Development of Bodily Coelom Flashcards
The coelom is formed by the splitting of the lateral mesoderm extending to the ____ and ____ but does not reach the level of the pharynx
thoracic and abdominal region
____ closes the coelom ventrally, except at the level of the ____
Lateral body folds
umbilicus
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
septum transversum
Dorsal to the septum transversum is the common ____ continuous with the peritoneal coelom
pleuropericardial cavity
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
laryngotracheal groove
refers to any median partition commonly used in reference to the thoracic cavity
Mediastinum
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
pleuropericardial folds
The diaphragm is composed of
two components:
septum transversum
caudal mediastinum sometimes called
dorsal mesentery
*DIAPHRAGM
(forms early during heart formation) that forms the central tendinous part of the diaphragm
septum transversum
*DIAPHRAGM
____ thru which the esophagus and caudal vena cava pass
caudal mediastinum (dorsal mesentery)
*DIAPHRAGM
Expansion of the ____ dorsoventrally causes
the roof of the pleural cavities to elevate on either side
caudal medistinum
*DIAPHRAGM
Final closure of the cavities is thru the growth of the ____ projecting the peritoneal cavity
pleuroperitoneal folds
*CLOACA
The ____ portion of the hindgut gives rise to the aboral portion of the transverse colon and the descending colon.
oral
*CLOACA
The more ____ portion of the hindgut gives rise to the rectum, and to the allantois and its derivatives.
aboral
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.
cloaca
cloacal membrane
*CLOACA
A layer of mesoderm that separates the allantoic duct and the hindgut.
URORECTAL SEPTUM
*URORECTAL SEPTUM
Divides the cloacal membrane into an ____ dorsally and a ____ ventrally.
anal membrane
urogenital membrane
- Continuous with the hindgut
- Becomes the rectum and most of the anal canal.
Dorsal chamber (of urorectal septum)
- The urogenital sinus
- Continuous with the allantois.
- Develops into the perineal body.
Ventral chamber (of urorectal septum)
Tissue surrounding the anal membrane grows caudally creating a depression called the ____.
proctodeum
- When the anal membrane degenerates, the proctodeum becomes incorporated into the anal canal.
- In carnivores, lateral diverticula of proctodeum ectoderm become ____.
anal sacs
Which mesentery?
fates: Greater omentum,
mesoduodenum,
mesentery (mesojejunum mesoileum),
mesocolon,
mesorectum
Dorsal mesentery
Which mesentery?
fates: Lesser omentum,
coronary,
falciform ligaments of the liver,
median ligament of the urinary bladder
ventral mesentery
Results from the lack of fusion of the
maxillary and medial nasal prominences
during embryonic development.
CHEILOSCHESIS (CLEFT LIP)
Result from partial or complete failure of apposition and fusion of the palate processes resulting in an open connection
between oral and nasal cavities.
PALATOSCHISIS
(CLEFT PALATE)
Complete absence of the lower jaw
MANDIBULAR AGNATHIA
- Short lower jaw or overshot or parrot mouth in horses
- The mandible is shorter than the maxilla.
MANDIBULAR BRACHYGNATHIA
- Prognathia or undershot in horses
- The mandible is longer than the maxilla.
MAXILLARY BRACHYGNATHIA
- The tongue is incomplete or abnormally
developed. - ‘Bird tongue’ in dogs and may be a
component of the fading puppy syndrome.
ANKYLOGLOSSIA
- Enlargement of the tongue
- Seen in Belted Galloway cattle but is rarely clinically significant
MACROGLOSSIA
Abnormally small tongue
MICROGLOSSIA
- Complete absence of teeth
- Results from disturbances in the interaction between the dental lamina and neural crest mesenchyme.
ANODONTIA
*Teeth abnormality
- Within the jawbone
EXTRA TEETH (SUPERNUMERARY TEETH)
*Teeth abnormality
In other areas of the head
HETEROTOPIC POLYDONTIA
*Teeth abnormality
- Administration of tetracyclines to pregnant females or to puppies younger than 6 months old.
ENAMEL DISCOLOURATION
- Abnormal narrowing or stricture of a portion of the digestive tract
- Observed more frequently in the small
intestine than elsewhere in the tract
STENOSIS
- Lack of epithelial canalization and gut wall development
- Results in feed impaction and death if
surgical intervention cannot be made.
ATRESIA OF THE JEJUNUM, ILEUM, COLON, RECTUM
- Esophageal dilation which sometimes occurs in dogs and cats
CONGENITAL MEGAESOPHAGUS
- Failure of the cricopharyngeus muscle to relax during swallowing
CRICOPHARYNGEAL ACHALASIA
- An appendix-like remnant of the yolk stalk.
- Persistence, inflammation, and rupture of this structure results in colic, with peritonitis.
MECKEL’S DIVERTICULUM
- Dilatation of the colon which occurs cranial to a contracted aganglionic segment of the intestine.
- Uncommon condition described in pigs and dogs.
MEGACOLON
(HIRSCHSPRUNG’S DISEASE)
- Results from lack of involution of the cloacal membrane
- Leads to fatal feed impaction.
IMPERFORATE ANUS
- 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
URORECTAL FISTULA
A condition in which both the thoracic and abdominal organs are transferred to the side opposite to that in which they are normally located.
SITUS INVERSUS
The intestinal loops fail to return to the abdominal cavity from the umbilical sac and protrude through an enlarged umbilical ring
OMPHALOCOELE
- Loops of intestine protrude through the abdominal wall and occupy a subcutaneous position.
- Occurs more commonly in pigs than in other domestic animals
CONGENITAL UMBILICAL HERNIA
