Mastication. Swallowing. Motor functions of the stomach. Regulation of the stomach emptying. Vomiting Flashcards
MASTICATION - definition
definition
= process of grinding down food in the mouth
MASTICATION - 1
- temporomandibular joint + teeth begin the process
- mechanical breakdown of food
MASTICATION - 2
SALIVATION
MASTICATION - 3
MUSCLES
- masster
- temporal
- pterygoid
- buccinator
MASTICATION - 4
bolus produced
SWALLOWING - definition
process of moving bolus from mouth -> pharynx -> osephagus -> stomach
SWALLOWING - PHASE 1
ORAL PHASE = voluntary
- bolus produced in mouth
- bolus pushed by tongue
SWALLOWING - PHASE 2
PHARYNGEAL PHASE = involuntary
bolus enters oropharynx
soft palate rises up to prevent entry into nasal cavity
epiglottis rises to prevent entry into airways
SWALLOWING - PHASE 3
OSEPHAGEAL PHASE = involuntary
bolus pushed from mouth -> stomach
- peristalsis
- osephagus sphincters
Motor functions of the stomach - 1
the thought / sight/ smell of food causes activation
signals sent vagus nerve
signals sent to medulla/pons in brainstem
Ach + Muscarinic Receptors
- parietal cells released HCl
- chief cells release pepsinogen
Motor functions of the stomach - 2
STORING
when fundus/ corpus stomach receives food it temporarily stores it
the stomach can expand if there is large amount of food to be stored due to rugae + vagovagal stretch receptors
G-cells release gastrin
enterochromaffin cells release histamine
Motor functions of the stomach - 3
MIXING
food mixed with stomach 3 layers:
- longitudinal = outer
- circular = medial
- oblique = inner
this forces contents to be mixed with gastric juices + gastric enzymes = chyme produced
Motor functions of the stomach - 4
EMPTYING
the end of the stomach is pars pylorica which stretches into small intestine
inhibitory hormones ensures negative feedback mechanisms to ensure chyme is ready to move from stomach -> SI
Regulation of the stomach emptying - NEURAL
PNS
SNS
ENS
Regulation of the stomach emptying - hormone 1
GASTRIN = stimulates
produced by G cells in stomach
producing of gastric acid for motility