June 2009, Medicine FCPS-1MCQs solved.

Q1: In kidney select the correct order of arteries:

a) Renal artery > Arcuate artery >Interlobar artery > Efferent arteriole

b) Renal artery > Interlobular artery > Interlobar artery> Arcuate artery > Efferent arteriole

c) Renal artery > Interlobar artery > Interlobular artery > Arcuate artery > Afferent arteriole

d) Renal artery > Interlobar artery> Arcuate artery > Interlobular artery> Afferent arteriole

Correct Answer: d

Explanation:

Renal artery gives off Interlobar arteries which run between the pyramids of medulla. Interlobar arteries give off arcuate arteries which run parallel to the junction of cortex and medulla. Arcuate arteries give Interlobular branches into the cortex which in turn give rise to the afferent arterioles.

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Q2: A patient has been taking anti-tuberculous therapy for MDR-TB. His drugs regimen contains 6 drugs. The patient eventually develops difficulty in distinguishing red & green colours. Which of the following drugs is responsible for this effect?

a) Amiodrone

b) Pyrazinamide

c) Rifampicin

d) Ethambutol

e) Ciprofloxacin

Correct Answer: d

Explanation:

Ethambutol is one of the drugs used in anti-tuberculous therapy. Optic neuritis is an important, though rare side effect of ethambutol. If optic neuritis develops, red-green colour vision may be lost first. This agent should probably not be used in young children in whom it may be difficult to assess vision.

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Q3: A patient with acute blood loss, the mechanism triggered immediately would be:

a) Baroreceptor Reflex

b) Renin-angiotensin System

c) Chemoreceptor

d) CNS ischemic response

Correct Answer: a

Explanation:

Most important and quick response in severe hemorrhage such as acute blood loss is the baroreceptor reflex. Baroreceptors are present in the aortic arch (signal transmitted via vagus nerve to medulla) & carotid sinus (signal transmitted via glossopharyngeal nerve to medulla). Barorecptors respond to changes in BP as following:

Hypotension àdecreased arterial pressure à decreased stretch on baroreceptors à decreased afferent baroreceptor firing à increased efferent sympathetic firing & decreased efferent parasympathetic stimulation à vasoconstriction, increase HR, increased contractility, increased BP.

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Q4: Captopril causes:

a) Hyperkalemia

b) Hypernatremia

c) Hypokalemia

d) Hypercalcemia

Correct Answer: a

Explanation:

Captopril is one of the ACEI (Angiotensin Converting Enzyme Inhibitor). Major side effects of ACEIs are cough (due to increased levels of bradykinin), angioedema, hyperkalemia ,proteinuria.

Hyperkalemia with ACEI therapy occurs because:

Renin-Angiotensin system is a potent stimulator of aldosterone release. Aldosterone inturn conserves sodium & increases the excretion of potassium. With ACEIs, the rennin-angiotensin system is inhibited, so is aldosterone secretion, resulting in low plasma levels of aldosterone. Low aldosterone prevents the excretion of potassium, which builds up in body resulting in hyperkalemia.

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Q5: Corneal opacities are caused by:

a) Ethambutol

b) Phenothiazines

c) Cholorquine

d) Penicillamine

Correct Answer: c

Explanation:

Chloroquine is commonly used anti-malarial used for the treatment & prevention of Malaria. One of its important side effects occurs in the eyes. It can cause corneal deposits, lenticular deposits & damage to the retina.

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Q6: Which of the following is an example of a pivot joint?

a) Temporomandibular Joint

b) Altanto-occipital Joint

c) Median Atlanto-axial Joint

d) Intervertebral joint

Correct Answer: c

Explanation:

Pivot Joint is type of joint in which rounded or conical surfaces of one bone fit into a ring of bone or tendon allowing rotation. An example of this type of joint is between axis and atlas in the neck that is the median atlanto-axial joint in which the dens (odontoid process) of axis articulates with inner surface of the arch of atlas.

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Q7: Which of the followings is P450 inducer?

a) Isoniazid

b) Phenobarbitone

c) Ketoconazole

d) Cimetidine

Correct Answer: b

Explanation:

Phenobarbitone is one of the anticonvulsant. Anticonvulsants in general are inducers of Cytochrome P450 system. Others inducers of P450 are: Rifampin, Griseofulvin, Carbamazepine, Phenytoin.

For inhibitors of P450 remember the Mnemonic: SICK EGgs inhibit your appetite.

S: Sulfonamides

I: Isoniazid

C: Cimetidine

K: Ketoconazole

E: Erythromycin

G: Grapefruit juice.

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Q8: Serum Gastrin levels are increased by prolonged use of:

a) H₂ Receptor blockers

b) Proton Pump Inhibitors

c) Antacids

d) Anticholinergics

Correct Answer: b

Explanation:

The most appropriate answer is Proton Pump Inhibitors (PPI) because they irreversibly inhibit H⁺ /K⁺ -ATPase in stomach parietal cells. H₂ blockers on the other hand cause a reversible block of histamine H2 receptors resulting in decreased production of H⁺. Since the PPI are irreversible blockers of the Proton pump they cause a more sustained decrease in H⁺ production. This, through positive feedback increases the secretion of Gastrin. Generally increased acid (H⁺ ions) causes decreased production of Gastrin & decreased acid (such as through PPI use) cause increase in Gastrin secretion.

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Q9: Gastroesophageal junction competence is increased by:

a) Lying supine

b) Paralysis of the diaphragm

c) Use of Morphine

d) Use of Metoclopromide

e) Increased intra-abdominal pressure

Correct Answer: d

Explanation:

Metoclopromide is D2 receptor antagonist that increased the resting tone of GIT, increases contractility & increases Lower esophageal junction tone. It is clinically used for Diabetic & post-surgery gastroparesis. Toxicity includes parkinsonian effects, restlessness, drowsiness, fatigue, depression, nausea, diarrhea. Contraindicated in patients with small bowel obstruction.

Other option under this question actually decrease the GE junction tone.

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Q10: Which of the followings cross placenta?

a) IgM

b) IgA

c) IgG

d) IgD

Correct Answer: c

Explanation:

Of all the immunoglobins only IgG is the only antibody that crosses placenta. It is main antibody in secondary response and the most abundant one. It fixes complement, opsonized bacteria, neutralizes bacterial toxins and viruses.

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Q11: Which of the followings is increased in first response?

a) IgM

b) IgD

c) IgE

d) IgG

Correct Answer: a

Explanation:

IgM is the antibody produced in primary response to an antigen. IgG is the main antibody in secondary response. IgM also fixes complement but does not cross placenta.

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Q12: A woman living at a hill station has had an uncomplicated pregnancy. She is brought to the hospital at the onset of labour. An ultrasound scan is performed which shows no fetal abnormality. The baby can still have which of the following conditions?

a) Transposition of great vessles

b) Patent ductus arteriosis

c) Limb defects

d) Tetrology of Fallot

Correct Answer: b

Explanation:

During fetal period, the ductus arteriosus shunts blood from the right to the left. It connects the pulmonary trunk with the aorta. Blood entering the pulmonary trunk from the right ventricle is shunted through ductus arteriosus into aorta. As the baby is born, the circulatory changes that occur also include closure of the ductus arteriosus. Closure of the ductus arteriosus is promoted by increase oxygen tension (when baby starts breathing) which decrease prostaglandin (PG) synthesis. At hill stations, the atmospheric oxygen pressure is low. A baby born and staying during the first few days of his life under such circumstances would lead to a decrease in oxygen tension and so failure of ductus arteriosus to close. Patency of ductus arteriosus can also be maintained by high PG levels such with use of indomethacin (a PG synthesis inhibitor). In summary low oxygen tension and high PG levels cause PDA.

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Q13: ECG of a patient shows progressively increasing PR intervals followed by dropped beat. What is the condition?

a) Third degree heart block

b) Mobitz Type 1

c) Sinus arrhythmia

d) Mobitz Type 2

Correct Answer: b

Explanation:

Heart blocks are of three types:

1. First degree heart block: PR interval prolonged (>200 ms)
2. Second degree heart block:

• Mobitz Type 1: Progressive lengthening of the PR interval until a beat is dropped (a P wave not followed by a QRS complex).
• Mobitz Type 2: Dropped beats that are not preceded by a change in the length of the PR interval

1. Third degree heart block: The atria & ventricles beat independently of each other.

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Q14: For good verbal communication skills which of the followings is necessary?

a) Good comprehension

b) Good vocabulary

c) Fluent Speech

d) Competence in presentation.

Correct Answer: c

Explanation:

This is one of the questions that only require common sense. So common sense tells us that fluent speech is an absolute requirement for good communication skills. The other three options simply don’t fit.

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Q15: Which of the followings is not caused by parasympathetic stimulation?

a) Micturation

b) Miosis

c) Increased GIT motility

d) Sweating

Correct Answer: d

Explanation:

Sweating is function of sympathetic stimulation rather than parasympathetic stimulation. In order to differentiate between parasympathetic & sympathetic effect and prevent any confusion, remember the following scenario.

You go out on a street and you are greeted to a fierce lion! In this situation you would want to:

• Have your pupils fully dilated (mydriasis), so that you can see the maximum of the lion and be prepared for an attack.
• Have you heart racing(tachycardia), so that when you start running your heart is able to meet the increased oxygen demand to the muscles
• Stop your bowel and bladder movement (urinary retentions & decreased GI motility), because you definitely don’t want to go to bathroom right now!
• Increase your metabolism and sweating for optimal temperature control so that you are not feeling cold when the lion bites you! (this is just an example to remember things)

Since you were met by a lion your response should be fright, fight or flight which is actually the sympathetic stuff. Everything opposite to this such as miosis, bradycardia, micturation & increased GI motility occur with parasympathetic stimulation.

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Q16: Ejaculation is mediated by:

a) Sympathetic stimulation

b) Parasympathetic stimulation

c) Both a & b

d) Pudendal nerve

Correct answer: d

Explanations:

Innervation of the male sexual response is as followings:

• Erection: Parasympathetic nervous system (through pelvic nerve)
• Emission: Sympathetic nervous system (through hypogastric nerve)
• Ejaculation: visceral & somatic nerves (though pudendal nerve)

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Q17: Alpha-1 receptor stimulation causes:

a) Pupillary dilatation

b) Increased heart rate

c) Increased contractility

d) Increased gastric motility

Correct Answer: a

Explanation:

Apha-1 receptor causes

• Increased smooth muscles contraction, such as in arterioles where it increases TPR & so BP
• Increased pupillary muscle dilatation (mydriasis)

Increased heart rate (choice b) & increased contractility (choice c) of heart, although a function of sympathetic system, is not mediated by alpha-1 receptors rather it is mediated by Beta-1 receptor stimulation in heart.

Also increased gut motility (choice d) is purely a parasympathetic function.

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Q18: Which muscle divides the Submandibular gland into deep & superficial parts?

a) Omohyoid

b) Sternothyroid

c) Mylohyoid

d) Anterior belly of diagastric

Correct Answer: c

Explanation:

Submandibular gland lies in the floor of the mouth. It has two parts, a deep part and a superficial part. The gland is hook shaped. It hooks around the origin of mylohyoid muscle from the mylohyoid line on the inner suface of body of mandible. As it hooks around this muscle, the gland is itself gets divided into a deep & superficial part. See diagram below for a conceptual view.

Mylohyoid Muscle & Submandibular gland

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Q19: A female with primary amenorrhea, webbed neck and a height of 141 cm. What would her karyotype show?

a) 45 XO

b) 45 XX

c) 46 XXY

d) 47 XYY

Correct Answer: a

Explanation:

Primary amenorrhea with a webbed neck and short stature( 141cm = 4’7”)is a classical presentation of Turner’s syndrome. The karyotype of Turner’s syndrome is 45 XO that is, one X chromosome is absent. Other features of Turner’s yndrome include streak ovaries (ovarian dysgenesis) and preductal coarctation of aorta. The patient is a female and has decreased estrogen and elevated FSH & LH levels.

It is the most common cause of primary amenorrhea.

Also in such patients there is no barr body. Since barr body is actually an inactivated X chromosome, and one X chromosome is only inactivated if one has two X chromosome. If there is already a single X chromosome, then it is not inactivated to form barr body. For this reason in Turner’s syndrome since there is only one X therefore there is no barr body.

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Q20: A patient has difficulty closing his right eye and also has distorted facial appearance. He has damage to:

a) Right facial nerve

b) Right trigeminal nerve

c) Left facial nerve

d) Left trigeminal nerve

Correct Answer: a

Explanation:

UMN Lesion:

Upper face receives bilateral Upper motor neuron (UMN) innervation while lower face receives only contra lateral UMN innervation, so that if there is an UMN lesion ther e is contralateral paralysis of lower face only.

LMN Lesion of Facial Nerve:

In LMN lesion of facial nerve, whole (upper plus lower) face on the ipsilateral side is affected. So if the patient is unable to close right eye (upper face part) this definitely means that there is a LMN lesion or in other words the facial nerve on the affected side is lesioned.

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Q21: Dose of Gentamicin is reduced in the elderly due to:

a) Liver failure

b) Reduced renal function

c) Decreased GI absorption

d) Decreased metabolism

Correct Answer: b

Explanation:

Gentamicin is one of the Aminoglycosides. In elderly like all other body functions renal function is also slightly reduced. For Aminoglycosides such as Gentamicin, remember the following three important side effects:

• Ototoxicity
• Nephrotoxicity
• Neurmuscular dysfunction
• Teratogenic

Aminoglycosides are used for severe gram negative rod infections. Since they require oxygen for their uptake, they are therefore ineffective against anaerobes.

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Q22: A patient has fracture of surgical neck of humerus. Now he cannot raise his arm above his shoulder and also has sensory loss on lateral surface of arm. Which of the following nerves is damaged?

a) Musculocutaneous nerve

b) Axillary nerve

c) Radial nerve

d) Ulnar nerve

Correct Answer: b

Explanation:

The Axillary Nerve comes off the posterior cord of brachial plexus and has a root value of C5 & C6. During its course it is accompanied by the posterior circumflex humeral artery and vein.

Motor Supply: Deltoid muscle (abductor at the shoulder joint), Teres Minor muscle

Sensory Supply: Skin over the lower half of deltoid muscle, shoulder joint

The nerve most commonly damaged due to fracture of surgical neck of humerus is the Axillary nerve. It is a very commonly tested nerve. Commit it to memory. It supplies the major abductor (unable to raise the arm above the head) of the arm – Deltoid muscle. Also there is loss of sensation from the lower half of skin covering the deltoid (lateral aspect of arm).

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Q23: Action of Gluteus Medius and Gluteus Minimus muscle is:

a) Abduction & Medial rotation

b) Abduction & lateral rotation

c) Adduction & medial rotation

d) Adduction & lateral rotation

Correct Answer: a

Explanation:

The Gluteus Medius & Gluteus Minimus abduct the thigh when the leg is fully extended. They also turn the thigh inward that is, medially rotate the thigh. Weakness of these two abductors of thigh such as due to a lesion of superior gluteal nerve (which supplies these two muscles) can result in Trendelenburg Gait.

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Q24: Thymus is derived from:

a) 4^th Pharyngeal pouch

b) 2^nd pharyngeal pouch

c) 3^rd pharyngeal pouch

d) Tuberculum impar

Correct Answer: c

Explanation:

Derivatives of pharyngeal pouches:

• 1^st pouch: Middle ear cavity, Eustachian tube, mastoid air cells
• 2^nd pouch: epithelial lining of palatine tonsil
• 3^rd pouch: inferior parathyroid gland + thymus
• 4^th pouch: superior parathyroid gland

NOTE: It might seem strange that the inferior parathyroid glands arise from the 3^rd pouch while the superior parathyroid glands arise from the 4^th pouch. But this is how it is.

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Q 25: Patient after an ischemic attack has ventricular Tachycardia. Drug of choice is:

a) Amiodrone

b) Metoprolol

c) Lidocaine

d) Verapamil

Correct Answer: c

Explanation:

Lidocaine is classified as a class Ib anti-arrhythmic drug. It is also used as a local anaesthetic. It selectively blocks sodium channels in depolarized cardiac cells (e.g; ischemic cardiac muscle). It is therefore considered as a first line drug in ventricular tachycardia in acute MI or after cardiac surgery. It is given through the IV route.

Adverse effects of Lidocaine:

• high concentrations may cause bradycardia, hypotension and even asystole
• in 10% of patients may induce ventricular arrhythmias
• GI upset with nausea and vomiting
• CNS: parasthesiae, twitching and generalized tonic-clonic seizures

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Q26: Apex beat is located in:

a) 4^th left intercostal space in midclavicular line

b) 3^rd right intercostal space in midclavicular line

c) 5^th right intercostal space in midclavicular line

d) 8 cm to the left of midline in the 5^th intercostals space

Correct Answer: d

Explanation:

Apex beat is the point of maximum cardiac impulse.

The normal apex beat can be palpated in the precordium , in left 5th intercostal space, at the point of intersection with the left midclavicular line. The midclavicular line lies about 8cm from the left sterna border.

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Q27: Hemophilia is:

a) X-linked recessive

b) Autosomal dominant

c) Autosomal recessive

d) X-linked dominant

Correct Answer: a

Explanation:

Hemophilia is a hereditary bleeding disorder that is X-linked recessive. In this disorder there is deficiency of Factor VIII. Lab findings in Hemophilia are:

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Q28: Patient has hemoptysis & glomerulonephritis. The most probable diagnosis is:

a) Wegner’s Granulomatosis

b) Good Pasture Syndrome

c) Diabetic glomerulopathy

d) SLE nephritis

Correct Answer: b

Explanation:

Goodpasture syndrome (GS) is the clinical entity of acute glomerulonephritis and pulmonary alveolar hemorrhage. GS is associated with anti–glomerular basement membrane (anti-GBM) antibodies. These anti-GBM antibodies produce a characteristic linear deposition along the glomerular basement membrane (GBM), one way in which Goodpasture syndrome is differentiated from Wegener granulomatosis.

Hemoptysis is the most common presenting symptom in Goodpasture syndrome (GS).

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Q29: Middle meningeal artery passes through:

a) Foramen Spinosum

b) Foramen lacerum

c) Foramen rotundum

d) Foramen Ovale

Correct Answer: a

Explanation:

The middle meningeal artery is a branch of the maxillary artery. It enters the middle cranial fossa through the foramen spinosum.

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Q30: Damage to middle meningeal artery causes hematoma formation between:

a) Dura mater & arachnoid mater

b) Arachnoid mater & pia mater

c) Dura mater & clavaria

d) Pia mater & cortex

Correct Answer:

Explanation:

The middle meningeal artery is a branch of the maxillary artery. It enters the middle cranial fossa through the foramen spinosum and divides into anterior and posterior branches:

The cranial dura mater is a thick, tough, outer covering of the brain. It consists of an outer periosteal layer and an inner meningeal layer. The outer periosteal layer is firmly attached to the skull, is the periosteum of the cranial cavity, and is continuous with the periosteum on the outer surface of the skull at the foramen magnum and other intracranial foramina.

The Middle meningeal artery runs between the inner meningeal layer of dura and the the periosteal layer which is adherent to calvaria (the bony skull). Trauma or a blow to the lateral aspect of skull can result rupture of this artery and hematoma formation.

Such hematoma is known as an extradural hematoma.

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Q31: Which of the following cranial nerves carry parasympathetic fibers?

a) I,II, IV,VI

b) III,VII,IX,X

c) V,VI,VIII,XII

d) II,V,XI,X

Correct Answer: b

Explanation:

While the sympathetic nervous system has a spinal segment T2-L1 outflow, the parasympathetic nervous system on the other hand has a cranio-caudal outflow. So the parasympathetic system flows peripherally in 4 cranial nerves and in sacral segments of the spinal cord. The four cranial nerves that carry the parasympathetic fibers from the CNS to the periphery are:

• Oculomotor Nerve (III)
• Facial Nerve (VII)
• Glossopharyngeal Nerve (IX)
• Vagus Nerve (X)

The preganglionic parasympathetic fibers in these nerves synapse in 4 peripheral ganglia located in the head and neck. These nerves are related to these ganglia as follows:

• Occulomotor—Ciliary Ganglion
• Facial Nerve—-Pterygopalatine ganglion & submandibular ganglion
• Glossopharyngeal—–Otic ganglion

(for Vagus nerve the ganglia lie in the or near the organs like thoracic & abdominal organ that it supplies)

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Q32: Which of the followings pass through the cavernous sinus?

a) Trochlear Nerve

b) Facial Nerve

c) Abducens Nerve

d) Trigeminal Nerve

Correct Answer: c

Explanation:

The paired cavernous sinuses are against the lateral aspect of the body of the sphenoid bone on either side of the sella turcica (see figure below). They are of great clinical importance because of their connections and the structures that pass through them.

The cavernous sinuses receive blood not only from cerebral veins, but also from the ophthalmic veins (from the orbit) and emissary veins (from the pterygoid plexus of veins in the infratemporal fossa). These connections provide pathways for infections to pass from extracranial sites into intracranial locations. In addition, because structures pass through the cavernous sinuses and are located in the walls of these sinuses they are vulnerable to injury due to inflammation.

Structures passing through each cavernous sinus are: the internal carotid artery; the abducent nerve [VI].

Structures in the lateral wall of each cavernous sinus are, from superior to inferior: the oculomotor nerve [III]; the trochlear nerve [IV]; the ophthalmic nerve [V1]; the maxillary nerve [V2].

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Q33: Bromocriptine causes decreased prolactin levels by acting on:

a)      Dopamine receptors

b)      Cholinergic receptors

c)       Adrenergic receptors

d)      GABA receptors

Correct Answer: a

Explanation:

Bromocriptine is a dopamine agonist. Prolactin is one  of the anterior pituitary hormone. It increases the synthesis & secretion of dopamine from hypothalamus. Dopamine in turn inhibits the prolactin secretion.

Dopamine agonists (e.g, Bromocriptine) inhibit prolactin secretion, while dopamine antagonists (e.g, metoclopromide, antipsychotics) stimulate prolactin secretion.

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Q34: Which of the following investigation is appropriate in Hemophilia?

a)      PT

b)      APTT

c)       Bleeding time

d)      Platelet count

Correct Answer: b

Explanation:

Hemophilia is an X-linked hereditary disorder due to deficiency of factor VIII (Hemophilia A) or factor IX (Hemophilia B).

In general, defects in extrinsic coagulation cascade lead to an increased PT, and defect in intrinsic coagulation cascade lead to an increased aPTT.

In Hemophilia (factor VIII/IX deficiency):

• aPTT: raised
• Platelet count: normal
• Bleeding count: normal
• PT is also normal because there is no deficiency in extrinsic coagulation cascade.

NOTE:

PT tests for function of factors I, II, V, VII,  X

aPTT tests for function of all factors except  VII & XIII

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Q35: Drug used of mountain sickness:

a)      Scopolamine

b)      Frusemide

c)       Acetozolamide

d)      Dimenhydrinate

Correct Answer: c

Explanation:

Acetazolamide is a carbonic anhydrase inhibitor. It causes NaHCO₃ diuresis & reduction in total body HCO3 stores. Clinically it is used for Glaucoma, urinary alkalinization, metabolic alkalosis & mountain sickness.

Toxicity results in hyperchloremic metabolic acidosis, neuropathy, NH₃ toxicity, sulpha allergy.

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Q36: Which causes decreased gastric motility?

a)      Magnesium hydroxide

b)      Aluminium hydroxide

c)       NaCO₃

d)      CaCO₃

Correct Answer: b

Explanation:

To remember which causes what, remember the following mnemonic:

Aluminimum amount of feces

Mg: Must go to bathroom

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