A&P II Digestive system
Name the cell that phagocytizes bacteria in the liver sinusoids
Kupffer cells
What is the function of the rugae
They help the stomach expand when necessary.
What prevents swallowed food from entering the airways?
Usually when food is swallowed, involuntary muscle contractions cause the soft palate to rise and close off the nasopharynx. The larynx also is pulled up, and the epiglottis folds over the glottis. These actions block off the air passages.
Name the major vitamin of blood clotting that is produced by the bacterial flora of the large intestine.
Vitamin K
Gastric mixing changes
a bolus into chyme
Fatty chyme entering the small intestine stimulates the secretion of _______, which stimulates the pancreas to secrete __________.
cholecystokinin; enzymes
Which structures in the intestine increase the surface area available for absorption
circular folds and villi
Teeth are composed primarily of a bonelike material called
dentin
Which of these cells secrete hormones
enteroendocrine cells
All of the following digestive structures produce secretions that aid in chemical digestion except
esophagus
Name the ligament that divides the liver into four lobes
falciform ligament
Name the connective tissue attached to the greater curvature of the stomach which extends down over the intestines
greater omentum
Large folds of the intestinal wall are called
haustra
Name the blood vessel that drains nutrient-rich blood from the intestine to the liver for processing and filtration
hepatic portal vein
Name the cell type that produces bile
hepatocytes
The condition in which the stomach protrudes above the diaphragm through the esophageal hiatus is known as
hiatal hernia
Which of all the secretions produced by the digestive tract has the lowest pH?
hydrochloric acid (HCl)
Name the type of tooth designed for nipping and biting
incisors
A yellowish coloration of the skin and mucous membranes is due to the buildup of bilirubin is called
jaundice
Name one example of a brush border enzyme produced in the small intestine which acts upon carbohydrates
lactase, maltase, sucrase
Name the layer composed of areolar connective tissue underlying the epithelium of the mucosa of the GI tract.
lamina propria
Where is indigestible waste compacted?
large intestine
Bike is produced by the ____ and stored in the ___.
liver, gallbladder
Name the sphincter muscle at the top of the stomach
lower esophageal sphincter (also called the gastroesophageal or cardiac sphincter)
Which peritoneal fold supports the large intestine?
mesocolon
Where does mechanical and chemical digestion begin
mouth
Which of the following accurately lists the four tissue layers of the alimentary canal, from innermost to outermost
mucosa, submucosa, muscularis, serosa
The taenia coli are bands of _______ running along the outside of the colon
muscle
Name one example of a brush border enzyme produced in the small intestine which acts upon nucleic acids
nucleosidases
Which of the following accurately lists the order of the structures through which food passes as it moves through the digestive system, starting with the entry of food into the mouth through to elimination
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anal canal
The cells that secrete insulin and glucagon are called
pancreatic islets (islets of Langerhans)
Gastric juice secretion is increased by _______ action potentials and the hormone gastrin, which is produced by the ________
parasympathetic; stomach
Which salivary gland is composed almost entirely of serous cells?
parotid glands
Name the activated enzyme of the stomach that breaks down proteins
pepsin
Chief cells of the stomach produce
pepsinogen
Name the substrate that trypsin acts upon
peptides
What organs are involved in swallowing and are just passageways that are not involved in mechanical nor chemical digestion
pharynx and esophagus
Name the modification of the rectum that prevents a person from defecating whenever they pass gas.
rectal valves
The last 15 cm of the large intestine is a storage area called the
rectum
In addition to the normal secretions by the stomach, infants produce ________ to help them digest milk proteins
rennin
Name the folds that are found in an empty stomach
rugae
Name the outer most layer of the digestive tract that forms the peritoneum
serosa
Secretin is a hormone that is secreted by the ______. That causes the pancreas to bicarbonate
small intestine
Name the lymphoid organ located inferior and lateral to the stomach and is responsible for purifying the blood and disposal of worn-out red blood cells
spleen
Name the substrate that salivary amylase acts upon
starch
Name the tissue of the mucosa within the oral cavity, pharynx, and upper esophagus
stratified squamous epithelium (non-keratinized)
Name the hardest substance in the human body
tooth enamel
Finger-like projections within the mucosa of the small intestines that increase surface area for absorption and digestion are called
villi
How many permanent teeth should a healthy adult have
32
Which of the following statements accurately distinguishes a bolus from chyme
A bolus is food that has been chewed and swallowed, whereas chyme is the mixture of food and digestive secretions created in the stomach.
Which of the following is an example of chemical digestion
An enzyme hydrolyzes bonds between glucose molecules
Name the "worm-like" lymphatic organ attached to the cecum
Appendix
If you wanted to explain the function f bacteria in the large intestine to someone who did not understand it, you might include all of the following except
Bacteria absorb water in the colon
Explain the role of bile salts and lecithin in the emulsification of lipids (fats).
Bile salts and lecithin can emulsify large lipid globules because they are amphipathic; they have a nonpolar (hydrophobic) region that attaches to the large fat molecules as well as a polar (hydrophilic) region that interacts with the watery chime in the intestine.
The scientific term for "swallowing" is
Deglutition
Peristalsis moves the bolus down the esophagus and toward the stomach. Esophageal glands secrete mucus that lubricates the bolus and reduces friction. When the bolus nears the stomach, the lower esophageal sphincter relaxes, allowing the bolus to pass into the stomach.
Describe the three processes involved in the esophageal phase of deglutition.
Which one of the following is the correct sequence of regions of the small intestine, from beginning to end?
Duodenum, jejunum, ileum
Which of the following describes how bile enters the duodenum
Hepatocytes in the liver secrete bile, which flows into the right and left hepatic ducts and then into the common hepatic duct. If the bile is not yet needed for digestion, it flows up the cystic duct and is stored in the gall bladder.
Bile and pancreatic enzymes empty into the small intestine through a common opening called the
Hepatopancreatic ampulla
Why is it important that chyme from the stomach is delivered to the small intestine slowly and in small amounts?
If large quantities of chyme were forced into the small intestine, it would result in osmotic water loss from the blood into the intestinal lumen that could cause potentially life-threatening low blood volume and erosion of the duodenum.
Explain the mechanism responsible for gastroesophageal reflux.
If the lower esophageal sphincter does not close completely, the stomach's acidic contents can back up into the esophagus, a phenomenon known as GERD.
How is vitamin B12 absorbed?
Intrinsic factor secreted in the stomach binds to the large B12 compound, creating a combination that can bind to mucosal receptors in the ileum.
If you were summarizing the defecation reflex, you might include all of the following except
Involuntary relaxation of the external anal sphincter allows defecation to occur.
Why is the hepatic portal system important?
It allows nutrients and wastes to be processed in the liver instead of entering the circulation directly
Which of the following statements accurately compares the small and large intestines
Most nutrient absorption takes place in the small intestine, whereas most water reabsorption takes place in the large intestine.
Which of these organs in not considered an accessory digestive structure?
Mouth
What is the correct order for the layers of the GI tract wall, from innermost ( next to lumen) to outermost?
Mucosa - submucosa - muscularis - adventitia/serosa
Explain how nutrients absorbed in the small intestine pass into the general circulation.
Nutrients from the breakdown of carbohydrates and proteins are absorbed through a capillary bed in the villi of the small intestine. Lipid breakdown products are absorbed into a lacteal in the villi, and transported via the lymphatic system to the bloodstream.
The composition of saliva varies from gland to gland. Discuss how saliva produced by the parotid gland differs in action from saliva produced by the sublingual gland.
Parotid gland saliva is watery with little mucus but a lot of amylase, which allows it to mix freely with food during mastication and begin the digestion of carbohydrates. In contrast, sublingual gland saliva has a lot of mucus with the least amount of amylase of all the salivary glands. The high mucus content serves to lubricate the food for swallowing.
Name the prominent bands of smooth muscle running longitudinally along the large intestine wall creating haustra
Taeniea coli
Which of the following is a good description of the function of the stomach sphincters
The cardiac sphincter is where a bolus enters the stomach from the esophagus. The pyloric sphincter is where chyme exits the stomach into the duodenum.
Explain how the enteric nervous system supports the digestive system. What might occur that could result in the autonomic nervous system having a negative impact on digestion?
The enteric nervous system helps regulate alimentary canal motility and the secretion of digestive juices, thus facilitating digestion. If a person becomes overly anxious, sympathetic innervation of the alimentary canal is stimulated, which can result in a slowing of digestive activity.
What involuntary movement prevents the bolus from entering the trachea?
The epiglottis folds down and covers the trachea.
Describe the location of hepatocytes in the liver and how this arrangement enhances their function.
The hepatocytes are the main cell type of the liver. They process, store, and release nutrients into the blood. Radiating out from the central vein, they are tightly packed around the hepatic sinusoids, allowing the hepatocytes easy access to the blood flowing through the sinusoids.
During a hockey game, the puck hits a player in the mouth, knocking out all eight of his most anterior teeth. Which teeth did the player lose and how does this loss affect food ingestion?
The incisors. Since these teeth are used for tearing off pieces of food during ingestion, the player will need to ingest foods that have already been cut into bite-sized pieces until the broken teeth are replaced.
All of the following are layers of the stomach wall except
The innermost serosa
What layer of the alimentary canal tissue is capable of helping to protect the body against disease, and through what mechanism?
The lamina propria of the mucosa contains lymphoid tissue that makes up the MALT and responds to pathogens encountered in the alimentary canal.
Offer a theory to explain why segmentation occurs and peristalsis slows in the small intestine.
The majority of digestion and absorption occurs in the small intestine. By slowing the transit of chyme, segmentation and a reduced rate of peristalsis allow time for these processes to occur.
Name the connective tissue found in the folds of the small intestine and anchors the large intestine
The mesentery
Describe three of the differences between the walls of the large and small intestines.
The mucosa of the small intestine includes circular folds, villi, and microvilli. The wall of the large intestine has a thick mucosal layer, and deeper and more abundant mucus-secreting glands that facilitate the smooth passage of feces. There are three features that are unique to the large intestine: teniae coli, haustra, and epiploic appendages.
Explain how the stomach is protected from self-digestion and why this is necessary.
The mucosal barrier protects the stomach from self-digestion. It includes a thick coating of bicarbonate-rich mucus; the mucus is physically protective, and bicarbonate neutralizes gastric acid. Epithelial cells meet at tight junctions, which block gastric juice from penetrating the underlying tissue layers, and stem cells quickly replace sloughed off epithelial mucosal cells.
If you were showing a friend a cross-section of a tooth, you could use all of the following to explain it except
The neck of the tooth sits in the alveolar process of the jaw bone
Why does the pancreas secrete some enzymes in their inactive forms, and where are these enzymes activated?
The pancreas secretes protein-digesting enzymes in their inactive forms. If secreted in their active forms, they would self-digest the pancreas. These enzymes are activated in the duodenum.
It has been several hours since you last ate. Walking past a bakery, you catch a whiff of freshly baked bread. What type of reflex is triggered, and what is the result?
The smell of food initiates long reflexes, which result in the secretion of digestive juices.
Describe unique anatomical features that enable the stomach to perform digestive functions.
The stomach has an additional inner oblique smooth muscle layer that helps the muscularis churn and mix food. The epithelium includes gastric glands that secrete gastric fluid. The gastric fluid consists mainly of mucous, HCl, and the enzyme pepsin released as pepsinogen.
What is the role of the tongue in chewing and swallowing
The tongue manipulates the chewed food into a small mass and moves it into the oropharynx.
The primary function of the large intestine is the _______
absorption of water and certain minerals and vitamins
Name the exocrine cells of the pancreas
acinar cells
Name one brush border enzyme produced in the small intestine which acts upon proteins.
aminopeptidase, dipeptidase, carboxypeptidase
From the cecum to the rectum, the regions of the colon are the
ascending colon, transverse colon, descending colon, sigmoid colon
"Segmentation" within the small intestine refers to the
back-and-forth motion that mixes chyme with glandular secretions.
Each of the following organs is a component of the digestive tract except the
bladder
The scientific term for food that is swallowed is
bolus
The large intestine includes the
cecum, colon, rectum
Gastric secretion occurs in three phases
cephalic, gastric, intestinal
The hormone produced by the brush border cells of the intestine that stimulates the ejection of bile from the liver and gallbladder and pancreatic juice from the pancreas is
cholecystokinin