4 Digestion and Nutrient Absorption Free Online FlashCards

How do digestion and absorption differ?

Digestion mechanically and chemically breaks food into molecules that can cross the digestive tract lining; absorption moves those molecules, water, and minerals into blood or lymph.

What is the order of the main digestive tract organs?

Food passes through the mouth, esophagus, stomach, small intestine, and large intestine before leaving through the rectum and anus.

What is peristalsis?

Peristalsis is a series of muscular waves that moves food through the digestive tract, including from the esophagus to the stomach.

What is chyme?

Chyme is the fluid mixture formed when the stomach mechanically mixes food.

Which enzyme begins starch digestion in the mouth?

Salivary amylase begins starch digestion in the mouth.

What roles do stomach acid and pepsin play?

Stomach acid helps unfold proteins and activates pepsin, which begins protein digestion.

What does pancreatic bicarbonate do in the duodenum?

The pancreas releases digestive enzymes and bicarbonate into the duodenum; bicarbonate helps neutralize acidic chyme.

How does bile help with fat digestion?

The liver produces bile, and the gallbladder stores and releases it. Bile disperses dietary fat into small droplets so lipase can act more easily.

How do folds, villi, and microvilli aid absorption?

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

Where do absorbed simple sugars go after entering intestinal cells?

The final products—glucose, galactose, and fructose—cross into intestinal cells and then enter the blood.

How do protein digestion products travel from the intestine?

Amino acids and small peptides cross intestinal cells and enter the blood, which carries them to the liver and other tissues.

What route do many long-chain fats take after absorption?

Many long-chain fats are reassembled and packaged into chylomicrons inside intestinal cells. They enter lymphatic vessels in the villi before reaching the bloodstream.