Pt 1 of Test 3 Flashcards
What are the main steps in the digestive process
- ingestion
- digestion
- absorption
- elimination
what is the main point in the digestive process
movement. food must be moved along the G.I. tract in order to fulfill all functions. (food must be first broken down)
explain the muscularity of the G.I. tract
highly muscular allowing to propel food stuff
what is ingestion
intake of food via the mouth
what is digestion
mechanically or chemically breaking down foods into their subunits
what would be an example of chemically digesting food into their subunits
by enzymes such as hydrolysis which is enzymatic break down using water (complex to simple)
what is absorption
movement of nutrients across the GI tract wall to be delivered to cells via blood (absorbing nutrients across membranes into bloodstream)
where does absorption mainly take place
jejunum of SMALL INTESTINE
what is elimination
removal of indigestible molecules (compaction and defecation- feces)
where does elimination usually occur
large intestine and anus
what is peristalsis
wave-like movement that propels food stuffs from one place to the next (rhythmic)
what is mechanical digestion
physical breakdown of food into smaller particles (mainly in mouth)
what are the ways to digest mechanically
cutting/grinding of teeth
churning action of stomach/small intestines
exposing more food surface to action of digestive enzymes
what does mechanical digestion do for the surface area of food stuff
increases it when bringing in to facilitate for chemical digestion and to be acted on by those enzymes
what is chemical digestion
a series of hydrolysis reactions that breaks dietary macromolecules into their monomers (residues). conducted by enzymes
how is chemical digestion carried out
by digestive enzymes produced by salivary glands, stomach, pancreas, and SMALL INTESTINE (starts in mouth, works in stomach, almost entirely done by small intestine)
what are the results of chemical digestion
polysaccharides into monosaccharides
proteins into amino acids
fats into monoglycerides and fatty acids
nucleic acids into nucleotides
do all nutrients have to be broken down?
no. some nutrients are present in a usable form in ingested food. they can be absorbed without being digested. Small things like vitamins, free amino acids, cholesterol, water
what are the 2 groups of organs in the digestive system
- alimentary canal
- accessory digestive organs
what does the alimentary canal do and what does it consist of
GI tract. mouth to anus. digests food and absorbs fragments. mouth, pharynx, esophagus, stomach, small intestine, and large intestine
what are accessory digestive organs
teeth, tongue, gallbladder
digestive glands
salivary glands
liver
pancreas
most material in the body is considered
external to the body until it is absorbed by the epithelial cells of the alimentary canal. (so basically defecated food residue was never in the body)
what is the alimentary canal order
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- rectum
- anus
what is the enteric nervous system
a quasi-autonomic nervous network in the esophagus, stomach, and intestines that regulate digestive tract motility, secretion, and blood flow (self regulating)