Unit 6b GI Regulation Phases

Question 1

What initiates the cephalic phase of digestion?
a) Stretching of the stomach
b) Food entering the duodenum
c) Sight, smell, or thought of food
d) Arrival of food in the colon

Answer 1

c) Sight, smell, or thought of food

Explanation: The cephalic phase is triggered by sensory inputs and prepares the GI tract via parasympathetic (vagal) stimulation.

Question 2

What is the primary trigger for the gastric phase of digestion?
a) Bile entering the duodenum
b) Distension and protein in the stomach
c) CCK secretion
d) Glucose in the small intestine

Answer 2

b) Distension and protein in the stomach

Explanation: The gastric phase is activated by stomach stretch and the presence of peptides, stimulating acid and enzyme secretion.

Question 3

Which hormone is released in the intestinal phase and inhibits gastric emptying?
a) Gastrin
b) Secretin
c) CCK
d) GLUT5
d) Both b and c

Answer 3

d) Both b and c

Explanation: Secretin and CCK are released in response to acid and fats in the duodenum; they slow gastric emptying to allow time for digestion.

Question 4

What is the role of the enteric nervous system (ENS) in GI regulation?
a) Locally regulates motility and secretion
b) Controls voluntary defecation
c) Sends signals to the brain
d) Absorbs nutrients

Answer 4

a) Locally regulates motility and secretion

Explanation: The ENS acts as a ‘second brain’ that coordinates digestive functions independently or with input from the CNS.

Question 5

Which nervous system branch primarily stimulates digestion?
a) Somatic
b) Sympathetic
c) Parasympathetic
d) Enteric

Answer 5

c) Parasympathetic

Explanation: Parasympathetic input (especially via the vagus nerve) increases secretion, motility, and enzyme release in the GI tract.