Lecture 30: Abdomen III Foregut Anatomy of Canines and Equines Flashcards
celiac artery: 3 branches
-splenic
-hepatic
-left gastric
2 branches of splenic artery
-left gastroepiploic
-small pancreatic branches
branch of left gastric artery
esophageal
3 branches of hepatic artery
-proper hepatic
-right gastric
-gastroduodenal
branch of proper hepatic artery
cystic
2 branches of gastroduodenal artery
-cranial pancreaticoduodenal
-right gastroepiploic
2 anastamoses within celiac artery branches
-right and left gastric
-right and left gastroepiploic
innervation of foregut: 3
-major and minor splanchnic nerves
-vagal trunks
-periarterial plexuses
periarterial plexuses: what kind of axons travel
postganglionic and preganglionic parasympathetics distributed to organs by traveling along with blood vessels
major and minor splanchnic nerves: axons, site of synapse
deliver preganglionic sympathetic axons from abdomen to synapse at celiac and cranial mesenteric ganglia
vagal trunks: axons, travel
travel through esophageal hiatus
-deliver preganglionic parasympathetic axons to foregut and midgut
where does the esophagus join the stomach after passing through the esophageal hiatus
cardia
tissues and cells required for esophagus to transfer food to stomach
-stratified squamous epithelial cells for protection
-mucous glands for lubrication
-skeletal and smooth muscle
esophagus is comprised of what kind of muscle tissue(s)
interwoven skeletal and smooth muscle
somatic motor innervation: esophagus
myenteric plexus between sublayers
transitional anatomy of esophagogastric junction (between esophagus and cardia)
stratified squamous to simple columnar with gastric pits
canine GI system: simple
GI tract 4x body length
GI of hindgut specialists/equine
-12x body length
-elaborated cecum for fermentation
-sacculated colon
GI of foregut specialists/bovine
-20x body length
-elaborated stomach for fermentation
-elongated ascending colon
functions of stomach (5)
-food reservoir
-secrete gastric juices
-rhythmic segmentation begins mechanical breakdown of food and mixes with gastric juices
-forms chyme
-initiate protein digestion
rugae definition and function
gastric folds that increase surface area and allow for stomach expansion
carnivoran stomach regions
-cardia
-pylorus
-fundus and body
which 2 stomach regions contain mucous glands
cardia and pyloris
which stomach region secretes gastric juices
fundus and body
6 cells comprising gastric/fundic glands
-surface lining
-regenerative
-mucous neck
-parietal
-chief
-enteroendocrine
surface lining cells
-secrete visible mucous that adheres to stomach lining to prevent autodigestion
-modify pH at cell membrane
mucous neck cells
produce soluble mucous that mixes with/lubricates chyme (reduce friction)
parietal cells
produce HCl
chief cells: location
at base of gland
chief cells
produce pepsinogen, rennin and gastric lipase to initiate protein digestion
enteroendocrine cells
release hormones in response to stimuli that activates enteric NS
what will be apparent in active parietal cells
more folds
initial stage of protein digestion
secretion of pepsinogen by chief cells
how is pepsinogen activated
exposed to stomach acid, cleaves protein molecule
what allows for gastric emptying in simple stomachs
relaxation of pyloric sphincter and contraction of muscularis externa
fundus and body of simple stomachs: serosa
-cuboidal mesothelium
-secretes serous fluid into peritoneal cavity for lubrication
fundus and body of simple stomachs: muscularis externa
inner oblique
middle circular
outer longitudinal
pyloric mucosa of simple stomachs: 4 defining characteristics
-deep gastric pits
-branching gastric glands
-gastric glands dominated by mucous secreting cells
NO RUGAE
which stomach regions contain mucuous glands only
pylorus and cardia
how/where are gastric glands formed
invagination of simple columnar epithelium (of mucosa)
downwards at gastric pits
what are gastric pits
invaginations
denote entrance to gastric glands
which tissue layer contains gastric pits and gastric glands
mucosa of stomach
the pyloric sphincter is continuous with what muscle layer
circular layer of muscularis externa
which region of the stomach lacks rugae
pylorus
which tissue layer are rugae found in
mucosa
