Campbell Biology Chapter 41
Terms in this set (59)
substances the body requires for normal growth and health but cannot manufacture in sufficient amounts: they must be obtained in the diet.
the process of absorbing nutrients into the body after digestion
the bodily process of discharging waste matter
the process of taking food into the body through the mouth (as by eating)
the organic process by which food is converted into substances that can be absorbed into the body
digestive tube that extends from the mouth to the anus
the process of wave-like muscle contractions of the alimentary tract that moves food along
ringlike valves of muscular layer of the digestive tube that close off the tube like drawstrings, regulating the passage of material between chambers of the canal
cavity that receives food for digestion
three pairs of exocrine glands in the mouth that secrete saliva; the parotid, submandibular (submaxillary), and sublingual glands
enzyme in saliva that breaks the chemical bonds in starches
protective secretion of the mucous membranes
throat; passageway for food to the esophagus and air to the larynx
the passage between the pharynx and the stomach
A term used to describe food after it has been chewed and mixed with saliva
an enlarged and muscular saclike organ of the alimentary canal
digestive secretions of the stomach glands consisting chiefly of hydrochloric acid and mucin and the enzymes pepsin and rennin and lipase
a semiliquid mass of partially digested food that passes from the stomach through the pyloric sphincter into the duodenum
precursor of pepsin, The inactive form of pepsin that is first secreted by specialized (chief) cells located in gastric pits of the stomach.
any enzyme that catalyzes the splitting of proteins into smaller peptide fractions and amino acids by a process known as proteolysis
an enzyme produced in the stomach that splits proteins into peptones
digestive organ in which most chemical digestion takes place, the longest part of the alimentary canal
organ that makes bile to break down fats; also filters poisons and drugs out of the blood, storage function
a muscular sac attached to the liver that secretes bile and stores it until needed for digestion
first part of small intestines, most digestion takes place, chemicals released from liver, gall bladder, and pancreas
gland that secretes pancreatic juice into the duodenum, where it mixes with bile to digest food
a substance produced by the liver that breaks up fat particles
Tiny finger-shaped structures that cover the inner surface of the small intestine and provide a large surface area through which digested food is absorbed
Tiny hair-like projections of the cytoplasmic membrane located only in the small intestine to facilitate absorption by increasing surface area.
hepatic portal vein
A vein connecting the capillary bed of the intestines with the capillary bed of the liver. This allows amino acids and gluocse absorbed from the intestines to be delivered first to the liver for processing before being transported throughout the circulatory system.
any of the lymphatic vessels that convey chyle from the small intestine to the thoracic duct
portions of the large intestine extending from the cecum to the rectum; identified by direction or shape
the cavity in which the large intestine begins and into which the ileum opens
the last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body
The last part of the digestive tract, through which stools are eliminated
undigested food material and other waste products that exit the body through the anus
A small, fingerlike extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.
Essential amino acids, essential fatty acids, vitamins, minerals
4 classes of essential nutrients
Bulk, suspension/filter, substrate, fluid
4 main feeding mechanisms of animals
alimentary canal, accessory glands
In mammals, the digestive system consists of the _______and various _______that secrete digestive juices through ducts into the canal.
3 pairs of Salivary glands, gallbladder, liver, pancreas
4 accessory glands in human digestive system.
Mucus, amylase, buffer
3 components of saliva.
Additional components of saliva include buffers, which help prevent tooth decay by neutralizing and __________ (e.g. lysozyme), protect against bacteria that enter the mouth with food.
pharynx, esophagus, trachea, stomach, lungs, epiglottis, larynx
The __________, or throat region, opens to two passageways: the __________ and the __________ (windpipe). The esophagus connects to the __________, whereas the trachea leads to the __________. When you swallow, a ﬂap of cartilage called the __________ covers the glottis—the vocal cords and the opening between them. Guided by the movements of the __________, the upper part of the respiratory tract, this swallowing reﬂex directs each bolus into the entrance of the esophagus
gastric juice, chyme
The stomach secretes a digestive ﬂuid called __________, and mixes this secretion with the food through a churning action. This mixture of ingested food and digestive juice is called __________.
hydrochloric acid (HCl), protease, pepsin
Two components of gastric juice carry out chemical digestion. One is _________,which disrupts the extracellular matrix that binds cells together in meat and plant material. The exposed bonds are attacked by the second component of gastric juice—a _____, or protein-digesting enzyme, called _______. Unlike most enzymes, this enzyme works best in a strongly acidic environment. By breaking peptide bonds, it cleaves proteins into smaller polypeptides
Parietal cells, lumen, chief cells
Further digestion to individual amino acids occurs in the small intestine. _______secrete hydrogen and chloride ions, which form HCl. Using an ATP-driven pump, these cells expel hydrogen ions into the _______. There, the hydrogen ions combine with chloride ions that diffuse into the lumen through speciﬁc membrane channels of the parietal cells. Meanwhile, _______release pepsin into the lumen in an inactive form called pepsinogen. HCl converts pepsinogen to active pepsin by clipping off a small portion of the molecule and exposing its active site. Through these processes, both HCl and pepsin form in the lumen of the stomach, not within the cells of the gastric glands.
Bile is stored and concentrated in here
epithelial lining, duodenum, jejunum, ileum
The _______of the duodenum is the source of several digestive enzymes. Some are secreted into the lumen of the duodenum, whereas others are bound to the surface of epithelial cells. While enzymatic hydrolysis proceeds, peristalsis moves the mixture of chyme and digestive juices along the small intestine. Most digestion is completed in the _______. The remaining regions of the small intestine, called the _______ and _______, function mainly in the absorption of nutrients and water.
The many side-byside microvilli give cells of the intestinal epithelium a brushlike appearance—reﬂected in the name _______.
colon, cecum, rectum
Components of the large intestine
In exiting the intestine, chylomicrons are ﬁrst transported from an epithelial cell into a _______, a vessel at the core of each villus.
If the lining of the colon is irritated—by a viral or bacterial infection, for instance—less water than normal may be reabsorbed, resulting in ________. The opposite problem, ________, occurs when the feces move along the colon too slowly.
deer, sheep, cattle
examples of ruminants
Ghrelin, PYY, leptin, insulin
hormones that trigger feelings of hunger and suppress appetite
Dipeptidase, carboxypeptidase, aminopeptidase, disaccharidase, phosphatase
5 small intestine digestive epithelium enzymes
gastrin, secretin, CCK (cholecystokinin)
3 hormones that control digestion
enteric division, endocrine system
A branch of the nervous system called the _________, which is dedicated to the digestive organs, regulates these events as well as peristalsis in the small and large intestines. The ________also plays a critical role in controlling digestion.
___________, the consumption of more calories than the body needs for normal metabolism, causes obesity, the excessive accumulation of fat.