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Biology

Key Terms

BiologyKey Terms

alimentary canal
tubular digestive system with a mouth and anus
aminopeptidase
protease that breaks down peptides to single amino acids; secreted by the brush border of small intestine
anus
exit point for waste material
bile
digestive juice produced by the liver; important for digestion of lipids
bolus
mass of food resulting from chewing action and wetting by saliva
carboxypeptidase
protease that breaks down peptides to single amino acids; secreted by the brush border of the small intestine
carnivore
animal that consumes animal flesh
cephalic phase
first phase of digestion, controlled by the neural response to the stimulus provided by food
cholecystokinin
hormone that stimulates the contraction of the gallbladder to release bile
chylomicron
small lipid globule
chyme
mixture of partially digested food and stomach juices
chymotrypsin
pancreatic protease
digestion
mechanical and chemical break down of food into small organic fragments
dipeptidase
protease that breaks down peptides to single amino acids; secreted by the brush border of small intestine
duodenum
first part of the small intestine where a large part of digestion of carbohydrates and fats occurs
elastase
pancreatic protease
endocrine system
system that controls the response of the various glands in the body and the release of hormones at the appropriate times
esophagus
tubular organ that connects the mouth to the stomach
essential nutrient
nutrient that cannot be synthesized by the body; it must be obtained from food
gallbladder
organ that stores and concentrates bile
gastric inhibitory peptide
hormone secreted by the small intestine in the presence of fatty acids and sugars; it also inhibits acid production and peristalsis in order to slow down the rate at which food enters the small intestine
gastric phase
digestive phase beginning once food enters the stomach; gastric acids and enzymes process the ingested materials
gastrin
hormone which stimulates hydrochloric acid secretion in the stomach
gastrovascular cavity
digestive system consisting of a single opening
gizzard
muscular organ that grinds food
herbivore
animal that consumes strictly plant diet
ileum
last part of the small intestine; connects the small intestine to the large intestine; important for absorption of B-12
ingestion
act of taking in food
intestinal phase
third digestive phase; begins when chyme enters the small intestine triggering digestive secretions and controlling the rate of gastric emptying
jejunum
second part of the small intestine
lactase
enzyme that breaks down lactose into glucose and galactose
large intestine
digestive system organ that reabsorbs water from undigested material and processes waste matter
lipase
enzyme that chemically breaks down lipids
liver
organ that produces bile for digestion and processes vitamins and lipids
maltase
enzyme that breaks down maltose into glucose
mineral
inorganic, elemental molecule that carries out important roles in the body
monogastric
digestive system that consists of a single-chambered stomach
omnivore
animal that consumes both plants and animals
pancreas
gland that secretes digestive juices
pepsin
enzyme found in the stomach whose main role is protein digestion
pepsinogen
inactive form of pepsin
peristalsis
wave-like movements of muscle tissue
proventriculus
glandular part of a bird’s stomach
rectum
area of the body where feces is stored until elimination
roughage
component of food that is low in energy and high in fiber
ruminant
animal with a stomach divided into four compartments
salivary amylase
enzyme found in saliva, which converts carbohydrates to maltose
secretin
hormone which stimulates sodium bicarbonate secretion in the small intestine
small intestine
organ where digestion of protein, fats, and carbohydrates is completed
somatostatin
hormone released to stop acid secretion when the stomach is empty
sphincter
band of muscle that controls movement of materials throughout the digestive tract
stomach
saclike organ containing acidic digestive juices
sucrase
enzyme that breaks down sucrose into glucose and fructose
trypsin
pancreatic protease that breaks down protein
villi
folds on the inner surface of the small intestine whose role is to increase absorption area
vitamin
organic substance necessary in small amounts to sustain life
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