Physiology Flashcards
What 3 nervous systems control the gut
Sympathetic, parasympathetic and enteric
What are the 2 plexuses in the enteric nervous system
Myenteric and submucosal
Where is the gut wall is the submucosal plexus found
Between the muscular layer and mucosa
Where in the gut wall is the myenteric plexus found
Between the 2 muscle layers
Which 3 nerves coming from the sympathetic nervous system control the gut
Greater, lesser and least splanchnic nerves
True or false: the sympathetic nervous system shuts off blood supply to the lungs
True - shutting off GI functions
What nerves from the parasympathetic nervous system control the GI
Vagus nerve and pelvic splanchnic nerve
True or false: the parasympathetic nervous system shuts off blood supply to the GI
False - it increases blood supply
What hormones are produced in the GI tract
Gastrin, CCK, secretin, GIP
What does gastrin do
Causes gastric acids secretion
What cells produce gastrin
G CELLS
What does CCK do
Stimulates secretions from pancreas and gallbladder
Where is CCK secreted
Duodenum and jejunum
What does secretin do
Causes an increase in bicarbonate production
What does GIP stand for
Gastrin inhibitory polypeptide
What is peristalsis
Muscular contractions to propel the bolus of food
True or false: the muscle behind the bolus relax during peristalsis
False - they contract, the muscles in front relax
What is segmentation
Contraction of the smooth muscle to split up the bolus
Why does segmentation occur
To increase the SA of the food and the epithelium
Which NS (sympathetic or parasympathetic) increases motility of the GI tract
Parasympathetic
Why do you get central abdominal pain first in appendicitis
The appendix inflames and irritates the visceral membrane which hasn’t got its only nerve supply. The region covering the appendix is supplied by the lesser splanchic nerve which comes from T10. Therefore, the body presumes the pain is coming from the T10 dermatome which covers the umbilicus giving pain in this area