Digestive System Anatomy and Physiology

C) Submucosa

D) Both statements are false.

Above the diaphragm, the outermost layer of the digestive tract is a connective tissue called adventitia. Below the diaphragm, it is called serosa.

A) Stomach

The stomach is part of the gastrointestinal or alimentary tract itself.

C) Both statements are true.

C) Mouth

The mouth, or oral cavity, is the first part of the digestive tract.

C) Only the first statement is true.

Posteriorly, the soft palate ends in a projection called uvula.

A) None of these

When food reaches the opening of the pharynx, sensory receptors around the fauces respond and initiate an involuntary swallowing reflex.

A) Its submucosa has glands that secrete mucus to keep the lining moist and well lubricated to ease the passage of food.

The mucosa of the esophagus has glands that secrete mucus to keep the lining moist and well lubricated to ease the passage of food.

A) Lower esophageal sphincter

The lower esophageal sphincter is sometimes called the cardiac sphincter and resides at the esophagogastric junction.

B) Only the first statement is true.

The lesser and greater curvatures are on the right and left sides, respectively, of the stomach.

B) Only the second statement is true.

The mucosal lining of the stomach is simple columnar epithelium with numerous tubular gastric glands.

C) The presence of basic chyme in the small intestine begins the intestinal phase.

The presence of acidic chyme in the small intestine begins the intestinal phase.

D) Only the second statement is true.

Relaxation of the pyloric sphincter allows chyme to pass from the stomach into the small intestine. Cardiac sphincter is synonymous with lower esophageal sphincter.

A) Small intestine

C) All of these

D) Cholecystokinin

Exocrine cells in the mucosa of the small intestine secrete mucus, peptidase, sucrase, maltase, lactase, lipase, and enterokinase. Endocrine cells secrete cholescystokinin and secretin.

D) Only the first statement is true.

This is largely a local reflex action in response to chemical and mechanical irritation from the chyme and in response to distention of the intestinal wall.

C) Epiploic appendages, pieces of fat-filled connective tissue, are attached to the inner surface of the colon.

Epiploic appendages, pieces of fat-filled connective tissue, are attached to the outer surface of the colon.

C) Only the first statement is true.

The rectum follows the curvature of the sacrum and is firmly attached to it by connective tissue.

D) Five

A) Both statements are true

Meanwhile, the external anal sphincter is found at the inferior end of the anal canal. This sphincter is composed of skeletal muscle and is under voluntary control.

A) It begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into monosaccharides.

The saliva begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into disaccharides.

D) It is primarily located in the right hypochondriac and epigastric regions of the abdomen, just above the diaphragm.

The liver is primarily located in the right hypochondriac and epigastric regions of the abdomen, just beneath the diaphragm.

D) Hepatic portal 

Meanwhile, freshly oxygenated blood is brought to the liver by the common hepatic artery, a branch of the celiac trunk from the abdominal aorta.

C) It is mainly composed of water, bile salts, bile pigments, and triglycerides.

Bile is mainly composed of water, bile salts, bile pigments, and cholesterol.

D) Stylopharyngeus

D) Soft palate

D) Epiglottis

False

True

False

The pyloric sphincter acts to prevent food from leaving the stomach.

A) Submucosa

D) Parasympathetic

B) Close off the nasal cavity during swallowing

B) Molar

A) Tongue

D) Sublingual

A) Sensory receptors detecting the bolus in the pharynx

A) Body

C) Parietal cells

Parietal cells are also known as oxyntic cells.

D) Cephalic phase

D) Pancreatic lipase

D) Secretin

A) Produces bile to emulsify fats in the small intestine

C) Components of lipids diffuse through small intestinal cell membranes, are reconstructed in the cells, then carried off by lacteals as chylomicrons.

B) To compact, store, and eliminate feces

A) Small intestine

B) Esophagus

C) Parotid

A) Root

D) Carbohydrates

C) Pharynx

B) Rugae

B) Stomach

B) Mesentery

B) Duodenum

D) Submucosa

A) Serosa

A) Small intestine

A) Ascending colon

B) K

True

Although a digestive role has not been elucidated for the appendix, this area does have numerous lymph nodes that play a role in defense against infection.

True

The descending colon is on the left abdominal area, while the ascending colon is on the right area.

True

The external anal sphincter is a skeletal muscle and is under voluntary control. Meanwhile, the internal anal sphincter is a smooth muscle and is under involuntary control.

True

Myocardial infarction is a possibility because the increase in thoracic pressure reduces blood flow to the heart. This maneuver will increase abdominal pressure and aid defecation.

True

One purpose of the visceral peritoneum is to allow the free movement of the intestines. The parietal peritoneum is the membrane that lines the inner wall of the abdominal cavity.

False

The enzyme amylase is produced by the serous cells of the salivary glands.

False

The Stensen's duct carries saliva from the parotid gland into the oral cavity next to the second upper molar.

The Wharton's duct carries saliva from the submandibular gland into the floor of the mouth.

The duct of Rivinus carries saliva from the sublingual gland into the floor of the mouth. The largest is the major duct of the sublingual salivary gland called Bartholin duct.

True

Swallowing is a complicated series of events that must prevent food from entering the nasal cavity and larynx. The epiglottis covers the opening of the larynx called the glottis.

True

The parietal (oxyntic) cells produce gastric intrinsic factor which is needed to absorb the vitamin B12 necessary for blood cell development.

False

The vomiting center is in the medulla oblongata and causes the diaphragm to contract which increases pressure within the stomach by its external force. Vomiting involves respiratory reflexes.

True

There are a number of nerve reflexes that aid in the proper movement of food. The entero-gastric reflex occurs as the duodenum fills with chyme and stimulates stretch receptors, which send an impulse to the stomach muscle preventing further movement of food into the duodenum.

True

Cystic fibrosis is a genetic disease that causes the production of a thick, fibrinous mucus secretion from respiratory or digestive lining cells and may block the ducts associated with the pancreas.

False

The hepatic portal veins drain the gastrointestinal areas and convey the blood to the liver. The hepatic veins then leave the liver.

True

The liver then converts these amino acids into glucose in a process known as gluconeogenesis.

True

Hepatitis A can be spread by oral or fecal sources, whereas hepatitis B is usually disseminated by way of the blood.

False

Hepatitis is an inflammation of the liver and is most commonly caused by infection with hepatitis A viruses. Drugs or chemicals can also cause hepatitis.

False

Hemolytic jaundice is a symptom of a disease which causes the rapid breakdown of red blood cells.

False

The gallbladder only stores the bile. The liver will continue to secrete bile in sufficient amounts to meet nutritional needs.

False

In lactose intolerance the person cannot digest lactose sufficiently and the combination of increased osmotic pressure and bacterial fermentation cause cramping to occur.

True

The lipoprotein complexes represent methods of transporting fatty substances, including cholesterol and are manufactured in the intestines.

C) Serosa

The outermost layer in the gastrointestinal tract is the serosa which is comprised of fibrous connective tissue.

C) Muscularis

The muscularis has circular and longitudinal muscles that cause the food to move in peristaltic, forward waves.

C) 9

The alimentary tube is about 9 meters or 28 feet long on the average.

D) Parasympathetic

The impulses from the parasympathetic nervous division act to promote the forward movement of food and other digestive activities. The sympathetic pattern includes an inhibition of digestive activity such as constriction of a sphincter.

C) Mastication

Mastication is the process of breaking food into smaller particles. Deglutition is the complex function involved in swallowing.

D) Tongue

The lingual frenulum is a membranous fold of the mucous membrane that surrounds the tongue and attaches to the midline of the floor of the oral cavity.

D) Attaches to the temporal bone

D) Around the frenulum

The tissue below the frenulum contains the sublingual salivary glands.

C) Palatine tonsils

The palatine tonsils are located in the fauces of the oral cavity and are frequent sites of tonsillitis and infection. Peyer's patches are in the wall of the ileum.

C) 52

There are 20 primary deciduous teeth which are replaced by 32 secondary teeth, giving a total of 52.

B) Third molar

The third molars erupt between 17 and 25 years of age and are therefore the last to appear. They do not erupt in all persons and may remain impacted.

C) Root

The crown is the portion above the surface, while the roots lies in the cavities of the mandible or maxillae.

A) Dentin

Cementum is a binding chemical substance.

D) Inferior constrictor

The inferior constrictor muscles of the pharynx originate from the larynx. Some remain in a state of constriction to prevent air from entering the esophagus during breathing.

A) Diaphragm

A hiatal hernia is a protrusion of the stomach or other structure through the opening of the diaphragm called the esophageal hiatus.

D) Cardia

There is a functional sphincter at the entrance of the stomach called the cardiac region or cardia. The fundus is the portion that serves as a temporary storage area.

C) Pyloric valve

The pyloric sphincter constricts to prevent food from passing prematurely into the first part of the small intestine (duodenum).

C) Chief

Chief (peptic) cells secrete enzymes, while the parietal (oxyntic) cells produce hydrochloric acid.

D) Pepsin

Pepsinogen is the inactive form that is activated by acidity and converted to pepsin.

B) Secretion of somatostatin

Somatostatin normally inhibits the production of hydrochloric acid and parasympathetic nerves promote digestion. Gastrin is a hormone which promotes gastric activity.

B) 1.5

One purpose of the hormone gastrin is to increase the acidity of the stomach. When the pH reaches 1.5 the gastrin is inhibited by negative feedback mechanisms.

C) Bicarbonate ions

As the body attempts to maintain a balance of ions, -HCO3 ions are absorbed into the blood as H+ ions enter the stomach lining from the blood. This exchange of bicarbonate for hydrogen following a meal is called the alkaline tide.

B) Lipids

Chyme rich in fats will stimulate the secretion of cholecystokinin from the intestine which will then cause the gall bladder to constrict.

D) Sphincter of Oddi

The hepatopancreatic sphincter prevents pancreatic and liver secretions from entering the small intestine at an inappropriate time.

C) Enterokinase

Enterokinase from the small intestine catalyzes the conversion of trypsinogen to trypsin which then activates chymotrypsin and carboxypeptidase.

C) Zymogen

Zymogen granules are the inactive forms of the proteolytic enzymes. Words that end with -ogen usually are in an inactive state.

C) Trypsin

The activation of trypsin from its inactive trypsinogen state can be caused by many factors including blockage of the duct. Trypsin will hydrolyze the protein molecules comprising the substance of the pancreatic tissue if the pancreas is inflamed (pancreatitis).

C) Pepsin

The alkaline pH conditions of the duodenum favor the activity of several enzymes except those from the stomach such as pepsin which operate under an optimal acidic pH.

B) Bicarbonate ions

Acid in the duodenum causes the release of the hormone secretin which stimulates the pancreas to produce a bicarbonate rich solution for the purpose of neutralizing the acidity.

B) Cholecystokinin

Cholecystokinin is the hormone that causes the gall bladder to constrict, while the others are enzyme terms.

D) Cholecystokinin

Cholecystokinin has several functions including the stimulation of the pancreatic acinar cells. Enterogastrone is an inhibitory hormone.

A) Liver

The liver contains the greatest number of and most diverse array of enzymes in the body and is capable of multiple biomolecular conversions.

B) Protein

Urea is formed by combining the amino groups from protein catabolism that otherwise would have the capability of causing pH imbalances such as from the creation of ammonia.

A) Iron

Iron is carried in the form of ferritin and plays a role in the mobilization of the iron needed for hemoglobin synthesis.

B) C

The liver stores fat soluble vitamins such as A and D and some water soluble vitamins such as B12, but not ascorbic acid to any extent.

B) Glycogen

Excess glucose is converted to glycogen in the liver by a process of glycogenesis, which also occurs in skeletal muscle.

C) Erythropoiesis

The synthesis of red blood cells is a function of the fetal liver; the adult liver however can serve as a blood storage area.

C) Sinusoids

Sinusoids are special blood channels that represent a merger of arteries and veins. These sinusoids can allow the permeability of proteins.

B) Falciform

The coronary ligament attaches the liver to the diaphragm.

Anatomically, the liver has four lobes: right, left, caudate, and quadrate.

A) Liver

Bile is secreted by the liver and stored in the gallbladder.

C) Liver

The liver Kupffer cells are phagocytic and also belong to as system of cells throughout the body called the reticuloendothelial system.

C) Obstructive jaundice

Obstructive jaundice arises from disease that affects the flow of bile. Excess bile pigments in the blood is hyperbilirubinemia.

B) Bilirubin

Bilirubin and biliverdin are bile pigments that arise from hemoglobin decomposition and cannot be readily recycled.

C) Cystic

Eventually, all ducts will merge to form the common bile duct.

C) Cystic

The common bile duct is formed as the cystic duct from the gallbladder joins the common hepatic duct. The common hepatic duct is the merger of the ducts from the four lobes of the liver.

C) Pancreatic

The ampulla of Water or duodenal papilla is the area that joins the duodenum and is guarded by the hepatopancreatic sphincter (sphincter of Oddi).

C) Cholelithiasis

Cholelithiasis means gallstones. Cholesterol is present in many of the precipitates found in the gallbladder and some kidney stones (calculi).

C) Emulsification

Bile salts contain unique molecules that have polar and non polar regions that cause large fat globules to physically break up into smaller units.

D) Micelles

Micelles are aggregates of fatty acids surrounded by bile salts in such a way to make the fatty acids more soluble in water.

A) C

Vitamin C and most of the B complex vitamins are water soluble. Vitamins A, D, E, and K are lipid soluble.

B) Somatostatin

Somatostatin is secreted from the stomach and duodenum in response to acidity, and therefore controls acid production by negative feedback.

B) Duodenum

The first section of the small intestine has its own enzyme secretions as well as those coming from the liver and pancreas.

A) Duodenum

The duodenum is only 10 to 12 inches long but is the most active and critical region of the small intestine.

The jejunum is 8 to 10 feet long.

The ileum is 8 to 10 feet long.

The colon may be 6 feet long.

B) Greater momentum

The mesentery acts to suspend the intestines to the body wall.

The visceral peritoneum surrounds the intestines.

The parietal peritoneum lines the abdominal wall.

The greater momentum is an extension of the peritoneum that is attached to the stomach.

D) Villi

The microvilli are the cell processes on the columnar cells that line the intestines.

The lumen is the space or opening.

The villi are the projections that contains the microvilli.

B) Lacteals

Lacteals enter the villi and convey their absorbed fats into the lymphatic vessels that return fluids to the circulation.

C) Large intestine

The small intestine has glands in the crypts of Lieberkuhn and folds called plicae.

B) Lipase

Lipase catalyzes the hydrolysis of lipids, whereas the other listed enzymes are disaccharides that break down double sugars.

C) Duodenum

Only the duodenal lining has mucosal cells that secrete the disaccharides that can hydrolyze sugars such as sucrose.

A) Stomach

The stomach does not have the pH or enzymes capable of starch digestion.

B) Jejunum

The jejunum is the site of most of the active absorption of glucose, amino acids, and fatty acids.

The duodenum is the site of active digestion.

The ileum functions in some minor absorption.

The colon only absorbs a few substances, such as water.

C) Chylomicrons

Chylomicrons are aggregates of lipids and lipoproteins. Liver and muscle cells contain lipoprotein lipases that hydrolyze the chylomicrons.

D) Na+

Ions with more than one charge such as magnesium, sulfates, and calcium are poorly absorbed. This is the reason why ocean water cannot be ingested without serious osmotic consequences.

A) Large intestine

The ileocecal valve constricts to prevent food from leaving the small intestine and is under neurological reflex control.

D) Diarrhea

Diarrhea is the elimination of a watery stool caused by poor absorption; Flatus is intestinal gas.

True

False

Insufficient proteins in the diet usually cause a state of nutritional edema as seen in kwashiorkor.

False

False

B) Essential nutrients

A) Cellulose

D) Maltose

C) Neurons

A) It is used for structural material in cell membranes.

B) 30%

D) To synthesize bile

C) Corn

B) The body is awake but resting

A) A

D) B12

C) Folic acid

Folic acid is also known as vitamin B9.

D) Sodium

B) Zinc

C) Marasmus

C) Anabolism

B) Cellulose

B) Lactose

D) Deoxyribose

B) Glycogen

B) Linoleic acid

A) Rice and beans

B) 96

Each gram of carbohydrate or protein yields four calories, whereas each gram of fat yields nine calories.

A) Thyroid hormone

D) Dihydroxycholecalciferol

C) K

A) Pantothenic acid

Pantothenic acid is also known as vitamin B5.

D) B12

Vitamin B12 is also known as cyanocobalamin.

A) Sulfur

True

Anorexia means loss of appetite and the major symptom of the psychological condition called anorexia nervosa, which has many causes.

True

Skeletal muscle stores the complex carbohydrate glycogen, which is a polymer of glucose.

False

Although humans lack the enzyme cellulase, the cellulose in plants such as lettuce has benefits as roughage which increases gastrointestinal motility.

True

Excess carbohydrates can be converted to lipids which are then stored in the adipose tissue. Therefore, a fat weight gain can be carbohydrate-induced.

True

The liver has enzymes that can catalyze the conversion of lipids and proteins into glucose and related compounds.

False

The liver has the capability of converting carbohydrates into other compounds. It is not the excess carbohydrate that causes problems but the deficiency of compounds such as certain amino acids and vitamins that are essential and cannot be manufactured.

True

A lack of adequate carbohydrate in the diet will cause the liver and skeletal muscles to break down their proteins and convert structures such as muscle proteins into glucose.

True

Nutritionists recommend that 3% of the energy intake in the infant formula be in the form of the essential linoleum fatty acid. Recall the liver in an infant is immature and does not have the capabilities to synthesize all the needed compounds.

False

Complete proteins contain eight essential amino acids but may not contain all 20 that are used by humans.

True

A positive nitrogen balance occurs whenever the body uses proteins to build tissues in excess of the amount that is oxidized or lost. Children have anabolic rates that exceed catabolic.

True

Protein deficiencies lead to mental retardation and bloated bellies or ascites. These are commonly seen in undeveloped countries.

True

Adults require around 1,500 kcal or 1,500,000 calories each day.

False

The food in a bomb calorimeter is burned completely to determine the total calories in a food sample. Foods are never completely oxidized in metabolism, therefore these values are actually higher than normal physiologic values.

False

The BMR is the minimal energy expenditure assessed rest following a fast.

False

The greatest source of heat is from skeletal muscle contraction, which is brought about by the hypothalamus in response to temperature receptors.

True

A positive energy balance occurs when the intake of calories exceeds the output. The excess nutrients are converted to fats stored in tissues such as the liver and adipose.

True

Current research has indicated that in reality people live longer when their weights are slightly higher than those found in desired weight tables.

False

People are obese if the excess is due to body adipose. However, they are not obese if the excess is due to muscle hypertrophy such as in athletes.

True

Some forms of diet and exercise accomplish a weight reduction from loss of body water. Since the amount of adipose tissue remains the same, the person quickly returns to the original obese condition.

True

Vitamins, especially the fat soluble, must be obtained at optimal levels. Maximal and minimal amounts will cause physiologic alterations.

True

Intestinal organisms produce vitamin K, which is needed to clot properly. All infants are sterile and must be given a supplement.

False

Biotin is most important in the reactions of amino acids, fatty acids, and nucleic acids.

False

Potassium is found in highest concentration within the cells because of the activity of the sodium-potassium membrane pump.

True

Scurvy causes bone, joint, and tooth abnormalities that manifest as bleeding gums and painful joints.

A) Carbohydrates

Most of the energy used by the cells is obtained from the oxidation of glucose which is derived from larger carbohydrates.

D) Glycogen

All of these are complex carbohydrates, but glycogen is produced by animal sources and is the only one among these that is digestible by humans.

A) Glucose

Glucose is the monosaccharide that enters the cell and becomes oxidized. The others sugars must be converted to glucose.

A) Ribose

The pentoses ribose and deoxyribose are components of the nucleotides that do not enter the oxidation route but are used form macromolecules such as DNA and RNA.

A) Nervous

Nervous tissue, especially the brain, cannot store carbohydrates and must receive a constant supply of glucose.

Skeletal muscle and liver are the main producers of glycogen, whereas cardiac muscle can store some glucose as glycogen.

B) 125

Estimates are around 100-125 grams of carbohydrates are required daily to prevent protein breakdown. Amounts over 300 grams are probably excessive and can become converted to fats.

D) Triglycerides

Of the lipids, the triglycerides are normally used for energy. Cholesterol is the precursor for steroid hormones, and along with phospholipids, is never burnt for energy.

C) Egg yolk

Of those listed, egg yolk has the highest amount of cholesterol. Cholesterol is not found in plant sources but is synthesized by animal tissues.

D) Cholesterol

Certain fatty acids such as linoleum acid cannot be synthesized in the liver and are called essential because they must be supplied in the diet. The liver plays an active role in cholesterol biosynthesis.

D) Triglycerides

Triglycerides are hydrolyzed by the liver and intestines into three fatty acids and a molecule of glycerol.

B) Under 30

The American Heart Association recommends less than 30% fat to reduce the risk of coronary disease, along with a preference of unsaturated over saturated fats.

C) Triglycerides

Tryglycerides provide the fatty acids and glycerol that can be used in the synthesis of other lipids.

D) 10

There are 8 essential amino acids required for adults and 10 for children. There are 20 amino acids that are used to build human proteins.

C) Alanine

The 8 essential adult amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Alanine can be converted from other compounds.

B) Histidine

There are two essential amino acids that must be supplied to growing children because their livers have not yet attained the capability to manufacture them on demand.

C) Corn

Milk and fish are excellent sources of complete proteins. Foods such as corn are incomplete because the zein, a protamine protein in them lacks tryptophan and lysine.

B) Utilization for energy

The main source of energy is from carbohydrates but proteins and lipids are oxidized for some daily energy. It is more important the proteins become cell structures an enzymes.

C) Cortisol

Some hormones are protein or amino acid derivatives, but steroid is a steroid related to the lipid cholesterol.

A) Protein

Nutritional edema refers to the increase in tissue fluids due to the lower blood osmotic pressure caused by blood protein deficiencies. Proteins are active osmotic molecules which remain within the capillaries.

D) 100 calories

The calorie is the amount of energy needed to raise 1 gram of water by 1 degree Celsius.

C) 10 gram cheese

Theoretically, fats yield 9.5 calories per gram while carbohydrates and proteins each yield 4.1 calories per gram. Therefore 10 grams of cheese would have the greatest amount of fat calories.

A) Kilogram

Although body requirements vary greatly among the variables of age, sex, lifestyle, and hormone levels, 1 calorie per kilogram per hour is a reasonable estimate.

C) Oxygen consumption

Since most energy reactions use oxygen and convert it to water, the consumption of oxygen would closely correlate with the total amount of energy being produced.

B) Thyroxine levels

Thyroxine (T4) is the most potent hormone which stimulates general cell metabolism. Females and genetically larger individuals have lower metabolic rates, females probably because of a reduced muscle mass and large persons because of their heat retention. Lower body temperatures directly correlates with lower metabolism.

B) Walking up stairs

Studies show that the stress used in walking up stairs uses more calories than running on a flat surface, partially because of the kinetics involved in the resistance of gravity.

A) 110

Studies estimate that her desired weight should be from 110-113 pounds.

A) 21%

The criterion for obesity is over 20% in excess of desired weight. Overweight has the criteria of 10%-20% over their weight.

B) B

Because of their structures, vitamins A, D, E, and K are fat-soluble, whereas vitamins B and C (polar molecules) are water-soluble.

B) Carrots

Vitamin A is only found in animal cells. Its precursor beta-carotene is found in vegetables and fruits.

B) Rhodopsin

Vitamin A is converted into compounds necessary for vision such as retinol pigment rhodopsin or visual purple. Beta-carotene converts into vitamin A in the liver. Bile salts and cholesterol are chemically unrelated to vitamin A.

C) Light

Vitamin A is relatively stable under varying pH changes and food preparation, but is unstable under sunlight and oxidizing conditions.

A) Kidney

The kidney converts hydroxycholecalciferol to dihydroxycholecalciferol by the enzyme alpha-hydroxylase.

B) Fortified milk

To fortify means to add a nutrient; enriched means to partially replace a nutrient lost in processing, and steroids are only animal compounds.

C) Bone growth

Since vitamin D is needed to allow calcium mobilization, the most obvious disease might be rickets or soft, deformed bones.

D) Alpha-tocopherol

The most active form of vitamin E is alpha tocopherol which can prevent the oxidation of compounds such as vitamin A.

A) K

Vitamin K (phytonadione or phylloquinone) is needed to synthesize the prothrombin by the liver, needed for blood clotting.

C) Spinach

Green leafy vegetables are the best sources of vitamin K.

C) Phylloquinone

Phylloquinone (phytomenadione) is vitamin K1.

C) B-complex

The most significant enzyme co-factors that are required for oxidation and energy production are found in the B vitamins.

A) B1(Thiamine)

All enzymes require a vitamin as part of their coenzyme activators. Thiamine is needed to oxidize carbohydrates.

D) Thiamine

Since thiamine is needed to oxidize alcohol, alcoholics require more than the average amounts of thiamine.

C) Riboflavin

Riboflavin (vitamin B2) is part of flavoadenine dinucleotide (FAD).

C) B3 (Niacin)

Niacin (nicotinic acid) is found in plants and niacinamide is the animal form. Humans can synthesize niacin from tryptophan.

D) Niacin

Niacin is part of nicotinamide adenine dinucleotide (NAD) or  coenzyme I, and of nicotinamide adenine dinucleotide phosphate (NADP) or coenzyme II.

D) Pellagra

Pellagra is a deficiency resulting in skin, digestive and neurological impairments. Beriberi results from thiamine deficiency.

A) B6

Vitamin B6 is called pyridoxine, pyridoxal, or pyridoxamine.

A) Pantothenic acid (vitamin B5)

 Pantothenic acid is absolutely essential because it is part of acetyl-coenzyme-A which enters the citric acid or Kreb's cycle.

C) B12

Vitamin B12 (cyanocobalamin) is essential for the production of red blood cells. Its absorption is facilitated by gastric intrinsic factor.

D) Collagen

Vitamin C (ascorbic acid) is required for the production of the collagen fibers in skin, bone and other tissues.

B) Glucose

Vitamins are distinct and do not belong to any typical chemical group, but ascorbic acid is remarkably similar to glucose but does not arise from it apparently.

A) Phosphate

Because of their presence in bone and other tissues, calcium phosphate salts comprise about 75% of the minerals in the body.

D) All of these

Phosphate is essential for cell structures, nerve conductivity, genetics, energy, and pH buffering as well as other functions.

B) Sulfur

All amino acids contain carbon, hydrogen, oxygen, and nitrogen, but only two also contain sulfur, methionine and cysteine.

B) Sodium

Of the positive ions, sodium is pumped out of cells by the sodium-potassium pump. Blood levels are maintained by the action of aldosterone on the kidneys.

B) Iron

Iron is the nucleus of the hemoglobin pigment in red blood cells that binds to oxygen.

C) Cu

Copper is required for red blood cell functioning, bone, melanin, and nerve functions although it is required in only small amounts.

C) Fungiform papillae

With the exception of the filiform papillae, these types of papillae contain taste buds and are known as the gustatory papillae. Meanwhile, the circumvallate (vallate) and foliate papillae contain gustatory corpuscles on there lateral side.

A) Filiform papillae

Unlike the other kinds of papillae, filiform papillae do not contain taste buds. Instead, they are responsible for giving the tongue its texture and are responsible for the sensation of touch.

C) Vallate papillae

B) Gustatory glands

D) Vallate papillae

A) Filiform papillae

Filiform papillae are the most numerous of the lingual papillae. They are fine, small, cone-shaped papillae covering most of the anterior two-thirds of the dorsum of the tongue.

B) Nonkeratinized stratified squamous epithelium

D) Epiglottis vallecula

C) Median sulcus of tongue

D) Elastic cartilage

D) Serous glands

The von Ebner glands, also known as serous glands, are minor salivary glands located on both sides of your oral cavity toward the back of your tongue. Part of their role is to secrete lipase and amylase, which are digestive enzymes that start to break down food as you chew.

D) Fungiform papillae

A) Vallate papillae

D) Foliate papillae

D) Pseudostratified columnar epithelium with kinocilia

D) Foliate papillae

C) Dense irregular connective tissue

B) Intercalated duct and serous acinus

A) Adipocyte

D) Myoepithelial cells

D) Serous

A) Facial nerve

The facial nerve (cranial nerve VII) gives rise to five terminal branches within the parotid gland.

B) Masseter muscle

The superficial part of the parotid gland covers the posterior part of the masseter muscle.

D) Interlobular duct

A) Zymogen granules

A) Striated duct

D) Connective tissue septum

B) Interlobular duct

B) Simple columnar epithelium

A) Intercalated ducts

D) Myoepithelial cells

C) Intercalated duct

C) Connective tissue septum

A) Serous demilune

Serous demilunes are also known as Crescents of Giannuzzi or Demilunes of Heidenhain.

D) Mucous acinus

Mucous cells stain very poorly because they contain little rough endoplasmic reticulum and their mucin granules tend to react poorly with most stains.

D) Mucous

A) Simple cuboidal epithelium

C) Sublingual caruncle

The sublingual caruncle is a site on either side of the frenulum linguae on the sublingual surface of the tongue. There it denotes the site at which the submandibular gland and the sublingual gland empty into the oral cavity.

A) Interlobular duct

B) Zymogen granules

A) Lingual frenulum

A) Seromucous (mixed)

C) Stratified cuboidal epithelium

A) Intercalated duct

B) Serous demilune

Serous demilunes, also known as Crescents of Giannuzzi or Demilunes of Heidenhain.

B) Interlobular duct

B) Submucosa

D) Thoracic part of esophagus

The esophagus is anatomically divided into three parts: cervical, thoracic, and abdominal.

B) Mucous

The mucin secreted by the mucous glands in the esophagus aids in lubrication, as well as in neutralization of the acidic gastric juices at the esophagoscope-gastric junction.

A) Diaphragm

The esophageal hiatus is the opening in the diaphragm through which the esophagus passes from the thoracic to abdominal cavity. It is one of three apertures in the diaphragm and is located in the right crus.

D) Myenteric plexus

Myenteric plexus is also known as Auerbach's plexus.

Hassal's corpuscles are found in the medulla of the thymus.

A) Cervical part of esophagus

The esophagus is anatomically divided into three parts: cervical, thoracic, and abdominal.

B) Loose connective tissue

B) Adventitia

C) Stomach

Barrett's esophagus is a condition in which the flat pink lining of the esophagus becomes damaged by acid reflux, which causes the lining to thicken and become red.

D) Nonkeratinized stratified squamous epithelium

D) Loose connective tissue

A) Pharynx and stomach

D) Smooth and skeletal muscles

C) Meissner's plexus

Meissner's plexus is also known as submucosal plexus.

D) Cardial orifice of esophagus

A) Zymogen granules

A) Gastric gland (proper)

C) Parietal cells

Parietal cells are also known as oxyntic cells.

B) Simple squamous epithelium

C) Simple squamous epithelium

A) Chief cells

Chief cells are also known as peptic cells.

Paneth cells are highly specialized secretory epithelial cells located in the small intestinal crypts of Lieberkühn.

Oxyphil cells are located in the parathyroid gland.

C) Gastric pits

B) Cardia and pylorus of stomach

B) Gastric pits

A) Fundus and body of stomach

B) Gastric folds

A) Enteroendocrine and mucous neck cells

C) Parietal and chief cells

Parietal cells are also known as oxyntic cells, whereas chief cells are also known as peptic cells.

C) Muscular coat

Auerbach's plexus is also known as myenteric plexus.

C) Lamina propria

B) Submucosa

Meissner's plexus is also known as submucosal plexus.

B) Simple columnar epithelium

A) Parietal cells

Parietal cells are also known as oxyntic cells.

B) Centroacinar cells

C) Serous acinus

B) Centroacinar cells

B) Fenestrated capillaries

D) Serous

B) Beta cels

A) Zymogen granules

D) Alpha cells

B) Reticular fibers

C) Duodenum

C) Beta cells

Hofbauer cells are macrophages found in the placenta.

C) Pancreatic acinar cells

A) Pancreatic islets (of Langerhans)

B) Duct cells

B) Intestinal crypt (of Lieberkuhn)

D) Paneth cell

C) Lacteal

D) Goblet cell

Mucous neck cells are found in the stomach.

A) Microvilli

C) Gland of Brunner

Gland of Brunner is also known as duodenal submucosal gland.

D) Gland of Brunner

B) Circular folds (of Kerckring)

The circular folds (of Kerckring), which is also known as plicae circulares, are most prominent in the distal duodenum and jejunum.

D) Auerbach's plexus

Auerbach's plexus is also known as myenteric plexus.

B) Enteroendocrine cell

C) Muscular coat

B) Enterocyte

C) Villi

B) Parietal cell

C) Gland of Brunner

Gland of Brunner is also known as duodenal submucosal gland.

B) Simple columnar epithelium

D) Submucosa

Meissner's plexus is also known as submucosal plexus.

B) Goblet cell

A) Enterocytes

A) Simple squamous epithelium

B) Teniae coli

The contractions of teniae coli facilitate the peristaltic action of the large intestine, propelling the fecal matter and forming the haus

B) Goblet cell

Mucous neck cells are found in the stomach.

A) Keratinized stratified squamous epithelium

A) Auerbach's plexus


Auerbach's plexus is also known as myenteric plexus.

D) Haustra

C) Submucosa

A) Simple squamous epithelium

A) Outer longitudinal layer of muscular coat

B) Paneth cells

Paneth cells are found in the small intestine.

A) Intestinal crypt (of Lieberkuhn)

B) Simple columnar epithelium with microvilli

B) Peyer's patches

D) Peyer's patches

A) Goblet cells

B) Has a wrinkled surface, forming rugae

The mucosa has a wrinkled surface, forming rugae that can help the stomach to expand during distension. It is made up of simple columnar epithelium covered in an alkaline mucous layer. 

The submucosa is made up of loose connective tissue and contains blood vessels and nerves. 

The middle circular layer of muscle is arranged concentrically around the stomach and forms the pyloric sphincter. 

The external longitudinal layer is only found at the two curvatures, and functions to contract and shorten the stomach during gastric peristalsis. 

The serosa is the layer that is made up of visceral peritoneum.

C) Fibrous capsule of the liver

A) Kupffer cells

Kupffer cells are also known as stellate macrophages.

D) Satellite cells

Satellite cells are found in the ganglia of peripheral nervous system.

A) Liver acinus

C) Inferior vena cava

B) Hepatic stellate cells

C) Central vein

D) Lysosomes

B) Bile canaliculus

D) Fibrous capsule of liver

B) Discontinuous

Discontinuous capillaries have discontinuous endothelium that serves as a location for mixing of the oxygen-rich blood from the hepatic artery and the nutrient-rich blood from the portal vein.

A) Hepatic lobule

D) Simple cuboidal epithelium

A) Rough endoplasmic reticulum

D) Hepatocytes

B) Smooth endoplasmic reticulum and peroxisome

C) Space of Disse

Space of Disse is also known as perisinusoidal space, whereas space of Mall is also known as periportal space.

D) Hepatic sinusoids

B) Central vein

C) Hepatic plexus

A) Interlobular artery

E) Hepatic stellate cells

D) Connective tissue septum

A) Loose connective tissue

B) Hepatic cord

D) Space of Mall

Space of Mall is also known as periportal space.

B) Interlobular vein

A) Smooth endoplasmic reticulum

C) Hepatic stellate cells

A) Sublobular vein

A) Smooth muscle

B) Mesothelium

A) Serosa

• The layers of the stomach wall, from internal to external can be remembered using M.S.M.S: 
• Mucosa
• Submucosa
• Muscularis externa
• Serosa

The muscularis mucosa is the innermost layer of the mucosa, after the epithelium and lamina propria.

B) Pylorus

The pylorus contains the pyloric glands that secrete gastrin. 

In the body and fundus of the stomach exist the gastric glands that secrete HCl and intrinsic factor. 

The glands that secrete mucous are called the cardiac glands and exist at the cardia. 

The esophagus contains mucous secreting glands.

C) Inner oblique layer

The stomach's muscularis externa is made up of the inner oblique layer, middle circular layer, and external longitudinal layer. The duodenum's muscularis externa is made up of the inner circular layer and outer longitudinal layer.

Therefore, the inner oblique muscle layer is unique to the stomach and is not found in the duodenum.

The circular layer and longitudinal layer are found in both the duodenum and the stomach. 

The transverse layer and outer oblique layer are not related to either the stomach or the duodenum.

D) Made of visceral peritoneum

The serosa layer is made up of visceral peritoneum.

The inner oblique layer of muscle is the innermost layer of the muscularis externa. It is located throughout the whole stomach and works with the other muscles for gastric peristalsis. 

The middle circular layer of muscle is arranged concentrically around the stomach and forms the pyloric sphincter. 

The submucosa is made up of loose connective tissue and contains blood vessels and nerves. 

The mucosa has a wrinkled surface, forming rugae that can help the stomach to expand during distension. It is made up of simple columnar epithelium covered in an alkaline mucous layer.

C) Simple columnar epithelium

Simple columnar epithelium lines the stomach wall.

Transitional epithelium is found in the bladder and ureters.

Simple squamous epithelium is found in capillaries, alveoli and glomeruli. 

Simple cuboidal epithelium is found on the surface of ovaries and the lining of nephrons and renal tubules.

Stratified squamous epithelium is found on the upper surface of the tongue and hard palate, as well as the esophagus.

B) Innermost layer of the muscular externa

The inner oblique layer of muscle is the innermost layer of the muscularis externa. It is located throughout the whole stomach and works with the other muscles for gastric peristalsis. 

The middle circular layer of muscle is arranged concentrically around the stomach and forms the pyloric sphincter. 

The submucosa is made up of loose connective tissue and contains blood vessels and nerves. 

The mucosa has a wrinkled surface, forming rugae that can help the stomach to expand during distension. It is made up of simple columnar epithelium covered in an alkaline mucous layer. 

The external longitudinal layer is only found at the two curvatures, and functions to contract and shorten the stomach during gastric peristalsis.

B) Stratified squamous epithelium

Stratified squamous epithelium lines the esophagus in health.

Simple columnar epithelium lines the stomach.

Transitional epithelium is found in the bladder and ureters.

Simple squamous epithelium is found in capillaries, alveoli and glomeruli. 

Simple cuboidal epithelium is found on the surface of ovaries and the lining of nephrons and renal tubules.

A) Cardia

The glands that secrete mucous are called the cardiac glands and exist at the cardia. 

In the fundus and body of the stomach exist the gastric glands that secrete HCl and intrinsic factor. 

The pyloric canal and pyloric antrum contain the pyloric glands that secrete gastrin.

E) Diet and lifestyle advice

The most likely diagnosis for this patient is irritable bowel syndrome (IBS), a functional disorder of the bowel causing abdominal pain, bloating and change in bowel habit. It is a diagnosis of exclusion. In this case, other differential diagnoses have been excluded (negative anti-TTG excludes coeliac disease, low faecal calprotectin and inflammatory markers make IBD unlikely).

The correct answer to this question is dietary and lifestyle advice, as this is the first-line treatment for IBS.

• Key elements of this include:
• Increased physical activity
• Increased water consumption
• Reduced caffeine, alcohol and fizzy drinks
• Review fibre intake

Appropriate drug management options for IBS treatment would include, antispasmodic drugs such as mebeverine hydrochloride and peppermint oil. Loperamide hydrochloride would also be appropriate for this patient to relieve her diarrhoea.

The other answers are not appropriate in this patient.

Linaclotide is a medication given to patients with IBS, who have had constipation for at least 12 months, having not responded to laxatives from the different classes. In this particular patient, this would not be appropriate, as she has not complained of constipation.

A gluten-free diet is key in the management of coeliac disease. This diagnosis would be made if the patient had positive anti-TTG antibodies. A gluten-free diet is not used in the management of IBS.

Mesalazine is a type of aminosalicylate. It is typically given as a suppository in the management of IBD (particularly ulcerative colitis). In IBD you would expect to see raised inflammatory markers, and raised faecal calprotectin.

Surgical removal of ovarian carcinoma is not appropriate. Ovarian cancer should be considered in the differential diagnosis, particularly in a patient of this age, presenting with bloating and abdominal pain. However, the patient has already had her ovaries removed, which rules out this diagnosis, and therefore this management plan is not appropriate.

A) Haemorrhoids

The most likely diagnosis is internal haemorrhoids given the history of painless rectal bleeding that is bright red in colour and not mixed within the stool. In addition, he has no systemic features to suggest malignancy or inflammatory bowel disease such as changes in bowel habit, abdominal pain, reduced appetite or weight loss. Internal haemorrhoids are abnormally enlarged vascular cushions that are located within the anal canal above the dentate line and are therefore not externally visible. In addition, they are painless unless they become thrombosed. In comparison, external haemorrhoids are located below the dentate line and are externally visible. They also have sensory innervation, meaning they often cause itching and pain. Management of haemorrhoids initially involves increased fibre intake, laxatives and simple analgesia. If they remain problematic they may require band ligation, injection sclerotherapy or haemorrhoidectomy. 

Anal cancer typically presents with perianal pain, bleeding, faecal incontinence, weight loss and a palpable mass on rectal examination. 

Proctitis involves inflammation of the anus and lining of the rectum. It typically presents with anal discomfort, tenesmus and bleeding. The patient's symptoms and examination findings in this scenario would not fit with this diagnosis.

Ulcerative colitis is a chronic inflammatory disease of the colon driven by an autoimmune process. It typically presents with bloody diarrhoea with other associated features including colicky abdominal pain, tenesmus, malaise and weight loss. These symptoms are not in keeping with the above scenario.

Anal fissures typically present with pain on defecation with associated bright red bleeding on the surface of stools and on toilet paper. Anal fissures are commonly caused by constipation, so asking about the patient's recent bowel habit is important. Rectal examination usually reveals a linear split on the anal mucosa on inspection, however, the examination can sometimes be difficult due to pain induced anal spasm. The absence of pain and a normal rectal examination in this scenario rules out this diagnosis.

D) Rovsing's sign

This is Rovsing's sign where palpation of LIF causes pain in RIF. It indicates appendicitis. Other symptoms of appendicitis include dull, poorly localised periumbilical pain that moves to RIF and becomes sharp, as well as anorexia, nausea, vomiting, and constipation.

Psoas sign (RIF pain with extension of the right hip or with flexion of the right hip against resistance), guarding, rebound tenderness, and percussion pain may also be present on examination - particularly at McBurney's point (located one third of the distance from the right anterior superior iliac spine to the umbilicus).

Kernig's sign: Severe stiffness of the hamstrings causes pain or an inability to straighten the leg (extend knee) when the hip is flexed to 90 degrees. It is indicative of meningitis or subarachnoid haemorrhage.

Murphy's sign: Palpate the right subcostal area while the patient takes in and holds a deep breath. If the pain occurs on inspiration, when the inflamed gallbladder comes into contact with the examiner's hand, Murphy's sign is positive. It is indicative of acute cholecystitis.

Psoas sign: Have the patient lie on their left side while their right hip is extended backward with their leg straight. Pain on passive extension may indicate an inflamed appendix overlying the psoas muscle. This is indicative of appendicitis.

Brudzinki's sign: Severe neck stiffness causes a patient's hips and knees to flex when the neck is passively flexed with the patient lying supine. This is an involuntary reaction to lessen the stretch on the inflamed meninges and so is indicative of meningitis.

A) Granulomata on histopathology

Presence of granulomata on histopathological analysis is pathognomonic of Crohn's disease.

Bloody diarrhea is a key part of the ulcerative colitis presentation.

Erythema nodosum can be seen generally in inflammatory bowel disease (IBD) - i.e. in both Crohn's disease and ulcerative colitis.

Pyoderma gangrenosum can be seen in both Crohn's disease and ulcerative colitis, and indeed is more common in the latter group.

Elevated faecal calprotectin levels following stool sample analysis indicate inflammation of the bowel (with a concomitant abundance of neutrophils in the intestinal mucosa and lumen) - this would, therefore, indicate diseases such as Crohn's, UC and coeliac disease, but could not be used to differentiate between them.

B) Acute viral hepatitis

This patient presents with stigmata suggestive of acute viral hepatitis -- as evidenced by the right upper quadrant tenderness, jaundice, deranged LFTs (specifically, the markedly elevated transaminases AST & ALT), and pyrexia.

• The other options are incorrect as follows:
• It is unlikely that the patient is presenting with an obstructive liver injury caused by a cholangiocarcinoma -- as this would lead to elevation of GGT and ALP in this patient, rather than elevated transaminases
• Alcoholic fatty liver disease (AFLD) is insidious with respect to onset and will present with vague, generalized symptoms - rather than the acute presentation in this patient. In addition, the AST and ALT will be elevated to a level some 8 - 10 times higher than the upper limit of normal in AFLD - rather than the some 25 times the upper limit of normal you see in acute viral hepatitis.
• In order to suspect Budd-Chiari syndrome (BCS), a patient needs to present with a classic tetrad - namely: abdominal pain, ascites, liver enlargement, and splenomegaly. This patient was not found to have ascites, nor did he have a palpable spleen. In addition the patient would need to be in somewhat of a hypercoagulable state to rule in primary BCS (as it is caused by hepatic vein thrombi) - and this patient has evident synthetic liver dysfunction (as evidence by hypoalbuminaemia) thus leading to his ecchymoses (failure of the liver to synthesis clotting factors).

C) Somatostatin

The are a number of ways in which acid production can be decreased in the stomach. One of which is via accumulation of acid in the empty stomach between meals. This increase in acid leads to a lower pH within the stomach, which inhibits the secretion of gastrin, via the production of somatostatin from D cells.

A) Foveolar cells

Gastric mucus is a gel-mucous barrier secreted by epithelial cells and glandular cells in the stomach wall. It acts as part of a barrier that protects the stomach wall from the acid and digestive enzymes within the stomach lumen.This barrier is also made up of a bicarbonate secretion and the epithelial cells.

Mucus is secreted by the stomach epithelial cells, but the mucus is mainly secreted from foveolar cells, found in the necks of the gastric pits. Mucus-secreting cells are the most abundant cell type in the stomach, giving indications of how important mucus is to the functioning stomach.

C) Sucrose

True

A) Enterochromaffin-like cell

Enterochromaffin-like cells can be stimulated by either gastrin (from adjacent G-cells in the stomach) or acetylcholine (from autonomic nerves) to release histamine. Histamine stimulates the gastric parietal cells to secrete acid.

Chief cells, are cells located in the stomach that secrete pepsinogen. Pepsinogen is a precursor to pepsin, which is an important proteolytic enzyme in digestion.

K-cells are cells in the duodenum/stomach that secrete gastric inhibitory peptide (GIP). GIP is a weak inhibitor of stomach acid secretion, but its more important role is to stimulate insulin secretion

Delta cells of the pancreatic islets and D-cells in the stomach both secrete somatostatin, which is the most important inhibitor of gastric secretion.

A) G cells

The main regulation pathway of acid production involves the hormone gastrin which is secreted from G cells in the stomach. G cells are activated by the vagus nerve and gastrin related peptide.

Activation of the G cells leads to the production of gastrin which is released into the blood and travels through the blood until it reaches the parietal cells. Gastrin binds to CCK receptors on the parietal cells which also elevates calcium levels causing increased vesicular fusion.

C) Alkaline

• The role of saliva is varied but includes:
•      1. Keeping mucosa moist
•      2. Lubrication of wet food
•      3. Washing teeth
•      4. Maintaining an alkaline environment - contains bicarbonate which helps with this
•      5. Contains a high concentration of calcium
•      6. Starts digestion of carbohydrates

B) Parietal cells

To begin with, water (H2O) and carbon dioxide (CO2) combine within the parietal cell cytoplasm to produce carbonic acid (H2CO3).  An enzyme called carbonic anhydrase converts carbonic acid into its component ions a hydrogen ion (H+) and a bicarbonate ion (HCO3–).

The bicarbonate ion is transported out of the cell into the blood via a transporter protein called anion exchanger which transports the bicarbonate ion out the cell in exchange for a chloride ion (Cl–). This chloride ion is then transported into the stomach lumen via a chloride channel.

Prior to this, the hydrogen ion that was formed via the splitting of carbonic acid is transported into the stomach lumen via the H+– K+ ATPase. This channel uses ATP energy to exchange potassium ions in the stomach with hydrogen ions in the parietal cell.

This results in both hydrogen and chloride ions being present within the stomach lumen which form hydrochloric acid.

C) Liver

Liver is the primary organ of the urea cycle. It converts toxic ammonia to urea through amino acid catabolism. 

Kidneys also carry out urea cycle but to a much lesser extent. Urea produced by the liver is filtered and eventually excreted by the kidneys.

Spleen is primarily a filtering organ for red blood cells and secondarily a lymphoid organ, which acts similar to a large lymph node.

Pancreas is an endocrine (secretes insulin and glucagon) or exocrine (secretes digestive enzymes) organ.

D) 10%

Digestion of lipids Is started by lingual and gastric lipases, but this only digests 10% of ingested lipids.

The remainder of the lipids are digested in the small intestine where bile aids digestion by emulsifying the fat goblets into micelles, which have a much larger surface area.

Pancreatic lipase, phospholipase A2 and cholesterol ester hydrolase (3 major enzymes involved in lipid digestion) hydrolyse the micelles, breaking them down into fatty acids, monoglycerides, cholesterol and lysolecithin.

D) Only the second statement is true.

Cholecystokinin is released by the small intestine in response to the presence of fatty acids in its lumen.

E) Release of serotonin

Enterochromaffin cells are mechanically stimulated by the presence of chyme in the small intestine. They release serotonin, which acts on the enteric nervous system to activate the cystic fibrosis transmembrane regulators (CFTR). This ion channel secretes Cl–ions into the intestinal lumen, with Na+ ions and H2O following. Na+ is required in the lumen for the absorption of a number of nutrients.

A) Pepsin

Protein digestion begins in the stomach with the action of pepsin, which breaks protein into amino acids and oligopeptides.

The process of digestion is completed in the small intestine with brush border and pancreatic enzymes. They split the oligopeptides into amino acids, dipeptides and tripeptides.

E) Vagus nerve

Increasing acid production can be via acetylcholine (ACh), which is released from the vagus nerve.

First released during cephalic phase of digestion, which is activated upon seeing or chewing food, leading to direct stimulation of parietal cells via the vagus nerve.

It is also produced during the gastric phase of digestion when intrinsic nerves detect distension of the stomach, stimulating the production of ACh by the vagus nerve.

B) H+/K+ ATPase

At rest, the number of H+– K+ ATPases present within the parietal cell membrane is minimal. The rest are sequestered within tubulovesicles in the parietal cell.

Upon stimulation, the vesicles fuse with the cell membrane which leads to the increased insertion of H+– K+ ATPase into the membrane.

This leads to increased movement of hydrogen ions into the stomach thus increasing acid production.

E) 1.5-3.5

The stomach is a gastrointestinal organ that is responsible for preliminary digestion and destroying any potential pathogenic microorganisms that may have been ingested.

It is an acidic environment with a pH that can vary between 1.5-3.5.

HCl is produced by the parietal cells of the stomach.

C) Enterocytes

• The epithelium of the small intestine lines the luminal surface and contain:
•      1. Enterocytes – tall columnar cells, which have an absorptive function; contain brush border enzymes on the surface which have an important digestive function
•      2. Goblet cells – exocrine glands which secrete mucin
•      3. Crypts of Lieberkuhn - contain enteroendocrine cells to synthesize and secrete hormones
•      4. Paneth cells - secrete protective agents (such as defensins and lysozymes)
•      5. Peyer’s patches - found in ilium and contain mucosal-associated lymphatic tissue (MALT) which house white blood cells and lymphocytes

B) Secretin

Secretin is secreted by S cells in the duodenum in response to fatty acids and H+ ions. Secretin stimulates the secretion of biliary and pancreatic HCO3-, which results in neutralization of duodenal contents.

Acetylcholine is also capable of stimulating release of HCO3- through the pancreatic duct, however its action is arises through a neurocrine mechanism and not hormonal.

Somatostatin and GIP are inhibitors of stomach acid secretion, but they do not have important actions on the neutralization of duodenal contents.

Cholecystokinin (CCK) is secreted by I cells of the duodenal and jejunal mucosa, and its primary role is to promote fat digestion. Its main effects are stimulation of bile secretion and pancreatic enzyme secretion. It also does promote secretion of ductal HCO3-, but this effect is much weaker compared to that of secretin.

C) Esophageal phase

At the beginning of the esophageal phase, the larynx lowers, returning to its normal position. The cricopharyngeus muscle then contracts to prevent reflux and respiration begins again.

The bolus is moved down the esophagus via peristalsis, which is coordinated by extrinsic nerves. Each area of muscle systematically relaxes to allow food through and contracts afterwards to propel it further. The transit time to the stomach takes around 10-12 seconds.

B) Cholecystokinin

• In the small intestine, I Cells secrete Cholecystokinin (CCK) in response to the presence of fat in the small intestine. CCK stimulates the contraction of the gallbladder (which pushes bile out into the cystic duct) and the release of pancreatic enzymes.
• Both bile and pancreatic enzymes have a key role in lipid digestion.

Secretin is secreted by the S cells, while GIP is secreted by K cells.

B) The vagus nerve uses the dorsal complex to initiate peristalsis.

The vagovagal reflex uses the dorsal vagus complex in the brain to control the peristaltic contractions of the gastrointestinal tract. This reflex is activated when food enters the stomach causing an increase in gastric acid secretion via acetylcholine binding to M3 receptors (using the parasympathetic vagus nerve circuit).

E) SGLT1

Disaccharides occurring naturally in food do not require amylase to break them down.

Brush border enzymes (lactase, sucrase, trehalase) hydrolyze these compounds into molecules of glucose, galactose and fructose.

Glucose and galactose are absorbed across the apical membrane by active transport through the Sodium-Glucose cotransporter (SGLT1).

Both glucose and galactose exit the cell via GLUT2 receptors across the basolateral membrane into the blood.

Fructose enters the cell by facilitated diffusion via GLUT5 and is transported into the blood via GLUT2 receptors.

C) Enterochromaffin cells

The walls of the large intestine contain gastrointestinal lymphoid tissue (GALT) that contributes to the body’s immune defenses.

• The GALT is made up of:
•      1. Waldeyers tonsillar ring - lymphoid tissue in the pharynx, swelling of which causes tonsilitis
•      2. Peyer's patches - oval/round lymphoid follicles involved in immune surveillance of the gut
•      3. Microfold (M cells) - make up Peyer's patches; their role is to sample antigen and present to antigen-presenting cells
•      4. Paneth cells - located in the epithelium of the small intestine, their role is to secrete antimicrobial peptides and proteins such as toll-like receptors (TLRs) to kill pathogens.

Enterochromaffin cells are located in the crypts between intestinal villi, and their function is to release serotonin in the enteric nervous system, therefore they are not involved in GALT or immune function.

B) Voluntary phase

• In the voluntary phase:
•      - Mastication leads to a bolus of food produced
•      - During this stage, the back of the tongue is elevated and the soft palate pulled anteriorly against it.
•      - This keeps the food within the oral cavity and allows the airway to remain open. The duration of this stage varies.
•      - Following this, inspiration is inhibited and the bolus of food is moved to the pharynx by the tongue. This leads to the stimulation of the swallowing reflex.

D) Intrinsic factor

Intrinsic factor is the only essential (i.e. essential to life) secretion produced by parietal cells in the stomach. Intrinsic factor is a glycoprotein that allows the body to absorb vitamin B12.

Hydrochloric acid activates pepsinogen produced by the stomach into its active form called pepsin. Pepsin is then involved in proteolysis which promotes digestion.

Gastrin is a hormone produced by stomach g-cells that promote the production of hydrochloric acid by parietal cells.

Cholecystokinin is produced by cells of the upper small intestine.

E) Cholecystokinin

Bile serves an important role in lipid digestion and is secreted from the gallbladder into the common bile duct, in response to CCK.

Bile is made up of bile acids, cholesterol, phospholipids, bile pigments (such as bilirubin and biliverdin), electrolytes and water.

• These are split into two main groups, known as the bile acid-dependent and bile acid-independent components:
•      1. The bile acid-dependent component is produced by hepatocytes. The hepatocytes secrete bile acids, bile pigments and cholesterol into canaliculi, which are small channels that transport the bile acid-dependent portion towards the bile ducts.
•      2. The bile acid-independent component is made by the ductal cells that line the bile ducts. These cells secrete an alkaline solution – similar to the fluid made by pancreatic duct cells. The hormone secretin stimulates this secretion.

D) Urea

Urea is formed when the blood is digested into protein and absorbed into the portal system, this is then metabolised into urea.

B) Inflammatory infiltrate (predominantly macrophages, lymphocytes and plasma cells)

Inflammatory infiltrate, predominantly macrophages, lymphocytes and plasma cells, is characteristic of non-specific chronic inflammation. Of the listed options, this is the most likely finding in a chronic peptic ulcer.

Inflammatory infiltrate of predominantly neutrophils is characteristic of acute inflammation. Neutrophils may feature in chronic inflammation, but they do not predominate.

Epithelioid macrophages are is associated with granulomatous inflammation, which is a form of specific chronic inflammation. Peptic ulcer disease is not characterized by granulomatous inflammation. Multinucleate giant cells are also associated with granulomatous inflammation.

Eosinophils can feature in chronic inflammation, but they do not make up the majority of the inflammatory infiltrate. Eosinophilic infiltration is particularly associated with parasitic infections and allergies.