Finals MCQ

Question 1

1. A 45 year old, non-pregnant, woman with heartburn, presented to your clinic complaining of swollen breasts and a milky nipple discharge. She revealed that she has been taking an H2-receptor antagonist for the last 3-months. Which of the H2-receptor agonist would most likely be responsible for the side effects experienced by this patient?
   a. Ranitidine
   b. Famotidine
   c. Nizatidine
   d. Cimetidine

Answer 1

Ranitidine
NB: Other side effects: Headaches, drowsiness, confusion, insomnia, abdominal pain, alopecia, constipation, diarrhea, impotence, pancreatitis and pancytopenia.

Question 2

2. A patient was diagnosed with pancreatitis due to a reflux of bile into the pancreatic duct caused by a gallstone. The stone is likely to be lodged at the:
   a. Hepatopancreatic ampulla
   b. Cystic duct
   c. Common bile duct
   d. Common hepatic duct

Answer 2

Hepatopancreatic ampulla

NB: The hepatopancreatic ampulla is the very short segment of duct which represents the joining of the common bile duct and the main pancreatic duct. Once these two ducts form the hepatopancreatic ampulla in the wall of the duodenum, the bile and pancreatic enzymes are emptied into the second portion of the duodenum, through the major duodenal papilla. If a gallstone was stuck in the hepatopancreatic ampulla, bile could back up and flow backwards into the main pancreatic duct. If a stone was lodged in the cystic duct, common hepatic duct, or common bile duct, bile would never even reach the pancreas.

Question 3

3. During emergency surgery, it was found that a chronic gastric ulcer had perforated the posterior wall of the stomach and eroded a large artery running immediately posterior to the stomach. The artery is the:
   a. Gastroduodenal
   b. Splenic
   c. Left gastreopiploic
   d. Superior mesenteric

Answer 3

Splenic

Question 4

4. Mr. AB has been told he has a severe inflammation of his ileum. How might this intestinal inflammation affect the normal functioning of his gastrointestinal system? It is likely to:
   a. Increase absorption of its in B12
   b. Decrease the release of secretin
   c. Decrease the size of the bile acid pool
   d. Increase colonic absorption of water

Answer 4

Decrease the size of the bile acid pool
NB: Crohn’s disease is a chronic transmural IBD that affects the distal ileum and colon but may occur in any part of the gastrointestinal tract. Symptoms include diarrhea and abdominal pain and usually causes B12 deficiency.

Question 5

5. Which of the following enzyme is involved in the generation of ATP via substrate level phosphorylation?
   a. Alpha-key dehydrogenase
   b. Phosphofructokinase
   c. Maleate dehydrogenase
   d. Pyruvate kinase

Answer 5

Pyruvate kinase

NB: other substrate level enzymes include: succinylcholine-CoA synthetics e, Acetate Kinase and Phosphoglycerate kinase

Question 6

6. A 26-year old woman with a body mass index (BMI) of 27kg/m2 started eating a 800 calorie diet daily for 4 weeks leading up to carnival. By carnival she was happy she had lost 10 pounds and had obtained a BMI of 23kg/m2. Which one of the following best describes her case?
   a. Disordered eating
   b. Eating disorder
   c. Unintentional weight loss
   d. Anorexia nervosa

Answer 6

Disordered eating

NB: Disordered eating includes the full spectrum of eating-related problems from dieting to clinical Eds.

Question 7

7. What is the standard Gibbs free energy for the redox half reaction below, given that ΔE+ = 0.05V and F=96.5kJ/mol? Fumarate + 2H + 2e -> Succinate
   a. +9.65 kJ/mol
   b. +19.30kJ/mol
   c. -19.30kJ/mol
   d. -9.65kJ/mol

Answer 7

-9.65kJ/mol

NB: Use the equation ΔG= -nFΔE

Question 8

8. The ligamentum venous is a ruminant of which of the following structures?
   a. The umbilical artery
   b. The vitelline duct
   c. The ductus venosus
   d. The ductus arteriousus

Answer 8

The ductus venosus

Question 9

9. PK, the sixty-five-year-old CEO of a large business, has been using NSAIDs to treat his severe arthritis for the past six months. He develops heartburn and visits his doctor, who prescribed medication and advised him to modify his lifestyle. Three weeks later PK returned in a worse state. He reports having take the medication whenever he got pain, whole he continued drinking and smoking at social functions. His diagnosis of peptic ulcer disease was confirmed. What is the most likely cause of the CEO’s peptic ulcer disease?
   a. Excess alcohol consumption
   b. Cigarette smoking
   c. Zollinger-Ellison syndrome
   d. Non-steroidal anti-inflammatory drugs

Answer 9

Non-steroidal anti-inflammatory drugs

Question 10

10. Which one of the following statements regarding obesity based on adult waist circumference is correct?
    a. A Caucasian male with a waist circumference of 36 is not obese
    b. An African male with a waist circumference of 36 is obese
    c. A South Asian male with a waist circumference of 36 is not obese
    d. A South Asian female with a waist circumference of 33 is not obese.

Answer 10

A South Asian male with a waist circumference of 36 is not obese

Question 11

11. A young male is being investigated at hospital and shows increased basal and maximal acid outputs. He is also found decreased serum calcium level and microcytic anaemia. The doctor tells hm that a part of his gastrointestinal tract is inflamed and this is what accounts for his results. Given this information, which part of his gastrointestinal tract would you expect to be inflamed?
    a. Stomach
    b. Gall bladder
    c. Jejunum
    d. Duodenum

Answer 11

Duodenum

Question 12

12. Which of the following layer of digestive tract contains pyloric glands?
    a. Mucosa
    b. Submucosa
    c. Serosa
    d. Muscularis externa

Answer 12

Mucosa

Question 13

13. A first year medical student was studying hepatic blood flow and was unsure of certain aspects. While studying she wondered: in a normal, healthy human which of the following would obtain?
    a. A flow rate decreases with exercise
    b. venous blood contains all the absorbed products of digestion
    c. Total flow from the liver equates to about one third of the venous return to the heart
    d. Arterial and portal venous blood maintain discrete channels throughout the sinusoids

Answer 13

venous blood contains all the absorbed products of digestion

Question 14

14. A radiological examination of a patient revealed a large tumor in the quadrate lobe of the liver. During the surgical removal of the tumor, the blood vessel that needs to be clamped to effectively control bleeding is the:
    a. Gastroduodenal artery
    b. Left gastric artery
    c. Left hepatic artery
    d. Right hepatic artery

Answer 14

Left hepatic artery
NB: The left and right hepatic arteries help support the parenchyma and stroma of the liver. The left hepatic artery supplies the left & quadrate lobes of liver, and part of the caudate lobe. The right hepatic artery supplies the right lobe and part of the caudate lobe. So, the left hepatic artery must be clamped to perform surgery on the quadrate lobe.

Question 15

15. A patient with jaundice was diagnosed with cancer of the head of the pancreas. Which structure was compressed by the tumor?
    a. Common bile duct
    b. Common hepatic duct
    c. Cystic duct

Answer 15

Common bile duct
NB: Tumors in the head of the pancreas often obstruct the common bile duct, blocking the normal bile recycling circuit. This blockade prevents excretion of bilirubin, a yellow-colored pigment that is a red blood cell breakdown product. The accumulation of bilirubin in various tissues, including the skin, causes jaundice. A tumor in the head of the pancreas would not block the other ducts

Question 16

16. In a normal healthy human, approximately one litre of flatus is produced daily by the colon. What is responsible for the production of flatus?
    a. Bacterial fermentation of undigested food
    b. Results of the interaction between HCO3- and H+
    c. Accumulation of swallowed atmospheric air durning speech
    d. Diffusion of CO2 from the blood

Answer 16

Bacterial fermentation of undigested food

Question 17

17. During physiological herniation of the gut the intestinal loops herniate into which of the following embryonic cavity?
    a. Ammniotic cavity
    b. Intraembtyonic coelom
    c. Yolk sac
    d. Extraembryonic coelom

Answer 17

Extraembryonic coelom

Question 18

18. Which of the following is essential for the continuation of the TCA cycle?
    a. Lactate
    b. Oxaloacetate
    c. Glucose-6-phosphate
    d. Fructose-1-phosphate

Answer 18

Oxaloacetate

Question 19

19. Chronic malnutrition in children is indicated by a low:
    a. Head circumference
    b. BMI
    c. Hip circumference
    d. Height to age ratio

Answer 19

Height to age ratio

Question 20

20. A forty-year-old man presents with severe muscle cramps. Laboratory investigations show a deficiency of muscle glycogen phosphorylase. Which of the following diseases presents with this deficiency?
    a. Pompe’s disease
    b. Mcarde’s disease
    c. Von-Gierke’s disease
    d. Anderson’s disease

Answer 20

Mcarde’s disease
NB: Glycogen storage disease type V (also known as GSDV or McArdle disease) is an inherited disorder caused by an inability to break down a complex sugar called glycogen in muscle cells. A lack of glycogen breakdown interferes with the function of muscle cells.

Question 21

21. Rectouterine pouch:
    a. Can be approached through vagina to drain the abscess
    b. Contains coils of jejunum
    c. Is the lowest part of the peritoneal cavity in the supine position in females
    d. Is located anterior to the sigmoid colon

Answer 21

Is the lowest part of the peritoneal cavity in the supine position in females
NB: In women, the rectouterine pouch is the deepest point of the peritoneal cavity. It lies posterior to the uterus and anterior to the rectum.

Question 22

22. Which one of the following regarding obesity is correct?
    a. It cannot be diagnosed in someone with a BMI of 24kg/m2
    b. Surgery has no role in its treatment
    c. It has been on the decline since the 1990’s
    d. It affects at least 10% of the world’s population

Answer 22

cannot be diagnosed in someone with a BMI of 24kg/m2

Question 23

23. An 18-year-old girl is extremely conscious about her appearance and has gone through a full day of fasting to fit into a dress which she intentionally bought a size too small. During her fast the organ involved in contributing to gluconeogenesis is:
    a. Kidney
    b. Brain
    c. Spleen
    d. Liver

Answer 23

Liver
NB: In the fasted state, the liver secretes glucose through both breakdown of glycogen (glycogenolysis) and de novo glucose synthesis (gluconeogenesis). During pronged fasting, hepatic gluconeogenesis is the primary source of endogenous glucose production.

Question 24

24. ATP is considered the currency of energy in cells because:
    a. It has a ΔG° & gt; & gt; 0, when hydrolysed to ADP and Pi
    b. It provides 3 phosphates which are used to create energy in glycolysis
    c. Its intermediate ΔG° allows it to couple many reactions
    d. It has an energy-rich adenine base

Answer 24

Its intermediate ΔG° allows it to couple many reactions

Question 25

25. A 50-year-old-man, diagnosed with recurring gastric ulcers was prescribed triple therapy including omeprazole, amoxicillin and clarithromycin for weeks. The patient was refractory to this treatment and quadruple therapy was recommended. What drug would be added to this patient’s treatment? a. Ranitidine b. Aluminum hydroxide c. Bismuth subsalicylate d. Misoprostol

Answer 25

Bismuth subsalicylate NB: Quadruple therapy (proton pump inhibitor, tetracycline, metronidazole and a bismuth salt) is a very effective regimen even in areas of high prevalence of antibiotic resistance, and may be an alternative first-line treatment.

Question 26

26. A deep laceration of the face in the middle of the parotid gland could affect which of the following structures? a. Lingual artery b. Hypoglossal nerve c. Facial nerve d. External jugular vein

Answer 26

Facial nerve NB: The facial nerve travels through the parotid gland--it could become injured if there was a deep laceration through the parotid gland. Two other structures found within the parotid gland which might be damaged: the retromandibular vein and the external carotid artery. The nerve is the most superficial structure in the gland. Then, the vein is under the nerve, and the artery is the deepest structure in the gland. The external jugular vein is a superficial structure on the lateral neck, so it's not really close to the parotid gland. The glossopharyngeal nerve is closely related to the stylopharyngeus muscle--it sweeps along the back of this muscle. It is not related to the parotid gland. The hypoglossal nerve travels laterally to the carotid vessels and then enters the floor of the mouth. This means that it travels inferior to the region of the parotid gland. Finally, the lingual artery is found in the floor of the mouth--far from the parotid gland

Question 27

27. Ritva is 1.52m tall, weighs 62kg, has a waist circumference of 80cm and a height circumference of 100cm. Two hours after being fed 50g of glucose her blood level of glucose was 180mg/dl. On consuming 70g of bread that contained 50g of carbohydrate, Ritva’s blood level glucose was found to be 90mg/dl after hours. An HbA1c test score gave her a value of 10. A BMI calculation for Ritva shows that she is: a. Normal b. Obese c. Overweight d. Underweight

Answer 27

Overweight

Question 28

28. Concerning the electron transport chain: a. Rotenone allows electron transport but inhibits ATP synthesis b. Amobarbital inhibits complex I c. Oxygen is reduced to water at complex II d. Antimycin A inhibits complex IV

Answer 28

Amobarbital inhibits complex I

Question 29

29. Forty-five-year old Jayan, was a normal, healthy with an adult family who loved to exercise. She went to the gym every week day morning, and walked every evening after work. Lately she was feeling exceptionally tired, noticed that she was having trouble sleeping at nights, and often was awakened by cramps in her calf muscles and feet. She went to the doctor and after a detailed history and examination the doctor asked if she was experiencing nausea or vomiting recently, and if she stopped taking her multi-vitamin tablets. Jayan responded affirmatively to both. What is the most likely cause of all the symptoms Jayan was experiencing? a. Deficiency of magnesium b. Deficiency of calcium c. Deficiency of iron d. Deficiency of zinc

Answer 29

Deficiency of calcium

Question 30

30. As the bowel is exposed, the surgeon says in amazement, “This is a loop of large bowel”. Which characteristic would identify it specifically as a large bowel? a. A serosa b. Payer’s patches c. Appendices epiplociae d. Circular folds

Answer 30

Appendices epiplociae

Question 31

31. Favism is linked to a deficiency of: a. Gluconolactonate dehydrogenase b. Glucose-6-phosphate dehydrogenase c. 6-phosphogluconate dehydrogenase d. 6-gluconolactone transketolase

Answer 31

Glucose-6-phosphate dehydrogenase NB: Favism is a genetic disease that affects people with a deficiency in glucose-6-phosphate dehydrogenase (G-6-PD), an enzyme. This deficiency means that those affected must be vigilant and take care to avoid certain foods.

Question 32

32. Ritva is 1.52m tall, weighs 62kg, has a waist circumference of 80cm and a height circumference of 100cm. Two hours after being fed 50g of glucose her blood level of glucose was 180mg/dl. On consuming 70g of bread that contained 50g of carbohydrate, Ritva’s blood level glucose was found to be 90mg/dl after hours. An HbA1c test score gave her a value of 10. All of the following are true except: a. Her waist hip ratio is normal b. She is at risk of developing type 2 diabetes c. Her HbA1c test score is within the acceptable range d. Her dietary intake of glucose is excessive

Answer 32

Her HbA1c test score is within the acceptable range

Question 33

33. Concerning the electron transport chain: a. Complex II is at a higher redox potential than complex III b. The intermembrane space is at a high pH than the matrix c. FADH2 is the substrate for complex I d. CO-enzyme Q shuttles electrons between complex I and complex III

Answer 33

CO-enzyme Q shuttles electrons between complex I and complex III

Question 34

Glucose 6- phosphate: a. Cannot inhibit hexokinase b. Is an intermedia of the citric acid cycle c. Cannot pass through the cell membrane d. Can inhibit phosphofructokinase

Answer 34

Cannot pass through the cell membrane

Question 35

35. Glucose molecules are absorbed across the intestinal epithelium into the enterocyte. What is the mechanism of glucose absorption? Through: a. The apical membrane by facilitated diffusion and leave through the basal membrane by facilitated diffusion also b. The apical membrane by facilitated diffusion and leave the cell through the basal membrane by co-transport with Na+ c. Glucose channels in the apical membrane, and leave the cell through the basal membrane by facilitated diffusion d. The apical membrane by co-transport with Na+ and leave the cell through the basal membrane by facilitated diffusion.

Answer 35

The apical membrane by co-transport with Na+ and leave the cell through the basal membrane by facilitated diffusion.

Question 36

36. If PK from the previous question were to go untreated and not modify his lifestyle, the most likely consequence of his condition would be: a. Perforation b. Penetration into nearby viscera c. Severe blood loss from the ulcer (haemorrhage) d. Pyloric obstruction (gastric outlet obstruction)

Answer 36

Severe blood loss from the ulcer (haemorrhage)

Question 37

37. LE decides to fast for a week for religious reason. Which of the following is likely to occur? Her: a. Insulin secretion will increase b. Blood glucose level will not fall lower than 50mg/dl c. Brain will metabolize free fatty acids d. Muscles will catabolize proteins

Answer 37

Muscles will catabolize proteins

Question 38

38. Which of the following hormones stimulates the release of gastric fluid? a. Secretin b. Angiotensin II c. Glucagon d. Cholecystokinin

Answer 38

Secretin

Question 39

39. The reversible phase of the pentose phosphate pathway is vital to the synthesis of: a. Flavin adenine dinucleotide b. Linoleic acid c. Pyridoxine d. Phenylalnine

Answer 39

Linoleic acid

Question 40

40. Prior to a race, many marathon runners will try to increase their glycogen load by consuming foods with a high starch content, such as potato pie. They do this because ɑ-amylase secreted by the pancreas will digest the starch into: a. Maltose, glucose and fructose b. Maltose, glucose and limit dextrin c. Galactose, glucose and sucrose d. Amylose, fructose and glucose

Answer 40

Maltose, glucose and limit dextrin

Question 41

41. Incapacity to protrude the mandible indicates a dysfunction of which of the following muscle? a. Laterial pterygoid b. Temporalis c. Masseter d. Buccinator

Answer 41

Laterial pterygoid NB: The lateral pterygoid muscle protrudes the mandible--it pulls the mandible forward to allow for depression of the chin (which is mostly produced by gravity). None of the other muscles help with this function. The anterior belly of the digastric and mylohyoid have similar functions: they both help elevate the hyoid bone and depress the mandible. The buccinator is a muscle in the cheek; it pulls the corner of mouth laterally and presses the cheek against the teeth. Temporalis is important for retracting and elevating the mandible.

Question 42

42. A 32- year female patient complained of parotid pain that increased while eating. Intraoral examination detected some pus oozing from the parotid duct opening. What was the most likely anatomical reference that the physician considered to locate the parotid duct opening? a. Mucosa of the floor of the mouth along the sublingual fold b. Mucosa of the cheek across the 2nd upper molar tooth c. Mucosa of the cheek behind the central incisor tooth d. Mucosa of the cheek across the 2nd lower molar tooth

Answer 42

Mucosa of the cheek across the 2nd upper molar tooth NB: The parotid duct opens into the vestibule of the mouth, draining into the mucosa of the cheek near the second upper molar tooth. The duct drains the parotid gland across the masseter and through the cheek. It passes through the buccinator muscle, and pours saliva into the vestibule of the mouth. The sublingual caruncle is a small bump in the floor of the mouth, near the frenulum of the tongue. This is the site of the opening of the submandibular duct, which drains saliva from the submandibular gland. The mucosa along the sublingual fold contains many openings for the ducts coming from the sublingual gland.

Question 43

43. Which of the following enzymes is activated in response to high blood glucose a. Glucose 6-phosphatase b. Pyruvate carboxylase c. Fructose 2,6-bisphosphase d. Phosphofructokinase-2

Answer 43

d. Phosphofructokinase-2

Question 44

44. While examining radiographs and angiograms of a 52 year old patient, the physician is trying to distinguish the jejunum from the ileum. He has observed that the jejunum has: a. Shorter vasa recta b. More fat in its mesentery c. Fewer arterial arcades d. Fewer plicae circulares

Answer 44

Fewer arterial arcades

Question 45

45. The mobile element of the electron transport chain is cytochrome: a. b b. aa3 c. c d. bc1

Answer 45

bc1

Question 46

46. The pharyngeal tonsils or adenoids, may become inflamed and in serious cases need to be removed. Where would the physician search for them? a. In the tonsillar fossa b. In the piriform recess c. Upon the dorsal surface of the tongue d. In the roof of the nasopharynx

Answer 46

Upon the dorsal surface of the tongue NB: The pharyngeal tonsil is located on the roof of the nasopharynx. The pharyngeal recess is a space located posterior to the torus tubarius in nasopharynx. The tonsillar fossa is the space where the palatine tonsil is located--it is found between the palatoglossal fold and the palatopharyngeal fold. The piriform recess is a shallow depression located lateral to the aryepiglottic fold in the laryngopharynx. This is a common place where food can get stuck. The piriform recess is also significant because the internal branch of the superior laryngeal nerve is located immediately deep to the mucosa of this region--so, an injury here may damage this nerve! Finally, the lingual tonsil is found on the dorsal surface of the tongue.

Question 47

47. Which of the following promotes glycogenolysis through the activation of glycogen phosphorylase? a. Muscle calcium b. Insulin c. Glucose-6-P d. ATP

Answer 47

Muscle calcium

Question 48

48. Concerning regulation of the TCA cycle, which of the following does not inhibit the enzyme citrate synthase? a. NADH b. ADP c. Succincyl CoA d. ATP

Answer 48

ADP

Question 49

49. Concerning the intake of adequate amounts of fibre in our diets, all of the following are true except: a. It lowers the risk of colon cancer b. It lowers the risk of heart disease c. It helps the growth of good gut bacteria d. It improves the reabsorption of cholesterol

Answer 49

It improves the reabsorption of cholesterol

Question 50

50. Which one of the following can occur from excessive alcohol intake? a. Reduced LDL cholesterol b. Reduced risk of breast cancer c. Elevated triglyceride levels d. Decreased blood pressure

Answer 50

Elevated triglyceride levels

Question 51

51. A 30 year old marathon runner has decided to go on a protein diet, after a few weeks he experienced decreased energy and was found to be hypoglycemic. A doctor told him that he most likely has a deficiency of the vitamin biotin. Which of the following enzymes is unable to catalyze the synthesis of glucose from pyruvate in this marathon runner? a. Pyruvate carboxylase b. Phosphoenolpyruvate carboxykinase c. Phosphoglycerate kinase d. Glucose-6-phosphatase

Answer 51

Pyruvate carboxylase

Question 52

52. Young house officer Athena was on duty when a medical student presented to the emergency room with a history of severe vomiting and dizziness on standing for the past two days. How is the student’s metabolic profile likely to appear? a. Hyperkalemia, hypochloremia, metabolic acidosis b. Hypokalemia, hypochloremia, metabolic alkalosis c. Hypokalemia, hypochloremia, metabolic acidosis d. Hyperkalemia, hyperchloremia, metabolic acidosis

Answer 52

Hypokalemia, hypochloremia, metabolic alkalosis

Question 53

53. All of the following coenzymes are essential for the formation of acetyl CoA from pyruvate except: a. CoASH b. NAD+ c. TPP d. PLP

Answer 53

PLP

Question 54

54. Complete aerobic oxidation of a molecule of glucose results in the net production of: a. 2ATP + 4GTP + 13NADH + 1FADH2 b. 6ATP + 2GTP + 6NADH + 6FADH2 c. 2ATP + 2GTP + 10NADH + 2FADH2 d. 4ATP + 4GTP + 4NADH + 4FADH2

Answer 54

2ATP + 2GTP + 10NADH + 2FADH2

Question 55

55. A patient is unable to taste a piece of chocolate placed on the anterior part of the tongue. Which of the following nerve is most likely to have a lesion? a. Hypoglossal nerve b. Vagus nerve c. Glossopharyngeal nerve d. Chorda tympani

Answer 55

Chorda tympani

Question 56

Cori's Cycle: a. Leads to heat production as a result of glycolysis and gluconeogenesis reaction active at the same time b. Is a glucose synthesis in the liver from glycerol supplied by adipose tissue c. Is a glucose synthesis in the liver from alanine supplied by muscles d. Is a glucose synthesis in the liver from glycerol supplied by muscles e. Is a glucose synthesis in the liver from lactate supplied by erythrocytes or muscles

Answer 56

Is a glucose synthesis in the liver from lactate supplied by erythrocytes or muscles

Question 57

Transketolase activity is affected in: a. Thiamine deficiency b. Biotin deficiency c. PABA deficiency d. Pyridoxine deficiency e. Manganese deficiency

Answer 57

Thiamine deficiency

Question 58

Glucagon release does not alter muscle metabolism because of which of the following? a. Muscle cells lack protein kinase A b. Muscle cells lack adenylate cyclase c. Muscle cells lack guanosine triphosphate (GTP) d. Muscle cells lack the glucagon receptor e. Muscle cells lack G-proteins

Answer 58

Muscle cells lack the glucagon receptor

Question 59

Substrate-level phosphorylation in the citric acid (Krebs) cycle depends directly on the energy of the Select one: a. FAD-dependent oxidation of succinate to fumarate b. Thioester bond of succinyl-CoA c. Phosphoanhydrate bond of 1,3-bisphosphoglycerate d. Oxidative decarboxylation of isocitrate to α-ketoglutarate e. Formation of citrate from oxaloacetate and acetyl-CoA

Answer 59

Thioester bond of succinyl-CoA | c. Phosphoanhydrate bond of 1,3-bisphosphoglycerate

Question 60

Substrate-level phosphorylation in the citric acid (Krebs) cycle depends directly on the energy of the Select one: a. FAD-dependent oxidation of succinate to fumarate b. Thioester bond of succinyl-CoA c. Phosphoanhydrate bond of 1,3-bisphosphoglycerate d. Oxidative decarboxylation of isocitrate to α-ketoglutarate e. Formation of citrate from oxaloacetate and acetyl-CoA

Answer 60

Thioester bond of succinyl-CoA | c. Phosphoanhydrate bond of 1,3-bisphosphoglycerate

Question 61

``` A patient diagnosed with thiamine deficiency exhibited fatigue and muscle cramps. The muscle cramps have been related to an accumulation of metabolic acids. Which of the following metabolic acids is most likely to accumulate in a thiamine deficiency? Select one: a. Oxaloacetic acid b. Succinic acid c. Malic acid d. Isocitric acid e. Pyruvic acid ```

Answer 61

Pyruvic acid

Question 62

``` A substance that is not an intermediate in the formation of D-glucuronic acid from glucose is: Select one: a. UDP-Glucose b. UDP-Glucuronate c. Glucose-1-P d. Glucose-6-P e. 6-phosphogluconate ```

Answer 62

6-phosphogluconate

Question 63

A 32-year-old bodybuilder has decided to go on a diet consisting of only egg whites to ensure optimal protein for muscle growth. After a few weeks, he notices decreased energy and is found to be hypoglycemic. A nutritionist tells the patient that he most likely has a functional biotin deficiency. Which of the following enzymes is unable to catalyze a key step in the synthesis of glucose from pyruvate? a. Phosphoglycerate kinase b. Glucose 6-phosphatase c. Pyruvate carboxylase d. Phosphoenolpyruvate carboxykinase e. Fructose 1,6-bisphosphatase

Answer 63

Pyruvate carboxylase

Question 64

``` The entry of bacteria through which space could lead to an infection in the mastoid air cells: a. Auditory (nasopharyngeal) tube b. Cochlea c. External acoustic meatus d. Internal acoustic meatus Sacculus ```

Answer 64

``` Auditory (nasopharyngeal) tube The auditory (nasopharyngeal) tube is a connection between the nasal portion of the pharynx and the tympanic cavity that allows pressure to equalize on either side of the tympanic membrane. It is located in the anterior wall of the middle ear and is comprised of bone at the tympanic end and cartilage on the pharyngeal end. The pharyngeal mucosa is continuous with the lining of the tympanic cavity and mastoid air cells. This allows infectious material to pass to the middle ear and mastoid area. ``` The cochlea is the organ of hearing that receives, interprets, and transmits sound via the vestibulocochlear nerve (CN VIII). The external acoustic meatus is the opening in the temporal bone that allows sound waves to reach the tympanic membrane. The internal acoustic meatus is the foramen in the temporal bone that allows the vestibulocochlear nerve and the facial nerve to pass into the skull at the base of the brain. Finally, the sacculus is a fluid filled sac that is part of the balancing apparatus of the ear - it is located in the vestibule of the ear.

Question 65

``` Most paranasal sinuses and/or air cells drain, directly or indirectly, into the: Inferior meatus Middle meatus Superior meatus Nasal vestibule Sphenoethmoidal recess ```

Answer 65

Middle meatus

Question 66

``` Irrigation of the maxillary sinus through its opening is a supportive measure to accelerate the resolution of a maxillary sinus infection. Which of the following nasal spaces is the most likely approach to the sinus opening? choana inferior meatus middle meatus sphenoethmoidal recess superior meatus ```

Answer 66

middle meatus The middle meatus contains the semilunar hiatus, which receives drainage from the maxillary sinus, the frontonasal duct (draining the frontal sinus), and the anterior ethmoidal air cells. The maxillary sinus is draining into the middle meatus, so it would be easiest to approach the maxillary sinus through this space. The choana is the space where the nasal cavity opens into the nasopharynx--it is found at the very posterior border of the nasal cavity. The inferior meatus receives the nasolacrimal duct which conducts tears from the orbit. The sphenoethmoidal recess is the opening for the sphenoethmoidal sinus. Finally, the superior meatus receives drainage from the posterior ethmoidal air cells.

Question 67

``` In assessing a deep laceration of the right side of the nose, the attending physician determines that the cartilage on the lateral side of the nostril has been cut. What cartilage was injured? Accessory Alar Lateral Septal None of the above ```

Answer 67

Alar The alar cartilage is found on the inferolateral side of the nose. This is probably the cartilage that was injured in this laceration. The septal cartilage creates the septum of the nose. The lateral cartilage is a specialization of the septal cartilage that is superior to the alar cartilage, also on the lateral side of the nose. The accessory cartilage is a small piece of cartilage between the alar cartilage and the lateral cartilage

Question 68

``` A 23-year-old man comes to you complaining that he can't stop crying, i.e. tears regularly run down the right side of his face. You suspect that one of the lacrimal ducts on the right side of the face is blocked. You look into an endoscope to see if the nasolacrimal duct is blocked. Into which part of the nasal cavity would you look to see the opening of the duct? Hiatus semilunaris Inferior meatus Middle meatus Sphenoethmoidal recess Superior meatus ```

Answer 68

Inferior meatus The inferior meatus receives the nasolacrimal duct which conducts tears from the orbit. So, this is the place where you should be looking to see the opening of the nasolacrimal duct. The semilunar hiatus is found in the middle meatus--it receives drainage from the frontonasal duct (draining the frontal sinus), the anterior ethmoidal air cells, and the maxillary sinus. The sphenoethmoid recess is the opening for the sphenoid sinus. The superior meatus is the opening for the posterior ethmoidal air cells.

Question 69

``` Which structure forms a border of the tonsillar fossa? Torus tubarius Palatopharyngeal fold Salpingopharyngeal fold Lateral glossoepiglottic fold Medial pterygoid plate ```

Answer 69

Palatopharyngeal fold The tonsillar fossa is the place where you find the palatine tonsil - it is a space found between the palatoglossal and palatopharyngeal folds. Torus tubaris is a mucosal fold covering the anteromedial end of the auditory tube cartilage - it projects toward the midline from the lateral wall of the nasopharynx. The salpingopharyngeal fold is a vertical fold of mucous membrane that extends from the medial end of the auditory tube - it covers the salpingopharyngeus muscle. The lateral glossoepiglottic fold is a small fold extending from the tongue to the epiglottis - it is found posterior to the tonsillar fossa. Finally, the medial pterygoid plate is a part of the sphenoid bone in the skull - it is the attachment of the superior pharyngeal constrictor muscle and the pharyngobasilar fascia.

Question 70

Following thyroid surgery, it was noted that a patient frequently aspirated fluid into her lungs. Upon examination it was determined that the area of the piriform recess above the vocal fold of the larynx was numb. What nerve may have been injured? External branch of the superior laryngeal Hypoglossal Internal branch of the superior laryngeal Lingual Recurrent laryngeal

Answer 70

Internal branch of the superior laryngeal The internal branch of the superior laryngeal is a sensory nerve that pierces the thyrohyoid membrane along with the superior laryngeal artery. It supplies sensory fibers to the mucous membrane of the larynx, superior to the vocal folds. Since this area lost sensation, it appears that the internal branch of the superior laryngeal nerve must have been injured. The external branch of the superior laryngeal nerve is a motor nerve that innervates the cricothyroid muscle--it does not provide any sensory innervation to the larynx. The recurrent laryngeal nerve ascends from the thorax and provides motor innervation to the upper esophagus, lower pharynx, and all the laryngeal muscles except cricothyroideus. The hypoglossal nerve supplies motor innervation to the muscles of the tongue. The lingual nerve is a sensory nerve for the anterior 2/3 of the tongue. These nerves are not important for innervating the larynx.

Question 71

``` The constrictor muscles of the pharynx receive their motor nerve supply from the: Glossopharyngeal nerve Hypoglossal nerve Spinal accessory nerve Sympathetic trunk Vagus nerve ```

Answer 71

``` Vagus nerve (CN X) The vagus nerve supplies motor innervation to the muscles of the larynx and pharynx, with the exception of stylopharyngeus (innervated by the glossopharyngeal nerve). It also supplies motor innervation to the palate muscles, with the exception of tensor veli palatini (innervated by the V3 division of the trigeminal nerve). The glossopharyngeal nerve (CN IX) provides the sensory, but not motor, innervation to the pharynx. The hypoglossal nerve (CN XII) provides motor innervation to the muscles of the tongue. The accessory nerve (CN XI) provides motor innervation to the trapezius and the sternocleidomastoid. Finally, the sympathetic trunk supplies sympathetic innervation to the head and neck. ```

Question 71

``` The constrictor muscles of the pharynx receive their motor nerve supply from the: Glossopharyngeal nerve Hypoglossal nerve Spinal accessory nerve Sympathetic trunk Vagus nerve ```

Answer 71

``` Vagus nerve (CN X) The vagus nerve supplies motor innervation to the muscles of the larynx and pharynx, with the exception of stylopharyngeus (innervated by the glossopharyngeal nerve). It also supplies motor innervation to the palate muscles, with the exception of tensor veli palatini (innervated by the V3 division of the trigeminal nerve). The glossopharyngeal nerve (CN IX) provides the sensory, but not motor, innervation to the pharynx. The hypoglossal nerve (CN XII) provides motor innervation to the muscles of the tongue. The accessory nerve (CN XI) provides motor innervation to the trapezius and the sternocleidomastoid. Finally, the sympathetic trunk supplies sympathetic innervation to the head and neck. ```

Question 72

``` Which organ becomes retroperitoneal during rotation of the gut tube? Duodenum Kidney Spleen Stomach Transverse Colon ```

Answer 72

duodenum This question is asking you to identify the organ that is secondarily retroperitoneal. This means that it started out peritonealized but became pressed against the posterior body wall and stuck there during development. Except for the first few centimeters of the superior segment and the duodenojejunal junction, the duodenum is a secondarily retroperitoneal organ - it used to have a mesentery, but that was lost during gut rotation. Although the kidney is a retroperitoneal organ, it is not secondarily retroperitoneal - it started developing in the retroperitoneum and stayed there. The spleen, stomach, and transverse colon are all peritonealized. What segments of the colon are peritonealized? The cecum, transverse colon, and the sigmoid colon are peritoneal, but the ascending and descending colon are retroperitoneal.

Question 73

``` A 40 year-old male with a long history of duodenal ulcer problems was brought in for emergency surgery to control severe hemorrhage into the peritoneal cavity. The surgeons found that erosion by the ulcer of a vessel passing behind the first part of the duodenum was the source of the hemorrhage. Which of the following vessels passes behind the first part of the duodenum and would need to be clamped off to control the bleeding? coronary vein gastroduodenal artery inferior pancreatoduodenal arcade proper hepatic artery splenic vein ```

Answer 73

gastroduodenal artery The gastroduodenal artery lies behind the superior part of the duodenum. It has three branches: the posterior superior pancreaticoduodenal artery, the anterior superior pancreaticoduodenal artery, and the right gastroomental artery. The other vessels are not near the superior duodenum. The coronary vein is made of the right and left gastric veins and located in the lesser curvature of the stomach. The inferior pancreatoduodenal arcade is found in the inferior part of the head of the pancreas. It supplies the pancreas and duodenum. It is near the horizontal (3rd) part of the duodenum, not the superior part. The proper hepatic artery is a branch of the common hepatic artery which delivers oxygenated blood to the liver. Finally, the splenic vein comes from the spleen--it joins the superior mesenteric vein to form the portal vein.

Question 74

``` During a cholecystectomy (removal of the gall bladder), the surgical resident accidentally jabbed a sharp instrument into the area immediately posterior to the epiploic foramen (its posterior boundary). He was horrified to see the surgical field immediately fill with blood, the source which he knew was the: aorta inferior vena cava portal vein right renal artery superior mesenteric vein ```

Answer 74

inferior vena cava The epiploic foramen, also called the omental foramen, is the passageway between the greater and lesser peritoneal sacs. The inferior vena cava lies immediately posterior to this foramen, so this is the vessel that was probably cut. The aorta lies next the inferior vena cava, but it is a little more to the left and a little deeper--it does not lie immediately posterior to the epiploic foramen. The hepatic portal vein is anterior to the epiploic foramen. The right renal artery is a branch off of the aorta. Like the aorta, it is too deep to be a vessel immediately behind the foramen. Finally the superior mesentric vein is anterior to the foramen. Remember, this is one of the two vessels that makes the hepatic portal vein, so if the hepatic portal vein is anterior to the foramen, the SMV should be too.

Question 75

The division between the true right and left lobes (internal lobes) of the liver may be visualized on the outside of the liver as a plane passing through the: gallbladder fossa and round ligament of liver falciform ligament and ligamentum venosum gallbladder fossa and inferior vena cava falciform ligament and right hepatic vein gallbladder fossa and right triangular ligament

Answer 75

gallbladder fossa and inferior vena cava This question is asking you to identify the structures that make the line that separates the true/functional lobes of the liver. The concept of functional lobes contrasts with traditional anatomical terminology, which separated the liver into the left, right, quadrate and caudate lobes. These traditional lobes were based on anatomical appearance, while the functional lobes are based on the distribution of the portal vein, hepatic arteries, and hepatic bile ducts. The functional lobes of the liver are separated into a right and left lobe by the gallbladder fossa and the inferior vena cava. So, the old "right lobe" corresponds to the functional right lobe, while the caudate, quadrate, and left lobes under anatomical terminology are lumped together as one big left lobe.

Question 76

``` To stop hemorrhaging from a ruptured spleen, it was necessary to temporarily ligate the splenic artery near the celiac trunk. The blood supply to which structure is least likely to be affected by the ligation? Duodenum Greater omentum Body of pancreas Tail of pancreas Stomach ```

Answer 76

Duodenum The duodenum receives blood from the gastroduodenal artery, a branch of the common hepatic artery. It also receives blood from the inferior pancreatoduodenal artery, which is a branch of the superior mesenteric artery. So, the duodenum is receiving blood from the common hepatic artery and the superior mesenteric artery, but it is not receiving any blood from the splenic artery. The splenic artery supplies blood to the body of the pancreas with the dorsal and superior pancreatic arteries; it supplies blood to the tail of the pancreas with the caudal pancreatic artery. The splenic artery supplies the fundus of the stomach with short gastric arteries and the left portion of the greater curvature with the left gastroomental artery. The left gastroomental artery also supplies blood to the greater omentum through omental branches. All of these structures would be affected if the splenic artery was ligated.

Question 77

``` A patient was admitted with symptoms of bowel obstruction. Further examination revealed that the obstruction was caused by the nutcracker-like compression of the bowel between the superior mesenteric artery and the aorta. The compressed bowel is most likely the: Duodenum Jejunum Ileum Ascending colon Transverse colon ```

Answer 77

Duodenum The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and food will not be able to pass through the duodenum. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum.

Question 78

``` A medical student was asked to identify a small specimen taken for pathological examination from a surgically removed duodenum. The student noted that the specimen revealed a thin wall and no circular folds. The specimen is from which segment? Superior Descending Horizontal Ascending ```

Answer 78

Superior The superior part of the duodenum is the one segment of the duodenum that has no circular folds. When food enters the duodenum from the pyloric sphincter, it enters the ampulla, which is a smooth area of the duodenum containing a high percentage of mucosal cells. These cells secrete mucus to neutralize the acidic contents of the stomach. If the stomach contents is not sufficiently neutralized, the thin wall of the ampulla may develop an ulcer. If the ulcer burns through the entire wall, it might jeopardize the gastroduodenal artery, lying behind the first segment of the duodenum. The descending, horizontal, and ascending portions of the duodenum all have circular folds

Question 79

You are observing a laparoscopic cholecystectomy. The surgeon states that he is next going to expose the cystic artery in order to staple across it. He asks you where he should look for it. You reply, "In the triangle of Calot." What stuctures form this triangle and are the keys to finding the artery? Common hepatic duct, liver and cystic duct Cystic duct, right hepatic artery and right hepatic duct Gall bladder, liver and common bile duct Left hepatic duct, liver and cystic duct Right branch of portal vein, liver and common bile duct

Answer 79

Common hepatic duct, liver and cystic duct The triangle of Calot is formed by the cystic duct laterally, the liver superiorly, and the common hepatic duct medially. It is an important landmark in this region, because the cystic artery can be found in the triangle of Calot. During a cholecystectomy, the cystic artery needs to be ligated. Although the cystic artery usually branches from the right hepatic artery, there is some variation. However, if you locate the triangle of Calot, you can find the cystic artery in that triangle, trace it back to its origin, and then ligate it there.

Question 80

``` Upon endoscopic examination of a 65-year-old man who had a history of a chronic duodenal ulcer, it was found that the ulcer had been eroding the posterior wall of the first part of the duodenum. If erosion perforates the wall, the gastric expellant of high acidity would endanger the structures in its vicinity. Which is least likely to be endangered? Common bile duct Gastroduodenal artery Main pancreatic duct Portal vein ```

Answer 80

Main pancreatic duct The pancreas is inferior to the superior portion of the duodenum, and the main pancreatic duct is found deep within the pancreas. It is not likely that this structure would be damaged by the duodenal ulcer. The portal vein, gastroduodenal artery, and the common bile duct all pass immediately deep to the first part of the duodenum. (The portal vein and common bile duct are associated with the proper hepatic artery, forming the portal triad.) These structures would all be at risk from the ulcer

Question 81

A 58-year-old patient was diagnosed with a severe case of portal hypertension due to alcoholic cirrhosis of the liver. It was determined that a bypass between the vessels of the portal and caval systems was necessary. The plan most likely to be successful is: Coronary vein to right gastro-omental vein Left colic vein to sigmoidal vein Inferior mesenteric vein to splenic vein Splenic vein to left renal vein Superior rectal vein to inferior rectal vein

Answer 81

Splenic vein to left renal vein The splenic vein is a major vein of the portal system, while the left renal vein is a major vein of the caval system. These veins are large, so a bypass between them could be useful for relieving the portal hypertension. The coronary vein, right gastro-omental vein, left colic vein, sigmoidal vein, inferior mesenteric vein, and splenic vein are all part of the portal system. Any bypasses among these veins will not relieve the portal hypertension. The superior and inferior rectal veins already form a portal-caval anastomosis; surgery would not be needed to connect these two venous channels. However, if too much blood tries to flow through this anastomosis, hemorrhoids will develop. These veins are not large enough to help relieve severe portal hypertension.

Question 82

``` A patient was admitted with symptoms of an upper bowel obstruction. Upon CT examination, it was found that the third (transverse) portion of the duodenum was compressed by a large vessel causing the obstruction. The vessel involved is most likely to be the: inferior mesenteric artery superior mesenteric artery inferior mesenteric vein portal vein splenic vein ```

Answer 82

Superior mesenteric artery The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and food won't be able to pass through the duodenum. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum

Question 83

``` An ulcer near the pyloroduodenal junction perforated and eroded a large artery immediately posterior to the duodenum. The ligation of the eroded vessel at its origin would LEAST affect the arterial supply to the: First part of the duodenum Second part of the duodenum Greater curvature of the stomach Head of the pancreas Tail of the pancreas ```

Answer 83

Tail of the pancreas The gastroduodenal artery is the artery that has ruptured. This artery gives off the anterior and posterior superior pancreatoduodenal arteries, which supply the first and second parts of the duodenum, as well as the head of the pancreas. The gastroduodenal artery also gives off the right gastroomental artery, which supplies the right half of the greater curvature of the stomach. In contrast, the tail of the pancreas is supplied by the caudal pancreatic artery, which is a branch of the splenic artery. It would not be affected by damage to the gastroduodenal artery.

Question 84

``` The inferior mesenteric vein usually joins which vein? Inferior vena cava Left renal Portal Splenic Superior mesenteric ```

Answer 84

Splenic

Question 85

A surgeon needs to construct a bypass between the veins of the portal and caval systems to circumvent insufficient drainage through the natural portacaval anastomoses. Which plan is likely to be successful? Coronary vein to right gastroepiploic vein Inferior mesenteric vein to splenic vein Left colic vein to middle colic vein Splenic vein to left renal vein Superior mesenteric vein to splenic vein

Answer 85

Splenic vein to left renal vein The splenic vein is a major vein of the portal system, while the left renal vein is a major vein of the caval system. These veins are large, so a bypass between them could be useful for relieving the portal hypertension. The coronary vein, right gastroepiploic vein, inferior mesenteric vein, splenic vein, left colic vein, middle colic vein, and superior mesenteric vein are all part of the portal system. Any bypasses among these veins will not relieve the portal hypertension.

Question 86

``` The structure that traverses the space between the aorta and first part of the superior mesenteric artery and is vulnerable to the nutcracker-like compression by these two vessels is the: Duodenum Jejunum Pancreas Splenic vein Transverse colon ```

Answer 86

Duodenum The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and the passage of food will be obstructed. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum

Question 87

``` A 60-year-old patient who has had a chronic ulcer of the duodenum for many years was admitted to the hospital with signs of a severe internal hemorrhage. The ulcer perforated the posterior wall of the first portion of the duodenum and eroded an artery in that position. The damaged artery was: Cystic Gastroduodenal Hepatic Left gastric ```

Answer 87

Gastroduodenal The gastroduodenal artery is a branch of the common hepatic artery--it passes immediately posterior to the first portion of the duodenum, and it can be damaged if there is an ulcer in this part ot the duodenum. The cystic artery supplies the gall bladder--it can be located in the triangle of Calot. The proper hepatic artery is a branch of the common hepatic artery--it travels superior to the first portion of the duodenum. The left gastric artery is a branch of the celiac trunk--it supplies the left side of the lesser curvature of the stomach.

Question 88

``` Which of the following veins does not run a course parallel to the artery of the same name? A) superior epigastric B) superficial circumflex iliac C) inferior mesenteric D) superior rectal E) ileocolic ```

Answer 88

C) inferior mesenteric The inferior mesenteric vein and inferior mesenteric artery do not run in tandem. The inferior mesenteric vein is part of the portal venous system--it drains into the splenic vein which drains into the hepatic portal vein. The inferior mesenteric artery is a branch off the descending aorta at the level of the L3 vertebral body. However, the inferior mesenteric artery and vein supply/drain the same region: the descending and sigmoid colon and the rectum.

Question 89

The presence of which feature (also obvious on a radiograph with barium contrast) distinguishes small from large bowel? A) Circular folds of the mucosa B) Circular smooth muscle layer in the wall C) Mucosal glands D) Longitudinal smooth muscle layer in the wall E) Serosa

Answer 89

A) circular folds of the mucosa The small intestine features circular folds of tissue that are covered with villi - these folds are very obvious on a radiograph with barium contrast. The colon does not have similar folds in the mucosa.

Question 90

``` Occlusion of the inferior mesenteric artery is seldom symptomatic because its territory may be supplied by branches of the: A) Gastroduodenal B) Ileocolic C) Middle colic D) Right colic E) Splenic ```

Answer 90

C) middle colic The middle colic artery is the branch from the superior mesenteric artery that supplies the transverse colon. This is the most distal part of the colon that receives blood from the SMA. Branches from the middle colic go to the marginal artery, which would be able to supply the descending colon, sigmoid colon, and rectum if the inferior mesenteric artery was occluded.

Question 91

``` During the surgical repair of a hiatal hernia, the celiac branch of the posterior vagal trunk was severed accidentally. The damage to this nerve would affect the muscular movements, as well as some secretory activities, of the gastrointestinal tract (GI). Which segment is least likely to be affected by the nerve damage? A) Ascending colon B) Cecum C) Jejunum D) Ileum E) Sigmoid colon ```

Answer 91

E) sigmoid colon The vagus nerve supplies parasympathetic fibers to all of the abdominal organs which receive blood from the celiac trunk or superior mesenteric artery. This means that the vagus supplies parasympathetics to the entire GI tract, up to the last part of the transverse colon. The end of transverse colon and all GI structures distal to that point receive parasympathetic innervation from the pelvic splanchnic nerves and blood from the inferior mesenteric artery. So, the ascending colon, cecum, jejunum, and ileum would all be affected by damage to the vagus nerve. The sigmoid colon, which receives parasympathetic innervation from the pelvic splanchnics, would not be affected.

Question 92

``` A 60-year-old woman arrived at the emergency room complaining of acute abdominal pain. She was diagnosed with ischemic bowel resulting from an obstruction of one or more branches of the inferior mesenteric artery. Which of the following is most likely NOT to be seriously affected by the ischemia? A) Cecum B) Descending colon C) Rectum D) Sigmoid colon E) Splenic flexure ```

Answer 92

A) cecum The inferior mesenteric artery supplies blood to the end of the transverse colon and all distal structures in the GI tract. This means that the splenic flexure, descending colon, sigmoid colon, and rectum would all be deprived of blood if the inferior mesenteric artery was occluded. The cecum receives blood from the superior mesenteric artery, so it would not be affected by the obstruction.

Question 93

``` The artery of the midgut is the: A) Celiac trunk B) Inferior mesenteric C) Proper hepatic D) Splenic E) Superior mesenteric ```

Answer 93

E) superior mesenteric The superior mesenteric artery is the artery of the midgut. The celiac trunk is the artery of the foregut, and the inferior mesenteric arery is the artery of the hindgut. The splenic artery is a branch of the celiac artery, and the proper hepatic artery is a branch of the common hepatic artery, which is a branch of the celiac artery.

Question 94

``` To drain an abscess (a closed collection of pus) affecting the cheek area, an emergency room physician used local anesthesia for the surgery. Which of the following nerves must be anesthetized because it carries pain sensation from the cheek area? buccal (V3) buccal (VII) inferior alveolar lingual ```

Answer 94

Buccal (V3) The buccal nerve is a branch of the mandibular division of the trigeminal nerve that transmits sensory information from the skin of the cheek area and the oral mucosa of the cheek. The buccal nerve is NOT the same as the buccal branches of the facial nerve, which are motor nerves that innervate the buccinator and the facial muscles of the upper lip. The buccal branches of the facial nerve do not have a sensory component! The inferior alveolar nerve is another branch of V3 that penetrates the mandibular foramen and is the sensory nerve for the mandible and all mandibular teeth. This is the nerve that dentists must anesthesize when they are working on the mandibular teeth. The lingual nerve is also a branch of V3--it transmits general sensation from the tongue. The lingual nerve also receives the chorda tympani, a branch of the facial nerve, which provides the lingual nerve with preganglionic parasympathetic fibers for the submandibular and and sublingual glands, as well as the taste fibers for the anterior 2/3 of the tongue. Finally, the mental nerve is a branch of V3 from the inferior alveolar nerve--it provides sensory innervation to the skin of the chin and lower lip.

Question 95

``` The muscle which separates the submandibular triangle from the paralingual space is the: Digastric, posterior belly Hyoglossus Mylohyoid Stylohyoid Styloglossus ```

Answer 95

mylohyoid The submandibular triangle is a space bounded by the anterior and posterior bellies of the digastric and the body of the mandible. It is found superficial to the mylohyoid muscle. The submandibular triangle contains the superficial submandibular gland, stylohyoid muscle, facial artery and facial vein. The paralingual space is a space found deep to the mylohyoid muscle, which makes the mylohyoid the dividing line between these two distinct spaces. It is bounded by the lateral tongue (including the hyoglossus, styloglossus, and genioglossus muscles), hyoid bone, and oral mucosa. It contains the deep portion of the submandibular gland, the submandibular duct and the sublingual caruncle, lingual nerve and submandibular ganglion, hypoglossal nerve, and sublingual gland and fold.

Question 96

``` The predominant muscle most associated with retraction of the mandible is the: lateral pterygoid masseter medial pterygoid temporalis mylohyoid ```

Answer 96

temporalis Temporalis is the one muscle responsible for retracting the mandible--it pulls the mandible backwards. The lateral pterygoid protracts the mandible, or pulls it forward. It is the one jaw muscle that allows for opening the mouth. The masseter is a powerful chewing muscle that elevates the mandible. The medial pterygoid also elevates the mandible; it has a similar position and action to the masseter, but the ramus of the mandible separates the two muscles. Mylohyoid elevates the hyoid bone and the tongue and depresses the mandible.

Question 97

All of the following may be found in the paralingual space EXCEPT: Hypoglossal nerve Lingual nerve Sublingual gland Submandibular gland duct Superficial lobe of the submandibular gland

Answer 97

Superficial lobe of the submandibular gland The paralingual space is found in the floor of the mouth, deep to the mylohyoid muscle. The space is bounded by the lateral tongue, the hyoid bone, and the oral mucosa. Remember--the submandibular gland has a deep and superficial portion. The deep portion of the submandibular gland is found deep to the mylohyoid muscle, while the superficial portion of the submandibular gland is found superficial to the mylohyoid muscle. So, the deep portion of the submandibular gland is in the paralingual space, while the superficial portion of the submandibular gland is not.. The paralingual space also contains the submandibular duct and sublingual caruncle, the lingual nerve and submandibular ganglion, the hypoglossal nerve, and the sublingual gland and fold.

Question 98

A 46-year-old female patient comes to the emergency department complaining of pain in the area just below her mandible on the right side of her face. She says that the pain is particularly severe when she eats. The area of the submandibular gland is tender and swollen, as is the area in the floor of her mouth lateral to the tongue. You suspect a stone in the submandibular duct, and a plain film radiograph shows a density in that region consistent with a stone. In order to remove the stone, the duct must be incised in the floor of the mouth. What nerve, that loops around the duct, is in danger in such an incision? Chorda Tympani Glossopharyngeal Hypoglossal Internal branch of the superior laryngeal Lingual

Answer 98

Lingual The lingual nerve is found in the floor of the mouth--it wraps around the submandibular duct. So that nerve might be injured as you try to remove the stone from the submandibular duct. The lingual nerve contains general sensory fibers for the anterior 2/3 of the tongue, and fibers from the chorda tympani that provide taste to the anterior 2/3 of the tongue. All of these sensory components might be lost if the lingual nerve was damaged. At the point where the lingual nerve is wrapping around the submandibular gland, the fibers from chorda tympani have already joined the lingual nerve.This means that fibers from chorda tympani might be damaged, but the chorda tympani itself is not near the submandibular duct. The glossopharyngeal nerve provides sensory and taste innervation to the posterior 1/3 of the tongue and sensory innervation to the pharynx--it is not associated with the submandbular duct. The hypoglossal nerve is in the sublingual space, just like the submandibular duct. However, it is deeper in the sublingual space and does not wrap around the duct. Remember--the lingual nerve is a much more superficial structure in the sublingual space. Finally, the internal branch of the superior laryngeal nerve crosses the thyrohyoid membrane to provide sensory innervation to the mucosa of the pharynx, superior to the vocal folds.

Question 99

``` Loss of sensation from the temporal region and loss of secretory function of the parotid gland would be caused by interruption of which nerve? Auriculotemporal Chorda tympani Deep temporal, posterior Facial Great auricular ```

Answer 99

Auriculotemporal nerve The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (V3). It has two important functions: First, it carries postganglionic parasympathetic fibers to the parotid gland. These fibers come from the otic ganglia, where they synapsed with the presynaptic fibers from the glossopharyngeal nerve (CN IX). Second, the auriculotemporal nerve provides sensory innervation to the skin of anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint. So, the listed symptoms match with an injury to the auriculotemporal nerve. Chorda tympani is a branch of the facial nerve that provides secretomotor innervation to the submandibular and sublingual glands. It carries preganglionic parasympathetic axons to the submandibular ganglion. In the infratemporal fossa, chorda tympani joins the lingual nerve--it continues with the lingual nerve to the tongue where it supplies taste to the anterior 2/3 of the tongue. The posterior deep temporal nerve is a branch of the mandibular division of the trigeminal nerve which supplies motor innervation to temporalis. The facial nerve (CN VII) innervates all of the muscles of facial expression, and, through the chorda tympani, provides secremotor innervation to the submandibular and sublingual glands as well as taste sensation to the anterior 2/3 of the tongue. Finally, the great auricular nerve comes from the cervical plexus--it provides sensory innervation to the skin of the ear and the skin below the ear.

Question 100

``` An elderly man presented with severe pain beneath the left eye, radiating into the lower eyelid, lateral side of the nose and upper lip. What nerve was involved? Buccal Infraorbital Mental Supratrochlear Zygomatic ```

Answer 100

infraorbital The infraorbital nerve is a cutaneous nerve from the maxillary division of trigeminal nerve (V2). It innervates the skin of the lateral nose, lower eyelid, upper lip and zygomatic region. This is exactly where this man's pain is, so it seems like his pain must be transmitted on the infraorbital nerve. The buccal branch of the trigeminal nerve is part of the mandibular division (V3)--this nerve provides sensory innervation to the skin of the cheek and the mucosal lining the cheek. It is not a motor nerve--only sensory! (NOTE: The buccal nerve is NOT the same as the buccal branch of the facial nerve. The buccal branch of the facial nerve is a motor nerve only--it innervates several muscles of facial expression. It does not have a sensory component--only motor!) The mental nerve is a branch of the inferior alveolar nerve, which is a branch of the mandibular division of the trigeminal nerve (V3). It provides sensory innervation to the skin of the chin and lower lip. The supratrochlear nerve is a branch of the frontal nerve, from the ophthalmic division of the trigeminal nerve. It gives sensory innervation to the skin of the medial forehead and the medial part of the upper eyelid. The zygomatic nerve is part of the maxillary division of the trigeminal nerve (V2). It provides sensory innervation to the skin of the face lateral and superior to the orbit.

Question 101

``` An elderly woman complained of a severe pain, felt above the right eye radiating to the upper eyelid, side of the nose and forehead. Branches of which of the following nerves convey pain sensations from areas of the skin described? maxillary (V2) greater auricular nerve ophthalmic (V1) mandibular (V3) facial (VII) ```

Answer 101

ophthalmic (V1) The ophthalmic division of the trigeminal nerve provides sensory innervation to the skin of the nose, upper eyelid, and forehead. This is exactly where this woman feels pain, so the ophthalmic division of the trigeminal nerve must be the nerve transmitting the pain. The maxillary division of the trigeminal nerve (V2) provides sensory innervation to the skin of the side of the nose, the cheek, lower eyelid, and upper lip. The mandibular division of the trigeminal nerve (V3) provides sensory innervation to the skin of the chin, lower lip, and lower jaw. The great auricular nerve is a branch of the cervical plexus which supplies sensory innervation to the ear region. Finally, the facial nerve is mostly a motor nerve--it only supplies taste to the anterior 2/3 of the tongue and gives some sensory innervation to the skin of the exernal auditory meatus.

Question 102

``` Due to multiple salivary calculi (stones) in the submandibular duct, the submandibular gland of a 45-year-old individual was surgically removed. What major artery directly related to the gland was of special concern to the surgeon? lingual superior thyroid facial ascending pharyngeal maxillary ```

Answer 102

facial The facial artery arises from the external carotid and winds toward the inferior border of the mandible, crossing over the submandibular gland. So, if the submandibular gland was removed, the facial artery might be damaged. The lingual artery is a branch of the external carotid that runs in the floor of the mouth. It is associated with the submandibular duct, but not with the gland itself. The superior thyroid artery is a branch of the external carotid which travels anteroinferiorly to supply the upper pole of the thyroid. The ascending pharyngeal artery is a posterior branch of the external carotid which supplies blood to the pharynx. Finally, the maxillary artery is one of the two terminal branches of the external carotid artery--it supplies blood to the maxillary region, muscles of mastication, infratemporal fossa, and deep face

Question 103

``` Which nerve provides motor innervation to the buccinator muscle? Auriculotemporal nerve Buccal branches of VII Buccal nerve Mandibular division of V Marginal mandibular nerve ```

Answer 103

buccal branches of VII The buccal branches of the facial nerve provide motor innervation to the buccinator muscle. Remember, these buccal branches of the facial nerve are motor nerves only--they do not do any sensory innervation. Don't mix this nerve up with the buccal nerve, which is a branch of the mandibular division of the trigeminal nerve (V3)! The buccal nerve is a sensory nerve only--it does not innervate any muscles; it only gives sensory innervation to the skin of the cheek and the mucosal lining of the cheek. The auriculotemporal nerve is also part of the mandibular division of the trigeminal nerve--it carries the postganglionic parasympathetic fibers to the parotid gland and provides sensory innervation to the skin of the anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint. The marginal mandibular nerve is another branch of the facial nerve--it innervates the muscles of facial expression on the lower lip and chin.