Bio - Digestion

Digestive system

A tube in the human body used for digestion, from the mouth to the anus.

Role of the digestive system

To break down large carbon compounds in food into smaller compounds that can be absorbed.

Surfactants

Substances required to break up lipid droplets during digestion.

Esophagus

Tube that moves food by peristalsis from the mouth to the stomach.

Stomach

Organ that churns and mixes food with secreted water and acid for initial protein digestion.

Small intestine

Site of final digestion of macromolecules and the main site of nutrient absorption.

Pancreas

Organ that secretes digestive enzymes such as lipase, amylase, and protease.

Liver

Organ that secretes bile to aid in the digestion of lipids.

Gall bladder

Organ that stores and regulates the release of bile.

Large intestine

Site for re-absorption of water and further digestion by symbiotic bacteria.

Serosa

Outer coat of the small intestine wall.

Mucosa

Lining of the small intestine, where nutrient absorption occurs.

Pancreatic juice

Contains enzymes that digest macromolecules, secreted into the small intestine.

Amylase

Enzyme that digests starch into maltose.

Lipase

Enzyme that digests triglycerides into fatty acids and glycerol.

Protease

Enzyme that digests proteins into shorter peptides.

Nucleases

Enzymes that digest DNA and RNA into nucleotides.

Maltase

Enzyme that digests maltose into glucose.

Lactase

Enzyme that digests lactose into glucose and galactose.

Sucrase

Enzyme that digests sucrose into glucose and fructose.

Villi

Finger-like projections in the small intestine that increase surface area for absorption.

Microvilli

Tiny projections on the surface of epithelial cells that increase surface area for absorption.

Active transport

Process requiring energy to move substances against a concentration gradient.

Facilitated diffusion

Passive transport process that uses carrier proteins to move substances across membranes.

Simple diffusion

Passive movement of molecules from an area of higher concentration to an area of lower concentration.

Exocytosis

Process by which substances are expelled from a cell.

Glycogen

Storage form of glucose in the liver, similar in structure to amylopectin.

Triglycerides

Fats composed of glycerol and fatty acids.

Glucose

Simple sugar absorbed from digestive processes.

Capillaries

Small blood vessels where nutrient absorption occurs.

Hepatic portal vein

Vein that carries blood from the digestive organs to the liver.

Peristalsis

Wave-like muscle contractions that move food through the digestive tract.

Isotonic

Solution with the same solute concentration as the cells, allowing for absorption.

Peptidases

Enzymes that digest peptides into amino acids.

Epithelium

Tissue lining the intestine that absorbs nutrients.

Symbiotic bacteria

Bacteria in the large intestine that aid in digestion, especially of carbohydrates.

Dipeptidases

Enzymes that digest dipeptides into amino acids.

Detoxification

Process of removing harmful substances from the body.

Cholesterol

Fatty substance that coalesces with triglycerides to form lipoprotein particles.

Amino acids

Building blocks of proteins, absorbed by the villi.

Aspartic acid

An amino acid not synthesized during digestion and must be absorbed.

Bile

Digestive fluid produced by the liver that emulsifies fats.

Dietary fiber

Plant material that cannot be digested and aids in digestive health.

Nutrient absorption

Process where nutrients are taken up by the cells lining the intestine.

Hydrolysis reactions

Chemical reactions that break down compounds through the addition of water.

Dextrins

Fragments of amylopectin that remain undigested by amylase.

Vascularization

The presence of a network of blood vessels to transport nutrients.

Cotransport

Process where two molecules are transported together across a membrane.

Alcohol absorption

Process by which alcohol is absorbed through the stomach lining before reaching the small intestine.

Nutritional requirements

Essential substances needed by the body that may be absorbed without digestion.