Motility Flashcards
What connects SM cells in gut
Nexus - areas of low resistance where cells activate each other when one is stimulated
2 phases of GI motility
Perstalasis (phasic)
Tonic
3 functions of chewing
Breaks down food
Mixes with saline
Lubricates it
Two functions of secondary peristalasis
Gets stuck food and gets rid of refluxed acid
Why is pressure inside the esophagus negative
Intrathoracic pressure is negative
LES sphincter is?
Physiologic - only neurogenic mechanisms keep it closed
Head of stomach features?
Orad: thin area of smooth muscle where acid secretin occurs
Ciudad regio of stomach features
Muscle increases (oblique layer added) Where mixing of food and most of the contractions occurs
3 main features of stomach motility
Storage (mostly in road area)
Reduction in particle size
Gastric emptying
What does the stomach do during a swallow
Orad portion of the stomach relaxes (reflexive relaxation)
What part of the stomach has the highest motility?
Caudad region
What’s responsible for most of the food breakdown in the stomach
Retropulsion
What causes contraction of stomach smooth muscle
If sufficient amplitude is reached
Frequency will not change
Why do liquids empty from the stomach more quickly than solids?
Lag phase needed to break down food
What does fat cause release of? what does that do?
CCK release: relaxes orad stomach and stimulated duodenal activity to prevent gastric emptying
3 things that delay gastric emptying
CCK, acid, and change from isotonicity
What type of solutions empty the stomach the fastest?
Isotonic
What type of ulcers typically slow gastric emptying? what type speed up?
Gastric ulcers slow emptying
Duodenal ulcers speed up emptying
two types of small intestine movement
Segmentation and persistalasis
What gets activated in SI during fasting
Migrating motor complex: activity increase every 90 minutes from motilin*
What increases SM contractions in Small intestine
Spiking determines contractions (amplitude does not)
What does the colon absorb
Small chain fatty acids and water
Longitudinal muscle in colon
Tenia coli
innervation in proximal colon? distal?
Vagus is proximal
Pelvic is distal
What does colonic distention cause
Iliocecal sphincter contraction to prevent backflow
What is colonic mass movement
2-3 times a day haustra disappear and peristalic contractions occur to move lots of poo
What is the rectosphinteric relfex
Internal anal sphincter relaxes, causing urge to defecate
What innervates the external anal sphincter
Pudental nerve
