upper GI tract structure & function Flashcards
whats in saliva?
- Water, softens, dilutes
- Mucins - protein, mucins + water = mucus, lubricant
- a-Amylase - catalsyt for carbs
- electrolytes -tonicity/pH
- Lysozyme - bacteriocidal
what is the epithelium of the oesophagus
stratified squamous non-keratinising epithelium
has submucosal glands
what is the muscle type of oesophagus in upper 1/3
skeletal
what is the muscle type of oesophagus in lower 2/3
smooth
what do the upper and lower oesophageal spinchters do
regulate movement
what is the reflex control mechanism involved in swallowing
in pharynx
- reflex contractions by pharyngeal muscles
- coordinated by swallowing centre in medulla
- soft palate reflected backward+upward (close off nasopharynx)
- upper oesophageal spinchter contracts (prevent food reflux)
what moves food down to stomach in oesophagus
peristaltic wave sweeps along oesophagus
lower oesophageal spinchter relaxes - bolus enter stomach
what are the functions of the stomach
sterilise ingested material
produce intrinsic factor
breakdown food
describe the muscularis externa in the stomach
3 layers
oblique (inner)
circular
longitudinal (outer)
what are rugae
submucosa + mucosa folded in stomach
what is on the surface of mucus cells
gastric pits with gastric glands
- mucous neck
- parietal cells
- chief cells
what do chief cells secrete
pepsinogen
what do parietal cells secrete
HCl and intrinsic factor
