4 Digestion and Nutrient Absorption Free Online FlashCards

How do digestion and absorption differ?

Digestion breaks food into small molecules; absorption moves those molecules, along with water, vitamins, and minerals, across the intestinal lining into blood or lymph.

What moves a bolus through the esophagus?

Peristalsis is a wave of muscular contractions that propels food along the digestive tract, including moving a swallowed bolus toward the stomach.

What is chyme, and where is it formed?

Chyme is the semifluid mixture produced when stomach muscles mix food with acid and enzymes.

Why is the small intestine especially effective at absorption?

The small intestine is the main site of digestion and nutrient absorption. Its folds, villi, and microvilli increase the surface area available for absorption.

What does the colon absorb from intestinal contents?

The colon absorbs much of the water and electrolytes remaining in intestinal contents. The remaining material becomes stool.

What does the pancreas contribute to digestion?

The pancreas supplies digestive enzymes and bicarbonate, which helps neutralize acidic chyme entering the small intestine.

How do mechanical and chemical digestion differ?

Mechanical digestion physically breaks up and mixes food; chemical digestion uses enzymes to split large food molecules into absorbable units.

What does carbohydrate digestion ultimately produce?

Salivary amylase begins starch digestion in the mouth. Further digestion produces simple sugars, mainly glucose, galactose, and fructose.

How does protein digestion begin in the stomach?

Stomach acid unfolds proteins, and pepsin begins cutting them into smaller peptides. Further digestion produces chiefly amino acids and small peptides.

What are the main products of triglyceride digestion?

Pancreatic lipase breaks triglycerides mainly into fatty acids and monoglycerides. Bile disperses fat droplets, increasing the area available to enzymes.

How do absorbed sugars and amino acids reach the liver?

Sugars and amino acids enter small blood vessels in the intestinal villi. Blood carries them first to the liver through the hepatic portal vein.

What is a bolus?

A bolus is a soft mass of food formed in the mouth as chewing breaks food into smaller pieces and saliva moistens it.