GI Motility and Regulation Flashcards
_______ is the predominant motor activity in the intestines, helping to ensure proper digestion and absorption
segmentation
describe segmentation
a contraction is isolated and not coordinated with movement above and below, it propels contents in both directions. When the contracting area relaxes, the contents flow back into the original segment with the result that mixing has occurred without net propulsion
if contractions of adjacent segments are coordinated in a proximal to distal manner, ______ occurs resulting in net propulsion of contents
peristalsis
In intestinal peristalsis, Isolated contraction of circular muscle ______ to intestinal contents, compounded by contraction of the longitudinal muscle ______to the intestinal content, results in its aboral (towards anus) movement along the gastrointestinal tract
proximal,
distal
Describe the basic electrical rhythm
spontaneous sub-threshold rhythmic waves of depolarization that is an intrinsic property of the smooth muscle.
when does swallowing become a reflex
When the bolus of food pushes the soft palate upward; the upper constrictor muscle contracts, and these actions together close off the nasopharynx.
Basic Electrical Rhythm ______ as you move towards the anus
increases
The esophageal peristaltic wave is controlled by the _______, which receives its signals from the ________
vagus nerve,
swallowing center
TRUE or FALSE
If the vagus nerve is severed, swallowing can still be maintained.
TRUE
a local myenteric complex can maintain swallowing
Describe retropulslon
Occurs when pyloric opening is small, contractions cause most food content to be reflected backward toward the body of the stomach.
Rate of Gastric emptying is increased by ________. Increased stretch leads to increased peristalsis through vagal and myenteric reflexes and decreases pyloric tone
distension
what 2 factors increase rate of gastric emptying
distension and gastrin
list the rates of gastric emptying for carbs fats and protien form fastest to slowest
carbs>protein>fat
describe the migrating (myoelectric) motor complexes (MMC)
A long wave of peristalsis begins in the stomach, travels to the ileocecal sphincter and then repeats every 90 minutes, performs a housekeeping role to remove bacteria and indigestible material. Only occurs during fasting states.
what is the Gastroileal reflex
Stomach activity stimulates movement of chyme through the ileocecal sphincter
