smooth moist epithelium that lines the digestive tract and air tubes leading to the lungs
tough fibers of the extra cellular matrix. they are made of collagen that are nonelastic and don't tear easily when pulled lengthwise
long threads made of the protein elastin. they provide a rubbery quality to the extracellular matrix that complements the nonelastic strength of collagenous fibers
very thin and branched fibers made of collagen. they form a tightly woven fabric that is continuous with the collagenous fibers of the extracellular matrix
loose connective tissue
The most widespread connective tissue in the vertebrate body. It binds epithelia to underlying tissues and functions as packing material, holding organs in place.
A type of cell in loose connective tissue that secretes the protein ingredients of the extracellular fibers.
An amoeboid cell that moves through tissue fibers, engulfing bacteria and dead cells by phagocytosis.
fibrous connective tissue
A dense tissue with large numbers of collagenous fibers organized into parallel bundles. This is the dominant tissue in tendons and ligaments.
a type of flexible connective tissue with an abundance of collagenous fibers embedded in chondrin
A type of connective tissue, consisting of living cells held in a rigid matrix of collagen fibers embedded in calcium salts.
a type of connective tissue with a fluid matrix called plasma in which blood cells are suspended
A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its cell membrane.
Tissue consisting of long muscle cells that are capable of contracting when stimulated by nerve impulses.
a muscle that is connected at either or both ends to a bone and so move parts of the skeleton
A type of muscle that forms the contractile wall of the heart. Its cells are joined by intercalated disks that relay each heartbeat.
A type of muscle lacking the striations of skeletal and cardiac muscle because of the uniform distribution of myosin filaments in the cell.
A membrane that suspends many of the organs of vertebrates inside fluid-filled body cavities.
The body cavity in mammals that houses the lungs and heart. It is surrounded in part by ribs and separated from the lower abdominal cavity by the diaphragm.
The body cavity in mammals that primarily houses parts of the digestive, excretory, and reproductive systems. It is separated from the more cranial thoracic cavity by the diaphragm.
coordination of body activities; detection of stimuli and formulation of responses to them
the internal environment of vertebrates, consisting of the fluid filling the spaces between cells
A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.
A physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change.
Organisms with bodies that are warmed by heat generated by metabolism. This heat is usually used to maintain a relatively stable body temperature higher than that of the external environment.
Organisms that do not produce enough metabolic heat to have much effect on body temperature.
basal metabolic rate (BMR)
the minimum number of kilocalories a resting animal requires to fuel itself for a given time
standard metabolic rate (SMR)
The metabolic rate of a resting, fasting, and nonstressed ectotherm at a particular temperature.
essential amino acid
Amino acids that an animal cannot synthesize itself and must be obtained from food. Eight of these are essential in the human adult.
an organic molecule required in the diet in very small amounts; they serve mainly as coenzymes or parts of coenzymes
in nutrition, a chemical element other than hydrogen, oxygen, or nitrogen that an organism requires for proper body functioning
An aquatic animal, such as a sponge, clam, or baleen whale, that feeds by sifting small food particles from the water.
a heterotroph, such as an earthworm, that eats its way through detritus, salvaging bits and pieces of decaying organic matter
A heterotrophic mode of nutrition in which other organisms or detritus are eaten whole or in pieces. step one of digestion
process of breaking down food into molecules small enough for the body to absorb; step two of digestion
the uptake of small nutrient molecules by an organism's own body; the third main stage of food processing, following digestion
the passing of undigested materials out of the digestive compartment; step four of digestion
The joining of food vacuoles and lysosomes to allow chemical digestion to occur within the cytoplasm of a cell.
complete digestive tract
A digestive tube that runs between a mouth and an anus; also called alimentary canal. An incomplete digestive tract has only one opening.
rhythmic waves of contractions of smooth muscle that push food along the digestive tract
A ringlike valve consisting of modified muscles in a muscular tube, such as a digestive tract; closes off the tube like a drawstring.
Exocrine glands associated with the oral cavity; the secretions of salivary glands contain substances to lubricate foods, adhere together chewed pieces into a bolus, and begin the process of chemical digestion
A gland with dual functions: The nonendocrine portion secretes 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.
the largest organ in the vertebrate body; it performs diverse functions such as producing bile, preparing nitrogenous wastes for disposal, and detoxifying poisonous chemicals in the blood
An area in the vertebrate throat where air and food passages cross; in flatworms, the muscular tube that protrudes from the ventral side of the worm and ends in the mouth.
a cartiliginous flap that blocks the top of the windpipe, the glottis, during swallowing, which prevents the entry of fluid or food into the respiratory system
The inactive form of pepsin that is first secreted by specialized (chief) cells located in gastric pits of the stomach.
In the vertebrate digestive tract, a muscular ring that regulates the passage of food out of the stomach and into the small intestine
the longest section of the alimentary canal; it's the principle site of the enzymatic hydrolysis of food macromolecules and the absorption of nutrients
The first section of the small intestine, where chyme from the stomach mixes with digestive juices from the pancreas, liver, and gallbladder as well as from gland cells of the intestinal wall.
A mixture of substances that is produced in the liver but stored in the gallbladder and that enables formation of fat droplets in water as an aid in the digestion and absorption of fats
an enzyme found in the duodenum; specific for peptide bonds adjacent to certain amino acids
an enzyme found within the small intestine that splits off one amino acid at a time beginning at the end of the polypeptide that has a free carboxyl group
An enzyme found within the small intestine that splits off one amino acid at a time, beginning at the opposite end of the polypeptide containing a free carboxyl group.
fine, finger-like projections of the epithelial cells in the lumen of the small intestine that increases its surface area
A tiny lymph vessel extending into the core of an intestinal villus and serving as the destination for absorbed chylomicrons
small intracellular globules composed of fats that are mixed with the cholesterol and coated with special proteins
hepatic portal vessel
A large circulatory channel that conveys nutrient-laden blood from the small intestine to the liver, which regulates the blood's nutrient content
a hormone released from the walls of the duodenum in response to the presence of amino acids or fatty acids
the last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body
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
A small, fingerlike extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.
immune and lymphatic system
bone marrow, lymph nodes, thymus, spleen, lymph vessels, white blood cells