7 The Digestive System Free Online FlashCards

How do mechanical and chemical digestion differ?

Mechanical digestion physically breaks down and mixes food; chemical digestion uses enzymes and other secretions to break large molecules into smaller ones.

What does salivary amylase begin digesting?

Salivary amylase begins starch digestion in the mouth.

What is a bolus?

A bolus is the swallowed mass of food that moves through the esophagus to the stomach.

What is chyme, and where is it formed?

The stomach churns food and mixes it with gastric juice to form chyme, a semifluid mixture.

What roles do stomach hydrochloric acid and pepsin have?

Hydrochloric acid creates an acidic environment, denatures proteins, and helps activate pepsin, which digests proteins.

Where is most chemical digestion completed?

Most chemical digestion is completed in the small intestine, which is also the main site of nutrient absorption.

What does pancreatic juice contribute to digestion?

Pancreatic juice supplies enzymes that digest carbohydrates, proteins, and fats. Its bicarbonate helps neutralize acidic chyme entering the small intestine.

What does bile do to fats?

Bile emulsifies fats into small droplets, increasing the surface available to digestive enzymes. Bile is not an enzyme.

How do folds, villi, and microvilli support absorption?

Folds, villi, and microscopic microvilli create a large surface area that supports absorption in the small intestine.

Where do many water-soluble nutrients travel after absorption?

Many water-soluble nutrients enter blood capillaries and travel first to the liver through the hepatic portal circulation.

How does much absorbed fat reach the bloodstream?

Much of the absorbed fat is packaged into particles that enter lymphatic vessels called lacteals before reaching the bloodstream.

What does the large intestine absorb as feces form?

The large intestine absorbs additional water and electrolytes as its contents become more solid and feces form.