

Question 32

* Complete absence of teeth * Results from disturbances in the interaction between the dental lamina and neural crest mesenchyme.

Answer 32

ANODONTIA

Question 33

*Teeth abnormality * Within the jawbone

Answer 33

EXTRA TEETH (SUPERNUMERARY TEETH)

Question 34

*Teeth abnormality In other areas of the head

Answer 34

HETEROTOPIC POLYDONTIA

Question 35

*Teeth abnormality * Administration of tetracyclines to pregnant females or to puppies younger than 6 months old.

Answer 35

ENAMEL DISCOLOURATION

Question 36

* Abnormal narrowing or stricture of a portion of the digestive tract * Observed more frequently in the small intestine than elsewhere in the tract

Answer 36

STENOSIS

Question 37

* Lack of epithelial canalization and gut wall development * Results in feed impaction and death if surgical intervention cannot be made.

Answer 37

ATRESIA OF THE JEJUNUM, ILEUM, COLON, RECTUM

Question 38

* Esophageal dilation which sometimes occurs in dogs and cats

Answer 38

CONGENITAL MEGAESOPHAGUS

Question 39

* Failure of the cricopharyngeus muscle to relax during swallowing

Answer 39

CRICOPHARYNGEAL ACHALASIA

Question 40

* An appendix-like remnant of the yolk stalk. * Persistence, inflammation, and rupture of this structure results in colic, with peritonitis.

Answer 40

MECKEL’S DIVERTICULUM

Question 41

* Dilatation of the colon which occurs cranial to a contracted aganglionic segment of the intestine. * Uncommon condition described in pigs and dogs.

Answer 41

MEGACOLON (HIRSCHSPRUNG’S DISEASE)

Question 42

* Results from lack of involution of the cloacal membrane * Leads to fatal feed impaction.

Answer 42

IMPERFORATE ANUS

Question 43

* Condition in which the rectum and the urogenital tract communicate openly * Results from an abnormality in the development of the urorectal septum that permits communication between the rectum and a derivative of the urogenital sinus * Termed recto-vesicular, recto-urethral, recto- vaginal or recto-vestibular

Answer 43

URORECTAL FISTULA

Question 44

A condition in which both the thoracic and abdominal organs are transferred to the side opposite to that in which they are normally located.

Answer 44

SITUS INVERSUS

Question 45

The intestinal loops fail to return to the abdominal cavity from the umbilical sac and protrude through an enlarged umbilical ring

Answer 45

OMPHALOCOELE

Question 46

* Loops of intestine protrude through the abdominal wall and occupy a subcutaneous position. * Occurs more commonly in pigs than in other domestic animals

Answer 46

CONGENITAL UMBILICAL HERNIA