KIN 110 – CHAPTER 2
Digestion: The process of transforming the foods into units for absorption
Absorption: Movement of substances into or across tissues
Chemosenses: Chemical sensing system in body, taste and smell
- Olfactory Cells: Smell cells
- Gustatory Cells: Taste cells
Cephalic Phase Responses: Psychological responses triggered by sight, smell,
thought, taste and sound of food
GI Tract
Gastrointestinal Tract: Hollow tube that begins at the mouth, and ends at the anus
-Innermost-Outer: Lumen, Epithelium, mucosa, submucosa, circular muscle,
longitudinal muscle serosa
Sphincters: Circular band of muscle fibers that act as entranceways
Chyme: Partially digested food and digestive juices
Peristalsis: Intestinal movement of moving forward
Segmentation: Intestinal movement of mixing
Digestion Process
Enzymes: Proteins in the body which speed up reactions, but is unchanged
Hydrolysis: To split compounds through the addition of water
Nutrient Absorption
Passive Diffusion: Simple diffusion from high to low concentration
Facilitated Diffusion: Diffusion via carrier protein transport
Active Transport: Transport across membranes from low to high concentrations,
requiring energy in the process (ATP)
Endocytosis: Uptake of a material by a cell by the indentation and pinching off of its
membrane to form a vesicle that carries material into the cell
Pinocytosis: Process of endocytosis, for fluids and macromolecules
Phagocytosis: Process of endocytosis, for large particles and small
microorganisms Digestive Assisting Organs
Salivary Glands: Produces saliva
Liver: Produces bile
Emulsifier: Term for agents that break up fat into smaller molecules
Bile: An emulsifying agent, produced by liver, stored in gallbladder
Enteroheptaic Circulation: Process of recycling bile from the intestine back
into the liver
Gallbladder: Stores bile
Cholecystokinin (CCK): Hormone that stimulates the release of digestive
enzymes from pancreas and bile gallbladder
Pancreas: Organ that secretes enzymes and hormones
Digestion Tract
Mouth
Food goes into the mouth, then is wetted with amylase, which breaks starch into
sugar. Lingual Lipase starts fat digestion and the chewed, moistened food
becomes a bolus. Then bolus then slides down to the stomach through the
esophagus. The esophageal sphincter opens and lets food into the stomach.
Stomach
The stomach has hydrochloric acid with a pH of 2. Mucus protects the stomach
lining. The hydrochloric acid digests protein by turning the shape of protein
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