Module 2: Fats (part 1) Flashcards
Atoms
The smallest units of a element that still retain the properties of that element
Elements
Substances that cannot be broken down into products with different properties
Molecules
Units of 2 or more atoms of the same or different elements bonded together
Cells
The basic structural & functional units of plant & animal life
Organs
Discrete structures composed of more than one tissue that perform a speacialized function
Tissues
4 types: muscle, nerve, epithelial, & connective
Organization of life
Begins with atoms that form molecules, which are organized into cells to form tissues, organs, organ systems, & whole organisms
Major functions of digestive system
Digestion & absorption
Digestion
The process of breaking food into components small enough to be absorbed into the body
Absorption
The process of taking substances into the interior of the body
Feces
Body waste, including unabsorbed food residue, bacteria, muscles, & dead cells, which is excreted from the gastrointestinal tract by passing through the anus
Gastrointestinal tract
Main part of digestive system - a hollow tube consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, & anus, in which digestion & absorption of nutrients occur
Organs of gastrointestinal tract
Runs from mouth to anus - mouth, pharynx, esophagus, stomach, small intestine, large intestine, & anus
Transit time
The time between the ingestion of the food & the elimination of the solid waste from that food (time it takes for the food to pass the length of the GI tract - from mouth to anus)
Mucosa
The layer of tissue lining the GI tract & other body cavities (protection layer) - responsible for the absorption of the end products of digestion
Mucus
A viscous fluid secreted by glands in the GI tract & other parts of the body, which acts to lubricate, moisten, & protect cells from harsh environments
Hormones
Chemical messengers that are produced in one location, released into the blood, and elicit responses at other locations in the body
Barrier function
The protective role that gastrointestinal cells have in limiting the absorption of harmful substances and disease-causing organisms
Antigens
A foreign substance (almost always a protein) that, when introduced into the body, stimulates an immune response
Antibodies
Proteins produced by cells of the immune system that destroy or inactivate foreign substances in the body
Allergen
A substance, usually a protein, that stimulates an immune response
Saliva
A watery fluid produced and secreted into the mouth by the salivary glands - it contains lubricants, enzymes, & other substances
Roles of saliva
Moistens the food so that it can easily be tasted & swallowed; it begins the enzymatic digestion of starch; it cleanses the mouth & protects teeth from decay; and it lubricates the upper GI tract
Salivary amylase
An enzyme secreted by the salivary glands that breaks down starch
Lysozyme
An enzyme in saliva, tears, and sweat that is capable of destroying certain types of bacteria
Pharynx
A funnel-shaped opening that connects the nasal passages & mouth to the respiratory passages and esophagus - it is a common passageway for food and air and is responsible for swallowing
Epiglottis
A piece of elastic connective tissue at the back of the throat that covers the opening of the passageway to the lungs during swallowing
Esophagus
A portion of the GI tract that extends from the pharynx to the stomach
Peristalsis
Coordinated muscular contractions that move food through the GI tract
Sphincter
A muscular valve that helps control the flow of materials in the GI tract
Chyme
A mixture of partially digested food and stomach secretions
Parietal cells
Cells in the stomach lining that make hydrochloric acid and intrinsic factor in response to nervous or hormonal stimulation
Pepsinogen
An inactive protein-digesting enzyme produced by gastric glands and activated to pepsin by acid in the stomach
pepsin
A protein-digesting enzyme produced by the gastric glands - it is secreted in the gastric juice in an inactive from and activated by acid in the stomach
Peptic ulcer
An open sore in the lining of the stomach, esophagus, or small intestine
Gastrin
A hormone secreted by the stomach mucosa that stimulates the secretion of gastric juice
Small intestine
Main site of digestion of food and absorption of nutrients
Villi
Finger-like protrusions of the lining of the small intestine that participate in the digestion & absorption of old nutrients
Microvilli
Minute, brush-like projections on the mucosal cell membrane that increase the absorptive surface area in the small intestine
Lacteal
A tubular component of the lymphatic system that carries fluid away from the body tissues
Segmentation
Rhythmic local constrictions of the intestine that mix food with digestive juices and speed absorption by repeatedly moving food mass over the intestinal wall
Pancreas
An organ that secretes digestive enzymes and bicarbonate ions into the small intestine during digestion
Gallbladder
An organ of the digestive system that stores bile, which is produced by the liver
Lipases
Fat digesting enzymes
Bile
A substance made in the liver and stored in the gallbladder, which is released into the small intestine to aid in fat digestion and absroption
Secretion
A hormone released by the duodenum that signals the release of pancreatic juice rich in bicarbonate ions and stimulates the liver to secrete bile into the gallbladder
Cholecystokinin (CCK)
A hormone released by the duodenum that stimulates the release of pancreatic juice rich in digestive enzymes and causes the gallbladder to contract and release bile into the duodenum
Simple diffusion
The movement of substances from an area of higher concentration to an area of lower concentration - no energy is required
Osmosis
The passive movement of water across a semipermeable membrane in a direction that will equalize the concentration of dissolved substances on both sides
Facilitated diffusion
The movement of substances across a cell membrane from an area of higher concentration to an area of lower concentration with the aid of a carrier molecule - no energy is required
Active transport
The transport of substances across a cell membrane with the aid of a carrier molecule and the expenditure of energy - this may occur against a concentration gradient
Colon
The largest portion of the large intestine
Rectum
The portion of the large intestine that connects the colon and anus
Intestinal microflora
Micro-organisms that inhabit the large intestine
Probiotics
Specific types of live bacteria found in foods that are believed to have beneficial effects on human health
Prebiotics
Indigestible carbs that pass into the colon, where they serve as a food supply for bacteria, stimulating the growth or activity of certain types of beneficial bacteria
