Topic 6.2 Flashcards
What are the 5 main functions of GI motility?
- Grinding
- Mixing
- Storage
- Propulsion
- Reflux inhibition
What is the role of grinding? (3)
Mechanical preparation,
increase surface,
eased propulsion
What is the role of mixing? (2)
Renewal of surface
Only nutrients near the wall are absorbed so mix
Why do we need storage in GI?
colon stomach : store for optimized digestion, absorption
Where do we have reflux inhibition in the GI tract?
In the proximal colon, which shows anti peristalsis
Which cells generate the slow waves of GI?
the interstitial cells / cajal cells in the GI wall
What is the average slow wave rythm?
3-10 cycles per minute : slow / basal rythm
What are the 6 main functions of the oral cavity and oropharynx?
- mastication
- swallowing
- immunological sampling of food for pathogens (Waldeyer lymph ring)
- Lubrication + tasting of food
- Vocalization
- Protection of teeth
What is xerostomia?
Dry mouth (can be due to drugs)
What are the 3 main parts of the esophagus?
- UES
- Body
- LES / cardia
What is the average travel speed down the esophagus?
5cm/s (depends on viscosity)
What are the 3 steps of swallowing?
- drop in neural tone of UES
- Inhibition of contraction in SM due to NO (relaxation of LES)
- Rebound contraction to push food downwards
What is akalesia?
condition where SM is not relaxing
How much food can the stomach store?
up to 1.5L
Volume of empty stomach
50mL
What is the size of the pylorus opening?
1mm
8 roles of the stomach
- Storage of ingested food
- Grinding and mixing with the secretion
- slow and controlled emptying of chyme in duodenum
- digestion of lipids and proteins
- limited absorption of lipids
- regulation of food intake by ghrelin
- VB12 uptake
- Chemical barrier for pathogens
What are the 3 functional parts of the stomach?
- proximal part
- pacemaker zone
- distal part
What is the pacemaker zone of the stomach?
the origin of the contractions which then go down
What are the roles of the proximal part of the stomach? (2)
- Storage function
- receptive and adaptative relaxation (steady mb pot)