Mastering A&P 2 Ch 23 HW

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

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

Anemia Correct 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.

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

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

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

Saliva contains enzymes that begin the chemical breakdown of proteins Correct 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 complex starches into smaller units in the mouth. Salivary amylase breaks down lipids into fatty acids in the mouth. Salivary amylase breaks down proteins into amino acids in the stomach. Salivary amylase breaks down steroid hormones into cholesterols in the stomach.

Salivary amylase breaks down complex starches into smaller units in the mouth Correct Salivary amylase in saliva breaks down starch into oligosaccharide

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

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

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

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

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

acinar cells Correct 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? protease samylases nuclease trypsin

amylase

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

being stressed or frightened Correct 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? intrinsic factor digestive enzymes such as CCK and secretin bile bicarbonate- and potassium-rich mucus

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

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

brush border

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

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

Which of the following is a source of dietary fiber and promotes timely movement through the colon? cellulose polypeptides amylase triglycerides

cellulose

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

chief Correct Yes, chief cells produce pepsinogen

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 __________. gallstones cystic fibrosis irritable bowel syndrome (IBS) diverticula

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

enteropeptidase Correct 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? fats carbohydrates proteins

fats

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

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

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

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

in the form of chylomicrons Correct 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.

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

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

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

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

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

intestinal phase Correct 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? Vasoactive intestinal peptide (VIP) hydrochloric acid intrinsic factor pepsinogen

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

Which of the following enzymes is important for breaking down protein? pancreatic lipase pancreatic amylase pepsin trypsin

pancreatic lipase

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

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

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 high-calorie dietary carbohydrates increase vitamin absorption reduce absorption of dietary fats

prevent inflammation caused by malabsorption of gluten protein Correct 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 is NOT correctly matched with its description? -propulsion: physical breakdown of ingested food in the GI tract -ingestion: taking food into the digestive tract -absorption: transport of chemically 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 Correct Propulsion is the movement of ingested food through the GI tract.

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

protease: lipid digestion

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

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

proteins

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

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

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) gastrin GIP (gastric inhibitory peptide) secretin

secretin Correct 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.

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

small intestine

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

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

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

sympathetic postganglionic fibers Correct 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 the large intestine? absorption of water synthesis of intrinsic factor absorption of electrolytes synthesis of vitamins

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

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 Correct The muscularis is a smooth muscle bilayer. Smooth muscle has a relatively slower rate of mitosis.

Which of the following is NOT a characteristic of the stomach? -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 muscularis externa has three layers of smooth muscle

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