Digestive System
Partially digested food is usually passed from the stomach to the small intestine about how long after consumption?
2-4 hours
Deciduous teeth
20 teeth, and by 2 years of age most children have all 20
Permanent teeth
32 teeth, and the wisdom teeth are the last to emerge
What is the purpose of stomach acid? How does the stomach protect itself from digestion?
Activates lipase, helps digest. Mucus
The function of the enzyme salivary amylase is to begin digesting proteins.
False, amylase digests starch
Pepsinogen is the precursor to the gastric enzyme for protein digestion and is secreted by the parietal cells.
False, pepsinogen is secreted by the chief cells
Chemical digestion of lipids is initiated in the mouth.
False, starch digestion beings in the mouth
Parietal cells of the stomach produce
HCl
What causes a peptic ulcer?
Peptic ulcers are erosions of the stomach wall. They are most commonly caused by the H. pylori bacterium.
What is heartburn and what causes it?
The acidic gastric juices are regurgitated into the esophagus. This may happen when someone has eaten or drunk to much. It can be caused by extreme obesity or pregnancy. It is sometimes due to obstructions or faults in the esophagus.
As food passes through the digestive tract, it becomes less complex and the nutrients are more readily available to the body.
True
Fats significantly delay the emptying of the stomach.
True
Food is contained in the gastrointestinal tract from the time of ingestion until it is completely digested and the waste prepared for elimination.
True
Kupffer cells are found in the liver and are responsible for removing bacteria and worn out cells.
True
Mumps is an inflammation of the parotid glands caused by myxovirus.
True
The digestive function of the liver is to produce bile.
True
The main chemical activity of the stomach is to begin the digestion of proteins.
True
The pancreas has both endocrine and exocrine function.
True
Define constipation and diarrhea and note possible causes of each.
Watery stools are called diarrhea. Constipation is a condition in which to much water has been absorbed and the stool becomes difficult to pass. Any condition such as irritation of the colon by bacteria that rushes food residue through the large intestine before that organ has had sufficient time to absorb the remaining water, is diarrhea. Constipation may ensue from a lack of fiber in the diet, improper bowel habits, laxative abuse or anything that decreases motility.
Process by which the products of digestion pass through the lumen of the gastrointestinal tract into the blood or lymph.
absorption
Intrinsic factor secreted by parietal cells of the stomach is required for
absorption of vitamin B12
secretes trypsinogen
acini of pancreas
The major digestive enzyme in salvia is
amylase
You have just eaten a meal high in complex carbohydrates. Which of the following enzymes will help to digest the meal?
amylase
_________ is the principal enzyme for breaking down complex carbohydrates.
amylase
Assume you have been chewing a piece of bread for 5 or 6 minutes. Why would the bread begin to taste sweet?
amylase working on starch, breaking down into maltose which is sweet
carbohydrates
amylase-oligosaccharides, disaccharides
Correct order of food movement in colon
ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon
The primary chemical digestion in the large intestine results from the action of
bacterial enzymes
A fluid secreted into the duodenum during digestion that contains cholesterol, emulsification agents and
bile
Trace a drop of bile from production by the hepatocyte until it leaves the body.
bile canaliculi, bile ductus, right and left hepatic ducts, common hepatic duct, cystic duct, bile duct, duct of pancreas, hepatopancreatic ampulla, duodenum, jejunum, ileum, ascending colon, transverse colon, sigmoid colon, rectum
Bile is secreted by hepatocytes into vessels called
bile conaliculi
The chief bile pigment is
bilirubin
The principle bile pigment is _____.
bilirubin
The normal color of feces is due primarily to the
breakdown products of hemoglobin
All of the microvilli of the epithelial cells of the small intestine collectively form a fuzzy line called the
brush border.
The appendix is attached to the
cecum
secretes gastrin
cells of stomach
The _____ phase of gastric secretions occurs before food enters the stomach.
cephalic
secretes pepsinogen
chief cells of stomach
Pepsinogen, an inactive form of the digestive enzyme is secreted by the
chief cells of the stomach
Gallstones are usually made of crystallized
cholesterol
Mixing waves of the stomach covert solid food into a liquid called
chyme.
Salvia
cleanses the mouth, moistens the food and aids in compacting of bolus, dissolves food chemicals so they can be tasted
The function of the hepatic portal circulation is to
collect absorbed nutrients for metabolic processing or storage.
The common bile duct is formed by the union of the
common hepatic and cystic ducts
Pancreatic amylase does NOT get into the small intestine via the
cystic duct
Increased activity of the sympathetic nervous system will
decrease production of digestive juices
The liver produces urea to
detoxify ammonia produced via deamination of protiens
Chemical or mechanical process of breaking down foodstuffs to substances that can be absorbed.
digestion
secretes alkaline mucus
duodenal glands of small intestine
Where is most of the water that enters the small intestine absorbed?
duodenum
____ is another word for vomiting.
emesis
Gastrin, histamine, endorphins, seotonin, cholecystokinin, and somatostatin are hormones or paracrine that are released directly into the lamina propria. Which cells yes synthesize and secrete these products.
enteroendocrine cells
The major stimulus for secretion of secretin is
entry of acid chyme into the small intestine
The opening in the diaphragm through which the esophagus passes is called the
esophageal hiatus
The stomach is considered an accessory digestive organ
false, it is an alimentary organ of the digestive system
The soft palate rises reflexively to open the nasopharynx when we swallow food.
false, rises to close
Bicarbonate ions are secreted into the lumen of the stomach along with the hydrogen ions to buffer them
false, the hydrogen bonds bind with chloride to create the acidic environment of the stomach. The bicarbonate goes into the blood.
The jejunum is the longest region of the small intestine
false, the ileum is longer
Cuspids are teeth specialized for grinding food
false, the molars specialize in grinding
cystic ducts
gallbladder
What has the lowest pH
gastric juice
During the gastric phase of the gastric digestion, acetylcholine from parasympathetic neurons stimulates secretion of the hormone ____.
gastrin
The end products of the hydrolysis reactions catalyzed by sucrase are ____ and _______.
glucose, fructorse
The greenish color of the bile is the result of the presence of breakdown products of
hemoglobin
The portal triad contains a branch of the _____ , a branch of the ______, and a _______.
hepatic artery, hepatic portal vein, bile duct
secrets bile
hepatocytes
The ducts that deliver bile and pancreatic juice from the liver and pancreas, respectively , unite to form the
hepatopancreatic ampulla
Enzymatic breakdown of any type of food molecule
hydrolysis
The type of chemical reaction catalyzed by the digestive enzymes in the digestive juices of the alimentary canal is
hydrolysis
The major chemical digestion that occurs in the adult stomach is
hydrolysis of proteins by pepsin
The function of bile is to
hydrolyze fats
Aggregated lymphatic follicles (Peyer's patches) are located in the mucosa of the ______ of the small intestine.
ileum
The longest portion of the small intestine is the
ileum
The terminal portion of the small intestine is the
ileum
In addition to storage and mechanical breakdown of food, the stomach
initiates protein digestion and denatures proteins
secretes maltase, lactase, sucrase
intestinal glands of small intestine
specific disaccharides are hydrolyzed by enzymes found in
intestinal juice
Parietal cells of the stomach secrete ______ and ________
intrinsic factor, HCL
What is not true of the large intestine
its longer than the small intestine ( It is shorter)
Hepatic macrophages called ____ cells are found in the liver sinusoids and they remove debris from the blood as it flows past.
kupffer
cecum
large intestine
Short chain triglycerides found in foods such as butterfat molecules in milk are spilt by a specific enzyme for preparation for absorption. Which enzyme is responsible?
lipase
fats and triglycerides
lipase- free fatty acids , monoglycerides
Digestion of which of the following would be affected the most if the liver were severely damaged?
lipids
Gastric emptying is the slowest after a meal rich in
lipids.
The _____ contains lobules with macrophage-lined sinusoids that lead to a central venous canal.
liver
caudate lobe
liver
The process of ______ results in the mechanical mixing of food with salvia and shaping of food into a bolus.
mastication
Which of the following is an example of mechanical digestion?
mastication
The sheet of peritoneal membrane that holds the small intestines in place is called
mesentery
The small intestine is attached to the posterior abdominal wall by a fold of the peritoneum called the
mesentery
The plicae circulares and intestinal villi are found in which of the four layers of the alimentary tube wall?
mucosa
The four basic layers of the lumen
mucosa , submucosa, muscularis externa , serosa
What causes lactose intolerance?
not producing enough lactase
hard palate
oral caivty
List the tubing in correct order of food movement
oropharynx, laryngopharynx, esophagus, stomach, pyloric valve
Which of the following would be considered an accessory organ of the digestive system?
pancreas
You have just eaten french fries, buttered toast, ice cream and whole milk. What gland is active in helping to digest this food?
pancreas
acini
pancreas
secretes insulin and glucagon
pancreatic islets
The principle triglyceride digesting enzyme in adults is
pancreatic lipase
________ is a hormone released from the duodenum in response to acidic chyme. It stimulates the pancreas to secrete more ________ to raise/lower the pH in the duodenum.
pancreatic protease, HCO3
Hydrochloric acid is secreted by which of the secretory cells of the stomach?
parietal
_____ cells of the stomach secrete HCl.
parietal
secretes hydrogen ions and chloride ions
parietal cells of stomach
secretes salvia
parotid glands
Proteins
pepsin - polypeptides
Chief cells of the stomach produce _____ and _____
pepsinogen , gastric lipase and chymosin
The hydrolytic reactions catalyzed by trypsin and chymotrypsin would result in the production of
peptides
The ______ ligament anchors a tooth in the alveolus of the jaw.
periodontal
The regular contractions of the muscular that push food through the entire gastrointestinal tract are known as
peristalsis
Wavelike smooth muscle contractions that move foodstuffs through the alimentary tube.
peristalsis
What increases the surface area of the mucosal lining?
plicae circulares and intestinal villi
What describes the location of the esophagus best
posterior to the trachea, anterior to the vertebral cool,m from laryngopharynx to stomach
Hepatocytes do not
produce digestive enzymes
The function of the goblet cells is to
produce mucus that protects parts of the digestive organs from the effect of powerful enzymes and acid
Gastrin is a digestive hormone that is responsible for the stimulation of acid secretions in the stomach. These secretions are stimulated by the presence of
proteins and peptide fragments
List the correct order of food movement in small intestine
pyloric valve, duodenum, jejunum, ileum, ileocecal valve
The ingestion of a meal high in fat content would cause what to occur?
release of bile from the gallbladder to emulsify the fat in the duodenum
nucleic acids
ribonuclease, deoxyrib. - pentase, sugars, N bases, phosphate ions
The folds of the gastric mucosa are called
rugae
Chemical digestion in the small intestine involves all of the following except
secretions from the spleen that contain all enzymes necessary for complete digestion
Chyme and digestive juices are mixed by localized contractions of the muscularis of the small intestine called ____________.
segmentations
Salivary glands are composed of which two types of secretory cells
serous cells and mucous cells
cephalic stage of gastric digestion
sight, smell , thought or taste of food trigger parasympathatic impulses
Most absorption of nutrients occurs in the
small intestine
jejunum
small intestine
About 90 percent of all absorption of nutrients occurs in the ______ , the other 10 percent occurs in the ____ and ________.
small intestine, stomach, large intestine
Chyme is created in the
stomach
fundus
stomach
The pyloric sphincter is located at the junction of the _____ and the _______.
stomach , duodenum
The muscularis of most organs of the gastrointestinal tract consists of two layers of smooth muscle except the
stomach, it has three layers.
The functions of the gallbladder include
storage and concentration of bile
cementum
teeth
Thickened portions of the longitudinal muscles of the large intestine are called _______ that gather the colon into pouches called ______.
teniae coli , haustra
Peristalsis occurs during
the pharyngeal stage of deglutition and the esophageal stage
Bicarbonate ions diffuse into blood capillaries of the stomach after a meal because
they are being exchanged for chloride ions that enter the stomach lumen ( chloride shift)
papillae
tongue
CCK stimulates ejection of bile from the gallbladder
true
Oxygenated and deoxygenated blood mix in the liver sinusoids
true
Peristalsis begins in the esophagus
true
The brush border of the small intestine is formed by the microvilli of the epithelial cells
true
The gastrocolic reflex triggers mass peristalsis
true
The substrate for salivary amylase is starch
true
Which of the following enzymes is specific for protiens
trypsin
The found ligament is a remnant of the fetal __________.
umbilical vein
During swallowing the nasal cavity is closed off by the soft palate and the
uvula
Folds in the mucosa of the small intestine that increase the surface area for diffusion are called
villi
The large intestine absorbs mostly
water
List the components of pancreatic juice
water, enzymes, electrolytes, (bicarbonate ions)