Stomach anatomy and motility

Question 1

Label this section through the GIT

Answer 1

Question 2

Describe the anatomy and function of the mucosal layer of the GIT

Answer 2

epithelial layer, protective, secretes + absorbs
Connective tissue layer (BVs, nerves, lymphatics)
Muscularis mucosae - thin smooth muscle layer

Question 3

Describe the anatomy of the submucosal layer of the GIT

Answer 3

connective tissue
BVs and nerves

Question 4

Describe the anatomy of the muscularis layer of the GIT

Answer 4

2 layers of smooth muscle (circular and longitudinal)
Myenteric plexus (network of nerve cells)

Question 5

Describe the anatomy of the serosa layer of the GIT

Answer 5

thin layer of connective tissue
peritoneum (epithelial cells)

Question 6

Describe the process of swallowing

Answer 6

Oral phase:
- food mixed with saliva
- tongue moves bolus to back of mouth
Pharyngeal stage:
- vocal folds close
- epiglottis covers entrance to trachea
Oesophageal phase:
- upper sphincter of oesophagus opens
- food passes into oesophagus
- entrance to trachea reopened and upper oesophageal sphincter closes (breathing resumes)
- swallowing centre in medulla initiates wave of contractions in circular layer of striated muscle (peristaltic)
- bolus move down oesophagus

Question 7

Label the stomach

Answer 7

Question 8

Label the histology of the stomach

Answer 8

Question 9

Describe the vascular supply to the stomach

Answer 9

Coeliac artery:
- hepatic
- splenic
- L gastric

Venous drainage via hepatic portal vein

Question 10

Describe the anatomy and function of the non-glandular region of the stomach

Answer 10

Protective function
- cornified/keratinised
- stratified, squamous epithelium

Question 11

Describe the function and anatomy of the glandular regions of the stomach

Answer 11

Mucus producing
- simple/one layer
- columnar epithelium

Question 12

What type of stomach tissue is this?

Answer 12

Non-glandular

Question 13

What kind of stomach tissue is this?

Answer 13

Glandular

Question 14

Which part of the stomach is non-glandular?

Answer 14

Eosophageal part

Question 15

What is the margo plicatus?

Answer 15

folded margin between non-glandular and glandular portion of stomach

Question 16

Why are gastric ulcers common in horses?

Answer 16

non-glandular regions not well protected from gastric juices so gastric juices splash up and cause damage -> ulcers

Question 17

In which part of the stomach does most of the gastric juice get produced?

Answer 17

corpus and pylorus

Question 18

Label this cross section of stomach tissue

Answer 18

Question 19

Describe the nervous supply of the stomach

Answer 19

Sympathetic and parasympathetic fibres
Intrinsic fibres of enteric nervous system

Question 20

Describe the general anatomy and function of the enteric nervous system

Answer 20

Controls:
- peristalsis
exocrine and endocrine secretions
- microcirculation of the GIT
- regulating immune and inflammatory processes

Largely controlled by reflexes:
- long reflex arcs involve the CNS
- short reflex arcs are contained within the wall of the GIT

Question 21

What do the plexuses of the enteric nervous system contain?

Answer 21

Question 22

What is the function and anatomy of the interstitial cell of Cajal

Answer 22

Modified smooth muscle cells central to GI motility regulation
Function as pacemaker for gut contraction

Question 23

Describe some problems/diseases that relate to the enteric nervous system

Answer 23

Ileus - GI stasis due to stress/dehydration/other primary condition
Spasmodic colic - change in gut activity causes muscular spasm of the intestines
Vagal indigestion - motor disturbances that hinder the passage of ingesta from reticulorumen, abomasum or both