digestive part 1

Ingestion

taking in food

digestion

breaking down food into nutrient molecules

Absorption

movement of nutrients into the bloodstream

Defecation

excretes to rid the body of indigestible waste

Alimentary canal (gastrointestinal, or Gl, tract)

continuous, coiled, hollow tube - Organs ingest, digest, absorb, defecate

Accessory digestive organs

Include teeth, tongue, and several large digestive organs - Assist digestion in various ways

Mouth

mucous membrane-lined cavity

Lips

—protect the anterior opening

Cheeks

form lateral walls

hard palate

—forms the anterior roof

soft palate

—forms the posterior roof

uvula

fleshy projection of the soft palate

vestibule

space between lips externally and teeth and gums internally

Oral cavity proper

area contained by the teeth

tongue

attached at hyoid bone and styloid processes of the skull, and by the lingual frenulum to the floor of the mouth

palatine

pair of tonsils located at posterior end of oral cavity

Lingual

single tonsil located at the base of the tongue

secrete digestive enzymes: amylase (carbs) and lipase (fats)

an important function of the mouth is?

pharynx

Serves as a passageway for foods, fluids, and air - Food passes from the mouth posteriorly

oropharynx

posterior to oral cavity

laryngopharynx

below the oropharynx and continuous with the esophagus

skeletal muscle

Food is propelled to the esophagus by two ___ layers in the pharynx

ICOL = inner circular; outer longitudinal

Also found in the deeper parts of GI tract but smooth muscles - Action: OL shortens and propel food downwards, and IC squeezes the food (proximal to distal) - Alternating contractions of the muscle layers (peristalsis) propel the food

esophagus

Conducts food by peristalsis (slow rhythmic squeezing) to the stomach - Passageway for food only (respiratory system branches off after the pharynx)