Digestive System

Background Information

• Total length: 8-9 meters and 2/3 of this is the small intestine

Digestive System Sequence

• Lips Tongue Salivary Glands Pharynx Epiglottis Esophagus stomach small intestines large intestine rectum anus

Functions

• Lips: holds food in• Teeth: chews up food• Tongue: moves food around• Salivary glands: produces saliva

containing salt, mucus, amylase (starch) and lysozome (bacteria) form a BOLUS

Functions (con’t)

• Pharynx: passage for food/air

• Epiglottis: covering for the glottis (opening to larynx)

• Esophagus: 25 cm. long; both voluntary and involuntary muscle

Stomach

• Storage and digestion• 2 sphincter muscles:

top- cardiac sphincterbottom- pyloric sphincter

• Lining secretes substances to break down food (i.e. HCl)

• Chyme: mixture produced by digestion in the stomach

Small Intestine

• Chemical digestion and absorb

• 3 sections: duodenum, jejunum, and ileum

• Surface contains microvilli (finger like projections) to move food along

Large Intestine

• Absorbs water and minerals

• Also called colon

• Different sections: ascending, transverse, descending and sigmoid

Accessory Organs

• Pancreas: produces enzymes that break down carbs, protein, lipids

• Liver: produces bile- dissolves fats; bile is stored in gallbladder

Movements

• Peristalsis: wavelike movement to move bolus toward stomach