Carnivore GI System Flashcards
What are the 4 tunics of the GI tract?
- Mucosa
- Submucosa
- Muscularis
- Serosa or adventitia
What are the three parts of the mucosa?
Epithelium
Lamina propria
Muscularis mucosa
What is Meissner’s nerve plexus?
Also known as Submucosal nerve plexus
Contains sympathetic and parasympathetic fibers.
What is Myenteric nerve plexus?
Also known as Auerbach’s plexus
Parasympathetic terminal ganglia and autonomic fibers between muscle layers.
What are the two layers of the tunica muscularis (in the typical gut section)?
- Inner circular muscle layer (forms sphincters)
- Outer longitudinal muscle layer (forms longitudinal bands)
Adventitia
ill-defined layer of connective tissue blending with surrounding connective tissue
Serosa
Thin connective tissue layer covered by mesothelium.
A simple squamous epithelium aka the visceral peritoneum.
Philtrum
Median cleft of the upper lip in carnivores and small ruminants.
Palatine rugae
A series of transverse ridges on the anterior part of the palatal mucosa of the hard palate.
Dental pad
Present in ruminants. Located in the rostral part of the hard palate. Replaces the upper incisors.
Incisive papilla
Small median swelling behind the incisor teeth. Incisive ducts to the vomeronasal gland.
Sublingual caruncles
Mucosal elevations on the floor of the oral cavity under the tongue and just caudal to the incisors.
Lingual frenulum
Central fold of mucous membrane connecting the floor of the oral cavity and the ventral surface of the tongue.
What cranial nerve innervates the lips?
CN 7, facial nerve.
What are the four muscles of mastication?
- Temporalis
- Masseter
- Pterygoideus medialis
- Pterygoideus lateralis
What are the characteristics of Filiform papillae? Is it mechanical, gustatory, or both?
Mechanical (functions to direct food caudally). Most numerous type of papillae.
Forms a velvety covering of the tongue.
Found on the dorsal surface of the rostral ⅔ of the tongue.
Apical processes are keratinized and point caudally.
Large and rough in cats and cattle; act as bristles for grooming.
What are the characteristics of Conical papillae? Is it mechanical, gustatory, or both?
Mechanical.
Located on the root of the tongue & cheek’s inner surface.
Large, keratinized epithelium and a large connective tissue core.
Not found in horses.
What are the characteristics of Lenticular papillae? Is it mechanical, gustatory, or both?
Mechanical.
Found in ruminants.
Large and grossly visible, lentil shaped. Keratinized.
Found on the dorsal prominence of the tongue.
What are the characteristics of Fungiform papillae? Is it mechanical, gustatory, or both?
Gustatory and possibly mechanical.
Scattered on the rostral dorsal surface of the tongue.
May be keratinized in herbivores.
What are the characteristics of Circumvallate papillae? Is it mechanical, gustatory, or both?
Gustatory.
Arranged in a “V” at the rostral border of the root of the tongue.
Each papillae is surrounded by a depression called a moat.
Taste buds are on the lateral surface and open in the moat.
Pigs/horses have 1 pair.
Carnivores have 2-3 pairs.
Ruminants have many pairs.
What are the characteristics of Foliate papillae? Is it mechanical, gustatory, or both?
Gustatory.
Found in a row at the lateral margin of the tongue.
Leaf-like and separated by furrows.
Found in pigs, horses, carnivores, and rabbits.
What is the difference between the parotid salivary gland secretions and the mandibular salivary gland secretions?
Parotid salivary gland produces serous secretion.
Mandibular salivary gland produces mixed mucous and serous secretion.
Is the esophagus dorsal or ventral to the trachea?
Dorsal to the trachea.
Which parts of the GI tract have submucosal glands?
Only found in the esophagus and duodenum.
Which species of animals have striated muscle only in the proximal portion of the esophagus?
Cats, pigs, and horses.
Where does the greater omentum attach to the stomach? The lesser omentum?
Greater omentum attaches to the greater curvature.
Lesser omentum attaches to the lesser curvature.
Cardia (of the stomach)
Opening or part of the stomach around the opening.
Closest to the heart.
Not to be confused with the cardiac gland region
Fundus (of the stomach)
Blind, expanded portion of the stomach
Body (of the stomach)
Largest part of the stomach
Pylorus (of the stomach)
Distal opening of the stomach.
Surrounded by a strong band of circular muscle (aka pyloric sphincter).
What is the margo plicatus and which two species of animals have it?
Irregular, raised line separating the glandular and non-glandular portions of the stomach. Both horses and pigs have this.
Glands in the cardiac region
Found near esophagus (close to the heart). May be quite small.
Contains predominantly mucus cells.
Pits and glands may be relatively short.
Have wide lumen.
Pits are lined by simple columnar epithelium.
Glands in the fundic region
Body and fundus of stomach.
Largest region (except in pig).
Greatest variety of cell types in glands.
In horse and pig, the stomach also contains a non-glandular area of the esophageal region which is lined by stratified squamous epithelium.
Produce the bulk of stomach secretion.
Glands in the pyloric region
Located near pylorus.
Generally have the deepest pits and short coiled glands.
Has the thickest tunica muscularis.
What are the two main types of cells in fundic glands? What do they secrete? Which one is pink and which one is purple?
Parietal cells - secrete hydrochloric acid. PINK.
Chief cells - secrete proteases (trypsin & chymotrypsin). PURPLE.
What are the three layers of smooth muscle in the stomach?
- Inner oblique
- Middle circular (sphincters)
- Outer longitudinal layer
What branch of the aorta supplies the stomach?
Celiac artery.
What are the three main branches of the celiac artery?
Left gastric artery
Splenic artery
Hepatic artery
What are the 3 divisions of the small intestine?
3 sections - duodenum, jejunum, ileum.
Which is most proximal (of the 3 divisions of the small intestine)?
Duodenum
Which is the longest section (of the 3 divisions of the small intestine)?
Jejunum
Which section has mesentery on two sides (of the 3 divisions of the small intestine)?
ileum
Which section has the longest villi (of the 3 divisions of the small intestine)?
Jejunum
Which section has Peyer’s Patches (of the 3 divisions of the small intestine)?
ileum
How is lymph pumped out of lacteals into larger lymphatic vessels?
Rhythmic contraction of the smooth muscle…
pumps lymph out of the lacteal and into larger lymphatic vessels.
What section of the small intestine has submucosal glands? What is another name for them?
Duodenum. Also known as “Brunner’s glands”.
What are Peyer’s Patches? Are they on the mesenteric or antimesenteric side?
Large submucosal lymphoid nodules that frequently contain germinal centers.
They are on the anti-mesenteric side.
What are the 3 divisions of the large intestine?
- Cecum
- Colon
- Rectum
What are the 3 divisions of the colon?
Ascending colon
Transverse colon
Descending colon
Which species has a spiral colon?
Pigs
What is the structure of mucosa in small intestine?
Contain surface modifications called villi.
Also contain intestinal villi & microvilli.
Central lacteal.
Blind-ended lymphatic in the center of the villus. Transports chylomicrons into general circulation.
Strands of smooth muscle extend from the muscularis mucosae into the villus.
Intestinal mucosal glands fill the lamina propria.
What is the structure of mucosa in large intestine?
Longitudinal folds in some areas.
Contain NO villi.
Surface epithelium is smooth.
Have deep mucosal glands that open onto luminal surface.
Abundant goblet cells, also enterocytes and enteroendocrine cells.
Lamina propria has many free cells and numerous lymphatic nodules.
What are the 3 main branches of the celiac artery which supply the stomach?
- Left gastric artery
- Splenic artery
- Hepatic artery
this is a repeated question
Which branch of the celiac artery supplies the duodenum?
Hepatic branch.
What structures are supplied by the caudal mesenteric artery?
Descending colon & cranial rectum.
Is the duodenum on the R or L side of the dog?
Right
Is the descending colon on the R or L side of the dog?
Left
Is the cecum on the R or L side of the dog?
Right
is the cecum on the R or L side of the pig?
Left
What layer of the large intestine (be as specific as possible) forms the tenia?
Outer longitudinal muscle layer.
What muscle type is found in the GI tract?
Smooth muscle.
What type of epithelium is found in the mouth?
stratified squamous
What type of epithelium is found in the esophagus?
stratified squamous
What type of epithelium is found in the tongue?
stratified squamous
What type of epithelium is found in the stomach of the dog?
simple columnar
What type of epithelium is found in the stomach of horses and pigs?
stratified squamous
What type of epithelium is found in the small and large intestine?
simple columnar
What type of epithelium is found in the rectum?
simple columnar
What cranial nerve innervates the muscles of mastication? Which branch?
Cranial nerve: Trigeminal nerve (CN V)
Branch: Mandibular nerve
What are the different cell types found in the small intestinal mucosa?
Enterocytes, goblet cells, enteroendocrine cells, paneth cells, M cells, intraepithelial lymphocytes.
Which branch of the abdominal aorta supplies the stomach?
celiac artery
Which branch of the abdominal aorta supplies the small intestine?
cranial mesenteric artery
Which branch of the abdominal aorta supplies the descending colon?
caudal mesenteric artery
Which branch of the abdominal aorta supplies the cranial rectum? caudal rectum?
Cranial rectum - caudal mesenteric artery
Caudal rectum - rectal branches of the pudendal artery
Of the celiac, cranial mesenteric, and caudal mesenteric arteries, know which is the most cranial and which is the most caudal?
Most cranial - celiac artery
Most caudal - caudal mesenteric artery
What major vein drains the stomach and intestines?
Cranial mesenteric vein.
Know the glands of the anal sacs, the anal glands, and the three types of circumanal glands.
Anal glands - Simple glands that secrete directly into the anal canal.
Glands of the anal sacs?
Circumanal glands:
Sebaceous gland
Hepatoid gland
Sudoriferous apocrine gland
