Digestive System Study Guide
6 primary functions of digestive system:
1. Ingestion- food intake
2. Secretion
3. Digestion- mechanical & chemical breakdown of food
Mechanical
Mastication- first step. Enables mixing with saliva to form bolus to be swallowed. Regulated by CNS.
Deglutition
Mixing/Churning
Peristalsis- movement of muscles within GI tract that facilitates movement of food
Chemical- Hydrolysis (using H2O) of macromolecules into monomers (residues) carried out by digestive enzymes produced by salivary glands, stomach, pancreas, & small intestine.
Carbohydrates Polysaccharides Monosaccharides
Proteins Polypeptides & Amino Acids
Fats Monoglycerides, glycerol & fatty acids nucleic acids nucleotides
4. Absorption- uptake of nutrients into epithelial cells of digestive tract & then into blood or lymph
5. Defecation- elimination of undigested residue
2 anatomical divisions of digestive system
1. Alimentary canal (GI Tract)- 30ft tube extending from mouth to anus oral cavity pharynx esophagus stomach small intestine large intestine
2. Accessory organs teeth tongue salivary glands liver gallbladder pancreas *Both are responsible for facilitating the body’s metabolic processes:
Catabolism- break down of larger molecules
Anabolism- smaller molecules are used as building blocks for lager molecules
4 Layers of Digestive Tract Walls (inner outer)
1. Mucosa- mucous membrane made of various types of epithelium sitting on lamina propria
Epithelium
Nonkeratinized stratified squamous epithelium (for protection) lines pharynx, esophagus, & anus
Simple columnar epithelium (for secretion/absorption) lines the stomach and intestines.
Lamina propria- loose CT. Contains prominent lymphoid tissue (mucosa-associated lymphatic tissue or “MALT”) that protect against disease
Muscularis mucosae- smooth muscle that increases surface area to aid digestion/absorption
2. Submucosa- thicker layer of loose CT. Contains blood & lymphatic
1. Ingestion- food intake
2. Secretion
3. Digestion- mechanical & chemical breakdown of food
Mechanical
Mastication- first step. Enables mixing with saliva to form bolus to be swallowed. Regulated by CNS.
Deglutition
Mixing/Churning
Peristalsis- movement of muscles within GI tract that facilitates movement of food
Chemical- Hydrolysis (using H2O) of macromolecules into monomers (residues) carried out by digestive enzymes produced by salivary glands, stomach, pancreas, & small intestine.
Carbohydrates Polysaccharides Monosaccharides
Proteins Polypeptides & Amino Acids
Fats Monoglycerides, glycerol & fatty acids nucleic acids nucleotides
4. Absorption- uptake of nutrients into epithelial cells of digestive tract & then into blood or lymph
5. Defecation- elimination of undigested residue
2 anatomical divisions of digestive system
1. Alimentary canal (GI Tract)- 30ft tube extending from mouth to anus oral cavity pharynx esophagus stomach small intestine large intestine
2. Accessory organs teeth tongue salivary glands liver gallbladder pancreas *Both are responsible for facilitating the body’s metabolic processes:
Catabolism- break down of larger molecules
Anabolism- smaller molecules are used as building blocks for lager molecules
4 Layers of Digestive Tract Walls (inner outer)
1. Mucosa- mucous membrane made of various types of epithelium sitting on lamina propria
Epithelium
Nonkeratinized stratified squamous epithelium (for protection) lines pharynx, esophagus, & anus
Simple columnar epithelium (for secretion/absorption) lines the stomach and intestines.
Lamina propria- loose CT. Contains prominent lymphoid tissue (mucosa-associated lymphatic tissue or “MALT”) that protect against disease
Muscularis mucosae- smooth muscle that increases surface area to aid digestion/absorption
2. Submucosa- thicker layer of loose CT. Contains blood & lymphatic