Grand tour of the alimentary canal Flashcards
What are the 4 functions of the digestive system?
Absorption,Secretion,Digestion and Motility
What are the 4 layers of the alimentary canal?
Mucosa,Submucosa,Muscularis externa and Serosa/Adventitia.
What are the 3 subtypes of mucosa?
Mucous epithelium,Lamina propria and the muscularis mucosae. From innermost out…
What are the 2 subtypes of muscularis and their function?
Circular muscle constricts lumen(inner) and longitudinal muscle shortens tube(outer)
What are the 2 subtypes of serosa?
Connective tissue(inner) and peritoneum(outer)
Which parts of the GI tract are stratified squamous epithelium?
Mouth,oesophagus and anal canal
Which parts of the GI tract are simple columnar epithelium?
Stomach,small and large intestines
What is the function of the epithelium?
Barrier separating lumen of alimentary canal from body
Synthesis and secretion of digestive enzymes, hormones, mucus
Absorbs products of digestion
What is the function of the lamina propria?
Loose connective tissue (glands, blood/lymph vessels)
What kind of muscle is the muscularis mucosae?
Thin smooth muscle layer
Where in the GI tract does the submucosa cover?
Submucosal glands in oesophagus and duodenum
What is the function of the submucosa?
Thick, irregular connective tissue supports mucosa
What does the submucosa contain?
Contains neurones, blood vessels ( mucosa, muscularis externa, serosa), lymphatic vessels
Neurones form extensive network submucosal (Meissner’s) plexus (parasympathetic)
What is the difference between adventitia and serosa?
The adventitia covers the retroperitoneal organs and the serosa covers the intraperitoneal organs.
Which plexus is in between the two muscularis layers?
What does it consist of?
Myenteric plexus
Axons and neuron cell bodies
