Nutrition Quiz 2 (Ch. 3 -5)

Digestive system, Carbohydrates and Lipids

Large intestine

A part of the digestive system that absorbs water, electrolytes, and vitamins produced by gut bacteria. It also compacts undigested food into feces for elimination and supports gut health through beneficial microbial activity.

Amylase

An enzyme that breaks down starches (carbohydrates) into simpler sugars like maltose and glucose. There are salivary amylase (in the mouth) and pancreatic amylase (in the small intestine). Initiates carbohydrate digestion, starting in the mouth and continuing in the small intestine.

teeth

Hard, calcified structures in the mouth that aid in mechanical digestion by chewing food into smaller pieces, making it easier to swallow and increasing the surface area for enzymes to work on, essential for efficient digestion and nutrient absorption.

Saliva

A digestive fluid produced by salivary glands in the mouth.Begins digestion by breaking down starches with the enzyme amylase. Aids in taste.

Prebiotic

It feeds the healthy gut microbiota, which is non-digestible food found in things like corn. The insoluble part of the corn feeds and supports the growth of healthy gut bacteria, and the corn fiber (Soluble) breaks down and forms a gel in the intestines, which can help with digestion, regularity, and nutrient absorption.

Chemical Digestion

uses certain enzymes to break down nutrients into smaller molecules, so that the body can absorb nutrients and use them for essential functions.

Gallbladder

Store and release bile, which helps the body digest fats.

Probiotic

Live microorganisms (bacteria and yeast), multiple stains in foods Ex. yogurt

Stomach

The stomach's process of digestion and mixing food with digestive juices produces a paste called chyme, using mechanical digestion (peristaltic contractions) to move food through the stomach and chemical enzymes like pepsin

Pancreas

Function: A gland that produces digestive enzymes (amylase, protease, lipase) and bicarbonate to neutralize stomach acid.

Role in Digestion: Enzymes break down carbohydrates, proteins, and fats in the small intestine

Lipase

• Definition: An enzyme that breaks down dietary fats into fatty acids and glycerol, aiding in fat digestion.

• Produced By: Pancreas, stomach, and salivary glands.

• Function: Essential for the digestion and absorption of fats in the small intestine.

• Importance: Helps the body utilize fats for energy and absorb fat-soluble vitamins (A, D, E, K).

Mouth

The starting point of digestion where mechanical (chewing) and chemical (saliva) processes begin breaking down food. Salivary amylase starts the digestion of carbohydrates. Minimal absorption occurs here.

Mucus

A thick, slippery substance produced by the mucous membranes lining the digestive tract. It protects the stomach and intestines from acidic gastric juices, lubricates food for easier passage, and aids in overall digestive health

Small Intestine

• Main site of digestion and nutrient absorption.

• Digestive Role: Receives bile from the liver/gallbladder and enzymes from the pancreas to break down carbohydrates, proteins, and fats.

• Absorption:

  • Duodenum: Absorbs minerals (iron, calcium, magnesium).

  • Jejunum: Absorbs most nutrients (carbs, proteins, fats, vitamins).

  • Ileum: Absorbs vitamin B12, bile salts, and remaining nutrients.

• Key Feature: Villi and microvilli increase surface area for maximum nutrient absorption.

Hydrochloric Acid

• Stomach.

• Function: Breaks down food, activates pepsin for protein digestion, and kills harmful bacteria.

• Importance: Essential for creating an acidic environment, aiding in nutrient absorption (e.g., iron, calcium).

Esophagus

A muscular tube that connects the mouth to the stomach. It transports food via peristalsis (wave-like muscle contractions) but does not participate in digestion or absorption. Its primary function is to move food safely from the throat to the stomach.

Pepsin

• Definition: A digestive enzyme produced in the stomach that breaks down proteins into smaller peptides.

• Produced By: Chief cells in the stomach lining as an inactive precursor called pepsinogen, which is activated by stomach acid (HCl).

• Function: Initiates protein digestion, making it easier for enzymes in the small intestine to further break down proteins into amino acids.

• Optimal pH: Works best in the acidic environment of the stomach (pH 1.5-3.5).

Liver

• Function: Processes and stores nutrients, detoxifies harmful substances, and produces bile to aid in fat digestion.

• Role in Digestion: Produces bile, which emulsifies fats in the small intestine, making them easier to digest and absorb.

• Nutrient Storage: Stores vitamins (A, D, B12), minerals (iron, copper), and glycogen (a form of stored glucose).

• Metabolism: Regulates metabolism of carbohydrates, fats, and proteins.

• Detoxification: Filters and breaks down toxins, drugs, and waste products from the blood.

Feces

waste material remaining after digestion and absorption is complete

Mucus

aids passage and mixing of chyme, and protects the epithelia against harsh dietary components, including the mucosal surface from its own acid, alkaline, and enzyme secretions.

Bile

a digestive fluid produced by the liver and stored in the gallbladder that helps break down fats in food, Bile breaks down fats into fatty acids, which are then absorbed by the digestive tract. It also helps digestive enzymes do their job

Nutrients

chemical substances required by the body to sustain basic functions and are optimally obtained by eating a balanced diet.

Functions of the Digestion System

Ingestion, Digestion, Absorption, Elimination