BODY SYSTEMS

DIGESTIVE SYSTEM

FUNCTION:
DIGESTION
and ABSORPTION

MOUTH

• Begins mechanical digestion
• Houses teeth and tongue

SALIVARY GLANDS

• Accessory organs
• Chemically digest food
• Help swallow
• Protect teeth

PHYARYNX

• Connects mouth to esophagus
• Swallows bolus
• Commonly called throat

Esophagus

• Connects pharynx to stomach
• Uses peristalsis to swallow

PERISTALSIS:

rhythmic contraction of muscles to push food down a tract

STOMACH

• Temporarily stores food
• Partially digests food
• Passes food to small intestine in a controlled manner

THE SMALL INTESTINE

• Duodenum
• Jejunum
• Ileum

DUODENUM

• Chyme mixes with bile and pancreatic juice
• Completes digestion

JEJUNUM

• Absorbs nutrients
• Majority of absorbtion

ILEUM

• Empties into large intestine
• Completes absorption

LARGE INTESTINE

• Cecum
• Colon
• Rectum
• Anus

CECUM

• Absorb fluids and salts
• Mix with mucus

COLON

• Lubricate waste products
• Absorb remaining fluid and salt
• Moves feces

RECTUM

• Receives stool from colon
• Temporary feces storage

ANUS

• Holds stool
• Keeps us continent

LIVER

• Processes nutrients
• Breaks down fat and toxins
• Makes bile
• Accessory organ

PANCREAS

• Accessory organ
• Secretes enzymes to duodenum
• Makes insulin

GALLBLADDER

• Accessory Organ
• Stores and concentrates bile
• Releases bile into duodenum

Digestion of large food molecules is essential because:

Food must be broken down and rearranged
and
Food must be small enough to be absorbed by villi in the intestine

We need enzymes in digestion because:

Enzymes break down food molecules

Enzymes speed up digestion without raising body temperature by lowering the activation energy

Chemical Digestion

• Uses enzymes, bases and acids
• More important than mechanical

MECHANICAL DIGESTION

• Breaks food into smaller particles
• Prepares food for chemical digestion

Carbohydrates are digested in the small intestine, using pancreatic amylase to split it into disaccharides.

Lipids are digested in the stomach, using HCl and gastric enzymes.

Proteins are digested with pepsin in the stomach and peptidase in the small intestine.

GASTRIC ULCERS

• Holes in the stomach lining
• caused by imbalance in stomach fluids
• Symptoms include stomach pain, vomiting, appetite loss

PREVALENCE AND TREATMENT

• over 3 million cases in the U.S. per year
• Treated with antibiotics and medication to inhibit acid production

HEMORRHOIDS

• Swollen blood vessels lining the anal opening
• Symptoms include anal itching and painless bleeding

PREVALENCE AND TREATMENT

• Up to 75% of Americans with be affected by hemorrhoids at one point
• Treated with hemorrhoid creams

SOURCES

• www.cliffsnotes.com/sciences/anatomy-and-physiology/the-digestive-system/fu...
• www.innerbody.com/image/digeov.html
• www.chp.edu/CHP/organs+intestine
• www.ivyroses.com/HumanBody/Digestion/Large-Intestine-diagram.php