stomach anatomy Flashcards
what do the layers of the mucosa contain
- epithelial layer with protective cells, secretion and absorption
- connective tissue layer, blood vessels, nerves, and lymphatics
- muscularis mucosae, and thin smooth muscle layer
what does the submucosa contain
- connective tissue
- blood vessels
- nerves
what does the muscularis contain
- 2 layers of smooth muscle (circular and longitudinal)
- myenteric plexus
what does the serosa contain
- thin layer of connective tissue
- peritoneum (epthelial cells)
what are the features of the oesophagus
- continuation of the laryngopharynx connecting the pharynx to the stomach
- dorsal to trachea on left hand side
- travels through the mediastinum
- passes through oesophageal hiatus of diaphragm
discuss the muscles of the oesophagus
- differ from elsewhere in the GIT
- striated to facilitate vomiting
- circular muscle layer particularly well developed in upper region and at junction of the stomach (sphincters)
what occurs during the oral phase of swallowing
- fod mixed with saliva to form bolus
- tongue moves bolus to back of the mouth
what occurs during the pharyngeal stage of swallowing
- vocal folds close
- epiglottis covers entrance to the trachea
what occurs during the esophageal stage of vomiting
- the upper sphincter of the esophagus opens
- food passes into the esophagus, entrance to trachea is reopened and upper esophageal sphincter closes. breathing can resume
- swallowing centre in medulla initiates a wave of contractions in the circular muscle layer
- the peristatic wave travels along the esophagus carrying the bolus ahead of it to the lower esophageal sphincter (quick)
- in many species the function of the lower (cardiac) sphincter is aided by the sharp angle at which the esophagus enters the stomach (acting as a one way valve)
label structures
the stomach lies on which side of the abdomen in the dog
left
label the zones of this dog stomach
this is a cross section of the stomach. label
discuss the blood supply to the stomach
- coeliac artery is cranial most supply branches into:
- hepatic
- splenic
- left gastric
what vein facilitates drainage from the stomach
hepatic protal vein
what structure is the arrow pointing to
coeliac artery
the non-glandular region of the stomach has what kind of epithelium
cornified (keratinized) stratified squamous epithelium
what is the function of the non gladular region of the stomach
protection
what is the function of the glandular regions of the stomach
mucus producing
discuss the epithelium of the glandular stomach
simple columnar epithelium
which of these images is glandular stomach and which is non-glandular
top = non-glandular
bottom = glandular
what structures of the stomach are non-glandular
portion of stomach closest to esophageal opening
fundus in horses
where are you most likely to find gastric ulder in horses
fundus of the stomach
what is the margo plitcatus
folded margin between non-glandular and glandular portion of stomach
what are the 4 regions of the stomach
- cardia
- fundus
- corpus
- pylorus
what is the function of the glandular stomach
chemical and mechanical digestion
- fundus = storage of food
- corpus = mixing
- pylorus = mixing and pyloric sphincter
which areas of the stomach is most gastric juice produced
corpus and pylorus
discuss innervation of the stomach
- sympathetic fibres
- parasympathetic fibres
- intrinsic fibres of enteric nervous system
discuss the enteric nervous system
- motility and secretion regulated by reflexes:
- long reflex arcs involve CNS stimuli
- short reflex arcs are contained within the wall of the GIT and are the primary ENS (functions independently from CNS)
the ENS controls what
- motility (peristalsis)
- exocrine and endocrine secretions
- microcirculation of the GIT
- regulating immune and inflammatory processes
discuss the interaction between the CNS and ENS
parasympathetic and sympathetic input from the CNS is exerted on nerve cells in GI wall (also direct sympathetic influence or arterioles and GIT smooth muscle
what are the interstitial cells of Cajal
- modified smooth muscle cells central to GI motility regulation
- function as a pacemaker for gut contraction
- different frequencies in different parts of the GI tract
list diseases associated with the ENS and the species they effect
- illeus: GI stasis caused by stress/dehydration/other primary condition in rabbits
- spasmodic colic: change in gut activity causes muscular spasm of the intestines in horses
- vagal indigestion: motor disturbances that hinder passage of ingesta fromreticulorumen, abomasum or both in ruminants
