Unit 6B Integrated GI Control Flashcards
What triggers the cephalic phase of digestion (feedforward)?
a) Food in the stomach
b) Stretch receptors
c) Acid in the duodenum
d) Sight, smell, or thought of food
d) Sight, smell, or thought of food
Explanation: The cephalic phase begins in the brain and triggers GI activity before food even enters the mouth, increasing secretion and motility via the vagus nerve.
What defines a ‘short reflex’ in GI regulation?
a) Entirely within the enteric nervous system
b) Goes from gut to CNS and back
c) Involves spinal cord but not brain
d) Involves only sensory receptors
a) Entirely within the enteric nervous system
Explanation: Short reflexes are mediated locally in the gut wall through the ENS without CNS involvement, triggered by local stimuli like stretch or acid.
What is the output of the enteric nervous system in GI control?
a) Vasoconstriction and sweating
b) Increased heart rate
c) Motility and secretion changes
d) Hunger suppression
c) Motility and secretion changes
Explanation: The ENS influences smooth muscle and secretory cells directly to adjust digestive processes in response to local signals.
How do gut peptides influence overall physiology?
a) Only act locally
b) Travel to the brain and endocrine pancreas
c) Stimulate only muscle contraction
d) Only inhibit secretion
b) Travel to the brain and endocrine pancreas
Explanation: Gut peptides can signal satiety to the brain and also stimulate or inhibit insulin and glucagon release from the pancreas.
What type of reflex is the vagus nerve involved in during digestion?
a) Short reflex
b) Long reflex
c) Somatic reflex
d) Defecation reflex
b) Long reflex
Explanation: Long reflexes involve integration through the CNS, especially the vagus nerve, which carries parasympathetic signals to increase secretion and motility.
