Eating and Digestion Overview

Average daily food intake per person is 1.5 kilograms, equating to approximately 550 kilograms annually.
This weight is more than that of two adult black bears.
Digestion is vital for converting large food items into smaller molecules necessary for cell nourishment.
The digestive system works alongside the circulatory system to deliver nutrients throughout the body.

Composed of seven main organs: mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.
These organs form the alimentary canal (gastrointestinal tract), serving as a continuous muscular tube.
Three additional glands support digestion: liver, pancreas, gallbladder, each secreting essential digestive chemicals.

Digestion starts with the anticipation of food, triggering saliva production and preparing digestive juices.
Mechanical digestion occurs as teeth break food into smaller pieces.
Saliva contains enzymes like amylase (for carbohydrates) and lingual lipase (for fats), forming a bolus.
Bolus travels down the esophagus via peristalsis, a series of involuntary muscle contractions.

The stomach acts as a muscular sack that continues the digestion process.
Secretes gastric juice (stomach acid and enzymes) to break down food and kill pathogens.
Hydrochloric acid is so strong it can dissolve metal and activates the enzyme pepsin for protein digestion.
Produces intrinsic factor, essential for vitamin B12 absorption and DNA synthesis.
The stomach churns food with peristalsis, transforming bolus into chyme over 1 to 4 hours.

The small intestine is about 20 feet long and consists of three parts: duodenum, jejunum, and ileum.
The duodenum signals hormone release to stop further digestion as the contents arrive from the stomach.
Pancreas secretes enzymes to digest proteins and fats, while the liver produces bile to emulsify fats.
Nutrient absorption occurs along the small intestine, aided by tiny villi that increase surface area.
Each section of the small intestine absorbs specific nutrients: iron in the duodenum, folic acid in the jejunum, and bile salts in the ileum.

The large intestine absorbs water and interacts with gut bacteria to break down fibers and synthesize vitamins.
Food takes about 36 hours to pass through the large intestine.
Indigestible waste accumulates in the rectum before being expelled through the anus.

Digestion is crucial for breaking down complex biomolecules into absorbable nutrients.
The process includes both mechanical (physical breakdown) and chemical (enzyme action) methods.
Gut health influences mood and overall immunity, with gut bacteria playing a mysterious but significant role in wellness.

Average food intake per person is 1.5 kilograms daily, totaling about 550 kilograms annually, surpassing the weight of two adult black bears.
Digestion transforms large food items into smaller molecules essential for cellular nourishment.
Collaborates with the circulatory system to distribute nutrients throughout the body.

Composed of seven primary organs: mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus, forming the alimentary canal (gastrointestinal tract).
Supported by three crucial glands: liver, pancreas, and gallbladder, each contributing essential digestive chemicals.

Digestion begins with food anticipation, stimulating saliva production and digestive juices.
Mechanical digestion occurs as teeth break food into smaller particles.
Saliva contains enzymes like amylase for carbohydrates and lingual lipase for fats, creating a bolus.
The bolus moves down the esophagus via peristalsis, which is the rhythmic contraction of muscles.

Acts as a muscular sac that furthers the digestion process.
Secretes gastric juice combining stomach acid and enzymes to degrade food and eliminate pathogens.
Hydrochloric acid is potent enough to dissolve metal and activates pepsin, an enzyme that digests proteins.
Produces intrinsic factor necessary for vitamin B12 absorption and DNA synthesis.
Churns food with peristalsis, converting bolus into chyme over 1 to 4 hours.

Approximately 20 feet long, divided into three regions: duodenum, jejunum, and ileum.
Duodenum triggers hormone release to halt digestion as contents enter from the stomach.
The pancreas releases enzymes for protein and fat digestion, while the liver generates bile to emulsify fats.
Nutrient absorption occurs throughout the small intestine, assisted by microscopic villi that increase surface area.
Specific nutrients are absorbed in designated sections: iron in the duodenum, folic acid in the jejunum, and bile salts in the ileum.

Absorbs water and collaborates with gut bacteria to decompose fibers and synthesize vitamins.
Takes roughly 36 hours for food to traverse the large intestine.
Indigestible residues accumulate in the rectum before elimination through the anus.

Essential for converting complex biomolecules into absorbable nutrients.
Involves both mechanical breakdown and chemical actions through enzymes.
Gut health impacts mood and overall immunity, with gut bacteria playing an essential yet mysterious role in wellness.