Grand tour of the Alimentary Canal Flashcards
What are the 3 pairs of salivary glands and where are they located?
Parotid (above)
sublingual
submandibular
What is the purpose of the oesophagus?
Conduit mouth - stomach
Stomach purpose?
Protein digestion, mixes everything together and reduces to liquid form (chyme), storage of food, sterilization
What is the liquid called that gets passed onto small intestine?
Chyme
Pancreas use?
Produces digestive enzymes, etc to break down and digest fats, carbs and proteins
What does the liver do?
Produce bile salts which help in the digestion of fats within the small intestine
Gall bladder function
Store and concentrate bile
Small intestine function
final stages of chemical digestion and nutrient absorption
Large Intestine function
Reabsorption of water, salt, bacteria for fermentation and formation of faeces
how long is the alimentary canal?
8m
What are the 4 layers (tunics)
Mucosa (epithelia, lamina propria, thin smooth muscle layer, muscularis mucosae)
Submucosa
Thicker more useful muscle - muscularis externa
Adventicia/serosa (within the peritoneal cavity)
Where are the submucosal glands found?
In the oesophagus and the duodenum
function of submucosa?
Glands, thick irregular connective tissue, blood supply for mucosa, mucularis externa and serosa) and lymphatic vessels
layers of muscularis externa
circular (innermost) and longitudinal
where are the 2 neural plexusses?
between the submucosal layer and circular muscle layer (submucosal plexus aka Meissner’s plexus), and between the circular and longitudinal muscle layers (Myenteric aka Auerbach’s)
epithelium stratified squamous where?
mouth and oesophagus, anal canal
simple columnar epithelium where?
Everywhere else! Stomach, small and large intestines
function of epithelial cells
meet and greet…
barrier, synthesis and secretion, aborption
Barrier separating lumen of alimentary canal from body
Synthesis and secretion of digestive enzymes, hormones, mucus
Absorbs products of digestion
Epithelium differs along length of gut tube - adaptation for function
What is the function of lamina propria?
Loose connective tissue (glands, blood/lymph vessels)
muscularis mucosae function
support mucosa, poitentially wiggle villi
Submucosa function and contents
Blood vessels (supplying other layers), lymph, neurons (submucosal (meissners) plexus)
Thick, irregular connective tissue - supports mucosa
Submucosal glands in oesophagus and duodenum
Serosa/adventicia function
connects structure and keeps in place:
Outside peritoneal cavity:
Adventitia attaches oesophagus and rectum to surrounding structures
Inside peritoneal cavity:
Serosa surrounds stomach, small intestine and large intestine
Muscularis externa features and function
circular one reduces the circumfrence (constricts lumen), the longitudinal one makes shorter.
Produce motility - peristalsis, segmentation
Also contains the myenteric (auerback’s) plexus between circular and longitudinal layers.
Autonomic control of the alimentary system
Long (vagus, cranial nerve 10) parasympathetic and ENS (Enteric nervous system - submucosal and myenteric layers, giving independant control of the gut)
