Function of the Digestive System
process nutrient fuel molecules. There are four parts to the digestive process: Ingestion, Digestion, Absorbtion, Movement
getting food into the body
breaking down food molecules
moving broken down food molecules out of the lumen of the gut into the bodys cells and blood. Requires lots of surface area
mechanical digestion in the stomach, and to move chyme through the GI tract
food after swallowing
food in the stomach
The primary components of the walls of GI tract
Mucosa, Submucosa, Muscularis, Serosa
formed by two facial bones, palatines and maxillae. Keeps food out of the nasal cavity airway
posterior to hard palate, Its most posterior extension is the uvula which closes off nasopharynx during swallowing.
closes off nasopharynx while swallowing
saliva moistens food, begins digestion and fights microbes.
anterior to ear and superficial to masseter muscle on both sides of face. They swell up during mumps.
aka submaxillary gland. lie along the medial surface of the mandibles on both sides of face.
mucous membrane which lines the lumen of the digestive system. Contains 3 sub layers: epithelium, lamina propria, muscularis mucosa
the layer of areolar CT which underlies the epithelium.contains blood vessels, lymph vessels and small scattered nodules of GALT
very thin layer of smooth muscle cells at the base of the mucosa layer. creates folds in the mucous membrane which increases surface area. Also helps move villi for absorbtion
another layer of areolar CT. binds the mucosa layer to muscularis layer. Has blood vessels, plus nerve plexi and secretory glands in some organs.
layer of muscle which moves bolus or chyme through alimentary canal.
the serous membrane the surrounds the outside of alimentary canal organs. made of areolar CT and simple squamous ET
runs between trachea and vertebral column in mediastinum and passes through diapragm. It delivers swallowed bolus from mouth to stomach. lined with stratified squamous ET for protection from rough edged food
in the submucosa, they secrete mucous which lubricates the bolus being swallowed.
in the mucosa of the small intestine
stores chyme also protects from pathogens. largest organ in the GI tract
the area of the stomach where the cardiac sphincter prevents backwards movement of chyme into esophagus.
just beyond the cardia where the stomach curves upward and to the left creating a round area (the fundus)
the beginning of the last part of the stomach, where the arc of the lesser curve changes sharply
large folds which allow fro expansion
produce hydrochloric acid to kill bacteria
produce digestive enzymes
produce useful secretions
controls exit of chyme into duodenum
chemical digestion and nutrient absorbtion. 3 regions: duodenum, jejunum, ileum
short beginning of the s. intestine just past the pyloric sphinctor
the longer middle region after the duodenum
the last region of s. intestine which connects to the l. intestine.
secrete bicarbonate rich mucous which neutralizes acidity of chyme. Contain Peyers Patches
large lymphoid nodules which usually appear in groups to perfor surveillance on chyme to control bacteria from backflow of chyme from l. intestine
large, ring shaped folds of mucosa+submucosa which project into the lumen
finger like protrusion of mucosa which bristle outward from the plicae
tiny cilia like extensions of plasma membranes of epithelial cells lining the lumen