Gastrointestinal system Flashcards
What makes up the GI tract?
mouth oesophagus stomach small intestine large intestine anus
What are the functions of the GI tract?
adsorption of dietary nutrients
storage
excretion
What are the layers of the GI tract?
mucosa
submucosa
muscularis externa
serosa
What is the mucosa made up of?
epithelium
lamina propia
muscularis mucosa
What is peristalsis?
wave of pressure generated that migrates down the oesophagus and pushes food ahead of it
What is GI function regulated by?
parasympathetic NS
sympathetic NS
enteric NS
How does the parasympathetic NS regulate GI function?
stimulates GI secretions and motility facilitating digestion and adsorption of nutrients
How does the sympathetic NS regulate GI function?
decreases GI secretions and motility
How are the enteric NS nerves organised?
myenteric plexus
submucosal plexus
What are GI hormones and their function?
gastrin - H+ secretion
motillin - increases motility
What are GI paracrine and their functions?
histamines - increase H+ production
somatostatin - decreases GI secretions
What are the 3 digestive phases?
cephalic
gastric
intestinal
What happens in the cephalic phase of digestion?
stimulates secretion and causes ACh and VIP release
What happens in the gastric phase of digestion?
elicits neural, hormonal and paracrine GI responses
What happens in the intestinal phases of digestion?
initiates neural, paracrine and mainly hormonal GI responses
What are the 3 salivary glands?
sublingual
submandibular
parotid
What is the function of the small intestine in digestion?
macronutrient, vitamin and mineral adsorption occurs
What is the large intestine made up of?
cecum
colons
rectum
anus
What is the function of the large intestine in digestion?
water and ion adsorption and motility of contents
