Life 51- Digestion Flashcards
Appendix
In the human digestive system, the vestigial equivalent of the cerum, which serves no digestive function
Gastric pits
Deep infoldings in the walls of the stomach lined with secretory cells
Carnivore
An organism that eats only animal tissues
Anus
An opening through which solid digestive wastes are expelled, located at the posterior end of a tubular gut.
Esophagus
That part of the gut between the pharnyx and the stomach.
Chyme
Created in the stomach; mixture of ingested food with the digestive juices secreted by the salivary glands and the stomach lining.
Macronutrient
In animals, a mineral elemen required in large amounts
Cholecystokinin
A hormone produced and released by the lining of the duodenum when it is stimulated by undigested fats and proteins. It stimulates the gallbladder to release bile and slows stomach activity.
Coprophagy
Ingesting ones own feces
Gastrin
A hormone secreted by cells in the lower region of the stomach that stimulates the secretion of digestive juices as well as movements of the stomach
Herbivore
An animal that eats only plant tissues
Gallbladder
In the human digestive system, an organ in which bile is stored
Very low-density lipoproteins (VLDLs)
Molecules that consist mainly of triglyceride fats, which they transport to fat cells in adipose tissues throughout the body; associted with excesive fat deposition and high risk for cardiovascular disease
Calorie
The amount of heat required to raise the temperature of 1 gram of water by 1 degree celcius
Small intestine
The portion of the gut between the stomach and the colon; consists of the duodenum, the jejunum, and the ileum
Chylomicron
Particles of lipid coated with protein, produced in the gut from dietary fats and secreted into the extracellular fluids.
Microvilli
Projections of epithelial cells, such as the cells lining the small intestine, that increases their surface area.
Micelle
A particle of lipid covered with bile salts that is produced in the duodenum and facilitates digestion and absorption of lipids.
Cecum
A blind branch off the large intestine. In many nonruminant mammals, it contains a colony of microorganisms that contributes to the digestion of food.
Filter feeder
An organism that feeds on organisms much smaller than itself that are suspended in water or air by means of a straining device.
Detritivore
An organism that obtains its energy from the dead bodies or waste products of other organisms
Micronutrient
In animals, a mineral element required in concentrations of less than 100 micrograms per day
Jejeunum
The middle division of the small intestine, where most absorption of nutrients occursl
Lumen
The open cavity inside any tubular organ or structure, such as the gut or renal tubule
Mouth
An opening through which food is taken in, located at the anterior end of a tubular gut.
Low-density lipoproteins (LDLs)
Molecules that transport cholesterol around the body for use in biosynthesis and for storage; are the “bad” molecules, associated with a high risk of cardiovascular disease.
Glucagon
Hormone produced by alpha cells of the pancreatic islets of Langerhans. It stimulates the liver to break down glycogen and release glucose into the circulation.
Pepsinogen
Inactive secretory product that is converted into pepsin by low pH or by enzymatic action
Colon
The large intestine
Vitamin
An organic compound that an organism cannot synthesize, but nevertheless requires in small quantities for normal growth and metabolism
Zymogen
The inactive precursor of a digestive enzyme; secreted into the lumen of the gut, where a protease cleaves it to form the active enzyme
Hihg-density lipoproteins (HDLs)
Molecules that remove cholesterole from tissues and carry it to the liver; are the “good” molecules, associated with good cardiovascular health
Fluid feeder
An animal that feeds on fluids it extracts from the bodies of other organisms; examples include nectar-feeding birds and blood-sucking insects
Pepsin
An enzyme in gastric juice that digests protein
Villus
A hairlike projection from a membrane; for example, from many gut walls
Leptin
A hormone produced by fat cells that is believed to provide feedback information to the brain about the status of the body’s fat reserves
Lipase
An enzyme that digests fats
Pancreas
A gland located near the stomach of vertebrates that secretes digestive enzymes into the small intestineand releases insulin into bloodstream
Peristalsis
Wavelike muscular contractions proceeing along a tubular organ, propelling the contents along the tube.
Omnivore
An orgnaism that eats both animal and plant material
Peritoneum
The mesodermal lining of the body cavity in coelomate animals
Gastrovascular cavity
Serving for both digestion and circulation; in particular, the central cavity of the body of jellyfish and other cnidarians
Duodenum
The beginning portion of the vertebrate small intestine
Heterotroph
An organism that requires performed organic molecules as food
Bile
A secretion of the liver made up of bile salts synthesized from cholesterol, various phospholipids, and bilirubin (the breakdown product of hemoglobin). Emulsifies fats in the small intestine
Rumen
The first division of the ruminant stomach; stores and initiates bacterial fermentation of food. Food is regurgitated for further chewing
Autocatalysis
A postive feedback process in which and activated enzyme acts on other inactive molecules of the same enzyme acts on other inactive molecules of the same enzyme to activate them.
Amylase
An enzyme that catalyzes the hydrolasis of starch, usually to maltose or glucose.
Trypsin
A protein-digesting enzyme. Secreted by the pancreas in its inactive form, it becomes active in teh duodenum of the small intestine.
Postabsorptive state
State in which no food remains in the gut and thus no nutrients are being absorbed.
Predator
An organism that kills and eats other organisms
Saprobe
An organism (usually a bacterium or fungus) that obtains its carbon and energy by absorbing nutrients from dead organic matter.
Intestine
The portion of the gut following the stomach, in which most digestion and absorption occurs.
Ileum
The final segment of the small intestine
Ruminant
Herbivorous, cud-chewing mammals such as cows or sheep, characterized by a stomach that consists of four compartments: the rumen, reticulum, omasum, and abomasum
Rectum
The terminal portion of the gut, ending at the anus
Gizzard
A muscular port of the stomach of birds that grinds up food, sometimes with the aid of fragments of stone .
Submucosa
The tissue layer just under the epithelial lining of the lumen of the digestive tract.
Feces
Waste excreted from the digestive system
Carbon skeleton
The chains or rings of carbon atoms that form the structural basis of organic molecules.
Secretin
A peptide hormone secreted by the upper region of the small intestine when acidic chyme is present. stimualtes the pancreatic duct to secrete bicarbonate ions.
Autotroph
An organsim that is capable of living exclusively on inorganic materials, water, and some energy source, such as sunlight or chemically reduced matter.
Mucosa
An epithelial membrane containing cells that secrete mucus. The inner cell layer of the digestive and respiratory tracts.
