physiology ch 17
Indicate which of the following are true regarding gastric and duodenal ulcers.
- Many can be treated by a short course of antibiotics. - They have been associated with infection by the bacterium Helicobacter pylori.
List in order the organs of the digestive tract starting from the oral cavity (at the top) and ending with the anal canal. Instructions Choice 1 of 7. esophagus toggle button esophagus Choice 2 of 7. large intestine toggle button large intestine Choice 3 of 7. pharynx toggle button pharynx Choice 4 of 7. stomach toggle button stomach Choice 5 of 7. oral cavity toggle button oral cavity Choice 6 of 7. small intestine toggle button small intestine Choice 7 of 7. anal canal toggle button anal canal
1. oral cavity 2. pharynx 3. esophagus 4. stomach 5. small intestine 6. large intestine
Match the portion of the esophagus with the type of muscle located there. Instructions
1. superior one-third of esophagus: skeletal muscle only 2. middle one-third of esophagus: mix of skeletal and smooth muscle 3. inferior one-third of esophagus: smooth muscle only
Place the phases of the swallowing mechanism in order, with the beginning phase at the top of the list.
1. voluntary phase; the tongue forces a bolus into oropharynx 2. soft palate elevates; epiglottis covers larynx; esophagus opens 3. peristalsis transports the food in the esophagus to the stomach
Describe the alimentary canal.
8-meter-long tube passes through thoracic and abdominopelvic cavities
When chyme containing proteins and fats enters the small intestine, cells in the duodenal wall release the peptide hormone called ___, which stimulates the release of pancreatic juice from acinar cells.
Cholecystokinin
What is contained in bile?
Cholesterol, pigments, bile salts, and phospholipids
Enzymes that breakdown lipids are secreted in an inactive form to prevent digestion of pancreatic tissues.
False
Why are the proteolytic enzymes that are produced by the pancreas stored in zymogen granules and secreted in an inactive form?
It prevents digestion of the proteins in secreting cells and ducts of the pancreas.
How does food pass from the stomach into the small intestines?
Peristaltic waves push small amounts of chyme into the small intestine at a time.
The hormone that stimulates the pancreas to secrete an abundant amount of fluid rich in bicarbonate ions when acidic chyme enters the duodenum is
Secretin
Which events take place during the swallowing reflex?
Soft palate raises, preventing food from entering the nasal cavity. The epiglottis covers the larynx. Constrictor muscles relax to open the esophagus.
Describe gastric emptying.
The rate at which the stomach empties depends on the fluidity of the chyme and the type of food present.
Name factors that influence stomach emptying.
The volume of food; the more food in the stomach the longer it takes to empty. The type of food; a meal high in carbohydrates empties the fastest.
Stomach infection by the bacterium Helicobacter pylori causes gastric ulcers.
True
What are functions of the stomach?
absorbs small amounts of nutrients starts the digestion of protein mixes food with gastric juice
Correctly pair each basic function of the digestive system with the correct description. Instructions absorption: digestion: mastication: propulsion:
absorption: movement of molecules from the digestive tract into the circulation or lymphatic system digestion: breakdown of large organic molecules into their component parts mastication: process by which teeth break food into smaller particles to increase the total surface area propulsion: movement of food from one end of the digestive tract to the other
Indicate which of the following organs are part of the alimentary canal and which are accessory organs of the digestive system. Instructions
accessory organs: liver, gallbladder alimentary canal: stomach, esophagus, small intestine
In the condition called cirrhosis, hepatocytes die and are replaced by scar tissue because the cells were overtaxed with efforts to detoxify
alcohol or drugs
What is the 8-meter-long tube that passes through the thoracic and abdominopelvic cavities of the body?
alimentary canal
The enzyme that begins starch and glycogen digestion in the mouth is called salivary ______.
amylase
The enzyme that is secreted into the mouth to begin starch digestion is salivary ______.
amylase
The pancreatic enzyme that digests starch is called pancreatic
amylase
Pancreatic juice has an alkaline pH, due to the presence of ___ ions.
bicarbonate
The hormone secretin stimulates the pancreas to secrete a solution high in ______.
bicarbonate ions
Which component of pancreatic juice helps to neutralize the acidic chyme that enters the duodenum from the stomach?
bicarbonate ions
Hepatic cells produce a yellowish-green liquid called ___ that assists with lipid digestion.
bile
A mass of chewed food mixed with saliva that is forced down the esophagus is called a(n)
bolus
Pancreatic amylase breaks ______ down into ______.
carbohydrates; disaccharides
Identify the major proteolytic enzymes produced by the pancreas.
carboxypeptidase trypsin chymotrypsin
A series of hydrolysis reactions that breaks dietary macromolecules into monomers is known as ___ digestion.
chemical
Breaking down macromolecules into building blocks, as when amino acids are released from proteins, occurs during ___ digestion.
chemical
What is a bolus?
chewed food mixed with saliva
The cells in the gastric glands that secrete pepsinogen, a digestive enzyme, are the ___ cells.
chief
Pepsinogen is secreted by ______ cells of the gastric glands, and is a precursor to ______.
chief; pepsin
The hormone ______ is secreted by the small intestine in response to fat and proteins in gastric contents entering the intestine.
cholecystokinin
Which hormone, when released by cells in the wall of the duodenum, stimulates the secretion of pancreatic juice containing a high concentration of digestive enzymes?
cholecystokinin
What are bile salts made from?
cholesterol
Once food is mixed with gastric juice, it is called
chyme
The soupy mixture of semidigested food formed in the stomach is known as
chyme
Which condition involves the buildup of scar tissue in the liver that results when cells are overtaxed by efforts to detoxify drugs and alcohol and subsequently die?
cirrhosis
Which are functions of saliva?
cleanses mouth and teeth aids in swallowing dissolves molecules so they can be tasted
What is the role of the hormone cholecystokinin?
decrease gastric motility
The mechanical and chemical breakdown of foods into forms that the cells can use is called ______.
digestion
The process of breaking down foods, either mechanically or chemically, into forms that cell membranes can absorb is called
digestion
The stomach is involved in which function(s) of the digestive system?
digestion, absorption, and movement of food
What do chief cells, found in gastric glands, secrete?
digestive enzymes
Mucous cells secrete mucus, which functions to ______.
ease the process of swallowing
Trypsinogen, a proteolytic enzyme secreted in the pancreas in its inactive form, is activated to trypsin when it interacts with the enzyme ______ which is secreted by the mucosa of the small intestine.
enterokinase
The ___ is a straight muscular tube conveying food from pharynx to the stomach.
esophagus
Which part of the alimentary canal has a muscularis that contains a region of only skeletal muscle and another region composed of a mix of skeletal and smooth muscle, in addition to an area with only smooth muscle?
esophagus
When does the pyloric sphincter open to let chyme enter the small intestine?
every time there is a peristaltic wave
What does pancreatic lipase break down?
fats
What are gastric rugae?
folds of the stomach lining
Which is NOT included in the alimentary canal?
gall bladder
Tubular glands that open into gastric pits of the fundus and body of the stomach are called ___ glands.
gastric
The medical term ______ refers to the condition where stomach contents back up into the esophagus resulting in a burning sensation.
gastric reflux
What do parietal cells, found in gastric glands, secrete?
hydrochloric acid
What is hepatitis?
inflammation of the liver
What are the basic functions of the digestive system?
ingestion digestion propulsion absorption defecation
An enzyme that digests dietary fats in the stomach is called gastric
lipase
The pancreatic enzyme that digests fats is called pancreatic
lipase
Which gastric enzyme digests dietary fats in the stomach?
lipase
Identify the accessory organs of the digestive system.
liver gallbladder pancreas salivary glands
The structure that prevents the stomach contents from spilling into the esophagus is the ___ esophageal sphincter.
lower
When stomach contents splash back into the esophagus, it causes a sensation called heart burn. This involves a failure of what sphincter to close?
lower esophageal sphincter
Mechanical breakdown of food in the mouth occurs by ______.
mastication
Mechanically breaking food down into smaller pieces by the mouth is called ___, also known as chewing.
mastication
The break down of large pieces of food into smaller pieces without changing their chemical composition is called ___ digestion.
mechanical
The physical breakdown of food into smaller particles (by processes such as chewing and segmentation) is known as ___digestion.
mechanical
Which cells in gastric glands release a viscous, alkaline secretion to prevent the stomach from digesting itself?
mucous neck cells
The component of saliva that binds, lubricates, and aids in swallowing is
mucus
The first stage of swallowing involves the tongue moving the bolus into the ______. This process is a(n) ______ action.
oropharynx; voluntary
Which is an accessory organ of the digestive system?
pancreas
The salivary glands, like the rest of the digestive system, are innervated by which part(s) of the nervous system?
parasympathetic and sympathetic nervous systems
The cells in the gastric glands that secrete hydrochloric acid and intrinsic factor are the ___ cells.
parietal
The enzyme that begins digestion of protein in the stomach is
pepsin
The inactive form of pepsin is
pepsinogen
Openings at the ends of tubular gastric glands in the gastric mucosa, as indicated by the arrows are called gastric
pits
Pepsin breaks down ______ into ______.
proteins and polypeptides
The muscular band that regulates the passage of chyme from the stomach to the duodenum is the ___ sphincter.
pyloric
Which muscular band regulates the passage of chyme from the stomach to the duodenum?
pyloric sphincter
The longitudinal wrinkles in the lining of the stomach are called gastric
rugae
The substance that functions to moisten the mouth, clean the teeth, inhibit bacterial growth, and aid in swallowing by moistening food is called
saliva
The motor functions of the alimentary canal are of two basic types: mixing movements also known as ___ and propelling movements also known as ___ .
segmentation peristalsis
As indicated in the picture by the letter "A," ______ is a mixing movement that occurs by alternately contracting and relaxing the smooth muscle in nonadjacent segments of the digestive tract. As indicated by the letter "B," ______ is a wavelike propelling movement that pushes the contents ahead.
segmentation; peristalsis
What are components of the alimentary canal?
small intestine, large intestine, rectum, and anus mouth, pharynx, esophagus, stomach
The organ that starts the digestion of proteins is the
stomach
The alimentary canal is innervated by the ___ and ___ divisions of the autonomic nervous system.
sympathetic parasympathetic
The alimentary canal of the digestive system is controlled by which nervous system?
sympathetic and parasympathetic nervous systems
Which nervous systems innervate the alimentary tract of the digestive system?
sympathetic division of autonomic nervous system parasympathetic division of autonomic nervous system
Match the nervous system division with its effect on the salivary glands. Instructions
sympathetic nervous system: minimal secretion of thick saliva parasympathetic nervous system: copious secretion of watery saliva
What is mechanical digestion?
the breakdown of large food particles into smaller ones
What is the role of the secretions of the mucous neck cells?
to prevent the stomach from digesting itself
Most of swallowing is an autonomic reflex. What part of swallowing is voluntary?
tongue pushing food into the oropharynx
Identify the enzyme that activates chymotrypsin and carboxypeptidase.
trypsin
Which enzyme breaks down proteins?
trypsin
The first stage of swallowing is a(n) ___ action involving the tongue moving the bolus into the ___ .
voluntary oropharynx
What is gastric reflux?
when stomach contents back up into the esophagus after a big meal
