-
Question 1
Incorrect
-
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: Muscularis mucosae
Correct 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 2
Incorrect
-
One litre of water at 0°C and a pressure of 1 bar is in a water-bath. A 1 kW element is used in heating it. Given that the specific heat capacity of water is 4181 J/(kg°C) or J/(kg K), how long will it take to raise the temperature of the water by 10°C?
Your Answer: 7 minutes
Correct Answer: 42 seconds
Explanation:The amount of energy required to change the temperature of 1 kg of a substance by 1°C is its specific heat capacity.
Energy required to increase the temperature of any object is given by the equation:
E = m × c × θ
Where:
E = energy required to heat an object
m = mass of object
c = specific heat capacity of the substance
θ = temperature changeThe specific heat capacity of water is 4181 J/(kg°C)
Therefore the energy required to raise 1kg of water by 10°C is:
1 kg × 4181 J/(kg°C) × 10°C = 41810 J
A 1 kW or 1000 W heater would be expected to supply 1000 J/s.
The approximate time it would take the 1 kW heater to raise the temperature of one Litre of water by 10°C is:
41810/1000 = 41.8 seconds.
-
This question is part of the following fields:
- Physiology
-
-
Question 3
Incorrect
-
The following statements are about changes that occur at birth. Which is accurate?
Your Answer: The pulmonary vascular resistance rises
Correct Answer: The systemic vascular resistance rises
Explanation:The umbilical vein closes once the umbilical cord is clamped following birth. This causes a rise in systemic vascular resistance, closing the ductus venosus.
Upon birth, the pulmonary vascular resistance is decreased as the lungs are aerated.
At birth, there is a rise in oxygen tension which causes the corresponding constriction of the ductus arteriosus. This prevents a left to right shunt as it stops aortic blood and blood from the pulmonary artery from mixing. The ventricles do no have an opening connecting them.
The foramen ovale closes soon after birth. It is the septum opening between the left and right atrium.
An adult’s cardiac output is expected to be 5 L/min.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 4
Incorrect
-
Which of the following is true regarding Noradrenaline (Norepinephrine)?
Your Answer: Has a half life around 15 mins
Correct Answer: Sympathomimetic effects work mainly through α1 but also β receptors
Explanation:Noradrenaline acts as a sympathomimetic effect via alpha as well as a beta receptor. However, they have weak β2 action.
Natural catecholamines are Adrenaline, Noradrenaline, and Dopamine
-
This question is part of the following fields:
- Pharmacology
-
-
Question 5
Correct
-
At what site would you palpate to assess the posterior tibial pulse?
Your Answer: Behind and below the medial ankle
Explanation:The posterior tibial artery originates from the popliteal artery in the popliteal fossa. It passes posterior to the popliteus muscle to pierce the soleus muscle. It descends between the tibialis posterior and flexor digitorum longus muscles.
The posterior tibial artery supplies blood to the posterior compartment of the lower limb. The artery can be palpated posterior to the medial malleolus.
There are 4 main pulse points for the lower limb:
1. Femoral pulse 2-3 cm below the mid-inguinal point
2. Popliteal partially flexed knee to loosen the popliteal fascia
3. Posterior tibial behind and below the medial ankle
4. Dorsal pedis dorsum of the foot over the navicular bone. -
This question is part of the following fields:
- Anatomy
-
-
Question 6
Correct
-
Which of the following is an expected change in pulmonary function seen during a moderate asthma attack?
Your Answer: Decreased forced expiratory volume in 1 sec (FEV1)
Explanation:Asthma is a lung condition that causes reversible narrowing and swelling of airway passages. It is classified by the frequency and severity of symptoms.
The following are symptoms of moderate asthma:
Symptoms include cough, wheezing, chest tightness, or difficulty breathing which occurs daily
Decreased activity levels due to flare-ups
Night-time symptoms 5 or more times a month
Lung function test FEV1 is 60-80% of predicted normal values
Peak flow has more than 30% variabilityWith moderate asthma attacks, the arterial pCO2 levels may decrease, but as severity increases, so does the pCO2, reaching normal levels, and then exceeding them in severe asthma attacks.
Airway obstruction increases the functional residual capacity.
Concentration of serum bicarbonate would not increase in moderate asthma, but it could possibly increase in life-threatening asthma via the same mechanism as what increases arterial PCO2.
FEV1 is a good measure of airway obstruction. and is reduced in acute asthma attacks.
In the case of a pneumothorax, a decrease in arterial PO2 is higher.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 7
Correct
-
At a pH of 7, pure water has an hydrogen ion concentration of?
Your Answer: 100 nanomol/L
Explanation:pH is the negative log to the base 10 of hydrogen ion concentration:
So, what power produces the answer?
pH = – log10 [H+]
Making [H+] the subject:
[H+] = 10-pH
Substituting, [H+] = 10-7
One nanomole = 1 x 10-9 or 0.000000001
10-7 = 1x 0.0000001 or 10 x 0.00000001 or 100 x 0.000000001
100 nanomole.
-
This question is part of the following fields:
- Basic Physics
-
-
Question 8
Incorrect
-
Typical sigmoid log dose-response curves are seen in agonists and are used to compare efficacy and potency. Which of the following opioids has a log dose-response curve furthest to the right?
Your Answer: Fentanyl
Correct Answer: Tramadol
Explanation:Lesser the potency of the drug, the higher the dose required to produce maximal receptor occupation. So, the least potent drug will have a log dose-response curve furthest to the right on X-axis.
Based on the option given, tramadol is the least potent drug and thus higher dose is required to produce maximal opioid receptor occupation.
Thus, Tramadol is the least potent opioid with a log dose-response curve furthest to the right on X-axis.
Note, Fentanyl is the most potent opioid with a log dose-response curve furthest to the left on the X-axis.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 9
Correct
-
The single most important prerequisite for accuracy in measuring basal metabolic rate (BMR) using indirect calorimetry is performing the test:
Your Answer: In a neutral thermal environment
Explanation:The basal metabolic rate (BMR) is the amount of energy required to maintain basic bodily functions in the resting state. The unit is Watt (Joule/second) or calories per unit time.
Indirect calorimetry measures O2 consumption and CO2 production where gases are collected in a canopy which is the gold standard, Douglas bag, face-mask dilution technique or interfaced with a ventilator.
The BMR can be calculated using the Weir formula:
Metabolic rate (kcal per day) = 1.44 (3.94 VO2 + 1.11 VCO2)
The BMR should be measured while lying down and at rest with the following conditions met:
It should follow a 12 -hour fast
No stimulants ingested within a 12-hour period
It should be done in a neutral thermal environment (between 20°C-25°C) -
This question is part of the following fields:
- Physiology
-
-
Question 10
Incorrect
-
Which of these statements is true about spirometry?
Your Answer: Total lung capacity equals the vital capacity and the functional residual capacity
Correct Answer: A capacity is the sum of two or more volumes
Explanation:Functional residual capacity (FRC) is 1.7 to 3.5L/kg
A capacity is the sum of two or more volumes. The total lung capacity (TLC) is total sum of the volume of gas present in all lung compartments upon maximum inspiration. It is represented mathematically as:
Total lung capacity (TLC) = Vital capacity (VC) + Residual volume (RV)
The residual volume (RV) is the volume of gas still present within the lung post maximum exhalation. It cannot be measured by spirometry, but can be using a body plethysmograph and also with the helium dilution technique.
Closing capacity (CC) is the volume of gas within the lungs at which small airways close upon expiration. It increases with age and is especially important when it surpasses the FRC as it causes changes in ventilation/perfusion mismatch and hypoxia.
In the supine position, a patient with a normal body mass index and no history of lung pathology, the CC equals the FRC at approximately 44, and at approximately 66 at standing position. -
This question is part of the following fields:
- Clinical Measurement
-
-
Question 11
Correct
-
Regarding aldosterone, one of the following is true.
Your Answer: Secretion is increased following haematemesis
Explanation:Aldosterone is produced in the zona glomerulosa of the adrenal cortex and acts to increase sodium reabsorption via intracellular mineralocorticoid receptors in the distal tubules and collecting ducts of the nephron.
Its release is stimulated by hypovolaemia, blood loss ,and low plasma sodium and is inhibited by hypertension and increased sodium. It is regulated by the renin-angiotensin system.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 12
Incorrect
-
A 76-year-old man, presents to his general practitioner with a lump in his left groin. Upon examination, his doctor is able to diagnose a direct inguinal hernia. There are many structures present in the inguinal canal. Where is the ilioinguinal nerve located in relation to the spermatic cord?
Your Answer: Posterior to the spermatic cord
Correct Answer: Anterior to the spermatic cord
Explanation:The answer is anterior to the spermatic cord.
The inguinal canal in men contains the ilioinguinal nerve, the genitofemoral nerve and the spermatic cord.
The ilioinguinal nerve arises of the L1 nerve root with the Iliohypogastric nerve, before entering the inguinal canal from the side, through the muscles of the abdomen, travelling superficial to the spermatic cord.
-
This question is part of the following fields:
- Anatomy
-
-
Question 13
Correct
-
A 54-year-old lady comes in for a right-sided elective bunionectomy with a realignment osteotomy under local anaesthetic on her first (large) toe. For the operation, which of the following nerve blocks will be most effective?
Your Answer: Superficial peroneal, deep peroneal and posterior tibial nerves
Explanation:An ankle block is commonly used for anaesthesia and postoperative analgesia when operating on bunions. It results in the selective block of the superficial peroneal, deep peroneal, and posterior tibial nerves.
The deep peroneal nerve supplies sensory input to the web space between the first and second toes (L4-5).
The L2-S1 nerve, often known as the superficial peroneal nerve, is a mixed motor and sensory neuron. It gives sensory supply to the anterolateral region of the leg, the anterior aspect of the 1st, 2nd, 3rd, and 4th toes, and innervates the peroneus longus and brevis muscles (with the exception of the web space between 1st and 2nd toes).
The sensory area of the saphenous nerve (L3-4) in the foot stretches from the proximal portion of the midfoot on the medial side to the proximal part of the midfoot on the lateral side.
The lateral side of the little (fifth) toe is innervated by the sural nerve’s sensory supply (S1-2). The heel, medial (medial plantar nerve), and lateral (lateral plantar nerve) soles of the foot are all served by the posterior tibial nerve.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 14
Correct
-
Health workers are at increased risks of anaesthetic exposure. Therefore, The Control of Substances Hazardous to Health (COSHH) regulations require measures implemented to assess and control the risks related to this exposure. Among the following control measures, which one is most likely to limit potentially harmful exposure to anaesthetic agents within an operating theatre?
Your Answer: Total intravenous anaesthesia (TIVA)
Explanation:Exposure to anaesthetic hazards is one among the occupational exposures in manipulating toxic agents or inhaling toxic gases during anaesthetic practices.
Toxic gases mainly nitrous oxide, is one of the most gaseous anaesthetic agents that constitutes an important source of pollution. One of the safe and effective technics used in anaesthesia and reducing the amount of pollution is the Total Intravenous Anaesthesia (TIVA) which consists of using opioids in analgesia and propofol for the induction and the maintenance of anaesthesia. It refers to the administration intravenously of an anaesthetic, sedative, and/or tranquilizer. A less polluting but not the best way to get rid of the toxic aesthetic agents is the scavenger system that collects and expels the gas outside the medical environment. Yet, this technique still represents a hazard for the environment and still increase the risk of exposure for the health workers and clinical staff.
Fume cupboards are also not recommended to use because of their high pollution potency, mainly of the air resulting in a great harm for medical workers.
Supraglottic airways as well as the Air Changes per Hour technics could be harmful for both patients and health workers, increasing the risks of transmitted diseases, namely nosocomial infections.
Therefore, the Total Intravenous Anaesthesia technique (TIVA) is most likely to be safe and recommended to use.
-
This question is part of the following fields:
- Anaesthesia Related Apparatus
-
-
Question 15
Incorrect
-
Which of the following statements is true regarding sucralfate?
Your Answer: Is a simple compound formed from sulphated sucrose
Correct Answer: Has very few side effects
Explanation:Sucralfate is an octasulfate of glucose to which Al(OH)3 has been added. It undergoes extensive cross-linking in an acidic environment and forms a polymer which adheres to the ulcer base for up to 6 hours and protects it from further erosion. Since it is not systemically absorbed it is virtually devoid of side effects. However, it may cause constipation in about 2% of cases due to the Aluminium component in it.
Sucralfate does not have antibacterial action against Helicobacter pylori. However, Bismuth has antibacterial action due to its oligodynamic effect.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 16
Incorrect
-
Following an acute appendicectomy, a 6-year-old child is admitted to the recovery unit. Your consultant has requested that you prescribe maintenance fluids for the next 12 hours. The child is 21 kg in weight. What is the most suitable fluid volume to be prescribed?
Your Answer: 61 ml
Correct Answer: 732 ml
Explanation:After a paediatric case, you’ll frequently have to calculate and prescribe maintenance fluids. The ‘4-2-1 rule’ should be used as a guideline:
1st 10 kg – 4 ml/kg/hr
2nd 10 kg – 2 ml/kg/hr
Subsequent kg – 1 ml/kg/hrHence
1st 10 kg = 4 × 10 = 40 ml
2nd 10 kg = 2 × 10 = 20 ml
Subsequent kg = 1 × 1 = 1 ml
Total = 61 ml/hr61 × 12 = 732 ml over 12 hrs.
-
This question is part of the following fields:
- Physiology
-
-
Question 17
Incorrect
-
Using a negative feedback loop, Haem production is controlled by which of these enzymes?
Your Answer: Ferrochelatase
Correct Answer: ALA synthetase
Explanation:Heme a exists in cytochrome a and heme c in cytochrome c; they are both involved in the process of oxidative phosphorylation. 5′-Aminolevulinic acid synthase (ALA-S) is the regulated enzyme for heme synthesis in the liver and erythroid cells.
There are two forms of ALA Synthase, ALAS1, and ALAS2.
-
This question is part of the following fields:
- Physiology
-
-
Question 18
Incorrect
-
Among the following which one is not a criterion for the assessment of causality?
Your Answer: Coherence
Correct Answer: Sensitivity
Explanation:For establishing a cause effect relationship, following criteria must be met:
1. Coherence & Consistency
2. Temporal Precedence
3. Specificity
As can be seen, sensitivity (The probability of a positive test) is not among these deciding factors..
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 19
Incorrect
-
Substitution at different positions of the barbituric ring give rise to different pharmacologic properties. Substitution with and at which specific site of the ring affects lipid solubility the most?
Your Answer: Aromatic group at position 5
Correct Answer: Sulphur atom at position 2
Explanation:Barbiturates are derived from barbituric acid, which itself is nondepressant, but appropriate side-chain substitutions result in CNS depressant activity that varies in potency and duration with carbon chain length, branching, and saturation.
Oxybarbiturates retain an oxygen atom on number 2-carbon atom of the barbituric acid ring.
Thiobarbiturates replace this oxygen atom with a sulphur atom, which confers greater lipid solubility. Generally speaking, a substitution such as sulphuration that increases lipid solubility is associated with greater hypnotic potency and more rapid onset, but shorter duration of action.
Addition of a methyl group to the nitrogen atom of the barbituric acid ring, as with oxybarbiturate methohexital, also results in a compound with a short duration of action.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 20
Incorrect
-
A current flows through a simple electric circuit. Which of the following electrical component configurations has the greatest potential difference?
Your Answer: Two 5 farad capacitors in parallel charged to 100 coulomb
Correct Answer: Two 5 ohm resistors in series with a passing current of 10 ampere
Explanation:According to the Ohm’s law, the potential difference is defined as
V(potential difference) = I(current) x (R) resistance
So, for one resistor of 5 ohms, a 10 ampere current will generate:
V = I x R
V = 10 x 5
V = 50 voltsThe formula for resistors in series can be defined as:
R(total) = R1+R2
Hence, when a current of 10 amperes passes through two 5 ohms resistors that are connected in series, the potential difference is:
V = I x (R1+R2)
V = 10 x (5+5)
V = 10 x 10
V = 100 voltsThe formula for resistors that are connected in a parallel circuit is:
1/ Rtotal = 1/R1 + 1/R2
Hence, when a current of 10 amperes passes through two 5 Ω resistors that are connected in a parallel circuit, the potential difference is:
Rtotal = R1 × R2/ R1 + R2
Rtotal = 25/10
Rtotal = 2.5
V = I x R
V = 10 x (R1xR2 / R1 + R2)
V = 10 x (25/10)
V = 10 x 2.5
V = 25 voltsCapacitors are electronic components that have the ability to store energy and charge (Q). The derived SI unit of capacitance (C) is the farad (F), which is equivalent to one coulomb per volt (V). The typical capacitors usually have a very small capacitance range, that ranges from pico to microfarads. On the contrary, supercapacitors can have a capacitance of up to 1-5000 F.
There are a number of factors that eventually determine the capacitance (C). They are as follows:
– Larger plate area (A)
– Closer plate spacing (d)
– Permittivity (ε) of the material (dielectric) between the plates (vacuum<<<glass), – C = ε × A/dThe units of stored charge are coulombs (Q), which is equal to the pathway of one ampere of current per second.
Stored charge, capacitance and voltage can be defined by the following equation:V (potential difference across capacitor) = Q(charge) / C (capacitance)
In a parallel circuit, the formula of capacitors is:
Ctotal = C1 + C2
Hence, two 5 farad capacitors in a parallel circuit arrangement with a charge of 100 coulomb and capacitance 10 F will give a potential difference of::
V = 100/10
V = 10 voltsIn a series circuit, the formula for capacitors is:
1/Ctotal = 1/C1 + 1/C2
Hence, two 5 farad capacitors with a charge of 100 coulomb will give:
Ctotal = C1 × C2/C1 + C2
In the example total capacitance = 25/10 = 2.5 F
V = 100/2.5
V = 40 volts. -
This question is part of the following fields:
- Anaesthesia Related Apparatus
-
-
Question 21
Correct
-
A 45-year old gentleman is in the operating room to have a knee arthroscopy under general anaesthesia. Induction is done using fentanyl 1mcg/kg and propofol 2mg/kg. A supraglottic airway is inserted and the mixture used to maintain anaesthesia is and air oxygen mixture and 2.5% sevoflurane. Using a Bain circuit, the patient breathes spontaneously and the fresh gas flow is 9L/min. Over the next 30 minutes, the end-tidal CO2 increase from 4.5kPa to 8.4kPa, and the baseline reading on the capnograph is 0kPa. The most appropriate action that should follow is:
Your Answer: Observe the patient for further change
Explanation:Such a high rise of end-tidal CO2 (EtCO2) in a patient who is spontaneously breathing is often encountered.
Close observation should occur for further rises in EtCO2 and other signs of malignant hyperthermia. If this were to rise even more, it might be wise to ensure that ventilatory support is available.
A lot would depend on whether surgery was almost completed. At this stage of anaesthesia, it would be inappropriate to administer opioid antagonists or respiratory stimulants.
-
This question is part of the following fields:
- Physiology
-
-
Question 22
Correct
-
A 55-year-old businesswoman presents to the emergency department complaining of shortness of breath and pleuritic chest pain. Her work requires her to travel internationally frequently. The consultant makes a diagnosis and treats her. Now, the consultant recommends placing a filter that will prevent future incidents. A needle is placed into the femoral vein and passed up into the abdomen to insert the filter. What is true regarding the organ where the filter is placed for this patient's condition?
Your Answer: It is located posteriorly to the peritoneum
Explanation:The patient likely suffers from pulmonary embolism due to her history of frequent international travels. A filter is placed in the inferior vena cava to decrease the risk of future episodes of pulmonary embolism. The IVC filter is a small, wiry device that can catch blood clots and stop them from going into the heart and lungs. Your IVC is a major vessel that brings deoxygenated blood from the lower body to the heart, from where it is pumped into the lungs.
The filter is placed via a thin catheter inserted into the femoral vein in the groin. The catheter is gently moved up into your IVC, and a filter is introduced.
The IVC is a retroperitoneal organ.
-
This question is part of the following fields:
- Anatomy
-
-
Question 23
Incorrect
-
All the following statements are false regarding carbamazepine except
Your Answer: Has no active metabolites
Correct Answer: Has neurotoxic side effects
Explanation:Phenytoin, Carbamazepine, and Valproate act by inhibiting the sodium channels when these are open. These drugs also prolong the inactivated stage of these channels (Sodium channels are refractory to stimulation till these reach the closed/ resting phase from inactivated phase)
Carbamazepine is the drug of choice for partial seizures and trigeminal neuralgia
It can have neurotoxic side effects. Major neurotoxic effects include dizziness, headache, ataxia, vertigo, and diplopia
The half-life of carbamazepine is about 13-17 years.
It is metabolized in liver into active metabolite, carbamazepine-10,11-epoxide.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 24
Correct
-
Which of the following statement is correct regarding the difference between dabigatran and other anticoagulants?
Your Answer: Competitive thrombin inhibitor blocking both free and bound thrombin
Explanation:Dabigatran template is a prodrug and its active metabolite is a direct thrombin inhibitor. It is a synthetic, reversible, non-peptide thrombin inhibitor. This inhibition of thrombin results in a decrease of fibrin and reduces platelet aggregation.
Drugs like warfarin act by inhibiting the activation of vitamin K-dependent clotting factors. These factors are synthesized by the liver and activated by gamma-carboxylation of glutamate residues with the help of vitamin K. Hydroquinone form of vitamin K is converted to epoxide form in this reaction and regeneration of hydroquinone form by enzyme vitamin K epoxide reductase (VKOR) is required for this activity. Oral anticoagulants prevent this regeneration by inhibiting VKOR, thus vitamin K-dependent factors are not activated. These factors include clotting factors II, VII, IX, and X as well as anti-clotting proteins, protein C and protein S.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 25
Correct
-
A randomized controlled trail has been conducted to compare two drugs used for the early management of acute severe asthma in the emergency department. After being allocated to the randomized groups, many patients have been excluded due to deleterious effect to the drugs. How the data would be analysed?
Your Answer: Include the patients who drop out in the final data set
Explanation:Randomized controlled trails will be analysed by the intention-to-treat (ITT) approach. It provides unbiased comparisons among the treatment groups. ITT analyses are done to avoid the effects of dropout, which may break the random assignment to the treatment groups in a study.
ITT analysis is a comparison of the treatment groups that includes all patients as originally allocated after randomization.
In order to include such participants in an analysis, outcome data could be imputed which involves making assumptions about the outcomes in the lost participants.
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 26
Correct
-
A 70-year-old man will have a PICC line inserted as he requires long-term parenteral nutrition. To gain venous access, the line is inserted into the basilic vein at the elbow region. As the catheter tip advances into the basilic vein, which venous structure will it first encounter?
Your Answer: Axillary vein
Explanation:A peripherally inserted central catheter (PICC) line is a long, thin tube inserted into the vein of a patient’s arm to gain access to the large central veins near the heart. PICC line is indicated for parenteral nutrition or to deliver medications. They can be used for medium-term venous access, defined as anywhere between several weeks to 6 months.
The veins of choice for PICC are:
1. Basilic
2. Brachial
3. Cephalic
4. Medial cubital veinThe vein of choice is the right basilic vein as it has a large circumference and is located superficially. It has the most straight route to the final destination of PICC (SVC or Right atrium). It courses through the axillary vein, then the subclavian, and finally settles into the SVC. It also has the least number of valves and a shallow angle of insertion when compared to the other veins.
The basilic vein drains the medial end of the dorsal arch of the upper limb, passes along the medial aspect of the forearm, and pierces the deep fascia at the elbow. The basilic vein joins the venae comitantes of the brachial artery to form the axillary vein at the elbow.
The posterior circumflex humeral vein is encountered before the axillary vein. However, a PICC line is unlikely to enter this structure because of its entry angle into the basilic vein. -
This question is part of the following fields:
- Anatomy
-
-
Question 27
Correct
-
An 80 year old woman is due for cataract surgery. There are no contraindications to regional anaesthesia so a peribulbar block was performed. 8mls of 2% lidocaine was injected using an infratemporal approach. However, there is still movement of the globe after 5 mins. The least likely extraocular muscle to develop akinesia is:
Your Answer: Superior oblique
Explanation:The fibrotendinous ring formed by the congregation of the rectus muscles at the apex of the orbit does not include superior oblique. This muscle is completely outside the ring and so it is the most difficult muscle to anaesthetise completely. A good grasp of the anatomy of the area being anaesthetised is important with all regional anaesthetic techniques so that potential problems and complications with a block can be anticipated.
The borders of this pyramid whose apex points upwards and outwards of the bony orbit are as follows:
Floor – Zygoma and Maxilla
Roof – frontal bone
Medial wall – maxilla, ethmoid, sphenoid and lacrimal bones.
Lateral wall – greater wing of the sphenoid and the zygoma.The four recti muscles (superior, medial, lateral and inferior) originate from a tendinous ring (the annulus of Zinn) and extend anteriorly to insert beyond the equator of the globe. Bands of connective tissue are present between the rectus muscles forming a conical structure and hinder the passage of local anaesthetic.
The superior oblique muscle is situated outside this ring and is the most difficult muscle to anaesthetise completely, particularly with a single inferotemporal peribulbar injection. An additional medial injection may help to prevent this.
The cranial nerve supply to the extraocular muscles are:
3rd (inferior oblique, inferior recti, medial and superior)
4th (superior oblique), and
6th (lateral rectus).The long and short ciliary nerves provide the sensory supply to the globe and these are branches of the nasociliary nerve, (which is itself a branch of the ophthalmic division of the trigeminal nerve).
To achieve anaesthesia for the eye, these nerves which enter the fibrotendinous ring need to be fully blocked to anaesthetise the eye for surgery.
-
This question is part of the following fields:
- Anatomy
-
-
Question 28
Correct
-
Which of the following statements is true with regards to the Krebs' cycle (also known as the tricarboxylic acid cycle or citric acid cycle)?
Your Answer: Alpha-ketoglutarate is a five carbon molecule
Explanation:Krebs’ cycle (tricarboxylic acid cycle or citric acid cycle) is a sequence of reactions in which acetyl coenzyme A (acetyl-CoA) is metabolised and this results in carbon dioxide and hydrogen atoms production.
This series of reactions occur in the mitochondria of eukaryotic cells, not the cytoplasm. The cycle requires oxygen and so, cannot function under anaerobic conditions.
It is the common pathway for carbohydrate, fat and some amino acids oxidation and is required for high energy phosphate bond formation in adenosine triphosphate (ATP).
When pyruvate enters the mitochondria, it is converted into acetyl-CoA. This represents the formation of a 2 carbon molecule from a 3 carbon molecule. There is loss of one CO2 but formation of one NADH molecule. Acetyl-CoA is condensed with oxaloacetate, the anion of a 4 carbon acid, to form citrate which is a 6 carbon molecule.
Citrate is then converted into isocitrate, alpha-ketoglutarate, succinyl-CoA, succinate, fumarate, malate and finally oxaloacetate.
The only 5 carbon molecule in the cycle is alpha-ketoglutarate.
-
This question is part of the following fields:
- Physiology
-
-
Question 29
Incorrect
-
A 50-year old female came to the Obstetric and Gynaecology department for an elective hysterectomy under general anaesthesia. Upon physical examination, she was noted to be obese (BMI = 40). Regarding the optimal dose of thiopentone, which of the following parameters must be considered for the computation?
Your Answer: Total body weight
Correct Answer: Lean body weight
Explanation:Using a lean body weight metric encompasses a more scientific approach to weight-based dosing. Lean body weight reflects the weight of all €˜non-fat’ body components, including muscle and vascular organs such as the liver and kidneys. As lean body weight contributes to approximately 99% of a drug’s clearance, it is useful for guiding dosing in obesity.
This metric has undergone a number of transformations. The most commonly cited formula derived by Cheymol is not optimal for dosing across body compositions and can even produce a negative result. A new formula has been developed that appears stable across different body sizes, in particular the obese to morbidly obese.
A practical downfall of the calculation of lean body weight (and other body size descriptors) is the numerical complexity, which may not be palatable to a busy clinician. Often limited time is available for prescribing and an immediate calculation is required. Lean body weight calculators are available online, for example in the Therapeutic Guidelines.
Using total body weight assumes that the pharmacokinetics of the drug are linearly scalable from normal-weight patients to those who are obese. This is inaccurate. For example, we cannot assume that a 150 kg patient eliminates a drug twice as fast as a 75 kg patient and therefore double the dose. Clinicians are alert to toxicities with higher doses, for example nephro- and neurotoxicity with some antibiotics and chemotherapeutics, and bleeding with anticoagulants. Arbitrary dose reductions or €˜caps’ are used to avoid these toxicities, but if too low can result in sub-therapeutic exposure and treatment failure.
Body surface area is traditionally used to dose chemotherapeutics. It is a function of weight and height and has been shown to correlate with cardiac output, blood volume and renal function. However, it is controversial in patients at extremes of size because it does not account for varying body compositions. As a consequence, some older drugs such as cyclophosphamide, paclitaxel and doxorubicin were €˜capped’ (commonly at 2 m^2) potentially resulting in sub-therapeutic treatment. Recent guidelines suggest that unless there is a justifiable reason to reduce the dose (e.g. renal disease), total body weight should be used in the calculation of body surface area, until further research is done. Little research into dosing based on body surface area has been conducted for other medicines.
Ideal body weight was developed for insurance purposes not for drug dosing. It is a function of height and gender only and, like body surface area, does not take into account body composition. Using ideal body weight, all patients of the same height and sex would receive the same dose, which is inadequate and generally results in under-dosing. For example a male who has a total body weight of 150 kg and a height of 170 cm will have the same ideal body weight as a male who is 80 kg and 170 cm tall. Both could potentially receive a mg/kg dose based on 65 kg (ideal body weight).
-
This question is part of the following fields:
- Pharmacology
-
-
Question 30
Incorrect
-
All of the following statements are false regarding tetracyclines except:
Your Answer: Are safe in pregnancy
Correct Answer: The simultaneous administration of aluminium hydroxide impedes its absorption
Explanation:Tetracyclines inhibit protein synthesis through reversible binding to bacterial 30s ribosomal subunits (not 50s) which prevent binding of new incoming amino acids (aminoacyl-tRNA) and thus interfere with peptide growth.
They penetrate macrophages and are thus a drug of choice for treating infections due to intracellular organisms.
Tetracycline does not inhibit transpeptidation. Meanwhile, it is chloramphenicol which is responsible for inhibiting transpeptidation.
Tetracycline can get deposited in growing bone and teeth due to its calcium-binding effect and thus causes dental discoloration and dental hypoplasia. Due to this reason, they should be avoided in pregnant or lactating mothers.
Simultaneous administration of aluminium hydroxide can impede the absorption of tetracyclines.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 31
Correct
-
When there is a relation between two variables due to the existence of a confounding factor, this association is termed as:
Your Answer: Indirect
Explanation:When the association among any two classes of object is defined by the presence of a third entity it is termed as indirect association. For an instance, the age of the employee may affect the rate of pay, which would have implications on job satisfaction. So, in this example, an indirect relationship between age and job satisfaction exists due to a third party i.e. rate of pay.
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 32
Correct
-
What is the mechanism of the pupillary reflex arc?
Your Answer: Oculomotor nerve fibres from the Edinger-Westphal nuclei
Explanation:Pupil size is reduced by the pupillary light reflex and during accommodation for near vision. In the pupillary light reflex, light that strikes the retina is processed by retinal circuits that excite W-type retinal ganglion cells. These cells respond to diffuse illumination. The axons of some of the W-type cells project through the optic nerve and tract to the pretectal area, where they synapse in the olivary pretectal nucleus. This nucleus contains neurons that also respond to diffuse illumination. Activity of neurons of the olivary pretectal nucleus causes pupillary constriction by means of bilateral connections with parasympathetic preganglionic neurons in the Edinger-Westphal nuclei. The reflex results in contraction of the pupillary sphincter muscles in both eyes, even when light is shone into only one eye.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 33
Correct
-
International colour coding is used on medical gas cylinders. Other characteristics also play a role in determining the gas's identity within a cylinder. Which of the following options best describes a cylinder containing analgesics for obstetrics?
Your Answer: Blue body, blue/white shoulder, full cylinder; 13700 KPa, gas mixture, requires a dual stage pressure regulator
Explanation:The body of the Entonox cylinder is usually blue (occasionally white), with blue and white shoulders. Entonox contains a 50:50 mixture of oxygen and nitrous oxide, with a full cylinder pressure of 13700 KPa (137 bar). The cylinder is equipped with a two-stage pressure regulator for safe operation.
The cylinder body and shoulder of nitrous oxide are (French) blue.
In today’s anaesthetic workstations, carbon dioxide cylinders are no longer used.
The body of an oxygen cylinder is black, with a white shoulder.
The white Heliox (21 percent oxygen and 79 percent helium) cylinder has a brown and white shoulder. The administration of this gas mixture, which is less dense than air, is used to reduce turbulence (stridor) of inspiratory flow in patients with upper airway obstruction.
-
This question is part of the following fields:
- Anaesthesia Related Apparatus
-
-
Question 34
Correct
-
Gentamicin is a drug used for the treatment of bronchiectasis. Which of the following is true regarding the mechanism of action of gentamicin?
Your Answer: Inhibit the 30S subunit of ribosomes
Explanation:Gentamicin is a broad-spectrum antibiotic whose mechanism of action involves inhibition of protein synthesis by binding to 30s ribosomes. Its major adverse effect is nephrotoxicity and ototoxicity
Aminoglycoside bind to 30s subunit of ribosome causing misreading of mRNA
Tetracyclines inhibit protein synthesis through reversible binding to bacterial 30s ribosomal subunits, which prevent binding of new incoming amino acids (aminoacyl-tRNA) and thus interfere with peptide growth.
Chloramphenicol binds to the 50s subunit and inhibits peptidyl transferase
Clindamycin binds to the 50s ribosomal subunit of bacteria and disrupts protein synthesis by interfering with the transpeptidation reaction, which thereby inhibits early chain elongation.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 35
Incorrect
-
Many of the processes we deal with in anaesthesia entail a relationship between two or more variables. Which of the following relationships is a linear relationship?
Your Answer: The relationship between the pressure of a fixed mass of gas and its volume at a fixed temperature
Correct Answer: The relationship between the junction potential and temperature in a thermocouple
Explanation:Two bonded wires of dissimilar metals, iron/constantan or copper/constantan, make up a thermocouple (constantan is an alloy of copper and nickel). At the tip, a thermojunction voltage is generated that is proportional to temperature (Seebeck effect).
All of the other connections are non-linear.
For a single compartment model, the relationship between a decrease in plasma concentration of an intravenous bolus of a drug and time is a washout exponential.
A sine wave is the relationship between current and degrees or time from a mains power source.
A sigmoid curve represents the relationship between efficacy and log-dose of a pure agonist on mu receptors.
The pressure of a fixed mass of gas and its volume (Boyle’s law) at a fixed temperature are inversely proportional, resulting in a hyperbolic curve.
-
This question is part of the following fields:
- Anaesthesia Related Apparatus
-
-
Question 36
Incorrect
-
Buffers are solutions that resist a change in pH when protons are produced or consumed. They consist of weak acids and their conjugate bases. Buffers are also present in our bodies, and they are known as physiologic buffers. Which of these is the most effective buffer in the blood?
Your Answer: Haemoglobin
Correct Answer: Bicarbonate
Explanation:The first line of defence against acid-base disorder is buffering. The blood mainly utilizes bicarbonate ion (HCO3-) for its buffering capacity (total of 53%, plasma and red blood cells combined).
Strong acids, when acted upon by a buffer, release H+, which then combines to HCO3- and forms carbonic acid (H2CO3). When acted upon by the enzyme carbonic anhydrase, H2CO3 dissociates into H2O and CO.
The rest are the percentage of utilization for the following buffers:
Haemoglobin (by RBCs) – 35%
Plasma proteins (by plasma) – 7%
Organic phosphates (by RBCs) – 3%
Inorganic phosphates (by plasma) – 2% -
This question is part of the following fields:
- Pharmacology
-
-
Question 37
Correct
-
Prophylactic antibiotics are required for which of the following procedures?
Your Answer: Caesarean section
Explanation:Staphylococcus aureus infection is the most likely cause.
Surgical site infections (SSI) occur when there is a breach in tissue surfaces and allow normal commensals and other pathogens to initiate infection. They are a major cause of morbidity and mortality.
SSI comprise up to 20% of healthcare associated infections and approximately 5% of patients undergoing surgery will develop an SSI as a result.
The organisms are usually derived from the patient’s own body.Measures that may increase the risk of SSI include:
-Shaving the wound using a single use electrical razor with a disposable head
-Using a non iodine impregnated surgical drape if one is needed
-Tissue hypoxia
-Delayed prophylactic antibiotics administration in tourniquet surgery, patients with a prosthesis or valve, in clean-contaminated surgery of in contaminated surgery.Measures that may decrease the risk of SSI include:
1. Intraoperatively
– Prepare the skin with alcoholic chlorhexidine (Lowest incidence of SSI)
-Cover surgical site with dressingIn contrast to previous individual RCT’s, a recent meta analysis has confirmed that administration of supplementary oxygen does not reduce the risk of wound infection and wound edge protectors do not appear to confer benefit.
2. Post operatively
Tissue viability advice for management of surgical wounds healing by secondary intentionUse of diathermy for skin incisions
In the NICE guidelines the use of diathermy for skin incisions is not advocated. Several randomised controlled trials have been undertaken and demonstrated no increase in risk of SSI when diathermy is used. -
This question is part of the following fields:
- Physiology And Biochemistry
-
-
Question 38
Correct
-
Which of the following statements is true regarding vecuronium?
Your Answer: Has a similar structure to rocuronium
Explanation:Vecuronium is used as a part of general anaesthesia to provide skeletal muscle relaxation during surgery or mechanical ventilation. It is a monoquaternary aminosteroid (not quaternary) non- depolarising neuromuscular blocking drug.
It has a structure similar to both rocuronium and pancuronium. The only difference is the substitution of specific groups on the steroid structure.
Vecuronium is not associated with the release of norepinephrine from sympathetic nerve endings. However, Pancuronium has norepinephrine releasing the property.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 39
Correct
-
A 63-year old man has palpitations and goes to the emergency room. An ECG shows tall tented T waves, which corresponds to phase 3 of the cardiac action potential. The shape of the T wave is as a result of which of the following?
Your Answer: Repolarisation due to efflux of potassium
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
-
-
Question 40
Incorrect
-
In the fetal circulation, the cerebral and coronary circulations are preferentially supplied by oxygen-rich blood over other organs. This is possible because of which phenomenon?
Your Answer: The pulmonary vascular resistance is very high and therefore a majority of blood passes from the right side of the heart through the ductus arteriosus
Correct Answer: Well oxygenated blood from the inferior vena cava is preferentially streamed across the patent foramen ovale
Explanation:During fetal development, blood oxygenated by the placenta flows to the foetus through the umbilical vein, bypasses the fetal liver through the ductus venosus, and returns to the fetal heart through the inferior vena cava.
Blood returning from the inferior vena cava then enters the right atrium and is preferentially shunted to the left atrium through the patent foramen ovale. Blood in the left atrium is then pumped from the left ventricle to the aorta. The oxygenated blood ejected through the ascending aorta is preferentially directed to the fetal coronary and cerebral circulations.
Deoxygenated blood returns from the superior vena cava to the right atrium and ventricle to be pumped into the pulmonary artery. Fetal pulmonary vascular resistance (PVR), however, is higher than fetal systemic vascular resistance (SVR); this forces deoxygenated blood to mostly bypass the fetal lungs. This poorly oxygenated blood enters the aorta through the patent ductus arteriosus and mixes with the well-oxygenated blood in the descending aorta. The mixed blood in the descending aorta then returns to the placenta for oxygenation through the two umbilical arteries.
-
This question is part of the following fields:
- Physiology
-
-
Question 41
Correct
-
Which of the following statements is true with regards to 2,3-diphosphoglycerate (2,3-DPG)?
Your Answer: Production is increased in heart failure
Explanation:During glycolysis, 2,3-diphosphoglycerate (2,3-DPG) is
created in erythrocytes by the Rapoport-Luebering shunt.The production of 2,3-DPG increases for several conditions
in the presence of decreased peripheral tissue O2 availability.
Some of these conditions include hypoxaemia, chronic lung
disease anaemia, and congestive heart failure. Thus,
2,3-DPG production is likely an important adaptive mechanism.High levels of 2,3-DPG cause a shift of the curve to the right.
Low levels of 2,3-DPG cause a shift of the curve to the left,
as seen in states such as septic shock and hypophosphatemia. -
This question is part of the following fields:
- Physiology
-
-
Question 42
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 43
Correct
-
An 81-year old man was admitted to the Pulmonology Ward due to chronic obstructive airway disease (COPD) exacerbation. Upon physical examination, he was hypertensive at 140/90 mmHg, tachycardic at 114 beats per minute, and tachypnoeic at 33 breaths per minute. Arterial blood gas analysis was obtained and showed the following results: pH: 7.25 (Reference range: 7.35-7.45), PaO2: 73 mmHg (9.7 kPa) (Reference range: 11.3-12.6 kPa), PaCO2: 56 mmHg (7.5 kPa) (Reference range: 4.7-6.0 kPa), SaO2: 90%, Standard bicarbonate: 29 mmol/L (Reference range: 20-28), BE: +4 mmol/L (± 2). Which of the following options has the most significant impact on his respiratory rate?
Your Answer: CSF pH
Explanation:The arterial blood gas analysis indicates presence of acute respiratory acidosis.
Central chemoreceptors are located in the ventral medulla and respond directly to presence of hydrogen ions in the CSF. When stimulated, it causes an increase in respiratory rate.
It is believed that hydrogen ions may be the only important direct stimulus for these neurons, however, CO2 is believed to stimulate these neurons secondarily by changing the hydrogen ion concentration.
Changes in O2 concentration have virtually no direct effect on the respiratory centre itself to alter respiratory drive. Although, O2 changes do have an indirect effect by acting through the peripheral chemoreceptors.
-
This question is part of the following fields:
- Pathophysiology
-
-
Question 44
Incorrect
-
All of the statements describing the blood brain barrier are false EXCEPT:
Your Answer: Is more permeable to water soluble drugs
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 45
Correct
-
Suppose the afterload and myocardial contractility remain unchanged, which of the following factors in the pressure-volume loop indicates an increase in the preload of the left ventricle?
Your Answer: Increased end-diastolic volume
Explanation:If the afterload and myocardiac contractility remains unchanged, an increase in the preload can be attributed to an increase in end-diastolic volume.
Preload can be defined as the initial stretching of the cardiac myocytes prior to contraction. Preload, therefore, is related to muscle sarcomere length. Because sarcomere length cannot be determined in the intact heart, other indices of preload are used such as ventricular end-diastolic volume or pressure. When venous return to the heart is increased, the end-diastolic pressure and volume of the ventricles are increased, which stretches the sarcomeres, thereby increasing their preload.
-
This question is part of the following fields:
- Basic Physics
-
-
Question 46
Correct
-
A 40-year-old obese woman has complaints of heartburn and regurgitation that is worse on lying flat. The doctor suspects gastroesophageal reflux due to a hiatus hernia. Lifestyle modifications to lose weight and antacids are prescribed to her. At which level of the diaphragm will you find an opening for this problem?
Your Answer: T10
Explanation:Hiatus is an opening in the diaphragm. A hiatal hernia is a protrusion of the upper part of the stomach through an opening in the diaphragm, the oesophageal hiatus, into the thorax. The oesophageal hiatus occurs at the level of T10 in the right crus of the diaphragm.
Other important openings in the diaphragm:
T8: vena cava, terminal branches of the right phrenic nerve
T10: oesophagus, vagal trunks, left anterior phrenic vessels, oesophageal branches of the left gastric vessels
T12: descending aorta, thoracic duct, azygous and hemi-azygous veinAn opening in the diaphragm is called a hiatus. The oesophageal hiatus is at vertebral level T10. A hiatus hernia is where the stomach bulges through the oesophageal hiatus hence the name – hiatus hernia.
-
This question is part of the following fields:
- Anatomy
-
-
Question 47
Incorrect
-
Which drug, if given to a pregnant woman, can lead to deleterious fetal effects due to its ability to cross the placenta?
Your Answer: Suxamethonium
Correct Answer: Atropine
Explanation:It is well known that atropine will cross the placenta and that maternal administration results in an increase in fetal heart rate.
Atropine is highly selective for muscarinic receptors. Its potency at nicotinic receptors is much lower, and actions at non-muscarinic receptors are generally undetectable clinically. Atropine does not distinguish among the M1, M2, and M3 subgroups of muscarinic receptors. In contrast, other antimuscarinic drugs are moderately selective for one or another of these subgroups. Most synthetic antimuscarinic drugs are considerably less selective than atropine in interactions with nonmuscarinic receptors.
A study on glycopyrrolate, a quaternary ammonium salt, was found to have a fetal: maternal serum concentration ratio of 0.4 indicating partial transfer.
Heparin, suxamethonium, and vecuronium do not cross the placenta.
-
This question is part of the following fields:
- Pharmacology
-
-
Question 48
Correct
-
Which of the following statements is correct about a characteristic that is normally distributed in a population?
Your Answer: There will be approximately equal numbers who have more or less of the characteristic than the mean
Explanation:68% of the population will be found in one standard deviation (SD) above plus one SD below the mean. Two SDs above plus two SDs below the mean will include 95% of the population.
The median can be greater or less than the mean as it is simply the mid point of the data after the data is arranged. Half the data are above and half below the median .
The mode is a true score, unlike the mean or the median. It is the most common score or the score obtained from the largest number of subjects in any given data.
-
This question is part of the following fields:
- Statistical Methods
-
-
Question 49
Correct
-
A cannula is inserted into the cephalic vein of a 30-year-old man. Which of the following structures does the cephalic vein pass through?
Your Answer: Clavipectoral fascia
Explanation:The cephalic vein is one of the primary superficial veins of the upper limb. The superficial group of upper limb veins begin as an irregular dorsal arch on the back of the hand.
The cephalic vein originates in the anatomical snuffbox from the radial side of the arch and travels laterally up, within the superficial fascia to join the basilic vein via the median cubital vein at the elbow.
Near the shoulder, it passes between the deltoid and pectoralis major muscles. It pierces the coracoid membrane (continuation of the clavipectoral fascia) to terminate in the axillary vein’s first part.
-
This question is part of the following fields:
- Anatomy
-
-
Question 50
Incorrect
-
A 72-year-old man complains of severe, central abdominal pain that radiates to the back. He has a past medical history of an abdominal aortic aneurysm. A focused abdominal ultrasonography test (FAST) is performed, revealing diffuse dilatation of the abdominal aorta. The most prominent dilatation is at the bifurcation site of abdominal aorta into the iliac arteries. What vertebra level corresponds to the site of the most prominent dilatation as evident on the FAST scan?
Your Answer: L3
Correct Answer: L4
Explanation:The important landmarks of vessels arising from the abdominal aorta at different levels of vertebrae are:
T12 – Coeliac trunk
L1 – Left renal artery
L2 – Testicular or ovarian arteries
L3 – Inferior mesenteric artery
L4 – Bifurcation of the abdominal aorta.
-
This question is part of the following fields:
- Anatomy
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)