The Digestive System Flashcards
the breakdown of complex food materials into simpler forms that can be used by the body
digestion
extends from the mouth to the anus and is about 30 ft long, does the actual digesting (breakdown and absorption)
alimentary canal
help the digestive process. includes teeth, tongue, salivary glands, gall bladder, and liver
accessory organs
the 6 digestive processes
ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation
when food enters the mouth
ingestion
moving food through the system
propulsion
chewing & mixing food by teeth and tongue
mechanical digestion
chemical breakdown of food so it can be absorbed by the epithelium
chemical digestion
transport of food particles from gut to blood or lymph
absorption
elimination of indigestible substance (fecal matter) from the body
defecation
4 layers of the alimentary tract
serosa, muscularis, submucosa, mucosa
outer membranous covering of digestive tract, lubricated by serous, continuous with mesentery
serosa
layer of smooth muscle composed of outer longitudinal fibers and inner circular fibers. accounts for movement of food
muscularis
loose connective tissue richly supplied with blood and lymphatic vessels (and sometimes glands)
submucosa
secretes mucus that lubricates inner lining of tract
mucosa
3 layers within the mucosa
muscularis mucosa (lies next to submucosa), lamina propria (middle layer), and epithelium (in small intestine, folded to form villi)
name the teeth (with quantities and function)
12 molars; flattened, made for crushing
8 premolars; fairly flat, made for grinding
4 canines; pointed, made for tearing
8 incisors; chisel shaped, made for biting
last molars, may fail to erupts and need to be extracted
wisdom teeth
tooth structure
enamel (outer layer made of calcium)
dentin (thick bone-like middle layer)
pulp (inner part, nerves and blood vessels)
occurs when bacterial acid corrodes teeth
tooth decay (AKA caries)
inflamed gums
gingivitis
loss of bone and loosening of teeth
periodontitis
anterior roof of mouth made up of palatine bones and processes of maxillae
hard palate
posterior roof of mouth made of muscle
soft palate
ending of soft palate in a suspended process
uvula
3 pairs of salivary glands which secrete saliva into mouth through ducts
parotid glands (side of face)
sublingual glands (under tongue)
submandibular glands (under lower jaw)
saliva contains:
water, mucus, and salivary amylase
digestive enzyme which breaks down starch
salivary amylase
inside the mouth made of muscle with an outer layer of mucus
the tongue
on the surface of tongue, can be either sensitive to the touch or taste buds
papillae
the tongue forms food into a _____ and pushes it back to the ________.
bolus, pharynx
the four different flavors your tongue can taste
bitter (back of tongue)
sour (posterior sides)
salty (tip)
sweet (directly behind tip)
region between the mouth and esophagus
pharynx
flap of tissue that closes off the trachea so food doesn’t enter
epiglottis
tube through which the bolus passes from pharynx to stomach
esophagus
rhythmic contraction that pushes the food along
peristalsis
when muscle tissue of diaphragm has weak area and part of stomach pushes into thoracic cavity (could cause gastric juice to back flow into esophagus)
hiatal hernia
ring of muscle where esophagus passes through diaphragm into stomach
gastroesophageal sphincter
reverse peristalsis results in
vomiting
thick walled j shaped organ just below the diaphragm
the stomach
the stomach can hold ____ gallon of food and liquid
1/2 (2 Liters)
regions of the stomach
cardiac region: adjacent to where esophagus enters
fundus: extends superiorly from cardiac region
body: main part
pylorus: narrow portion near the small intestine
separated stomach from the small intestine
pyloric sphincter
internal lining of stomach (in the mucosa) has deep folds called
rugae
inner mucus membrane of the stomach consist of a single layer of columnar epithelium cells interrupted by
millions of gastric pits which open into the gastric glands
stomach cells that produce mucus
mucous neck cells
stomach cell that produces pepsinogen
chief cells
stomach cells that produce hydrochloric acid
parietal cells
stomach cell that produces gastrin
enteroendocrine cells
pH of gastric acid
2
hydrochloric acid mixes with pepsinogen to become
pepsin
pepsin is a digestive enzyme which
breaks down protein molecules into peptides
how many feet long is the small intestine and what’s its diameter
20ft long, 1 inch diameter
three regions of small intestine in order
duodenum, jejunum, ileum
in the duodenum, _____ is mixed with secretions from ______ and _______.
chyme,
liver,
pancreas
the liver produces _______
bile (a yellowish green fluid)
where is bile stored
gallbladder
vent through which bile goes from liver to duodenum
bile duct
bile contains ______, which break down fats and oils into tiny droplets in a process called ______.
bile salts, emulsification
pancreatic juice enters the duodenum by way of the _______ (endo or exo?)
pancreatic duct, exocrine portion of gland
pancreatic juice has a pH of
8.5 (neutralizes the acidic chyme)
enzyme that breaks down starch into maltose (from pancreatic juice)
pancreatic amylase
enzyme that breaks down proteins into peptides (in pancreatic juice)
trypsin
enzyme that breaks down fat droplets after they’ve been emulsified by bile salts into glycerol and fatty acids
lipase
walls of the small intestine contain intestinal glands that secrete
peptidase and maltase
peptidase breaks down….
peptides into amino acids
maltase breaks down….
maltose (disaccharide) into glucose (monosaccharide)
blood capillaries and lymph vessels within the villi of intestinal wall are called
lacteals
most nutrients diffuse into the capillaries, then into bloodstream, but blood capillaries are relatively impermeable to ______, so they enter the _____.
fat globules, lymph capillaries
ileum contains _____ in the ________
Peyer’s Patches, submucosa
the small intestine ends at the
ileocecal valve
the large intestine is composed of the
cecum, colon, rectum, and anal canal
the _______ lies below the entrance of the small intestine and has a small projection attached to it called the _______
cecum, vermiform appendix
the appendix contains _____ and plays a role in ______
lymphatic tissues, immunity
4 regions of the colon
- ascending,
2.transverse,
3.descending, - sigmoid
the _______ ends in the ______ which opens at the anus.
rectum, anal canal
no ______ are produced in the large intestine
enzymes
the principal function of the large intestine is
reabsorption of water
function of Escherichia coli
break down undigested material further, giving off vitamin K and B
bacteria accounts for ____ of the weight of dry feces
1/3 (most of feces is cellulose)
blood vessels of the many villi merge to form the
hepatic portal vein, which carrie’s blood to the liver
the right and left lobes of the liver are separated by the
falciform ligament
six functions of the liver
- destroy old red blood cells and convert hemoglobin to bilirubin and biliverdin
- produces bile (stored in gallbladder)
- stores glycogen to maintain glucose concentration of blood between meals
- produces urea from breakdown of amino acids
- produces blood proteins
- detoxifies blood
jaundice is caused by an excess of
bilirubin or from hepatitis A from food or B from bodily fluids/blood
gallstones are made up of cholesterol and sometimes calcium,
clog up bile duct or clog up gallbladder so bile can’t pass through
acini are
small clusters of cells produced by digestive enzymes of the pancreas
the pancreatic duct joins the _____ and the two enter the _____
common bile duct, duodenum
which vitamin is mainly formed by E. coli
K
which structure does the appendix come off of
ascending colon
where are lacteals located
small intestine
outer layer of the instestines
serosa
which of these does not directly promote hydrolysis of food
submucosa
what does the pancreatic duct directly join to
duodenum
what normally holds the intestines in position in the abdominal cavity
mesentery
where would the least amount of bacteria be found
the stomach
where are the palatine tonsils located
pharynx
which gland is closest to the joint between the mandible and temporal bone?
parotid
where does the greatest amount of digestion occur
small intestine
primary function of the large intestine
compact, store, and eliminate feces
what hormone does the small intestine release in response to acidic chyme
secretin
the pancreas secretes exhumes that enter the small intestine and chemically digest chyme. which enzyme breaks down fats?
pancreatic lipase
during which phase of gastric secretion do gastric glands actually begin secreting gastric juice
cephalic phase
intrinsic factor is secreted by which of the gastric glands?
parietal cells
what initiates the swallowing reflex?
sensory receptors detecting the bolus in the pharynx
