chapter 47 ~ digestive system Flashcards
The processes by which an organism takes in, digests, absorbs, and converts food into organic compounds.
Nutrition
The feeding methods used to take food into the digestive cavity.
Ingestion
The splitting of carbohydrates, proteins, lipids, and nucleic acids in foods into chemical subunits small enough to be absorbed into the body fluids and cells of an animal.
Digestion
The uptake of food from the surroundings.
Feeding
An animal that obtains energy and nutrients primarily by eating plants.
Herbivores
An animal that primarily eats other animals.
Carnivores
An animal that feeds at several trophic levels, consuming plants, animals, and other sources of organic matter.
Omnivores
A form of malnutrition. A condition in animals in which intake of organic fuels is inadequate, or whose assimilation of such fuels is abnormal.
Undernutrition
A form of malnutrition. The condition caused by excessive intake of specific nutrients.
Overnutrition
A condition resulting from a diet in which intake of organic fuels is inadequate or whose assimilation of such fuels is abnormal (=undernutrition), or in which there is excessive intake of specific nutrients (=overnutrition).
Malnutrition
Any amino acid that is not made by the human body but must be taken in as part of the diet.
Essential amino acids
Any fatty acid that the body cannot synthesize but needs for normal metabolism.
Essential fatty acids
An organic molecule required in small quantities that the animal cannot synthesize for itself.
Vitamins
Any inorganic element such as calcium, iron, or magnesium that is required in the diet of an animal or, in the case of plants, that generally must be present in soil.
Essential minerals
Any of the essential amino acids, fatty acids, vitamins, and minerals required in the diet of an animal.
Essential nutrients
An animal that obtains nourishment by ingesting liquids that contain organic molecules in solution.
Fluid feeders
An animal that ingests small food items suspended in water.
Suspension feeders
An animal that consumes particles of organic matter from the solid substrate on which it lives.
Deposit feeders
An animal that consumes sizeable food items whole or in large chunks.
Bulk feeders
A process in which chemical bonds are broken by the addition of H + and OH-, the components of a molecule of water.
Enzymatic hydrolysis
An enzyme that catalyzes the hydrolysis of starches.
Amylases
A pancreatic enzyme that hydrolyzes fats.
Lipases
An enzyme that hydrolyses proteins.
Proteases
An enzyme that digests a nucleic acid molecule.
Nucleases
The process in which cells take in food particles by endocytosis.
Intracellular digestion
Digestion that takes place outside body cells, in a pouch or tube enclosed within the body; in fungi, extracellular digestion occurs by way of enzymes released to the environment where they break down nearby organic matter into particles the fungus can absorb.
Extracellular digestion
A saclike body cavity with a single opening, a mouth, which serves both digestive and circulatory functions.
Gastrovascular cavity
The throat. In some invertebrates, a protrusible tube used to bring food into the mouth for passage to the gastrovascular cavity; in mammals, the common pathway for air entering the larynx and food entering the esophagus.
Pharynx
Part of an extracellular digestive system; it is tubelike with two openings that form a separate mouth and anus. Digestive contents move in one direction through specialized regions of the tube, from the mouth to the anus.
Digestive tract
The inside of the digestive tube.
Lumen
A connecting passage of the digestive tube.
Esophagus
Of birds, an enlargement of the digestive tube where the digestive contents are stored and mixed with lubricating mucus.
Crop
The part of the digestive tube that grinds ingested material into fine particles by muscular contractions of the wall.
Gizzard
The portions of digestive system where organic matter is hydrolyzed by enzymes secreted into the digestive tube. As muscular contractions of the intestinal wall move the mixture along, cell lining the intestine absorb the molecular subunits produced by digestion.
Intestine
A vitamin with a high proportion of oxygen and nitrogen able to form hydrogen bonds with water.
Water-soluble vitamins
A vitamin that dissolves in liquid fat or fatty oils, in addition to water.
Fat-soluble vitamins
The lining of the digestive tract, which contains epithelial and glandular cells, connective tissue, and some smooth muscle.
Mucosa
The thick layer of elastic connective tissue in the digestive tract that contains neuron networks, blood and lymph vessels, and glands.
Submucosa
The muscular coat of a hollow organ or tubular structure.
Muscularis
The outermost layer of the digestive tract consisting of a layer of epithelium on the outside of the tube with a layer of connective tissue beneath it. Cells of the serosa protect the underlying tissues and secrete an aqueous, slippery fluid that lubricates the areas between the digestive organs and other organs, reducing friction between them as they move together as a result of muscle movement.
Serosa
A powerful ring of smooth muscle that forms a valve between major regions of the digestive tract.
Sphincters