Chapter 21 Flashcards
intestine
The region of a digestive tract located between the gizzard or stomach and the anus and where chemical digestion and nutrient absorption usually occur.
hepatic portal vein
A blood vessel that conveys nutrient-laden blood from capillaries surrounding the intestine directly to the liver
essential nutrient
A substance that an organism must absorb in preassembled form because it cannot be synthesized from any other material. In humans, there are essential vitamins, minerals, amino acids, and fatty acids.
carnivore
An animal that mainly eats other animals.
alimentary canal
A digestive tract consisting of a tube running between a mouth and an anus.
duodenum
the first portion of the vertebrate small intestine after the stomach, where chyme from the stomach mixes with bile and digestive enzymes.
ruminant
An animal, such as a cow or sheep, with a multichambered stomach housing microorganisms that can digest cellulose.
gastrovascular cavity
A digestive compartment with a single opening, the mouth; may function in circulation, body support, waste disposal, and gas exchange, as well as digestion.
mineral
In nutrition, a simple inorganic nutrient that an organism requires for proper body functioning.
bulk feeder
An animal that eats relatively large pieces of food.
kilocalorie (kcal)
A quantity of heat equal to 1,000 calories. Used to measure the energy content of food, it is usually called a “Calorie”.
high-density lipoprotein (HDL)
A cholesterol-carrying particle in the blood made up of cholesterol and other lipids surrounded by a single layer of phospholipids in which proteins are embedded. An HDL particle carries less cholesterol than a related lipoprotein, LDL, and may be correlated with a decreased risk of blood vessel blockage.
salivary glands
Glands associated with the oral cavity that secret substances to lubricate food and begin the process of chemical digestion.
fluid-feeder
An animal that lives by sucking nutrient-rich fluids from another living organism.
appendix
A small, fingerlike extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.
liver
The largest organ in the vertebrate body. The liver performs diverse functions, such as producing bile, preparing nitrogenous wastes for disposal, and detoxifying poisonous chemicals in the blood.
intestine
The region of a digestive tract located between the gizzard or stomach and the anus and where chemical digestion and nutrient absorption usually occur.
hepatic portal vein
A blood vessel that conveys nutrient-laden blood from capillaries surrounding the intestine directly to the liver
essential nutrient
A substance that an organism must absorb in preassembled form because it cannot be synthesized from any other material. In humans, there are essential vitamins, minerals, amino acids, and fatty acids.
carnivore
An animal that mainly eats other animals.
alimentary canal
A digestive tract consisting of a tube running between a mouth and an anus.
duodenum
the first portion of the vertebrate small intestine after the stomach, where chyme from the stomach mixes with bile and digestive enzymes.
ruminant
An animal, such as a cow or sheep, with a multichambered stomach housing microorganisms that can digest cellulose.
gastrovascular cavity
A digestive compartment with a single opening, the mouth; may function in circulation, body support, waste disposal, and gas exchange, as well as digestion.
mineral
In nutrition, a simple inorganic nutrient that an organism requires for proper body functioning.
bulk feeder
An animal that eats relatively large pieces of food.
kilocalorie (kcal)
A quantity of heat equal to 1,000 calories. Used to measure the energy content of food, it is usually called a “Calorie”.
high-density lipoprotein (HDL)
A cholesterol-carrying particle in the blood made up of cholesterol and other lipids surrounded by a single layer of phospholipids in which proteins are embedded. An HDL particle carries less cholesterol than a related lipoprotein, LDL, and may be correlated with a decreased risk of blood vessel blockage.
salivary glands
Glands associated with the oral cavity that secret substances to lubricate food and begin the process of chemical digestion.
fluid-feeder
An animal that lives by sucking nutrient-rich fluids from another living organism.
appendix
A small, fingerlike extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.
liver
The largest organ in the vertebrate body. The liver performs diverse functions, such as producing bile, preparing nitrogenous wastes for disposal, and detoxifying poisonous chemicals in the blood.
saliva
Salivary gland secretion that contains substances to lubricate food, buffers, antibacterial agents, and the digestive enzyme amylase.
oral cavity
The mouth of an animal.
colon
Large intestine; the tubular portion of the vertebrate alimentary tract between the small intestine and the anus; functions mainly in water absorption and the formation of feces.
peristalsis
Rhythmic waves of contraction of smooth muscles. Peristalsis propels food through a digestive tract and also enables many animals, such as earthworms, to crawl.
chyme
The mixture of partially digested food and digestive juices formed in the stomach.
substrate feeder
An organism that lives in or on its food source, eating its way through the food.
omnivore
An animal that eats animals as well as plants or algae.
vitamin
An organic nutrient that an organism requires in very small quantities. Vitamins generally functions as coenzymes.
mouth
An opening through which food is taken into an animals body.
suspension feeder
An aquatic animal that sifts small food particles from the water.
rectum
The terminal portion of the large intestine where the feces are stored until they are eliminated.
esophagus
the channel that conducts food by peristalsis, usually from the pharynx to the stomach.
bolus
a lubricated ball of chewed food.
recommended daily allowance (RDA)
a recommendation for daily nutrient intake established by nutritionists.
gizzard
A pouch-like organ in a digestive tract where food is mechanically ground.
villus
(plural, villi) 1) a fingerlike projection of the inner surface of the small intestine. 2) A fingerlike projection of the chorion of the mammalian placenta. Large numbers of villi increase the surface areas of these organs.
gastrin
A digestive hormone that stimulates the secretion of gastric juice.
feces
The wastes of the digestive tract
ingestion
The act of eating; the first main stage of food processing in animals.
microvillus
(plural, microvilli) A microscope projection on the epithelial cells in the lumen of the small intestine that increases its surface area.
pharynx
the organ in a digestive tract that receives food from the oral cavity; in terrestrial vertebrates, the throat region where the air and food passages cross.
gastric juice
The collection of fluids (mucus, enzymes, and acid) secreted by the stomach.
low-density lipoprotein (LDL)
A cholesterol-carrying particle in the blood, made up of cholesterol and other lipids surrounded by a single layer of phospholipids in which proteins are embedded. An LDL particle carries more cholesterol than a related lipoprotein, HDL, and high LDL levels in the blood correlate with a tendency to develop blocked blood vessels and heart disease.
metabolic rate
The total amount of energy an animal uses in a unit of time.
bile
A mixture of substances that is produced by the liver and stored in the gallbladder; it emulsifies fats and aids in their digestion.
basal metabolic rate (BMR)
The number of kilocalories a resting animal requires to fuel its essential body processes for a given time.
crop
a pouchlike organ in a digestive tract where food is softened and may be stored temporarily.
small intestine
The longest section of the alimentary canal. It is the principal site of the enzymatic hydrolysis of food macromolecules and the absorption of nutrients.
sphincter
a ringlike valve, consisting of modified muscles in a muscular tube, that regulates passage between some compartments of the alimentary canal.
elimination
The passing of undigested material out of the digestive compartment; the fourth and final stage of food processing in animals.
stomach
A pouch-like organ in a digestive tract that grinds and churns food and may store it temporarily.
anus
the opening which undigested materials are expelled.
digestion
the mechanical and chemical breakdown of food into molecules small enough for the body to absorb; the second main stage of food processing in animals.
gallbladder
An organ that stores bile and releases it as needed into the small intestine
herbivore
an animal that eats only plants or algae.
pancreas
a gland with dual functions: the digestive portion secrets digestive enzymes and an alkaline solution into the small intestine via a duct. The endocrine portion secretes the hormones insulin and glucagon into the blood.
