GI Tract Flashcards
How long is the gi tract?
About 8 long.
What organs make up the GI tract?
Stomach, small and large intestines, pancreas and gallbladder
What is the function of the GI tract?
Efficient digestion and absorption of ingested nutrients
What quantity of food and water enter the small intestine and what quantity reaches the large?
~10mL enters the small intestine and only ~1.5mL reaches the large
What is digestion?
Digestion is the chemical processing of food into absorbable substance
Where does digestion begin?
In the mouth
What are the three phases of the digestive process?
Neurogenic
Gastric
Intestinal
What happens in the neurogenic phase of digestion?
Sight, smell and taste of food stimulates the brain. The brain sends impulses to the stomach via the vagus nerve and this nerve innervates the stomach inducing peristalsis and gastric secretion of HCl and gastrin
What nerve in from the brain stimulates the stomach to release HCl and gastrin?
Vagus nerve
What does the vagus nerve stimulate in the stomach?
Peristalsis and gastric secretion of HCl and gastrin
What is the second phase of the digestive process?
Gastric phase
What phase in the digestive process is initiated by the entry of food into the stomach and stomach distention?
Gastric phase
How is the gastric phase initiated?
By the entry of food into the stomach and stomach stretching.
What is the pH of HCL?
1-2
What cells release HCl? Why?
The parietal cells of the stomach. Due to cell stimulation, stretching and gastrin release
What is the major digestive hormone of the stomach?
Gastrin
What cells release gastrin?
G cells
What is the function of gastrin hormone?
Gastrin causes enzyme and gastric fluid to be released, and the start of stomach motility/churning
This hormone causes enzymes and gastric fluids to be released, and the start of stomach motility.
Gastrin
What is the major digestive enzyme of the stomach?
Pepsin
What cells release pepsin?
Gastric chief cells
This enzyme released by gastric chief cells serve in the hydrolysis of proteins.
Pepsin
Food mixed with gastric fluid is called?
Chime
What phase of the digestive process begins when chime enters the duodenum?
The intestinal phase