Digestive System
hydrochloric acid
(HCl) works in the stomach in the presence of pepsinogen . Used in protein digestion. Breaks down protein into large polypeptides.
amount of gastric juice produced by gastric glands each day
2-3 L
length of GI tract (living and cadaver)
5m/16ft and 9m/30ft
4 fat soluble vitamins
A, D, E, K
duodenum, jejunum, ileum, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum
After the food leaves the stomach, in what order does it travel through the lower digestive tract?
vitamin k
Bacteria in the large intestine is responsible for producing this vitamin.
hormones secreted during intestinal phase of gastric activity
CCK, secretin, GIP
bile
Chemical produced by the liver that enters the small intestine to help digest fats
salivary amylase
Chemical secreted into the mouth that digests carbohydrates
enteroendocrine cells in the stomach and the hormone they secrete
G cells; gastrin
immunoglobulin found in saliva and its funciton
IgA; inhibits bacterial growth
gastric pits
Inside the rugae of the stomach are ____________.
intestinal villi
Most carbohydrates, fats, proteins, and water are absorbed through this part of the small intestine
small intestine
Most nutrient absorption occurs in this organ
segmentation
Muscular contractions that churn and fragment food
carbohydrates
Pancreatic amylase digests __________.
fats
Pancreatic lipase digests __________.
proteins
Pancreatic protease digests ____________.
gallbladder
Pear-shaped muscular sac that stores bile.
plica
Ridges in the wall of the small intestines
stomach
Segmentation mainly occurs in the ___________.
esophageal sphincter
Structure located at entrance of stomach that closes so food does not regurgitate into the esophagus
pyloric sphincter
Structure located at the exit of the stomach that closes and prevents movement of stomach contents into small intestine
tongue
Structure that moves food around and has taste receptors that promotes the hunger drive
parietal cells
Structures in the gastric pit that produce hydrochloric acid and digest proteins
chief cells
Structures in the gastric pit that produce pepsin and digest proteins
teeth
Structures that break down food through mastication
salivary glands
Structures that produce chemicals that help lubricate and break down food
carbohydrates, proteins, lipids, water, vitamins, minerals
The GI tract absorbs which six nutrients?
digestion
The breakdown of nutrients into components that can be absorbed into the body
inner
The defectation reflex relaxes which anal sphincter?
pancreas
The enzymes produced by this organ enter into the small intestine for the purpose of digestion.
mucosal
The innermost layer of the GI tract
bacteria
The large intestine contains ___________ which is important for the production of vitamin K and the digestion of proteins and carbohydrates
plica, intestinal villi
The lining of the small intestine is made up of these two structures.
deglutition
The process of food passing through the pharynx and esophagus
absorption
The process of nutrients being taking into the blood and carried to tissues and cells
secretion
The process of producing and releasing chemicals that aid in digestion
ingestion
The process of taking in food.
excretion
The removal of waste
90
The small intestine absorbs _______ percent of nutrients.
aspirin, alcohol
The stomach can absorb two chemicals: _________ and _________.
3
The stomach has _________ layers of muscle.
rugae
The stomach is lined by ridges called _________.
hepatocytes
These form the hepatic portal system.
gastric pits
These structures are lined with cells that produce chemicals that help the stomach digest food.
liver, gallbladder, pancreas
These three structures produce chemicals that travel into the small intestine and aid in digestion
mucus layer
This lines the stomach protecting it from acids
liver
This organ filters blood and regulates nutrient levels.
small intestine
This organ plays a key role in the digestion and absorption of nutrients.
liver
This organ produces bile and detoxifies blood
ileocecal valve
Valve that separates the ileum and cecum
blood clotting
Vitamin K is important for this bodily function to occur.
peristalsis
Waves of muscular contractions that move the food along the length of the digestive tract
salivary glands, liver, gall bladder, pancreas
What are the four accessory structures of the digestive system?
mucosal, submucosal, muscularis, serosa
What are the four layers of the gastrointestinal tract?
ascending, transverse, descending, sigmoid
What are the four parts of the colon?
ingestion, taste, secretion, digestion, absorption, excretion
What are the six functions of the digestive system?
cecum, colon, rectum
What are the three major parts of the large intestine?
duodenum, jejunum, ileum
What are the three sections of the small intestine?
digestive tract, accessory structures
What are the two major subsystems of the digestive system?
accessory
What structures collectively produce chemicals that aid in digestion?
outer
Which anal sphincter do we have control over?
stomach
Which organ contracts strongly to break up and liquify food?
buccal
Which phase of deglutition do we consciously control?
esophageal
Which phase of deglutition involves food being pushed down into stomach through peristalsis?
pharyngeal
Which phase of deglutition involves the food being pushed down the pharynx?
amylase, lipase, protease
Which three enzymes are produced by the pancreas?
large intestine
While this organ absorbs some nutrients, its main function is to excrete waste.
bile
a digestive juice secreted by the liver and stored in the gallbladder; aids in the digestion of fats.
3 sources of blood supply
abdominal aorta --> celiac --> hepatic a. sm. intestine --> hepatic portal vein hepatic veins --> inferior vena cava
deglutition
aka swallowing. Is the result of skeletal muscle activity and occurs in two phases: buccal (mouth) and pharyngeal-esophageal.
3 alternate names for the digestive system/tract
alimentary, enteron, gastrointestinal
cell types that make up pancreatic islets
alpha and beta cells
term for socket in which a tooth sits
alveolus
brush border enzymes: protein digestion
aminopeptidase, dipeptidase. Works in the small intestine.
lipase
an enzyme secreted in the small intestine that catalyzes the breakdown of fats into individual fatty acids that can be absorbed into the bloodstream.
effect of CCK
bile and pancreatic enzyme release
alternate name for microvilli
brush border
enzyme produced by parietal cells that aids in production of HCl in stomach
carbonic anhydrase (CAH)
3 brush border enzymes found in the small intestine
carboxypeptidase, aminopeptidase, dipeptidase
4 regions of the stomach
cardiac, fundic, body, pyloric
pouch-like region at the beginning of the large intestine
cecum
blood supply to the stomach
celiac artery --> gastric artery
covering of the tooth below the gum
cementum
central drainage of a lobule
central vein
3 phases of gastric activity
cephalic, gastric, intestinal
hydrolysis
chemical reaction in which water reacts with a compound to produce other compounds; involves the splitting of a bond to break down into monomers.
cells that produce pepsinogen in the stomach
chief cells
hormone secreted by the duodenum upon arrival of fats
cholecystokinin
term for food mixed with gastric secretions
chyme
2 actions of trypsin
chymotrypsinogen is converted to chymotrypsin procarboxypeptidase is converted to carboxypeptidase
alternate name for swallowing
deglutition
hard yellowish tissue that makes up majority of the tooth
dentin
alternate name for "teeth"
dentition
cells that release HCO3- in the pancreas
ductal cells
effect of secretin
ductal cells release HCO3-
3 regions of small intestine from start to finish
duodenum, jejunum, ileum
covering of the tooth above the gum
enamel
enzyme produced by brush border cells
enterokinase
salivary amylase
enzyme produced by salivary glands and secreted into the mouth. Used in carbohydrate digestion. Breaks down starch into dissacharides.
temperature in enzyme activity
enzymes work best at 37-40* C. Any higher temperature would denature them and they would not function properly.
3 types of lingual papillae
filliform, fungiform, vallate
intestinal villi
finger-like projections in the small intestine that aid in digestion and absorption
structure that stores and concentrates bile
gall bladder
ridges in the stomach
gastric rugae
hormone secreted by alpha cells
glucagon
alternate name for "taste"
gustation
pouches on the midline of the large intestine
hastrum
3 vessels that compose the hepatic triad
hepatic portal vein, hepatic artery, bile ductile
cells in liver that oxygen and nutrients from sinusoids
hepatocytes
cells in liver that produce bile that is sent to the bile ductule
hepatocytes
process of chemical digestion that breaks down carbs, fats, protein
hydrolysis
2 muscle layers of the muscularis externa and the type of muscle
inner circular, outer longitudinal, both smooth muscle
hormone secreted by beta cells
insulin
depressions in the small intestine surface
intestinal crypts
brush border enzymes: carbohydrate digestion
lactase, maltase. Works in the small intestine.
component of saliva that breaks down lipids
lingual lipase
lipase that requires gastric acid activation
lingual lipase
name of enzyme group that breaks down lipids
lipases
subunit of the liver
lobules
segmental movements
local constrictions of the organ wall that occur rhythmically. Mixes foodstuffs with digestive juices and increase the rate of absorption.
antibacterial enzyme found in saliva
lysozyme
enzyme produced by paneth cells
lysozyme
region of brain that controls swallowing reflex
medulla oblongata and pons
folds/projections on the surface of cells
microvilli
4 layers of the esophageal wall
mucosa (inner), submucosa, muscularis externa, serosa
cells that produce mucus in stomach
mucous cells
type of tissue that covers the tongue
non-keratinized stratified squamous epithelium
name of enzyme group that breaks down nucleic acids
nucleases
enzyme that breaks oligosaccharides into disaccharides
pancreatic amylase
chymotrypsin
pancreatic enzyme that works in the small intestine. Works in protein digestion. Breaks down large polypeptides into small polypeptides.
trypsin
pancreatic enzyne that works in the small intestine. Works in protein digestion. Breaks down large polypeptides into small polypeptides.
4 active enzymes produced by acinar cells
pancreatic lipase, pancreatic amylase, ribonuclease, deoxyribonuclease
cell type found in intestinal crypts
paneth cells
neural reflex that stimulates pancreatic juice production
parasympathetic
cells that produce IF and HCl in the stomach
parietal cells
3 sets of salivary glands
parotid, submandibular, sublingual
protease found in the stomach
pepsin
the active form of pesinogen
pepsin
enzymes activated by HCl
pepsin and lipase
pH in enzyme activity
pepsinogen and HCl (combine to make pepsin), work best at pH of 2, an acidic environment to enable gastric digestion and the breakdown of food to occur. Intestinal digestion occurs at pH 6, and enables the further breakdown so that absorption can take place.
connective tissue that lines the alveolus and penetrates the cavity and tooth to hold it in place
periodontal ligament
tissue covering the digestive organs
peritoneum
alternate name for lymphatic nodules found in the ileum
peyer's patches
name of enzyme group that breaks down proteins
proteases
2 areas of tooth that contains arteries, veins, nerves, and loose connective tissue
pulp cavity and root canal
network of ducts that dump into the small intestine
r. and l. hepatic ducts --> common hepatic --> joins cystic duct --> joins pancreatic duct --> hepatopancreatic ampulla --> sm. intestine
function of large intestine
reabsorb water and electrolytes
2 nucleases found in pancreatic juice
ribonuclease, deoxyribonuclease
2 regions of the liver
right hypochondriac and epigastric
component of saliva that breaks down starch
salivary amylase
enzyme in mouth that breaks carbs into oligosaccharides
salivary amylase
hormone secreted by duodenum upon arrival of acid
secretin
3 hormones secreted by the duodenum
secretin, cholecystokinin, glucose-dependent insulinotropic peptide
chyme
semi-solid acidic food mass that enters the duodenum from the stomach.
cell type of endothelium of large intestine
simple columnar epithelium
cell type of mucosa of stomach wall
simple columnar epithelium
organ where emulsification of lipids occurs
small intestine
digestion of protein and lipids lab
starting material: litmus milk enzymes: pancreatin powder reagent: litmus in the milk results: digestion occurs in the presence of an acidic environment (test tube turned purple-red). The product of protein digestion is amino acids, and the product of lipids are fatty acids. Because these products are acids, they increase acidity overall.
gastric digestion lab
starting material: powdered albumin enzymes: pepsin, hydrochloric acid, gastric juice (pepsinogen and HCl combined) reagent: Biuret results: gastric digestion occurs only with gastric juice and proper temperature of 37* (test tube turned pink-purple). Acidic environment is necessary.
digestion of starch lab
starting material: starch solution enzymes: pancreatic juice reagent: iodine-potassium iodide solution results: digestion occurs only with proper temperature (body temp of 37*) (test tube turned light brown). Too hot denatures the enzyme. The product of starch digestion is glucose.
small intestine absorption lab
starting material: starch, glucose enzymes: none reagent: Benedict's solution, iodine-potassim iodide results: glucose has small molecules that can be absorbed by the small intestine. starch molecules are too large (macromolecules) and can't fit through the pores of the small intestine.
3 layers of the mucosa
stratified squamous epithelia, lamina propria, muscularis mucosae
muscle type that composes the pharynx
striated skeletal muscle
two salivary duct orifices
sublingual and submandibular
two parasympathetic nerve plexuses of the enteric nervous system
submucosal (Meissner) myenteric (Auerbach)
connection between upper lip and gums
superior labial frenulum
neural reflex that inhibits pancreatic juice production
sympathetic
peristaltic movement
the major means of propelling food through most of the digestive viscera. Waves of contraction followed by waves of relaxation that squeeze foodstuffs through alimentary canal.
serosa
the outermost layer of the GI tract
submucosal
the second layer of the GI tract (from the inside)
muscularis
the third layer of the GI tract (from the inside)
action of enterokinase
trypsinogen is converted to trypsin
3 zymogens produced by acinar cells
trypsinogen, chymotrypsinogen, procarboxypeptidase
muscle composure of length of esophagus
upper 1/3rd = skeletal lower 1/3rd = smooth
finger-like projections of the small intestine
villi
pancreatic amylase
works in the small intestine and used in carbohydrate digestion. Breaks down starch into dissacharides.
pepsin
works in the stomach in the presence of HCl. Used in protein digestion. Breaks down protein into large polypeptides.
