Digestive System and Nutrition (Video Notes)

Flashcards cover digestion, absorption, GI tract organs and functions, enzymatic digestion, bile and liver functions, the pancreas, alcohol metabolism, absorption mechanisms, GERD, and common digestive disorders.

What is digestion?

The breakdown of substances in the digestive system.

What is absorption?

The process by which substances move from the digestive system into the blood or lymph.

Which organs constitute the main parts of the GI tract mentioned in the notes?

Mouth, Esophagus, Stomach, Small intestine, and Large intestine.

What enzyme in saliva begins carbohydrate digestion?

Amylase.

What is the function of the thick mucus layer in the stomach?

To protect the stomach lining from acidic gastric juice.

What is chyme?

The semi-liquid mixture of partially digested food that leaves the stomach for the small intestine.

What is the pyloric sphincter?

A valve that controls the passage of chyme from the stomach to the small intestine and helps prevent reflux.

Name the three main digestive enzymes and their substrates.

Amylase (carbohydrates), Protease (proteins), Lipase (fats).

What neutralizes stomach acid as chyme enters the small intestine?

Bicarbonate (neutralizer) from pancreatic juice.

What organs produce and store bile, and what is bile’s function?

Liver produces bile; Gallbladder stores bile; bile emulsifies fats.

Through which vessel does nutrient-rich blood from the digestive system reach the liver?

The portal vein (hepatic portal system).

What ducts transport bile to the small intestine?

The hepatic ducts join to form the common bile duct, which releases bile into the small intestine.

What is the role of the pancreas in digestion?

Secretes digestive enzymes (amylase, protease, lipase) and bicarbonate; produces hormones insulin and glucagon.

What is the function of the liver beyond digestion?

Filters the blood, detoxifies toxins, and helps regulate blood glucose (e.g., makes glucose for the body).

What is the function of the lymphatic system in digestion?

Transports fat-soluble nutrients from the digestive tract.

What is GERD and its common triggers?

Gastroesophageal reflux disease; triggers include overeating, caffeine, alcohol, lying down, obesity, and sometimes aspirin or pregnancy factors.

What role does the lower esophageal sphincter (LES) play?

Prevents reflux by keeping the esophagus closed; if it malfunctions, reflux occurs.

What is peristalsis?

Waves of muscle contractions that move food through the digestive tract (begins in the esophagus).

What are the primary sites for absorption in the GI tract?

Small intestine; absorption occurs via passive diffusion, facilitated diffusion, and active transport.

What are the outlines of diffusion and transport in nutrient absorption?

Passive diffusion (high to low concentration), Facilitated diffusion (carrier-mediated), Active transport (requires energy).

What is constipation and how can it be prevented?

Difficult or infrequent bowel movements; prevent with adequate fiber, fluids, and physical activity.

What is diarrhea and its potential consequence?

Rapid movement of waste through the intestine; can lead to dehydration and malnutrition if severe or persistent.

What is the role of the stomach’s pyloric region and pyloric sphincter in digestion?

Controls emptying of stomach contents into the small intestine and prevents reflux.

What are the effects of alcohol on the body as noted?

Affects brain/memory, can cause liver cirrhosis and heart disease risk, headaches, dehydration, higher triglycerides, fetal alcohol spectrum disorder, stomach irritation, sleep disruption.

What enzyme metabolizes alcohol in the liver?

Alcohol dehydrogenase.

What does “proof” mean in alcohol labeling?

Proof is double the alcohol by volume (ABV); e.g., 80 proof equals 40% ABV.