A&P II Mastering A&P Chapter 23 homework
Which digestive process does NOT occur in the mouth?
Segmentation (segmentation is the back & forth mixing movement of food in the small intestine.The process of chewing and mixing food w/saliva in the mouth is mastication)
Amylase is secreted by
both the salivary glands and the pancreas
The function of the hepatic portal circulation is to ________
collect absorbed nutrients for metabolic processing in the liver
Which structure is highlighted?
dentin
Maltose is a
disaccharide
Which of the following is an essential role played by large intestine bacteria?
fermentation of indigestible carbohydrates -absorb bilirubin -produce gas -synthesize vitamins C and D -fermentation of indigestible carbohydrates
In the small intestine, which of the following enzymes breaks down oligosaccharides?
glucoamylase Yes, glucoamylase breaks down oligosaccharides.
Bile is produced by the __________ under hormonal influence of __________
liver; secretion (The liver secretes bile, especially when influenced hormonally by secretin.)
Enzymes are
made of protein and are catalysts
The sheets of peritoneal membrane that hold the digestive tract in place are called ________.
mesenteries
Carbohydrates are digested into __________.
monosaccharides Monosaccharides are sugars, the building blocks of carbohydrates such as starch or glycogen.
Which layer of the stomach contains the gastric pits that secrete mucous, acid, and digestive enzymes?
mucosa The mucosa of the stomach contains the epithelial lining and the gastric pits, which extend down into the mucosa but do not penetrate the submucosa.
What is a major function of pancreatic juice?
neutralizing chyme entering the small intestine from the stomach Pancreatic juice contains bicarbonate (as baking soda does) that can neutralize the pH of acidic chyme coming from the stomach.
Which of these structures is found in the stomach but nowhere else in the alimentary canal?
oblique muscle layer All areas of the alimentary canal have a circular and a longitudinal layer of muscle. The stomach has an additional oblique layer of muscle for "wringing" itself while processing food
Which of the following enzymes is important for the digestion of fat?
pancreatic lipase Yes, pancreatic lipase is important for the digestion of fats. It is secreted by the pancreas and works in the small intestine.
Which of the following enzymes is important for breaking down protein?
pepsin Yes, pepsin breaks down proteins in the stomach.
Which of the following are NOT correctly matched?
protease: lipid digestion (Proteases digest proteins.) -nuclease: DNA and RNA digestion -protease: lipid digestion -lipase: fat digestion -amylase: carbohydrate digestion
Enzymatic breakdown of which of the following compounds doesn't begin until it reaches the stomach?
proteins Yes, enzymatic breakdown of proteins begins in the stomach.
Which structure is highlighted?
simple columnar epithelium
Generally the hormones secretin and cholecystokinin which are released by duodenal enteroendocrine cells will ________.
slow the activities of the stomach
In what portion of the gastrointestinal tract does most salt and water absorption occur?
small intestine Yes, most absorption of salt and water occur in the small intestine.
Which layer of the alimentary canal contains not only glands and blood vessels but also a nerve plexus that helps regulate digestive activity?
submucosa
The substance that the enzyme acts on is called its
substrate
The absorptive effectiveness of the small intestine is enhanced by increasing the surface area of the mucosal lining. Which of the following accomplish this task?
villi, and microvilli
The _____ is the serous membrane that covers the abdominal organs.
visceral peritoneum
Most nutrients are absorbed through the mucosa of the intestinal villi by active transport. T/F
true
The digestive function of the liver is to produce bile. T/F
true
The deciduous dentition consists of __________ teeth.
20 The deciduous, or primary, dentition consists of 20 teeth.
Select the correct statement about electrolyte absorption.
Answer: -Iron and calcium are absorbed mostly by the duodenum -Potassium moves across the epithelium by active transport. -Iron and calcium are absorbed mostly by the duodenum -If vitamin B is not present, calcium is not absorbed. -Chloride ion absorption is coupled to glucose and amino acid transport.
Which of the following is NOT a characteristic of the stomach?
Answer: -The stomach releases enzymes to digest carbohydrates. -The stomach has three layers of muscle in the muscularis tunic. -The stomach releases enzymes to digest carbohydrates. -The stomach produces a double-layered coat of alkaline mucus. -The stomach mucosa is folded into rugae.
Choose the incorrect statement regarding bile.
Answer: Bile contains enzymes for digestion. -Bile is both an excretory product and a digestive secretion. -Bile functions to carry bilirubin formed from breakdown of worn-out RBCs. -Bile contains enzymes for digestion. -Bile functions to emulsify fats
Which of the following is NOT a function of saliva?
Answer: Saliva contains enzymes that begin the chemical breakdown of proteins. Saliva contains components with functions ranging from starch breakdown to fighting bacterial infection, but it does not contain any enzymes that digest protein.
All but one of the following is a function of the low pH found in the stomach. Select the description below that does not reflect a role of stomach acid.
Answer: The stomach's acid catabolically breaks down food stuffs in preparation for absorption. -The stomach's acid catabolically breaks down foodstuffs in preparation for absorption. -Stomach acid denatures proteins making the polypeptide chain more accessible to pepsin digestive enzymes. -Low pH converts pepsinogen to its active form, pepsin. -Many potentially harmful bacteria will be prevented entry to the small intestine by stomach acid.
Which of these best describes a lacteal?
Answer: a lymphatic vessel designed to help introduce fats to the blood Lacteals are lymphatic vessels located in the intestinal villi. Their ability to accept large materials makes them helpful in transporting large fat particles (called chylomicrons) into the lymph and eventually the bloodstream.
When we ingest large molecules such as lipids, carbohydrates, and proteins, they must undergo catabolic reactions whereby enzymes split these molecules. This series of reactions is called ________.
Answer: digestion The chemical and mechanical processes of food breakdown are called digestion
Which of the following is NOT a means of mechanically breaking down food?
Answer: peristalsis Peristalsis is a physical process used for propulsion, or movement, through the GI tract. -mastication -segmentation -churning -peristalsis
Hepatocytes do not ________.
Answer: produce digestive enzymes -detoxify toxic chemicals -store fat-soluble vitamins -produce digestive enzymes -process nutrients
Which of the following is NOT a function of the large intestine?
Answer: production of intrinsic factor Intrinsic factor is produced by the stomach to help vitamin B12 be absorbed before ever reaching the large intestine. -absorption of electrolytes -production of intrinsic factor -absorption of water -absorption of vitamins
Which of the following functions is NOT correctly matched with its description?
Answer: propulsion: physical breakdown of ingested food in the GI tract Propulsion is the movement of ingested food through the GI tract. -absorption; passage of digested nutrients into the blood or lymph -mechanical breakdown: churning movements in the GI tract -propulsion: physical breakdown of ingested food in the GI tract -ingestion: intake of food nutrients
Which organ of the digestive tract is the body's major digestive organ?
Answer: small intestine The small intestine is the major digestive organ because it is the site of the majority of enzymatic digestion and absorption of nutrients.
Which of the organs listed below is involved in all of the following processes: secretion, mechanical breakdown of food, digestion and absorption?
Answer: stomach -the liver -the stomach -the esophagus -the large intestines
Which vitamin requires intrinsic factor in order to be absorbed?
B12
The breakdown products of which of the following are absorbed into lacteals?
Fats Yes, chylomicrons are absorbed into lacteals because they are too large to pass through the basement membrane of a capillary and into the blood.
Peyer's patches are found in the submucosa of the distal end of the small intestine. T/F
True
The pancreas has both an endocrine and an exocrine function. T/F
True
When swallowing, the epiglottis covers the larynx. T/F
True
Which of the following constitute a portal triad?
a bile duct along with a portal venule and arteriole A bile duct along with a portal venule and arteriole constitute a portal triad. The blood vessels provide blood flow to the lobule and the bile duct drains bile.
Pepsinogen, an inactive digestive enzyme, is secreted by the
chief cells of the stomach
Where are the enzymes for digestion of disaccharides and small polypeptides located?
brush border Yes, the enzymes for digestion of disaccharides and small polypeptides are found in the brush border of most the absorptive cells of the small intestine.
Which of the following is a source of dietary fiber and promotes timely movement through the colon?
cellulose Yes, the polysaccharide cellulose is not digested and is used as a source of dietary fiber.
The ducts that deliver bile and pancreatic juice from the liver and pancreas, respectively, unite to form the ________
hepatopancreatic ampulla
The mechanical and chemical receptors that control digestive activity are located ________.
in the walls of the tract organ
Which teeth are best suited for cutting or nipping off pieces of food in the permanent dentition?
incisors
Most absorption of nutrients occurs in the __________.
jejunum As digesting foods make their way through the jejunum, the majority of nutrients are absorbed at this time.
Short-chain triglycerides found in foods such as butterfat molecules in milk are split by a specific enzyme in preparation for absorption. Which of the following enzymes is responsible?
lipase
Which of the following is the best explanation of the benefit in the digestive system having the largest collection of lymphoid tissue (MALT) at the distal end of the small intestine?
the huge numbers of bacteria living in the large intestine must be prevented from entering the lumen of the small intestine and being absorbed with food's nutrients into the blood stream.
What triggers the release of secretin from the small intestine?
the presence of acidic, fatty chyme in the small intestine The presence of acidic, fatty chyme in the small intestine causes the release of secretin, which in turn inhibits further entry of stomach contents into the intestine until the fat has been emulsified and the pH raised.
All the chemical and mechanical phases of digestion and mechanical breakdown from the mouth through the small intestine are directed toward changing food into forms that can pass through the epithelial cells lining the mucosa into the underlying blood and lymphatic vessels T/F
true
Peristaltic waves are ________.
waves of muscular contractions that propel contents from one point to another
The formation of diverticula involves, most significantly, the ______.
weakening of the colon's submucosa The submucosa is composed of dense connective tissue containing elastic fibers, blood and lymphatic vessels, lymph nodes, and nerves.
