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Question 1
Incorrect
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Regarding dynamic compression of the airways, which of the following statements is CORRECT:
Your Answer: It is brought about by reflex activation of parasympathetic nerves.
Correct Answer: It occurs during forced expiration.
Explanation:Dynamic compression occurs because as the expiratory muscles contract during forced expiration, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume). Physiologically this is important as a completely deflated lung with collapsed alveoli requires significantly more energy to inflate. Dynamic compression does not occur in normal expiration because the intrapleural pressure is negative throughout the whole cycle.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Incorrect
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Question 3
Incorrect
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Regarding antihistamines, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Elderly patients and children are more susceptible to side effects.
Explanation:Elderly patients and children are more susceptible to side effects. Antihistamines are competitive inhibitors at the H1-receptor. The newer antihistamines e.g. cetirizine cause less sedation and psychomotor impairment than the older antihistamines because they are much less lipid soluble and penetrate the blood brain barrier only to a slight extent. Antihistamines are used as a second line adjunct to adrenaline in anaphylaxis.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 4
Incorrect
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You are prescribing ipratropium bromide for a patient who has presented with an exacerbation of her COPD. What is the mechanism of action of ipratropium bromide:
Your Answer:
Correct Answer: Muscarinic antagonist
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.
The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.
The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.
The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma) -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 5
Incorrect
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Question 6
Incorrect
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All of the following cause bronchodilation, EXCEPT for:
Your Answer:
Correct Answer: Stimulation of irritant receptors
Explanation:Factors causing bronchodilation: Via beta2-adrenoceptors
Sympathetic stimulation:
Adrenaline (epinephrine)
Beta2-adrenergic agonists e.g. salbutamol
Anticholinergic and muscarinic antagonists e.g. ipratropium -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 7
Incorrect
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A 53 year old women presents to the emergency room with a chronic cough. The pulmonary receptors likely to be involved in causing her cough are:
Your Answer:
Correct Answer: Irritant receptors
Explanation:Throughout the airways, there are irritant receptors which are located between epithelial cells which are made of rapidly adapting afferent myelinated fibres in the vagus nerve. A cough is as a result of receptor stimulation located in the trachea, hyperpnoea is as a result of receptor stimulation in the lower airway. Stimulation may also result in reflex bronchial and laryngeal constriction. Many factors can stimulate irritant receptors. These include irritant gases, smoke and dust, airway deformation, pulmonary congestion, rapid inflation/deflation and inflammation. Deep augmented breaths or sighs seen every 5 – 20 minutes at rest are due to stimulation of these irritant receptors. This reverses the slow lung collapse that occurs in quiet breathing.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 8
Incorrect
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A 21 year old student presents to the emergency room with severe acute asthma. Salbutamol and ipratropium bromide nebuliser are prescribed. The most appropriate dose of salbutamol that should be prescribed initially for this patient is which of the following?
Your Answer:
Correct Answer: 5 mg every 15 - 30 minutes
Explanation:The first line treatment for acute asthma is high-dose inhaled short-acting beta2-agonists like salbutamol or terbutaline. Oxygen use should be reserved for hypoxemic patients in order to maintain oxygen saturations of 94 – 98%. In patients with moderate to severe asthma, a pressurised metered dose inhaler with spacer device is preferred (4 puffs initially, followed by 2 puffs every 2 minutes according to response, up to 10 puffs, whole process repeated every 10 – 20 minutes if necessary). For patients with life-threatening features or poorly responsive severe asthma, the oxygen-driven nebuliser route is recommended (salbutamol 5 mg at 15 – 30 minute intervals). In patients with severe acute asthma that is poorly responsive to initial bolus dose, continuous nebulisation should be considered (salbutamol at 5 – 10 mg/hour). For those in whom inhaled therapy cannot be used reliably, the intravenous route is usually reserved.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 9
Incorrect
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You suspect an anaphylactic reaction in a patient who is hypotensive, with trouble breathing after eating peanuts. Which of the following diagnostic tests will confirm this?
Your Answer:
Correct Answer: Mast cell tryptase
Explanation:The concentration of serum tryptase rises in anaphylaxis and anaphylactoid responses.
Because tryptase is a significant component of mast cell granules, mast cell degranulation causes elevated tryptase levels in the blood.
Although tryptase levels are not always high during anaphylaxis, it is considered a particular marker.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 10
Incorrect
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Which of the following drugs decreases plasma-theophylline levels:
Your Answer:
Correct Answer: Carbamazepine
Explanation:Examples of enzyme-inhibiting drugs (raise plasma theophylline level):
Erythromycin
Clarithromycin
Ciprofloxacin
Fluconazole
Verapamil
Allopurinol
Cimetidine
Examples of enzyme-inducing drugs (lower plasma theophylline level):
Primidone
Phenobarbital
Carbamazepine
Phenytoin
Ritonavir
Rifampicin
St John’s Wort -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 11
Incorrect
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Regarding airway resistance, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: In the lower respiratory tract, airway resistance is mostly determined by the smallest bronchioles.
Explanation:Airway resistance is primarily determined by the airway radius according to Poiseuille’s law, and whether the flow is laminar or turbulent. The major site of airway resistance is the medium-sized bronchi. The smallest airways would seem to offer the highest resistance, but they do not because of their branching parallel arrangement.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 12
Incorrect
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Which of the following statements is correct regarding the partial pressure of oxygen during respiration?
Your Answer:
Correct Answer: Exhaled PO 2 > Alveolar PO 2
Explanation:Because of humidification, inspired PO2 in the airways is less than inhaled PO2.
Because of gas exchange, alveolar PO2 is less than inhaled or inspired PO2.
Because of mixing with anatomical dead space (air that has not taken part in gas exchange, exhaled PO2 is greater than alveolar O2, and therefore that has relatively higher PO2 on the way out, but is less than inhaled or inspired PO2.
Typical values for a resting young healthy male (in kPa) are shown below:
-Inhaled air: PO221.2, PCO20.0
-Inspired air in airways (after humidification): PO219.9, PCO20.0
-Alveolar air (after equilibrium with pulmonary capillaries): PO213.3, PCO25.3
-Exhaled air (after mixing with anatomical dead space air): PO215.5, PCO24.3 -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 13
Incorrect
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Stimulation of J receptors located on alveolar and bronchial walls results in all of the following EXCEPT for:
Your Answer:
Correct Answer: Tachycardia
Explanation:Juxtapulmonary or ‘J’ receptors are located on alveolar and bronchial walls close to the capillaries. Their afferents are small unmyelinated C-fibres or myelinated nerves in the vagus nerve. Activation causes depression of somatic and visceral activity by producing apnoea or rapid shallow breathing, a fall in heart rate and blood pressure, laryngeal constriction and relaxation of skeletal muscles via spinal neurones. J receptors are stimulated by increased alveolar wall fluid, pulmonary congestion and oedema, microembolism and inflammatory mediators. J receptors are thought to be involved in the sensation of dyspnoea in lung disease.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 14
Incorrect
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What is the appropriate dose of 1:1000 adrenaline solution for a 15-year-old patient with suspected anaphylactic shock?
Your Answer:
Correct Answer: 500 micrograms intramuscularly
Explanation:1: 1000 Adrenaline solution dosage for children above the age of 12 and adults, including pregnant women (over 50 kg) is 0.50 mL, which is equivalent to 500 mcg of adrenaline.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 15
Incorrect
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Transfer of oxygen is usually perfusion-limited.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs until equilibrium is reached, but random movement of particles continues to occur and this is known as dynamic equilibrium. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO), not by measuring total lung capacity. The rate of transfer of a gas may be diffusion or perfusion limited; carbon monoxide transfer is diffusion-limited, oxygen transfer is usually perfusion-limited.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 16
Incorrect
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Which of the following is NOT a common side effect of antihistamines:
Your Answer:
Correct Answer: Tremor
Explanation:Common side effects of antihistamines may include:
Anticholinergic effects (blurred vision, dry mouth, urinary retention)
Headache
Gastrointestinal disturbances
Psychomotor impairment (sedation, dizziness and loss of appetite)
These side effects are significantly reduced with second-generation agents. -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 17
Incorrect
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Which of the following is NOT an indication for a H1 receptor antihistamine:
Your Answer:
Correct Answer: Gastroesophageal reflux disease
Explanation:Antihistamines are competitive inhibitors at the H1-receptor (in contrast to H2 receptor antagonists used to decrease gastric acid secretion in gastroesophageal reflux disease).
Indications:
Allergic rhinitis and conjunctivitis
Urticarial rashes, pruritus, insect bites and stings
Angioedema
Anaphylaxis (second line adjunct to adrenaline)
Nausea/vomiting and prevention of motion sickness
Insomnia -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 18
Incorrect
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Which of the following medications can block the effect of adrenaline?
Your Answer:
Correct Answer: Beta-blockers
Explanation:Beta-blockers may reduce the response to adrenaline in the treatment of anaphylactic reactions.
Noncardioselective beta-blockers in particular can antagonize the broncho dilating and cardio stimulatory effects of adrenaline by blocking beta-2 adrenergic receptors in the smooth muscles of the bronchial tree and in the heart muscles.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 19
Incorrect
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Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 20
Incorrect
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Which of the following statements is INCORRECT. Fick's law tells us that the rate of diffusion of a gas across a membrane increases as:
Your Answer:
Correct Answer: the partial pressure gradient decreases.
Explanation:Fick’s law tells us that the rate of diffusion of a gas increases:
the larger the surface area involved in gas exchange
the greater the partial pressure gradient across the membrane
the thinner the membrane
the more soluble the gas in the membrane
the lower the molecular weight of the gas -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 21
Incorrect
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Regarding chemical control of respiration, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The blood-brain barrier is freely permeable to HCO3 - ions.
Explanation:CSF is separated from the blood by the blood-brain barrier. This barrier is impermeable to polar molecules such as H+and HCO3-but CO2can diffuse across it easily. The pH of CSF is therefore determined by the arterial PCO2and the CSF HCO3-and is not affected by blood pH.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 22
Incorrect
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In patients requiring oxygen, who are at risk of hypercapnic respiratory failure, oxygen saturations should be maintained at:
Your Answer:
Correct Answer: 88 - 92%
Explanation:A lower target of 88 – 92% oxygen saturation is indicated for patients at risk of hypercapnic respiratory failure e.g. patients with COPD. Until blood gases can be measured, initial oxygen should be given using a controlled concentration of 28% or less, titrated towards the SpO2 of 88 – 92%. The aim is to provide the patient with enough oxygen to achieve an acceptable arterial oxygen tension without worsening carbon dioxide retention and respiratory acidosis.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 23
Incorrect
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A 27-year-old man was sent to the emergency department by ambulance with suspected anaphylaxis. What is the best first-line treatment for this patient?
Your Answer:
Correct Answer: 500 micrograms of adrenaline intramuscularly
Explanation:Anaphylaxis is the sudden onset of systemic hypersensitivity due to IgE-mediated chemical release from mast cells and basophils.
If anaphylaxis is suspected, 500 micrograms of adrenaline should be administered promptly (0.5 ml of 1:1000 solution).
In anaphylaxis, the intramuscular route is the most immediate approach; the optimal site is the anterolateral aspect of the middle part of the thigh.
Intravenous adrenaline should only be given by people who are well-versed in the use and titration of vasopressors in their routine clinical practice.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 24
Incorrect
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Which of the following is caused by an alpha-1 antitrypsin deficiency?
Your Answer:
Correct Answer: Early onset emphysema
Explanation:Mucus contains chemicals such as alpha-1-antitrypsin, lysozyme, and IgA that protect the airway from pathogens and damaging proteases released from dead bacteria and immune cells. Early-onset emphysema results from a genetic deficit of alpha-1-antitrypsin, which is caused by unregulated protease activity in the lungs, which results in the degradation of elastin in the alveoli.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 25
Incorrect
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Ipratropium bromide should be used with caution in patients with which of the following conditions:
Your Answer:
Correct Answer: Prostatic hyperplasia
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.
The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.
The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.
The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma) -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 26
Incorrect
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Which of the following presentations is NOT consistent with the diagnosis of anaphylaxis following exposure to a known allergen:
Your Answer:
Correct Answer: Generalised urticaria and angioedema alone
Explanation:Anaphylaxis is characterised by sudden onset and rapidly developing, life-threatening airway, breathing and circulation problems associated with skin and/or mucosal changes. Reactions can vary greatly, from hypotension alone, to reactions with predominantly asthmatic features, to cardiac/respiratory arrest. Skin or mucosal changes may be absent or subtle in up to 20% of cases but skin or mucosal changes alone are not a sign of an anaphylactic reaction.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 27
Incorrect
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Which of the following states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each of the gases in the mixture:
Your Answer:
Correct Answer: Dalton's law
Explanation:Dalton’s law states that when two or more gases, which do not react chemically, are present in the same container, the total pressure is the sum of the partial pressures of each gas.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 28
Incorrect
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The second generation antihistamine, cetirizine is a less-sedating antihistamine than the older antihistamine, chlorphenamine because:
Your Answer:
Correct Answer: It is less lipid-soluble so less able to cross the blood brain barrier.
Explanation:All older antihistamines such as chlorphenamine cause sedation. The newer antihistamines e.g. cetirizine cause less sedation and psychomotor impairment than the older antihistamines because they are much less lipid soluble and penetrate the blood brain barrier only to a slight extent.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 29
Incorrect
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Regarding pressures and airflow during the normal breathing cycle, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Negative intrapleural pressure causes dynamic compression of the airways.
Explanation:Dynamic compression occurs during forced expiration, when as the expiratory muscles contract, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 30
Incorrect
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Carbon dioxide is transported in the blood approximately:
Your Answer:
Correct Answer: 60% as bicarbonate ions, 30% as carbamino compounds and 10% dissolved in plasma.
Explanation:Carbon dioxide is transported in the blood from tissues to the lungs in three ways as bicarbonate ions (60%), as carbamino compounds with proteins (30%) or simply dissolved in plasma (10%).
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
