Digestive System

Aliment-

food

chym-

juice

decidu-

falling off

gastr-

stomach

hepat-

liver

lingu-

tongue

nutri-

nourish

peri-

around

pyl-

gatekeper

vill-

hairy

Digestion

breaking down of large nutrient molecules into molecules small enough to be absorbed; occurs by hydrolysis

Mechanical digestion

breaks large pieces of food into smaller ones without altering their chemical composition

Chemical digestion

breaks down larger nutrient molecules into simpler chemicals, allowing them to be absorbed.

alimentary canal

tubular part of the digestive tract from the mouth to the anus

accessory organ

organ that supplements the function of other organs

Alimentary canal organs

includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus

Accessory organs organs

include salivary glands, liver, gallbladder, and pancreas

mucosa

innermost layer of the alimentary canal

mucous membrane

type of membrane that lines tubes and body cavities that open to the outside of the body

lumen

hollow part of a tubular structure such as a blood vessel or intestine

submucosa

layer of the alimentary canal beneath the mucosa

muscularis

smooth muscle layers of the alimentary canal

serosa

outer covering of the alimentary canal

peristalsis

rhythmic waves of muscular contraction in the walls of certain tubular organs

lingual frenulum

fold of tissue that anchors the tongue to the floor of the mouth

papilla

tiny, nipplelike projection

palate

roof of the mouth

uvula

fleshy part of the soft palate that hangs down above the root of the tongue

palatine

pertaining to the palate

dentin

bone like substance that forms the bulk of a tooth beneath the enamel

enamel

hard covering on the exposed surface of a tooth

dentin

bonelike substance that forms the bulk of a tooth beneath the enamel

cementum

bonelike material that surrounds the root of a tooth

periodontal ligament

dense connective tissue that surrounds the root of a tooth and attaches the tooth to the jawbone

salivary glands

any of the glands, associated with the mouth, that secrete saliva

mucus

fluid secretion of the mucous cells

parotid gland

large salivary gland on the side of the face just in front of and below the ear

sublingual

beneath the tongue

pharynx

the space posterior to the nasal cavity, the oral cavity, and the larynx

nasopharynx

part of the pharynx posterior to the nasal cavity

oropharynx

part of the pharynx posterior to the oral cavity

larygnopharynx

lower part of the pharynx, posterior to the larynx, that leads to the esophagus.

esophagus

tubular part of the digestive tract connecting the pharynx to the stomach

stomach

digestive organ between the esophagus and small intestine

gastric gland

any of the glands in the stomach lining that secretes gastric juice

mucous cell

glandular cell that secretes mucus

chief cell

cell type in a gastric gland that secretes digestive enzymes

parietal cell

cell of a gastric gland that secretes hydrochloric acid and intrinsic factor

gastric juice

secretion of the gastric gland in the stomach containing mucus, digestive enzymes, and hydrochloric acid

pepsin

protein-splitting enzyme that the gastric glands secrete

pepsinogen

inactive form of pepsin

intrinsic factor

substance that gastric glands produce that promotes intestinal absorption of vitamin B12

gastrin

hormone secreted by the stomach that stimulates gastric juice secretion

cholcystokinin

hormone that small intestine secretes the stimulates release of pancreatic juice from the pancreas and bile from the gallbladder.

chyme

semifluid mass of partially digested food that passes from the stomach to the small intestine

pancreas

glandular organ in the abdominal cavity that secretes the hormones insulin and glucagon into the bloodstream, and a variety of digestive enzymes into the small intestine

pancreatic juice

digestive secretions of the pancreas

trypsin

enzyme in pancreatic juice that breaks down protein molecules

chymotrypsin

protein-splitting enzyme in pancreatic juice

carboxypeptidase

protein-splitting enzyme in pancreatic juice

hepatic lobule

functional unit of the liver

kupffer cell

large, fixed macrophage in the liver that removes bacterial cells from the blood by phagocytosis

common hepatic duct

tube that transports bile from the liver to the bile duct

bile

fluid secreted by the liver and stored in the gallbladder that acts to emulsify fats

gallbladder

saclike organ associated with the liver that stores and concentrates bile

cystic duct

tube that connects the gallbladder to the bile duct

bile duct

tube that transports from the cystic duct and common hepatic duct to the duodenum

emulsification

breaking up of fat globules into smaller droplets by the action of bile salts

mesentery

fold of peritoneal membrane that attaches abdominal organs to the posterior abdominal wall

intestinal villus

tiny, fingerlike projection that extends from the inner lining of the small intestine into the lumen

lacteal

lymphatic capillary associated with a villus of the small intestine

intestinal gland

tubular gland at the base of a villus in the intestinal wall

goblet cell

epithelial cell specialized to secrete mucus

sucrase

digestive enzyme that catalyzes the breakdown of sucrose

maltase

enzyme that catalyzes breakdown of maltose into glucose

lactase

enzyme that catalyzes the breakdown of lactose into glucose and galactose

chylomicron

microscopic droplet of fat encased in protein that forms during fat absorption

feces

material expelled from the digestive tract during defecation

nutrients

chemical that the body requires from the environment

macronutrient

nutrient (carbohydrate, lipid, or protein) required in a large amount

micronutrient

nutrient (vitamin or mineral) required in a small amount

calorie

unit that measures heat energy and the energy content of foods

carbohydrates

organic compound consisting of carbon, hydrogen, and oxygen

glycogen

polysaccharide that stores glucose primarily in the liver and muscles

cellulose

polysaccharide abundant in plant tissues that human digestive enzymes cannot break down

glucose

monosaccharide in the blood that is the primary source of cellular energy

lipids

group of organic compounds that include triglycerides (fats), steroids, and phospholipids

triglyceride

lipids composed of three fatty acids and a glycerol molecule; also called fat

cholesterol

a lipid produced in the body and acquired from food that cells use to synthesize steroid hormones

beta oxidation

chemical process that breaks fatty acids down to form acetyl coenzyme A, which can enter the citric acid cycle

ketone body

compound produced during fat catabolism, including acetone, acetoacetic acid, and betahydroxybutyric acid

essential fatty acid

fatty acid required for health that body cells cannot synthesize in adequate amounts; must be obtained in the diet

proteins

nitrogen-containing organic compound composed of a chain of many bonded amino acid molecules

essential amino acid

amino acid required for health that body cells cannot synthesize in adequate amounts; must be obtained in the diet

complete protein

protein that contains adequate amounts of the essential amino acids to maintain body tissues and to promote normal growth and development

incomplete protein

protein with inadequate amounts of essential amino acids

deamination

removing amino groups (-NH2) from amino acids

minerals

inorganic element essential in human metabolism