digestive system

In what form do fats first enter the bloodstream? in the form of micelles in the form of fatty acids and glycerol in the form of glycerol in the form of chylomicrons

in the form of chylomicrons Within enterocytes, fats are combined with phospholipids and cholesterol, and coated with proteins to form water-soluble lipoprotein droplets called chylomicrons. Chylomicrons are secreted first into lymphatic vessels where they are eventually emptied into the bloodstream.

During which phase in the control of the digestive system would bicarbonate and bile be stimulated? intestinal phase cephalic phase gastric phase

intestinal phase Yes, food in the intestines initiates a reflex that stimulates secretions of bicarbonate, digestive enzymes, and bile.

Which of the following is produced in the stomach and contributes directly to the absorption of vitamin B12? hydrochloric acid intrinsic factor Vasoactive intestinal peptide (VIP) pepsinogen

intrinsic factor Without the production of intrinsic factor by gastric parietal cells, the body would not be able to absorb vitamin B12 in the small intestine.

What is a possible side effect of weakening of the cardiac sphincter? acid reflux into the esophagus uncontrollable bowel movements heart attack rapid overfilling of the stomach

acid reflux into the esophagus

In response to a steak dinner, certain secretions are needed to aid digestion. What cells in the pancreas would provide these secretions? acinar cells islet of Langerhans cells duct cells

acinar cells Yes, in response to a high fat and protein meal, CCK would be stimulated and in turn would stimulate an enzyme-rich secretion from the pancreas.

Which enzyme(s) is/are responsible for the chemical breakdown of carbohydrates? trypsin nuclease amylases proteases

amylases

The alkaline tide uses a(n)______ in the basolateral membrane to move ______ out of the cell and _______ into the parietal cell. symporter; chloride; bicarbonate symporter; bicarbonate; chloride antiporter; chloride; bicarbonate anitporter; bicarbonate; chloride

antiporter; bicarbonate; chloride

Which of the following inhibits salivation? ingestion of spicy foods being stressed or frightened relaxing after a meal the sight or smell of food

being stressed or frightened The sympathetic division of the autonomic nervous system is associated with fight-or-flight responses. Stimulation of the salivary glands by the SNS tends to inhibit flow, as when you are scared or nervous and your mouth "goes dry."

The secretion in the large intestine consists of which of the following? digestive enzymes such as CCK and secretin intrinsic factor bicarbonate- and potassium-rich mucus bile

bicarbonate- and potassium-rich mucus Yes, an alkaline mucus secretion of bicarbonate and potassium protects the large intestinal wall from acids produced by resident bacteria.

When your stomach growls in response to an ad on TV for food, the __________ phase of gastric secretion is initiated. cephalic gastric intestinal gastrin

cephalic

the majority of______ occurs in the mouth, stomach, and small intestine. ingestion chemical digestion mechanical digestion absorption

mechanical digestion

which is true of intestinal juice? 24 liters are produced daily pH range from 7.4 to 7.8 it is hypotonic to blood plasma it is composed mostly of bicarbonate ions.

pH range from 7.4 to 7.8

Digestion of which of the following might be inhibited if a patient chronically consumes an antacid? lipid carbohydrate sugar protein

protein

Which of the following digestive processes could be affected by a patient's taking a large amount of antacids? carbohydrate digestion protein digestion lipid digestion nucleic acid digestion

protein digestion Protein digestion is partially accomplished by pepsin, an enzyme that works best in a pH range of 1.5 to 2.5.

Which of the following is NOT a function of the large intestine? absorption of electrolytes synthesis of intrinsic factor synthesis of vitamins absorption of water

synthesis of intrinsic factor Intrinsic factor is produced in the stomach; it is required for absorption of vitamin B12 in the small intestine.

Your patient has had a total gastrectomy (removal of the stomach). Which of these potential problems are you MOST concerned about? Anemia Excessive bleeding as a result of absent clotting factors in the blood. Inability to tolerate fats because of absent bile salts Inability to digest starch because of the absence of amylase

Anemia The parietal cells of the stomach produce intrinsic factor, which permits the absorption of vitamin B12, a nutrient required for the maturation of red blood cells. Unless your patient receives vitamin B12 replacement therapy, he or she will develop pernicious anemia.

_______ stimulates the gallbladder to contract secretin CCK gastrin fatty chyme

CCK

Which of the following intestinal hormones stimulates the release of bile from the gall bladder? motilin CCK (cholecystokinin) gastrin GIP (gastric inhibitory peptide)

CCK (cholecystokinin) Yes, CCK causes the gall bladder to contract, releasing bile and an enzyme-rich pancreatic juice to be secreted from the pancreas.

a patient with a low RBC count receives vitamin B 12 injections every two weeks. Why? This patient is training for a triathlon. This patient is anemic and has low iron. Parietal cells in this patient's stomach have ceased producing intrinsic factor. This patient's parietal cells have stopped secreting HCl.

Parietal cells in this patient's stomach have ceased producing intrinsic factor.

Where are the enzymes for digestion of disaccharides and small polypeptides located? saliva brush border stomach secretions from the pancreas

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? polypeptides cellulose amylase triglycerides

cellulose Yes, the polysaccharide cellulose is not digested and is used as a source of dietary fiber.

HCl secretions convert pepsinogen to the active hormone pepsin. What cells in the gastric pits produce pepsinogen? chief parietal paracrine (also known as enteroendocrine cells) G cells

chief Yes, chief cells produce pepsinogen, the inactive form of pepsin.

_______ involves over 22 muscle groups and includes the buccal phase and the pharygneal- esophageal phase. mastication bolus formation deglutition peristalsis

deglutition

In the small intestine, which of the following enzymes breaks down oligosaccharides? glucoamylase pancreatic amylase sucrase lactase

glucoamylase

Which teeth in the permanent dentition are best suited for cutting or nipping off pieces of food? molars premolars (bicuspids) incisors canines

incisors The location and shape of the incisors make them ideally suited for cutting and nipping food.

Meals high in protein __________ gastrin secretion from the gastric glands. increase decrease have no affect upon delay

increase

Chyme entering the large intestine normally consists of __________. excess nutrients that the body does not need indigestible fiber, enteric bacteria, and water large proteins, nucleic acids, and other molecules not generally utilized as an energy source all fat-soluble molecules that are unable to cross the small intestine epithelium

indigestible fiber, enteric bacteria, and water The small intestine absorbs virtually all nutrients from chyme before it reaches the large intestine, leaving only indigestible wastes, water, and millions of bacteria.

a meal high in fat would _______. stimulate rapid gastric emptying stimulate the intensity of the stomach's peristaltic waves increase gastrin secretion inhibit gastric emptying

inhibit gastric emptying

cirrhosis of the liver would most severly impact digestion of_______. carbohydrates amino acids proteins lipids

lipids

Which of the following enzymes is important for the digestion of fat? pancreatic amylase pancreatic lipase trypsin pepsin

pancreatic lipase Yes, pancreatic lipase is important for the digestion of fats. It is secreted by the pancreas and works in the small intestine.

This group of enzymes digests the majority of ingested fat. lingual lipases pepsin and stomach acid bile salts pancreatic lipases

pancreatic lipases Pancreatic lipases break the bonds between fatty acid chains and glycerol after the fats have been emulsified.

the______ cells are responsible for HCl production. goblet mucous parietal chief

parietal

Enzymatic breakdown of which of the following compounds doesn't begin until it reaches the stomach? lipids proteins carbohydrates

proteins Yes, enzymatic breakdown of proteins begins in the stomach.

you would expect blood levels of ______ to be highest when the pH of stomach chyme entering the duodenum is at its lowest. secretin Cl gastrin H+

secretin

Which of the following GI hormones promotes a pancreatic juice rich in bicarbonate ions? gastrin motilin GIP (gastric inhibitory peptide) secretin

secretin Yes, secretin (from S cells in the duodenum) causes both the liver and pancreas to secrete bicarbonate into the small intestine.

This type of chemical reaction typically occurs as nutrients are digested in the body. hydrolysis dehydration synthesis endergonic anabolic

hydrolysis Hydrolysis refers to the enzymatic breakdown of large polymers into monomers while adding the parts of a water molecule to the broken bonds.

In what portion of the gastrointestinal tract does most salt and water absorption occur? mouth small intestine stomach colon

small intestine

the majority of absorption occurs in the_______. stomach small intestine large intestine mouth

small intestine

Absorption of nutrients primarily occurs in the __________. large intestine stomach small intestine mouth

small intestine Most nutrients are absorbed in the small intestine before the chime reaches the ileum.

Norepinephrine is the neurotransmitter released by which fibers? both sympathetic and parasympathetic preganglionic fibers interneurons of the enteric nervous system parasympathetic postganglionic fibers sympathetic postganglionic fibers

sympathetic postganglionic fibers Yes, norepinephrine is the neurotransmitter of the sympathetic postganglionic fibers. An increase in the sympathetic system would decrease digestion.

Which of the following is NOT a function of saliva? Saliva cleanses the mouth. Saliva moistens food and helps compact it into a bolus. Saliva dissolves food chemicals so that they can be tasted. Saliva contains enzymes that begin the chemical breakdown of proteins.

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.

Salivary amylase is a digestive enzyme not featured in the Concept Map. Which of the following describes its function? breaks down complex starches into smaller units, and where in the body does this occur? Salivary amylase breaks down proteins into amino acids in the stomach. Salivary amylase breaks down lipids into fatty acids in the mouth. Salivary amylase breaks down steroid hormones into cholesterols in the stomach. Salivary amylase breaks down complex starches into smaller units in the mouth.

Salivary amylase breaks down complex starches into smaller units in the mouth. Salivary amylase in saliva breaks down starch into oligosaccharides.

Which of the following is NOT a characteristic of the stomach? The muscularis externa has three layers of smooth muscle. The stomach releases enzymes that digest carbohydrates. The mucosa is organized into large, longitudinal folds called rugae. The stomach produces a double-layered coat of alkaline mucus.

The stomach releases enzymes that digest carbohydrates. The chief cells of the stomach secrete enzymes that chemically digest lipids and proteins, but not carbohydrates.

Enteric interneurons that are inhibitory to smooth muscle use which of the following neurotransmitters? norepinephrine substance P VIP (vasoactive intestinal peptide) ACh (acetylcholine)

VIP (vasoactive intestinal peptide) Yes, both VIP and NO (nitric oxide) are inhibitory to smooth muscle.

When the diet lacks fiber and the volume of residues in the colon is small, the colon narrows and its contractions become more powerful, increasing the pressure on its walls. This promotes formation of __________. diverticula irritable bowel syndrome (IBS) gallstones cystic fibrosis

diverticula When the diet lacks fiber and the volume of residues in the colon is small, the colon narrows and its contractions become more powerful, increasing the pressure on its walls. This promotes formation of diverticula, small herniations of the mucosa through the colon walls. This condition, called diverticulosis, most commonly occurs in the sigmoid colon, and affects over half of people over age 70. In 4-10% of cases, diverticulosis progresses to diverticulitis, in which the diverticula become inflamed and may rupture, leaking into the peritoneal cavity, which can be life-threatening.

Which cells produce CCK in the intestine? simple columnar cells goblet cells intrapeithelia lymphocytes enteroendocrine cells

enteroendocrine cells

Cancer treatments such as chemotherapy target rapidly dividing, cancerous cells, but can also destroy noncancerous cells with a rapid rate of mitosis. Which small intestinal features are LEAST likely to be damaged by chemotherapy? enterocytes microvilli the muscularis layer of the intestine mucosal stem cells

the muscularis layer of the intestine The muscularis is a smooth muscle bilayer. Smooth muscle has a relatively slower rate of mitosis.

The human GI tract is home to a complex ecosystem of microbial cells, which comprise the gut microbiota. Which of the following is true of the microbiota? Generally, the highest concentration of GI tract microbes is found in the colon. Metabolism by the gut microbiota results in small amounts of vitamins and short-chain fatty acids which can be absorbed and utilized by cells of the body. Normally, beneficial bacteria vastly outnumber harmful bacteria in the microbiota. All of the above.

All of the above.

why is the small intestine well adapted for nutrient absorption? acid secretions from the stomach are neutralized in the duodenum. CCK is released from the duodenum to promote liver and pancreatic secretion. Large surface area due to the presence of plicae circulares, villi, and microvilli. The small intestine is very long and thin.

Large surface area due to the presence of plicae circulares, villi, and microvilli.

Which of the following does NOT correctly describe basic regulation of digestive activity? Short reflexes act locally in the GI tract. pH, stretch, and osmolarity are some of the stimuli that can trigger digestive reflexes. Digestive system effectors are smooth muscle and glands. The enteric nervous system is under conscious control.

The enteric nervous system is under conscious control. Neural control over the digestive system is through the autonomic nervous system, which does not function under conscious control mechanisms

How are vitamins A, D, E, and K absorbed by the body? by direct simple diffusion in the jejunum by active transport of vitamin pumps in the intestinal epithelia by binding to intrinsic factor to trigger receptor-mediated endocytosis by being incorporated into micelles

by being incorporated into micelles Fat-soluble vitamins are incorporated into micelles when fats are present. Without dietary fats available, these vitamins are not absorbed.

the gallbladder______ bile by_____water and ions. concentrates; absorbing stores; preventing absorption of dilutes; secreting modifies; secreting

concentrates; absorbing

Which chemical activates the transformation of trypsinogen to trypsin? enteropeptidase amylase chymotrypsin carboxypeptidase

enteropeptidase Enteropeptidase is a protein produced by and bound to the membranes of intestinal cells. Contact with this protein converts trypsinogen to trypsin, the active form of the enzyme.

The breakdown products of which of the following are absorbed into lacteals? proteins fats carbohydrates

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.

Salivation is controlled almost entirely by the nervous system. Which of the following stimuli would inhibit salivation? a lemon fear nausea the thought of food

fear Yes, fear, sleep, fatigue, and dehydration all inhibit salivation.

which of the following enzymes break down lipids? amylase pepsin bile none of the above

none of the above

Which of the following enzymes is important for breaking down protein? bile salts lipase amylase pepsin

pepsin Yes, pepsin breaks down proteins in the stomach.

An individual diagnosed with celiac disease would be prescribed a gluten-free diet in order to __________. prevent inflammation caused by malabsorption of gluten protein reduce absorption of dietary fats increase vitamin absorption reduce absorption of high-calorie dietary carbohydrates

prevent inflammation caused by malabsorption of gluten protein In a person with celiac disease, gluten breakdown products interact with the immune system in the digestive tract, leading to damage of the intestinal lining.

Which of the following functions is NOT correctly matched with its description? absorption: transport of chemically digested nutrients into the blood or lymph mechanical breakdown: churning movements in the GI tract ingestion: taking food into the digestive tract propulsion: physical breakdown of ingested food in the GI tract

propulsion: physical breakdown of ingested food in the GI tract Propulsion is the movement of ingested food through the GI tract.

Which of the following are NOT correctly matched? protease: lipid digestion amylase: carbohydrate digestion nuclease: DNA and RNA digestion lipase: fat digestion

protease: lipid digestion Proteases digest proteins.

The stomach is able to expand nearly 80 times its empty volume partly due to _____ in its walls. microvilli rugae plicae circulares haustra

rugae

An increase in HCl (hydrochloric acid) arriving in the duodenum would stimulate which hormone that would help to counteract the effects of HCl? CCK (cholecystokinin) secretin gastrin GIP (gastric inhibitory peptide)

secretin Yes, secretin stimulates the duct cells in the pancreas and liver to secrete a bicarbonate-rich solution that will bind hydrogen ions and increase the pH.