Digestive system components

Primary functions and important details

Mouth

• Ingestion• Hard palate: works with tongue for swallowing• Soft palate: uvula closes the nasopharynx

Salivary Gland Functions

• Creates salvia which:• Cleans the mouth• Dissovles some food chemicals• Moistens food• Produces amylase which

breaks down starch

Salivary gland details

• Saliva is 97% water. Enzymes, antibodies and proteins are also produced

• Mumps is a viral disease that causes swelling

Tongue

• Mechanical digestion and propulsion

• Forms food into a bolus

• Contains papillae with taste buds

Teeth

• Mechanical digestion• 4 types: incisors, canines,

premolars, molars• 3 parts: crown, neck, root• Cavities are caused by

the most common bacterial infection fund in humans

Pharynx

• Propulsion• Has three layers

of skeletal muscle (no smooth)

Esophagus

• Propulsion• Has layers of skeletal and smooth muscle

Stomach Functions

• Mechanical digestion using 3 layers of muscle

• Chemical digestion• Absorption: asprin,

some prescription drugs, and alcohol

• Temory storage of chyme

Stomach details

• Gastric glands secrete: mucous, HCl acid, pepsin enzyme, gastrin hormone, serotonin and somatostatin hormone, and histamine.

• Rennin is an enzyme only produced in childhood

• Emetic center controls vomiting

Small Intestine Functions

• Mechanical mixing of food with digestive juices

• Chemical digestion

• absorption

Small intestine details

• 3parts: doudenum, jejunum, ileum

• Villi and microvilli create the brush border for increasing surface area for absorption

• Neutralizes acidic chyme

Liver

• Creates bile• Composition

of bile: fats, bile salts, pigment, cholesterol, phospholipids

Gall Bladder

• Stores bladder• Gallstones can form

to clog the bile duct

Pancreas

• Creates pancreactic digestive juices• PDJ contains water, enzymes, bicarbonate

Large Intestine functions

• Absorption of water

• Propulsion• Defecation• Small role in

chemical digestion

Large intestine details

• 3 parts: ascending, transverse, descending• Bacterial living in the lg. intestine help break down

indegestible carbohydrates such as cellulose• These bacterial flora also synthesize B and K vitamins