DEVELOPMENT OF THE DIGESTIVE SYSTEM Flashcards
The digestive system consists of the;
mouth (oral cavity); pharynx, esophagus, stomach; and small intestine; colon and cecum; rectum; anal canal; and the liver,
pancreas, and salivary glands.
is derived from stomodaeum, a depression of surface ectoderm cranial to the pharynx.
Formation of Oral Cavity
The structures associated with the oral cavity
lips, gums, teeth, tongue and
salivary glands.
cleft palate caused by failure of the median palatine process (primary palate) and the lateral palatine processes (secondary palate) to close along the midline,
leaving a gap or cleft.
Palatoschisis
Caudal third of the secondary
palate does not ossify and become the
soft palate
derived from the stomodeal ectoderm.
Lips and Gum
forms along the upper and lower jaws.
labiogingival lamina,
invaginates to form dental bud.
dental lamina
Each bud assumes a cup-shaped configuration becoming an
enamel organ
The lamina invaginates into
underlying ectomesenchyme, forming a
labiogingival groove
Ectomesenchyme three layers;
outer cells of dental sac
middle layer of dental sac
inner cells of the sac
Tongue develops from four swellings
(2 distal, 1 median and 1 proximal tongue swellings)
bulge).The root of the tongue is formed by the
proximal swelling or copula
are derived from stomodeal ectoderm or pharyngeal endoderm
Salivary glands
The foregut becomes flattened or compressed laterally and presents in sequence 5 bilateral outpocketings of its endoderm to form the
pharyngeal pouches
A midline evagination of the floor of the pharynx gives rise to the
laryngotracheal groove
MALFORMATIONS OF PHARYNGEAL POUCHES
Brachial cyst
Brachial sinus
Brachial fistula
epithelial-lined brachial cavity that does not open unto the skin surface. (no opening)
Brachial cyst
epithelial-lined brachial cavity that opens unto the skin surface or into the pharyngeal pouch. (one opening).
Brachial sinus
epithelial-lined brachial cavity that opens to both the skin surface and the pharyngeal pouch. (two openings).
Brachial fistula
develops from a tubular segment of the Foregut, Caudal to the
Pharynx. Its principal morphogenic development is elongation.
Esophagus
is present in most domestic mammals. This develops from a tubular segment of foregut caudal to the esophagus.
Simple Stomach
consists of three compartments (rumen, reticulum, and omasum)
and one glandular compartment (abomasum). Early development of the ruminant stomach is the same as the simple stomach.
Ruminant Stomach
develops as an expansion of the fundus.
rumen