stomach anatomy

Question 1

what do the layers of the mucosa contain

Answer 1

• epithelial layer with protective cells, secretion and absorption
• connective tissue layer, blood vessels, nerves, and lymphatics
• muscularis mucosae, and thin smooth muscle layer

Question 2

what does the submucosa contain

Answer 2

• connective tissue
• blood vessels
• nerves

Question 3

what does the muscularis contain

Answer 3

• 2 layers of smooth muscle (circular and longitudinal)
• myenteric plexus

Question 4

what does the serosa contain

Answer 4

• thin layer of connective tissue
• peritoneum (epthelial cells)

Question 5

what are the features of the oesophagus

Answer 5

• 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

Question 6

discuss the muscles of the oesophagus

Answer 6

• 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)

Question 7

what occurs during the oral phase of swallowing

Answer 7

• fod mixed with saliva to form bolus
• tongue moves bolus to back of the mouth

Question 8

what occurs during the pharyngeal stage of swallowing

Answer 8

• vocal folds close
• epiglottis covers entrance to the trachea

Question 9

what occurs during the esophageal stage of vomiting

Answer 9

• 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)

Question 10

label structures

Answer 10

Question 11

the stomach lies on which side of the abdomen in the dog

Answer 11

left

Question 12

label the zones of this dog stomach

Answer 12

Question 13

this is a cross section of the stomach. label

Answer 13

Question 14

discuss the blood supply to the stomach

Answer 14

• coeliac artery is cranial most supply branches into:
• hepatic
• splenic
• left gastric

Question 15

what vein facilitates drainage from the stomach

Answer 15

hepatic protal vein

Question 16

what structure is the arrow pointing to

Answer 16

coeliac artery

Question 17

the non-glandular region of the stomach has what kind of epithelium

Answer 17

cornified (keratinized) stratified squamous epithelium

Question 18

what is the function of the non gladular region of the stomach

Answer 18

protection

Question 19

what is the function of the glandular regions of the stomach

Answer 19

mucus producing

Question 20

discuss the epithelium of the glandular stomach

Answer 20

simple columnar epithelium

Question 21

which of these images is glandular stomach and which is non-glandular

Answer 21

top = non-glandular
bottom = glandular

Question 22

what structures of the stomach are non-glandular

Answer 22

portion of stomach closest to esophageal opening
fundus in horses

Question 23

where are you most likely to find gastric ulder in horses

Answer 23

fundus of the stomach

Question 24

what is the margo plitcatus

Answer 24

folded margin between non-glandular and glandular portion of stomach

Question 25

what are the 4 regions of the stomach

Answer 25

- cardia - fundus - corpus - pylorus

Question 26

what is the function of the glandular stomach

Answer 26

chemical and mechanical digestion - fundus = storage of food - corpus = mixing - pylorus = mixing and pyloric sphincter

Question 27

which areas of the stomach is most gastric juice produced

Answer 27

corpus and pylorus

Question 28

discuss innervation of the stomach

Answer 28

- sympathetic fibres - parasympathetic fibres - intrinsic fibres of enteric nervous system

Question 29

discuss the enteric nervous system

Answer 29

- 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)

Question 30

the ENS controls what

Answer 30

- motility (peristalsis) - exocrine and endocrine secretions - microcirculation of the GIT - regulating immune and inflammatory processes

Question 31

discuss the interaction between the CNS and ENS

Answer 31

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

Question 32

what are the interstitial cells of Cajal

Answer 32

- 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

Question 33

list diseases associated with the ENS and the species they effect

Answer 33

- 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