Takes in Food (mouth)

Hydrolyzes macromolecules to their basic units. (see next slide)

Absorbs the broken down food into the blood stream which delivers it to your tissues and organs.

Carbohydrate Digestion

Salivary amylase (made by salivary glands)…works in mouth Pancreatic amylase (made by pancreas)…works in small intestine Maltase (made by small intestine)…works in small intestine Lactase (made by small intestine)…works in small intestine

Protein Digestion

Pepsin (made by stomach)…works in stomach Trypsin (made by pancreas)…works in small intestine Peptidases (made by small intestine)…works in small intestine

Fat Digestion

Lipase (made by pancreas)…works in small intestine

Nucleic Acid Digestion

Nuclease (made by pancreas)…works in small intestine Nucleosidases (made by small intestine)…works in small

intestine

CHEWINGCHEWING: breaks food into smaller pieces (increases surface area) “Mechanical” digestion (20 baby teeth, 32 adult)

SALIVASALIVA: slightly basic

SWALLOWINGSWALLOWING: soft palate is pushed up to close nasal passages, trachea moves up under the epiglottis to close the glottis.

PERISTALSISPERISTALSIS: muscle contraction that moves food through the digestive tract.

Moves food from mouth to stomach in 5-8 seconds.

Lower Gastroesophageal Lower Gastroesophageal Sphincter:Sphincter: entrance of esophagus to stomach. Food passes when relaxed.

Stores food and initiates digestion of protein.

Very muscular. It contracts to mix food,”mechanical digestion”

Lined with millions of glands that secrete HCl (acidic) and Pepsin (enzyme) “chemical digestion”

Food stays there for 2-4 hours

Gastric bypass attaches the upper part of the stomach to the middle of the small intestine.

StructureStructure:

Muscular tube about 6m long

“Small” because of its diameter

Duodenum (first 25 cm) of small intestine…this is where enzymes from the pancreas and liver are collected.

Bile from the liver causes fat droplets to disperse in water. Since the fat molecules are smaller, lipase can now work.

This is where nutrients are absorbed into the blood.

Food stays in the small intestine for 3-5 hours.

Also known as the “Colon”

Only contains things that can’t be digested…waste

1.5m long and 6.5cm wide

Water is absorbed into the blood here

Bacteria live in here to further break down matter, produce B complex vitamins (coenzymes) and most of the vitamin K (needed for blood clotting) needed by our bodies

18-24 hours in the large intestine before the feces reaches the rectum and leaves the anus.

Total time it takes to digest is 24-33 hoursTotal time it takes to digest is 24-33 hours