Digestive system Flashcards
nutrients
substances the body needs for
growth, maintenance, and
repair; carbohydrates,
proteins, fats, vitamins,
minerals, and water
digestion
the process of breaking food
alimentary canal
a long tube, open at both
ends, through which food
passes as it is digested
GI tract
another term for the
alimentary canal
Accessory organs
organs that assist in the process of digestion, but food does not pass through them
ingestion
the voluntary process of
taking food or drink into the
body through the mouth
propulsion
the forceful movement of food
from one organ to the next
peristalsis
alternating waves of contraction and relaxation that push food along the GI
tract
mechanical
digestion
the physical breakdown of
food into smaller particles
segmentation
moves food back and forth to
mix it in the small and large
intestines
chemical
digestion
food molecules are broken
down into their building
blocks by their enzymes
enzymes
proteins that speed up
chemical reactions in the body
absorption
the process of food nutrients
moving from the small
intestine into the bloodstream
defecation
elimination of solid waste from the body
feces
solid waste; a combination of undigested and/or
unabsorbed food, water,
bacteria, etc.
mechanoreceptors
control digestive activity by
detecting stretching of organ
walls
chemoreceptors
control digestive activity by
detect factors such as solute
concentration, pH, and the
presence of substrates and
end products
oral cavity
the mouth; site of mechanical
teeth
responsible for mechanical
digestion in the mouth; tear
food apart during chewing
Mastication
another term for chewing
tongue
moves food around the mouth
to mix it with saliva and push
it between the teeth
salivary amylase
the enzyme in saliva which
begins the chemical digestion
of carbohydrates
salivary glands
Three pairs of glands produce saliva; parietal, submandibular, and
sublingual
saliva
mixture of water, salivary amylase, mucus, and
antibacterial substances;
produced by salivary glands
deglutition
swallowing; a coordinated activity that pushes the food
bolus to the back of the
mouth
Bolus
ball of partially digested food
that is swallowed
pharynx
the area behind the nose and mouth that is a common
passageway for food, air and liquids.
esophagus
tube that extends from the pharynx to the stomach which
conducts the food bolus by
peristalsis
stomach
J-shaped muscular organ that
secretes enzymes that digest
protein; three layers of muscle
contribute to mechanical
digestion
cardioesophageal
sphincter
or cardiac sphincter; a ring of
muscle that controls the
entrance of food from the
esophagus into the stomach
pyloric sphincter
ring of muscle that controls the entrance of food from the
stomach into the duodenum
gastric pits
small pores in the stomach
lining that secrete gastric juice
intrinsic factor
substance that allows vitamin B12 to be absorbed in the
small intestine; secreted by
parietal cells
HCl
activates pepsinogen and
transforms in into pepsin;
secreted by parietal cells
Gastrin
hormone that is released when stimulated by the
presence of food and a lower
pH; triggers increased
secretion of gastric juice
Chyme
thick, semi-liquid form of food
that leaves the stomach
Small intestine
the body’s major digestive organ; all nutrient digestion is
completed here and almost all
absorption occurs here
mesentery
broad, fan-shaped fold of
tissue that anchors the small
intestine and carries blood
vessels, nerve and lymphatic
vessels throughout
plicae circularis
deep circular folds of the
villi
fingerlike projections of the
intestinal lining
microvilli
tiny projections of the plasma
membrane of epithelial cells
on the surface of villi
duodenum
the first portion of the small
intestine where chemical
digestion is completed
intestinal juice
composed mostly of water and an alkaline mucus to
neutralize chyme; secreted by
glands at the base of the villi
Brush border
enzymes bound to the surface of microvilli that complete the final states of carbohydrate and protein digestion
Liver
produces bile; the largest
internal organ
Bile
slightly alkaline substance that emulsifies fats; produced
by the liver and stored in the
gallbladder
Gallbladder
stores bile until it is released
into the duodenum through
the bile duct
emulsification
the process of breaking large fat droplets into smaller ones
to increase surface area for
digestion
pancreas
organ that produced powerful enzymes to break down all
three nutrients; sits behind
the stomach
pancreatic juice
substance which contains
enzymes to break down all
three nutrients and
bicarbonate; released into the
duodenum
proteases
pancreatic enzymes (trypsin,
chymotrypsin, and
carboxypeptidase) that
complete the digestion of
proteins in the duodenum
pancreatic
amylase
works with brush border
enzymes to complete the
digestion of carbohydrates in
the duodenum
lipases
fat-digesting enzymes that are assisted by the emulsification
lacteals
lymphatic vessels in the villi
that absorb fats
large intestine
organ of the GI tract that does
not produce enzymes, but
absorbs water and produces
solid waste; surrounds the
small intestine on three sides
ileocecal valve
controls the entrance of into the large intestine; prevents
food from re-entering the
small intestine
Cecum
a pouch just below the ileocecal valve from which the
appendix hangs
appendix
fingerlike projection suspended from the cecum
that may play an important
role in the immune system
sigmoid colon
s-shaped region of the colon that stores feces; located
between the descending colon
and the rectum
rectum
final storage area for feces
where water is absorbed and
mucus is secreted
anus
the opening of the anal canal
goblet cells
cells that secrete mucus in the
large intestine to aid in
defecation
Bowel movements
long, slow-moving contractions of the colon that
push contents of the colon
towards the rectum
GERD
when stomach acids
frequently back up into the
esophagus causing a burning
sensation; aka
gastroesophageal reflux
disease
stomach ulcers
a hole or damaged area in the lining of the stomach usually
caused by bacteria; aka
gastric or peptic ulcers
gallstones
hard deposits of cholesterol that cause pain when moving
through the bile duct
hepatitis
liver inflammation caused by
a virus; most deadly infectious
disease in the US
pancreatitis
inflammation of the pancreas
caused by early activation of
digestive enzymes
inflammatory
bowel disease
chronic inflammation of the
digestive tract, especially the
large intestine (includes
Crohn’s and colitis)
appendicitis
inflammation of the appendix that causes severe pain in the
lower, right abdomen; usually
surgically removed
cystic fibrosis
an inherited disease that
causes thick mucus to form in
the pancreas (and other
organs) leading to digestive
problems
hemorrhoids
swollen veins in the lower
rectum and anus causing pain,
itching and bleeding
vomiting
forceful expulsion of stomach
contents usually caused by a
bacterial or viral infection
diarrhea
frequent discharge of watery
feces usually caused by a
bacterial or viral infection
cleft lip & palate
common birth defect that occurs when the lip and/or
palate fails to close completely during development resulting in a
split or cleft; corrected with
surgery
PKU
rare genetic disorder that
causes a build-up of the amino
acid phenylalanine, which
may lead to brain damage if
untreated; aka
phenylketonuria
rooting reflex
infant feeding reflex that causes the baby’s head to turn
towards anything that
touches the cheek or mouth
sucking reflex
infant feeding reflex triggered
by anything that touches the
roof of the mouth
colorectal cancer
cancer of the large intestine, one of the most common
types of cancer
Functions of the digestive system
Ingestion
Digestion
Absorption
Extraction
Vitamins
boost the immune system, support normal growth and development, and help cells and organs do their jobs.
Fats
helps give your body energy, protects your organs, supports cell growth, keeps cholesterol and blood pressure under control, and helps your body absorb vital nutrient
Proteins
build and repair muscles and bones and to make hormones and enzymes.
