-
Question 1
Incorrect
-
The half-empty cylinder weighs 4.44 kg. The tare weight of a nitrous oxide cylinder is 4 kg. The molecular weight of nitrous oxide is 44gm. Based on the data, how many litres of nitrous oxide remains in the cylinder for use?
Your Answer: 112 litres
Correct Answer: 224 litres
Explanation:The Tare weight of a cylinder is the weight when it is empty. So,
Weight of cylinder – tare weight = weight of remaining N2O (g).
4.44 kg – 4 kg = 0.44 kg
Here,
0.44 kg of nitrous oxide remains in the cylinderSince the molecular weight of nitrous oxide is 44 g and one mole of an ideal gas will occupy a volume of 22.4 litres at STP
Therefore amount left in the cylinder is several (gN2O/44) x 22.4 litres of N2O.(440/44) x 22.4 = 224 litres.
-
This question is part of the following fields:
- Basic Physics
-
-
Question 2
Correct
-
A 33-year old man was referred to you because of difficulty moving his limbs. History revealed that he was placed under anaesthesia for a major surgery 12 hours prior to the referral. Other symptoms were noted such as anxiousness, agitation, and fever of 38°C. Upon physical examination, he was tachycardic at 119 beats per minute. Moreover, his medical history showed that he was on Fluoxetine for clinical depression. The nurses reported that, because of his frequent complaints of axillary pain, he was given tramadol with paracetamol. Which of the following is responsible for his clinical features?
Your Answer: Tramadol
Explanation:Tramadol is weak agonist at the mu receptor. It inhibits the neuronal reuptake of serotonin and norepinephrine, and inhibits pain neurotransmission. It is given for moderate pain, chronic pain syndromes, and neuropathic pain.
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). It inhibits the neuronal reuptake of serotonin by inhibiting the serotonin transporter (SERT). It is the drug of choice for major depressive disorder, and is given for other psychiatric disorders such as anxiety, obsessive-compulsive, post-traumatic stress, and phobias.
When tramadol is given with SSRIs, serotonin syndrome may occur. Serotonin syndrome is characterized by fever, agitation, tremors, clonus, hyperreflexia and diaphoresis. The onset of symptoms may occur within a few hours, and the first-line treatment is sedation, paralysis, intubation and ventilation.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 3
Correct
-
A weakly acidic drug with a pKa of 8.4 is injected intravenously into a patient. At a normal physiological pH, the percentage of this drug unionised in the plasma is?
Your Answer: 90
Explanation:Primary FRCA is concerned with two issues. The first is a working knowledge of the Henderson-Hasselbalch equation, and the second is a working knowledge of logarithms and antilogarithms.
The pH at which the drug exists in 50 percent ionised and 50 percent unionised forms is known as the pKa.
To calculate the proportion of ionised to unionised form of a drug, use the Henderson-Hasselbalch equation.
pH = pKa + log ([A-]/[HA])
or
pH = pKa + log [(salt)/(acid)]
pH = pKa + log ([ionised]/[unionised])Hence, if the pKa ˆ’ pH = 0, then 50% of drug is ionised and 50% is unionised.
In this example:
7.4 = 8.4 + log ([ionised]/[unionised])
7.4 ˆ’ 8.4 = log ([ionised]/[unionised])
log ˆ’1 = log ([ionised]/[unionised])Simply put, the antilog is the inverse log calculation. In other words, if you know the logarithm of a number, you can use the antilog to find the value of the number. The antilogarithm’s definition is as follows:
y = antilog x = 10x
Antilog to the base 10 of 0 = 1, ˆ’1 = 0.1, ˆ’2 = 0.01, ˆ’3 = 0.001 and, ˆ’4 = 0.0001.
[A-]/[HA] = 0.1
Assuming that we can apply the approximation [A-] << [HA} then this means the acid is 0.1 x 100% = 10% ionised
so the percentage of (non-ionized) acid will be 100% – 10% = 90%
-
This question is part of the following fields:
- Pharmacology
-
-
Question 4
Incorrect
-
A 43-year old woman, presented to the emergency department. She has suffered trauma to her right orbital floor. On examination, it is noted that her right eye is deviated upwards when compared to her left. She also has a deliberate tilt in her head to the left in an attempt to compensate for loss of intorsion. This clinical sign is caused by damage to which of the following cranial nerves?
Your Answer: Abducens nerve
Correct Answer: Trochlear nerve
Explanation:The trochlear nerve (CN IV) is the fourth and smallest cranial nerve. It’s role is to provide somatic motor innervation of the superior oblique muscle which is responsible for oculomotion.
Injury to the trochlear nerve will result in vertical diplopia, which worsens when looking downwards or inwards. This diplopia presents as an upward deviation of the eye with a head tilt away from the site of the lesion.
The abducens nerve (CN VI) provides somatic motor innervation for the lateral rectus muscle which functions to abduct the eye. Injury to this nerve will cause diplopia and an inability to abduct the eye, causing the patient to have to rotate their head to look sideways.
The facial nerve (CN VII) provides sensory, motor and parasympathetic innervations. It’s motor aspect controls the muscles of facial expression. Damage will cause paralysis of facial expression.
The oculomotor nerve (CN III) provides motor and parasympathetic innervations. Its motor component controls most of the other extraocular muscles. Damage to it will result in ptosis, dilatation of the pupil and a down and out eye position.
The ophthalmic division of the trigeminal nerve (CN VI) is responsible for sensory innervation of skin, mucous membranes and sinuses of the upper face and scalp.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 5
Correct
-
A 62-year-old woman, presents to emergency department with an ischaemic left colon. Multiple arteries arise from the aorta at the level of the L3 vertebrae, which is most likely to be involved in this pathology?
Your Answer: Inferior mesenteric artery
Explanation:The inferior mesenteric artery arises from the abdominal aorta at the level of the L3 vertebrae and supplies blood to the final third of the transverse colon, the descending colon, the sigmoid colon and the uppermost part of the rectum.
It is the artery most likely to affect the left colon.
-
This question is part of the following fields:
- Anatomy
-
-
Question 6
Correct
-
This vertebrae can be easily differentiated from the rest because of its prominent spinous process.
Your Answer: C7
Explanation:The spinous process is the part of a vertebrae that is directed posteriorly.
Typical cervical vertebra have spinous processes that are small and bifid, except for C7, which has a long and prominent spinous process.
-
This question is part of the following fields:
- Anatomy
-
-
Question 7
Correct
-
At 37 weeks' gestation, a 29-year-old parturient is admitted to the labour ward. Her antenatal period was asymptomatic for her. The haematological values listed below are available: Hb concentration of 100 g/L (115-165), 200x109/L platelets (150-400), MCV 81 fL (80-96). Which of the following is the most likely reason for the problem?
Your Answer: Iron deficiency
Explanation:This patient’s limited haematological profile includes mild normocytic anaemia and a normal platelet count.
Iron deficiency is the most common cause of anaemia during pregnancy. It affects 75 to 95 percent of patients. A haemoglobin level of less than 110 g/L in the first trimester and less than 105 g/L in the second and third trimesters is considered anaemia. There will usually be a low mean cell volume (MCV), mean cell haemoglobin (MCH), and mean cell haemoglobin concentration in addition to a low haemoglobin (MCHC). The MCV may be normal in mild cases of iron deficiency or coexisting vitamin B12 and folate deficiency.
To determine whether you have an iron deficiency, you’ll need to take more tests. Low serum ferritin (15 g/L) and less reliable indices like serum iron and total iron binding capacity are among them.
A number of factors contribute to iron deficiency in pregnancy, including:
Insufficient dietary iron to meet the mother’s and foetus’ nutritional needs
Multiple pregnancies
Blood loss, as well as
Absorption of iron from the gut is reduced.The volume of plasma increases by about 50% during pregnancy, but the mass of red blood cells (RBCs) increases by only 30%. Dilutional anaemia is the result of this situation. From the first trimester to delivery, the RBC mass increases linearly, while the plasma volume plateaus, stabilises, or falls slightly near term. As a result, between 28 and 34 weeks of pregnancy, haemoglobin concentrations are at their lowest. The effects of haemodilution will be negated in this patient because she is 37 weeks pregnant.
Vitamin B12 and folate deficiency are less common causes of anaemia in pregnancy. The diagnosis could be ruled out if the MVC is normal.
During pregnancy, the platelet count drops, especially in the third trimester. Gestational thrombocytopenia is the medical term for this condition. It’s due to a combination of factors, including haemodilution and increased platelet activation and clearance. Pre-eclampsia and HELLP syndrome are common causes of thrombocytopenia. Pre-eclampsia isn’t the only cause of anaemia during pregnancy.
A typical blood picture of a haemoglobinopathy like sickle cell disease shows quantitative and qualitative defects, with the former leading to a severe anaemia exacerbated by haemodilution and other factors that contribute to iron deficiency. Microcytic cells are the most common type.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 8
Incorrect
-
A chain smoker is interested in knowing how many years of his life would be lessened by smoking. You tell him explicitly that precise determination is impossible but you can tell him the proportion of people who died due to smoking. Which of the following epidemiological term is apt in this regard?
Your Answer: Attributable proportion - the risk of an event relative to exposure.
Correct Answer: Attributable risk - the rate in the exposed group minus the rate in the unexposed group
Explanation:Attributable proportion is the proportion of disease that is caused due to exposure. It refers to the proportion of disease that would be eradicated from a particular population if the disease rate was diminished to match that of the unexposed group.
Risk ratio (relative risk) compares the probability of an event in an exposed (experimental) group to that of an event in the unexposed (control) group. Thus two are not the same.
The attributable risk is the rate of a disease in an exposed group to that of a group that has not been exposed to it i.e. how many deaths did the exposure cause.
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 9
Correct
-
An aged patient that has been suffering from diabetes criticised the health minister for his comments on incidence and prevalence. The minister had said that they both are two separate entities. It can be therefore inferred that the patient thinks that prevalence and incidence are the same thing. Is he right?
Your Answer: No. In chronic disease prevalence is greater than incidence.
Explanation:Only on rare occasions has it been found that the prevalence and incidence were same. Incidence can be greater than prevalence in acute cases only. In case of chronic diseases prevalence is far greater than incidence. One needs to have a deeper understanding of both the concepts to understand the health literature.
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 10
Correct
-
A 20-year-old female presents to the emergency department. She complains of increased shortness of breath and wheezing over the last 48 hours. On examination, she is found to have tachycardia, tachypnoea, and oxygen saturation at 91% on air. She admits to a previous medical history of asthma, diagnosed 4 years ago. She requires further investigations for diagnosis. Which of the following is true about the assessment of a patient with symptomatic asthma?
Your Answer: Oxygen saturations of 91% on air would be an indication for performing arterial blood gases
Explanation:A patient presenting with symptomatic asthma should be assessed for severity to determine appropriate management options. Indications of acute severe asthma are:
Peak expiratory flow rate (PEFR): 33-50% best/predicted
Respiratory rate: ‰¥25/min
Heart rate: ‰¥110/min
Inability to finish a complete sentence in a single breath.Oxygen saturation should be measured. Any measurement of an oxygen saturation of 92% or less, either on air or on oxygen, indicates severe, life threatening asthma, and requires an arterial blood gas (ABG) to detect normo- or hypercarbia.
A chest x-ray would not be routine as it will not provide any relevant information. It is only required in specific cases, including:
Diagnosis of a subcutaneous emphysema
Indications of a unilateral pneumothorax
Indications of a lobar collapse of consolidation
Treatment-resistance life-threatening asthma
If mechanical ventilation is indicatedA peak expiratory flow rate (PEFR) can provide relevant information to help distinguish between acute, moderate, severe and life threatening asthma. However, it is not necessary as other parameters exist that can also help make the same distinction.
An ECG is indicated in this case as the patient has tachycardia and tachypnoea which are indicative of acute severe asthma. The ECG would indicate if arrhythmia is also present which would suggest life-threatening asthma.
-
This question is part of the following fields:
- Clinical Measurement
-
-
Question 11
Incorrect
-
A 25-year -old man, presents with a suspected uretic colic and is placed on admission. An abdominal x-ray of the kidney, ureter and bladder (KUB) is ordered. Where is the stone most likely to be located on x-ray?
Your Answer: Over the sacrococcygeal joint
Correct Answer: The tips of the transverse processes between L2 and L5
Explanation:The ureter runs anterior to the vertebrae at the level of L2 to L5, and stones are usually seen at these points on x-ray.
They can also be seen at the level of the sacro-iliac joints.
-
This question is part of the following fields:
- Anatomy
-
-
Question 12
Incorrect
-
For a rapid sequence induction of anaesthesia, you are pre-oxygenating a patient using 100% oxygen and a fresh gas flow equal to the patient's minute ventilation. Which would be the most suitable choice of anaesthetic breathing system in this situation?
Your Answer: Mapleson C system
Correct Answer: Mapleson A system
Explanation:The Mapleson A (Magill) and coaxial version of the Mapleson A system (Lack circuit) are more efficient for spontaneous breathing than any of the other Mapleson circuits. The fresh gas flow (FGF) required to prevent rebreathing is slightly greater than the alveolar minute ventilation (4-5 litres/minute). This is delivered to the patient through the outer coaxial tube and exhaust gases are moved to the scavenging system through the inner tube. In the Lack circuit, the expiratory valve is located close to the common gas outlet away from the patient end. This is the main advantage of the Lack circuit over the Mapleson A circuit.
The Mapleson E circuit is a modification of the Ayres T piece and the FGF required to prevent rebreathing is 1.5-2 times the patient’s minute volume.
The Bain circuit is the coaxial version of the Mapleson D circuit.
The FGF for spontaneous respiration to avoid rebreathing is 160-200 ml/kg/minute.
The FGF for controlled ventilation to avoid rebreathing is 70-100 ml/kg/min.
-
This question is part of the following fields:
- Anaesthesia Related Apparatus
-
-
Question 13
Incorrect
-
All of the statements describing the blood brain barrier are false EXCEPT:
Your Answer: The chemoreceptor trigger zone is located inside the blood brain barrier
Correct Answer: Inflammation alters its permeability
Explanation:The blood brain barrier (BBB) consists of the ultrafiltration barrier in the choroid plexus and the barrier around cerebral capillaries. The barrier is made by endothelial cells which line the interior of all blood vessels. In the capillaries that form the blood€“brain barrier, endothelial cells are wedged extremely close to each other, forming so-called tight junctions.
Outside of the BBB lies the hypothalamus, third and fourth ventricles and the chemoreceptor trigger zone (CTZ).
Water, oxygen and carbon dioxide cross the BBB freely but glucose is controlled. The ability of chemicals to cross the barrier is proportional to their lipid solubility, not their water solubility. It’s ability to cross is inversely proportional to their molecular size and charge.
In neonates, the BBB is less effective than in adults. This is why there is increased passage of opioids and bile salts (kernicterus) into the neonatal brain.
In meningitis, the effectiveness and permeability of the BBB is affected, and as a result, this effect helps the passage of antibiotics which would otherwise not normally be able to cross.
-
This question is part of the following fields:
- Physiology
-
-
Question 14
Incorrect
-
A 30-year-old man has been diagnosed with a direct inguinal hernia. A direct inguinal hernia passes through Hesselbach's triangle. What forms the medial edge of this triangle?
Your Answer: Inferior epigastric artery
Correct Answer: Rectus abdominis muscle
Explanation:The inguinal triangle of Hesselbach’s is an important clinical landmark on the posterior wall of the inguinal canal. It has the following relations:
Inferiorly – medial third of the inguinal ligament
Medially – lower lateral border of the rectus abdominis
Laterally – inferior epigastric vesselsDirect inguinal hernia is when the bowel bulges directly through the abdominal wall. These hernias usually protrude through Hesselbach’s triangle.
-
This question is part of the following fields:
- Anatomy
-
-
Question 15
Correct
-
An older woman has been brought into the emergency department with symptoms of a stroke. A CT angiogram is performed for diagnosis, which displays narrowing in the artery that supplies the right common carotid. Which of the following artery is the cause of stroke in this patient?
Your Answer: Brachiocephalic artery
Explanation:The arch of aorta gives rise to three main branches:
1. Brachiocephalic artery
2. Left common carotid artery
3. Left subclavian arteryThe brachiocephalic artery then gives rise to the right subclavian artery and the right common carotid artery.
The right common carotid artery arises from the brachiocephalic trunk posterior to the sternoclavicular joint.
The coeliac trunk is a branch of the abdominal aorta.
The ascending aorta supplies the coronary arteries. -
This question is part of the following fields:
- Anatomy
-
-
Question 16
Correct
-
A 10-year-old boy is undergoing investigations for coeliac disease. Tissue biopsies were taken from both the small and large intestinal linings. Which of the following is found in the small intestine lining but not in that of the large intestine in a normal biopsy?
Your Answer: Villi
Explanation:The small and large intestinal walls are composed of the following common layers:
1. Mucosa
2. Submucosa
3. Muscularis Externa
4. AdventitiaIntestinal villi are highly vascular projections of the mucosal surface that cover the entire small intestinal mucosa. They increase the lumen’s surface area, which aids in absorption and digestion, the primary functions of the small intestine. Villi are large and most abundant in the duodenum and jejunum.
In both the small and large intestines, the muscularis mucosae are found within the mucosa. The myenteric nerve plexus is found innervating the muscularis externa. The mucosa is lined with columnar epithelial cells, and goblet cells may be present to secrete mucins.
-
This question is part of the following fields:
- Anatomy
-
-
Question 17
Incorrect
-
The Fick principle can be used to determine the blood flow to any organ of the body. At rest, which one of these organs has the highest blood flow (ml/min/100g)?
Your Answer: Kidney
Correct Answer: Thyroid gland
Explanation:After the carotid body, the thyroid gland is the second most richly vascular organ in the body.
The global blood flow to the thyroid gland can be measured using:
1. Colour ultrasound sonography
2. Quantitative perfusion maps using MRI of the thyroid gland using an arterial spin labelling (ASL) method.This table shows the blood flow to various organs of the body at rest:
Organ Blood Flow(ml/minute/100g)
Hepatoportal 58
Kidney 420
Brain 54
Skin 13
Skeletal muscle 2.7
Heart 87
Carotid body 2000
Thyroid gland 560 -
This question is part of the following fields:
- Physiology
-
-
Question 18
Incorrect
-
A 61-year-old woman with myasthenia gravis is admitted to the ER with type II respiratory failure. There is a suspicion of myasthenic crisis. She is in a semiconscious state. Her blood pressure is 160/90 mmHg, pulse is 110 beats per minute, temperature is 37°C, and oxygen saturation is 84 percent. With a PaCO2 of 75 mmHg (10 kPa) breathing air, blood gas analysis confirms she is hypoventilating. Which of the following values is the most accurate representation of her alveolar oxygen tension (PAO2)?
Your Answer: 8.3
Correct Answer: 7.3
Explanation:The following is the alveolar gas equation:
PAO2 = PiO2 ˆ’ PaCO2/R
Where:
PAO2 is the partial pressure of oxygen in the alveoli.
PiO2 is the partial pressure of oxygen inhaled.
PaCO2 stands for partial pressure of carbon dioxide in the arteries.
The amount of carbon dioxide produced (200 mL/minute) divided by the amount of oxygen consumed (250 mL/minute) equals R = respiratory quotient. With a normal diet, the value is 0.8.By subtracting the partial pressure exerted by water vapour at body temperature, the PiO2 can be calculated:
PiO2 = 0.21 × (100 kPa ˆ’ 6.3 kPa)
PiO2 = 19.8Substituting:
PAO2 = 19.8 ˆ’ 10/0.8
PAO2 = 19.8 ˆ’ 12.5
PAO2 = 7.3k Pa -
This question is part of the following fields:
- Physiology
-
-
Question 19
Correct
-
Which of the following causes a left shift of the haemoglobin dissociation curve?
Your Answer: With decreased 2,3-DPG in transfused red cells
Explanation:With respect to oxygen transport in cells, almost all oxygen is transported within erythrocytes. There is limited solubility and only 1% is carried as solution. Thus, the amount of oxygen transported depends upon haemoglobin concentration and its degree of saturation.
Haemoglobin is a globular protein composed of 4 subunits. Haem is made up of a protoporphyrin ring surrounding an iron atom in its ferrous state. The iron can form two additional bonds – one is with oxygen and the other with a polypeptide chain.
There are two alpha and two beta subunits to this polypeptide chain in an adult and together these form globin. Globin cannot bind oxygen but can bind to CO2 and hydrogen ions.
The beta chains are able to bind to 2,3 diphosphoglycerate. The oxygenation of haemoglobin is a reversible reaction. The molecular shape of haemoglobin is such that binding of one oxygen molecule facilitates the binding of subsequent molecules.The oxygen dissociation curve (ODC) describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood.
Of note, it is not affected by haemoglobin concentration.Chronic anaemia causes 2, 3 DPG levels to increase, hence shifting the curve to the right
Haldane effect – Causes the ODC to shift to the left. For a given oxygen tension there is increased saturation of Hb with oxygen i.e. Decreased oxygen delivery to tissues.
This can be caused by:
-HbF, methaemoglobin, carboxyhaemoglobin
-low [H+] (alkali)
-low pCO2
-ow 2,3-DPG
-ow temperatureBohr effect – causes the ODC to shifts to the right = for given oxygen tension there is reduced saturation of Hb with oxygen i.e. Enhanced oxygen delivery to tissues. This can be caused by:
– raised [H+] (acidic)
– raised pCO2
-raised 2,3-DPG
-raised temperature -
This question is part of the following fields:
- Physiology And Biochemistry
-
-
Question 20
Correct
-
A 35-year old male is found to be bradycardic in the emergency room. His cardiac muscle will most likely stay in a prolonged phase 4 state of the cardiac action potential. During phase 4 of the cardiac action potential, which of these occurs?
Your Answer: Na+/K+ ATPase acts
Explanation:Cardiac conduction
Phase 0 – Rapid depolarization. Opening of fast sodium channels with large influx of sodium
Phase 1 – Rapid partial depolarization. Opening of potassium channels and efflux of potassium ions. Sodium channels close and influx of sodium ions stop
Phase 2 – Plateau phase with large influx of calcium ions. Offsets action of potassium channels. The absolute refractory period
Phase 3 – Repolarization due to potassium efflux after calcium channels close. Relative refractory period
Phase 4 – Repolarization continues as sodium/potassium pump restores the ionic gradient by pumping out 3 sodium ions in exchange for 2 potassium ions coming into the cell. Relative refractory period
-
This question is part of the following fields:
- Physiology And Biochemistry
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)