The Human Digestive System

Oral Cavity

Food is mechanically chewed by teeth, shaped into bonus

Salivary Amylase (Oral Cavity)

From salivary glands, initiates breakdowns of poly saccharides into monosaccharides

Lingual Lipase (Oral Cavity)

From tongue, initiates the breakdowns of of triglycerides into fatty acids

Esophagus

Moves food into the stomach

Peristalsis (Esophagus)

Waves of esophageal muscle contractions

Bird Crop

Modified esophagus, food stored/processed, saves for regurgitation

Stomach

Mechanically and chemically digests food, pH = 2 from hydrochloric acid

Parietal Cells (Stomach)

Secrets HCL, contributes to low pH of stomach

Mucous Cells (Stomach)

Secrets mucus, prevents stomach lining from acidic gastric juice

Chief Cells (Stomach)

Secrets pepsinogen (inactive form of PEPSIN that is activated by acidic environment, pepsin breaks down proteins

Ruminants (Rumen)

Modified stomach organs, uses symbiotic protists and bacteria containing cellular enzymes to break down cellulose

Gizzard

Stomach organ for mechanical digestion, animals swallow sand or stones to lodge into gizzard

Small Intestine

Digests and absorbs nutrients, high surface area from microbilli

Liver

Contains BILE, emulsifies fats

Pancreas

Secrets pancreatic amylase, pancreatic lipase, nucleuses, inactive protease (trypsinogen), releases insulin to lower blood sugar levels

Insulin (Pancreas)

Hormone, lowers blood sugar levels

Glucagon (Pancrease)

Hormone, raises blood sugar levels

Secretin (Small Intestine)

Hormones, induces flow of bicarbonate ions (raise pH)

Cholecystokinin CCK (Small Intestine)

Hormone, stimulates gall bladder/pancreatic enzyme secretion

Large Intestine

Absorbs water and electrolytes

Colon (Large Intestine)

Compacts waste

Rectum (Large Intestine)

Stores waste

Cecum (Large Intestine)

Receives party digested food and begins absorbing process

Microbiome (Large Intestine)

Collection of microorganisms living in and on the body