Chapter 41 - Animal Nutrition Flashcards
nutrition
The process by which an organism takes in and makes use of food substances.
herbivore
An animal that mainly eats plants or algae.
carnivore
An animal that mainly eats other animals.
omnivore
An animal that regularly eats animals as well as plants or algae.
essential nutrient
A substance that an organism cannot synthesize from any other material and therefore must absorb in preassembled form.
essential amino acid
An amino acid that an animal cannot synthesize itself and must be obtained from food in prefabricated form.
essential fatty acid
An unsaturated fatty acid that an animal needs but cannot make.
vitamin
An organic molecule required in the diet in very small amounts. Many vitamins serve as coenzymes or parts of coenzymes.
mineral
In nutrition, a simple nutrient that is inorganic and therefore cannot be synthesized in the body.
ingestion
The first stage of food processing in animals: the act of eating.
suspension feeder
An aquatic animal, such as sponge, clam, or baleen whale, that feeds by sifting small organisms or food particles from the water.
substrate feeder
An animal that lives in or on its food source, eating its way through the food.
fluid feeder
An animal that lives by sucking nutrient-rich fluids from another living organism.
bulk feeder
An animal that eats relatively large pieces of food.
digestion
The second stage of food processing in animals: the breaking down of foot into molecules small enough for the body to absorb.
absorption
The third stage of food processing in animals: the uptake of small nutrient molecules by an organism’s body.
elimination
The fourth and final stage of food processing in animals [and humans]: the passing of undigested material out of the body.
gastrovascular cavity
A central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both the digestion and distribution of nutrients.
alimentary canal
A complete digestive tract, consisting of a tube running between a mouth and an anus.
peristalsis
(1) Alternating waves of contraction and relaxation in the smooth muscles lining the alimentary canal that push food along the canal. (2) A type of movement on land produced by rhythmic waves of muscle contractions passing from front to back, as in many annelids.
sphincter
A ringlike band of muscle fibers that controls the size of an opening in the body, such as the passage between the esophagus and the stomach.
oral cavity
The mouth of an animal.
salivary gland
A gland associated with the oral cavity that secretes substances that lubricate food and begin the process of chemical digestion.
amylase
An enzyme that hydrolyzes starch (a glucose polymer from plants) and glycogen (a glucose polymer from animals) into smaller polysaccharides and the disaccharide maltose.
mucus
A viscous and slippery mixture of glycoproteins, cells, salts, and water that moistens and protects the membranes lining body cavities that open to the exterior.
bolus
A lubricated ball of chewed food.
pharynx
(1) An area in the vertebrate throat where air and food passages cross. (2) In flatworms, the muscular tube that protrudes from the ventral side of the worm and ends in the mouth.
esophagus
A muscular tube that conducts food, by peristalsis, from the pharynx to the stomach.
stomach
An organ of the digestive system that stores food and performs preliminary steps of digestion.
gastric juice
A digestive fluid secreted by the stomach.
chyme
The mixture of partially digested food and digestive juices formed in the stomach.
protease
An enzyme that digests proteins by hydrolysis.
pepsin
An enzyme present in gastric juice that begins the hydrolysis of proteins.
pepsinogen
The inactive form of pepsin secreted by chief cells located in gastric pits of the stomach.
small intestine
The longest section of the alimentary canal, so named because of its small diameter compared with that of the large intestine; the principal site of the enzymatic hydrolysis of food macromolecules and the absorption of nutrients.
duodenum
The first section of the small intestine, where chyme from the stomach mixes with digestive juices form the pancreas, liver, and gallbladder as well as from gland cells of the intestinal wall.
pancreas
A gland with exocrine and endocrine tissues. The exocrine portion functions in digestion, secreting enzymes and an alkaline solution into the small intestine via a duct; the ductless endocrine portion functions in homeostasis, secreting the hormones insulin and glucagon into the blood.
bile
A mixture of substances that is produced in the liver and stored in the gallbladder; enables formation of fat droplets as an aid in the digestion and absorption of fats.
liver
A large internal organ in vertebrates that performs diverse functions, such as producing bile, maintaining blood glucose level, and detoxifying poisonous chemicals in the blood.
gallbladder
An organ that stores bile and releases it as needed into the small intestine.
villus
(1) A finger-like projection of the inner surface of the small intestine. (2) A finger-like projection of the chorion of the mammalian placenta. Large numbers of fill increase the surface areas of these organs.
microvillus
One of many fine, finger-like projections of the epithelial cells in the lumen of the small intestine that increase its surface area.
hepatic portal vein
A large vessel that conveys nutrient-laden blood from the small intestine to the liver, which regulates the blood’s nutrient content.
chylomicron
A lipid transport globule composed of fats mixed with cholesterol and coated with proteins.
lacteal
A tiny lymph vessel extending into the core of an intestinal villus and serving as the destination for absorbed chylomicrons.
large intestine
The portion of the vertebrate alimentary canal between the small intestine and the anus; functions mainly in water absorption and the formation of feces.
colon
The largest section of the vertebrate large intestine; functions in water absorption and formation of feces.
cecum
The blind pouch forming one branch of the large intestine.
appendix
A small, finger-like extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.
feces
The wastes of the digestive tract.
rectum
The terminal portion of the large intestine, where the feces are stored prior to elimination.
ruminant
An animal, such as cow or a sheep, with multiple stomach compartments specialized for an herbivorous diet.
leptin
A hormone produced by adipose (fat) cells that acts as a satiety factor in regulating appetite.
