3. Anatomy, Histology and Control of GI Tract Flashcards
Which organs compose the alimentary canal?
Mouth - Pharynx - Oesophagus - Stomach - Small Intestine - Large Intestine
Where does the alimentary canal terminate?
Anus
Outline the accessory digestive organs
Teeth - Tongue - Gall Bladder - Salivary Glands - Liver - Pancreas
What colour does glandular mucosa stain and why?
Dark purple - epithelial and connective tissue nuclei within
What marks the muscularis mucosa?
Thin strip
What is the submucosa composed of?
Mainly dense collagen fibres
How many muscularis externa layers are present?
- Wide inner band of circular SMC and narrow outer band of longitudinal SMC
What can trigger changes in GI tract functions other than local stimuli?
CNS signals - anticipation of food
What local stimuli can trigger changes in function of GI Tract?
Concentration of specific nutrients Osmolarity pH Distension Stimulation leads to action on sensory receptors in mucosal layer of tract to initiate reflexes
Elaborate on nervous control of the GI tract
Extrinsic: autonomic nerves of CNS via parasympathetic vagus nerve Stimulates blood flow, motility, secretion, relaxes sphincters Sympathetic nerves do the opposite
What cell aids the production of gastric acid via release of histamine?
Enterochromaffin-like cells which are scattered through the mucosal layer
Label this
A) Oesophagus
B) Cardia
C) Fundus
D)Serosa
E)body
F) Rugae of mucosa
G) Greater curvature
H) Pyloric antrum
I) Pyloric canal
J) pyloric sphinter
K) duodenum
L) Pylorus
M) Oblique layer
N)circular layer
O) longitudinal layer
O (above)) Muscularis externa
P) Pyloric sphincter
Q) Pyloric antrum
Label this
A) Serosa
B) Muscularis externa
C) Muscularis interna
D) Myenteric plexus
E) Submucosa
F) Submucous plexus
