Divisions of the Digestive System
1) Alimentary Tract, Gastrointestinal Tract, Digestive Tract(tube like structure that extends from the mouth to the anus
2) Accessory Organs(Organs necessary for digestion but not part of the Gi tract(Salivary glands, liver, gall bladder, pancreas
Functions of the Digestive System(Ingestion)
- eating
Functions of the Digestive System(Digestion)
Functions of the Digestive System(Absorption)
-transfer of digested nutrients from the gi tract to the bloodstream
Functions of the Digestive System(Elimination)
-undigested material eliminated from tract; deformation
Functions of the Digestive System?
Walls of the digestive tract(Innermost to outermost)
Mucosa
Muscle
-smooth muscle
most of gi tract has 2 layers:
-inner layer has fibers that are arranges in a circular pattern(contraction narrows the lumen)
-outer layer has fibers that are arranged in a longitudinal pattern(contractions make the gi tract shorter)
-combination of contractions of both muscle layers produce peristalsis
-stomach has an extra layer(total of 3 layers) to strengthen it and help with mixing food and digestive enzymes
Serosa
Peritoneal Membrane
Mouth; Oral Cavity; Buccal Cavity(Function)
-ingestion
-mastication(chewing
mechanical digestion of food in smaller particles performed mainly by the teeth assisted with tongue, cheeks, lips, mixes food with saliva for lubrication
-saliva begins the chemical digestion of starch
-deglutition; swallowing, amount of food we swallow is bolus
Mouth; Oral Cavity; Buccal Cavity(Structure)
Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Tongue
Tongue
Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Salivary Glands
Salivary Glands -three pairs: Parotid,Submandibular,Sublingual Parotid -anterior and inferior(largest Submandibular -near body of mandible Sublingual -under tongue Function: -secrete saliva -moistens food -helps with mastication and deglutition -amylase converts starch to sugar
Mouth; Oral Cavity; Buccal Cavity(Accessory Structure)-Teeth
Teeth
Pharynx(throat)
Esophagus(Gullett)
Stomach(Function)
Stomach(location)
-upper right quadrant
Stomach(Muscle Layers, spincters)
-J shaped organ
-2spincters
-cardiac sphincter(lower esophageal spinster) at entrance
-pyloric sphincter at the exit
Three layers of muscle
-circular, longitudinal, oblique(strengthens for mixing/churning)
-when empty it has folds called rugae
Regions
Fundus -superior rounded edge of stomach -part next to diaphragm Body -greater and lesser curvature Pylorus -next to pyloric spinster
Gastric Pits
- secretion of gastric pits are called gastric juices
Goblets Cells
- protects lining of stomach