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  • Question 1 - An 80-year-old man visits the GP clinic for a routine hearing examination. He...

    Incorrect

    • An 80-year-old man visits the GP clinic for a routine hearing examination. He reports a decline in hearing ability in his left ear for the past few months. After conducting Rinne and Weber tests, you determine that he has conductive hearing loss in the left ear. Upon otoscopy, you observe cerumen impaction.

      What are the test findings for this patient?

      Your Answer: Rinne: air conduction > bone conduction in right ear; Weber: lateralising to right ear

      Correct Answer: Rinne: bone conduction > air conduction in right ear; Weber: lateralising to right ear

      Explanation:

      Rinne’s and Weber’s Test for Differentiating Conductive and Sensorineural Deafness

      Rinne’s and Weber’s tests are used to differentiate between conductive and sensorineural deafness. Rinne’s test involves placing a tuning fork over the mastoid process until the sound is no longer heard, then repositioning it just over the external acoustic meatus. A positive test indicates that air conduction (AC) is better than bone conduction (BC), while a negative test indicates that BC is better than AC, suggesting conductive deafness.

      Weber’s test involves placing a tuning fork in the middle of the forehead equidistant from the patient’s ears and asking the patient which side is loudest. In unilateral sensorineural deafness, sound is localized to the unaffected side, while in unilateral conductive deafness, sound is localized to the affected side.

      The table below summarizes the interpretation of Rinne and Weber tests. A normal result indicates that AC is greater than BC bilaterally and the sound is midline. Conductive hearing loss is indicated by BC being greater than AC in the affected ear and AC being greater than BC in the unaffected ear, with the sound lateralizing to the affected ear. Sensorineural hearing loss is indicated by AC being greater than BC bilaterally, with the sound lateralizing to the unaffected ear.

      Overall, Rinne’s and Weber’s tests are useful tools for differentiating between conductive and sensorineural deafness, allowing for appropriate management and treatment.

    • This question is part of the following fields:

      • Respiratory System
      15.8
      Seconds
  • Question 2 - An 80-year-old man with metastatic lung cancer arrives at the acute medical unit...

    Incorrect

    • An 80-year-old man with metastatic lung cancer arrives at the acute medical unit with sudden shortness of breath. A chest x-ray shows a malignant pleural effusion encasing the right lung. The medical registrar intends to perform a pleural tap to drain the effusion and send a sample to the lab. The registrar takes into account the effusion's position around the lung. What is the minimum level of the effusion in the mid-axillary line?

      Your Answer: 9th rib

      Correct Answer: 10th rib

      Explanation:

      The parietal pleura can be found at the 10th rib in the mid-axillary line, while the visceral pleura is closely attached to the lung tissue and can be considered as one. The location of the parietal pleura is more inferior than that of the visceral pleura, with the former being at the 8th rib in the midclavicular line and the 10th rib in the midaxillary line. The location of the parietal pleura in the scapular line is not specified.

      Anatomy of the Lungs

      The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.

    • This question is part of the following fields:

      • Respiratory System
      19.9
      Seconds
  • Question 3 - A 53-year-old man arrives at the Emergency Department with jaundice and a distended...

    Correct

    • A 53-year-old man arrives at the Emergency Department with jaundice and a distended abdomen. He has a history of alcoholism and has been hospitalized before for acute alcohol withdrawal. During the examination, you observe spider naevi on his upper chest wall and detect a shifting dullness on abdominal percussion, indicating ascites. Further imaging and investigation reveal portal vein hypertension and cirrhosis.

      Where does this vessel start?

      Your Answer: L1

      Explanation:

      Portal hypertension is commonly caused by liver cirrhosis, often due to alcohol abuse. The causes of this condition can be categorized as pre-hepatic, hepatic, or post-hepatic, depending on the location of the underlying pathology. The primary factors contributing to portal hypertension are increased vascular resistance in the portal venous system and elevated blood flow in the portal veins. The portal vein originates at the transpyloric plane, which is situated at the level of the body of L1. Other significant structures found at this location include the neck of the pancreas, the spleen, the duodenojejunal flexure, and the superior mesenteric artery.

      The Transpyloric Plane and its Anatomical Landmarks

      The transpyloric plane is an imaginary horizontal line that passes through the body of the first lumbar vertebrae (L1) and the pylorus of the stomach. It is an important anatomical landmark used in clinical practice to locate various organs and structures in the abdomen.

      Some of the structures that lie on the transpyloric plane include the left and right kidney hilum (with the left one being at the same level as L1), the fundus of the gallbladder, the neck of the pancreas, the duodenojejunal flexure, the superior mesenteric artery, and the portal vein. The left and right colic flexure, the root of the transverse mesocolon, and the second part of the duodenum also lie on this plane.

      In addition, the upper part of the conus medullaris (the tapered end of the spinal cord) and the spleen are also located on the transpyloric plane. Knowing the location of these structures is important for various medical procedures, such as abdominal surgeries and diagnostic imaging.

      Overall, the transpyloric plane serves as a useful reference point for clinicians to locate important anatomical structures in the abdomen.

    • This question is part of the following fields:

      • Respiratory System
      30.2
      Seconds
  • Question 4 - Samantha is a 67-year-old woman who visits her doctor complaining of muscle weakness...

    Incorrect

    • Samantha is a 67-year-old woman who visits her doctor complaining of muscle weakness and blurred vision. She works as a librarian, drinks about 15 units of alcohol per week, and has smoked about 25 cigarettes a day for 35 years.

      During the examination, her blood pressure is found to be elevated at 152/98 mmHg. There are reduced breath sounds over the area of the right lower lobe. Some of her blood test results are as follows:

      - Hb 120 g/L (Female: 115-160)
      - Platelets 420 * 109/L (150-400)
      - WBC 9.1 * 109/L (4.0-11.0)
      - Na+ 148 mmol/L (135-145)
      - K+ 3.2 mmol/L (3.5-5.0)
      - Urea 8.5 mmol/L (2.0-7.0)
      - Creatinine 150 µmol/L (55-120)
      - 24-hour urine free cortisol 260 ug/l (10-100)
      - Glucose 17.8 mmol/l (4.0-7.0)

      She mentions that, aside from a persistent cough due to smoking, which occasionally produces blood, she feels fine.

      What is the most probable diagnosis?

      Your Answer: Adrenal adenoma

      Correct Answer: Small cell lung carcinoma

      Explanation:

      A small cell lung carcinoma that secretes ACTH can lead to Cushing’s syndrome, as seen in this patient. The history and examination findings suggest lung cancer, and the raised cortisol level can be explained by the paraneoplastic syndrome caused by ACTH release. Muscle weakness and blurred vision are typical symptoms of Cushing’s syndrome. Squamous cell lung carcinoma and adrenal adenoma are less likely causes, while Cushing’s disease is not applicable in this case.

      Lung cancer can present with paraneoplastic features, which are symptoms caused by the cancer but not directly related to the tumor itself. Small cell lung cancer can cause the secretion of ADH and, less commonly, ACTH, which can lead to hypertension, hyperglycemia, hypokalemia, alkalosis, and muscle weakness. Lambert-Eaton syndrome is also associated with small cell lung cancer. Squamous cell lung cancer can cause the secretion of parathyroid hormone-related protein, leading to hypercalcemia, as well as clubbing and hypertrophic pulmonary osteoarthropathy. Adenocarcinoma can cause gynecomastia and hypertrophic pulmonary osteoarthropathy. Hypertrophic pulmonary osteoarthropathy is a painful condition involving the proliferation of periosteum in the long bones. Although traditionally associated with squamous cell carcinoma, some studies suggest that adenocarcinoma is the most common cause.

    • This question is part of the following fields:

      • Respiratory System
      65.2
      Seconds
  • Question 5 - A 65-year-old man is undergoing an upper GI endoscopy due to difficulty swallowing....

    Incorrect

    • A 65-year-old man is undergoing an upper GI endoscopy due to difficulty swallowing. During the procedure, a suspicious-looking blockage is found at 33 cm from the incisors. The endoscopist tries to widen the area with a balloon, but the tumor causes a rupture in the oesophageal wall. Where will the contents of the oesophagus now drain?

      Your Answer: Peritoneal cavity

      Correct Answer: Posterior mediastinum

      Explanation:

      The oesophagus is expected to remain within the thoracic cavity and situated in the posterior mediastinum at this point.

      The mediastinum is the area located between the two pulmonary cavities and is covered by the mediastinal pleura. It extends from the thoracic inlet at the top to the diaphragm at the bottom. The mediastinum is divided into four regions: the superior mediastinum, middle mediastinum, posterior mediastinum, and anterior mediastinum.

      The superior mediastinum is the area between the manubriosternal angle and T4/5. It contains important structures such as the superior vena cava, brachiocephalic veins, arch of aorta, thoracic duct, trachea, oesophagus, thymus, vagus nerve, left recurrent laryngeal nerve, and phrenic nerve. The anterior mediastinum contains thymic remnants, lymph nodes, and fat. The middle mediastinum contains the pericardium, heart, aortic root, arch of azygos vein, and main bronchi. The posterior mediastinum contains the oesophagus, thoracic aorta, azygos vein, thoracic duct, vagus nerve, sympathetic nerve trunks, and splanchnic nerves.

      In summary, the mediastinum is a crucial area in the thorax that contains many important structures and is divided into four regions. Each region contains different structures that are essential for the proper functioning of the body.

    • This question is part of the following fields:

      • Respiratory System
      27.4
      Seconds
  • Question 6 - The pressure within the pleural space is positive with respect to atmospheric pressure,...

    Incorrect

    • The pressure within the pleural space is positive with respect to atmospheric pressure, in which of the following scenarios?

      Your Answer: At the end of expiration

      Correct Answer: During a Valsalva manoeuvre

      Explanation:

      Extrinsic compression causes an increase in intrapleural pressure during a Valsalva manoeuvre.

      Understanding Pleural Pressure

      Pleural pressure refers to the pressure surrounding the lungs within the pleural space. The pleura is a thin membrane that invests the lungs and lines the walls of the thoracic cavity. The visceral pleura covers the lung, while the parietal pleura covers the chest wall. The two sides are continuous and meet at the hilum of the lung. The size of the lung is determined by the difference between the alveolar pressure and the pleural pressure, or the transpulmonary pressure.

      During quiet breathing, the pleural pressure is negative, meaning it is below atmospheric pressure. However, during active expiration, the abdominal muscles contract to force up the diaphragm, resulting in positive pleural pressure. This may temporarily collapse the bronchi and cause limitation of air flow.

      Gravity affects pleural pressure, with the pleural pressure at the base of the lung being greater (less negative) than at its apex in an upright individual. When lying on the back, the pleural pressure becomes greatest along the back. Alveolar pressure is uniform throughout the lung, so the top of the lung generally experiences a greater transpulmonary pressure and is therefore more expanded and less compliant than the bottom of the lung.

      In summary, understanding pleural pressure is important in understanding lung function and how it is affected by various factors such as gravity and muscle contraction.

    • This question is part of the following fields:

      • Respiratory System
      12.8
      Seconds
  • Question 7 - A senior citizen who has been a lifelong smoker visits the respiratory clinic...

    Incorrect

    • A senior citizen who has been a lifelong smoker visits the respiratory clinic for a check-up on his emphysema. What alterations in his lung function test results would you anticipate?

      Your Answer: Normal residual volume and normal vital capacity

      Correct Answer: Increased residual volume and reduced vital capacity

      Explanation:

      Emphysema causes an increase in residual volume, leading to a decrease in vital capacity. This is due to damage to the alveolar walls, which results in the formation of large air sacs called bullae. The lungs lose their compliance, making it difficult to fully exhale and causing air to become trapped in the bullae. As a result, the total volume that can be exhaled is reduced, leading to a decrease in vital capacity.

      Understanding Lung Volumes in Respiratory Physiology

      In respiratory physiology, lung volumes can be measured to determine the amount of air that moves in and out of the lungs during breathing. The diagram above shows the different lung volumes that can be measured.

      Tidal volume (TV) refers to the amount of air that is inspired or expired with each breath at rest. In males, the TV is 500ml while in females, it is 350ml.

      Inspiratory reserve volume (IRV) is the maximum volume of air that can be inspired at the end of a normal tidal inspiration. The inspiratory capacity is the sum of TV and IRV. On the other hand, expiratory reserve volume (ERV) is the maximum volume of air that can be expired at the end of a normal tidal expiration.

      Residual volume (RV) is the volume of air that remains in the lungs after maximal expiration. It increases with age and can be calculated by subtracting ERV from FRC. Speaking of FRC, it is the volume in the lungs at the end-expiratory position and is equal to the sum of ERV and RV.

      Vital capacity (VC) is the maximum volume of air that can be expired after a maximal inspiration. It decreases with age and can be calculated by adding inspiratory capacity and ERV. Lastly, total lung capacity (TLC) is the sum of vital capacity and residual volume.

      Physiological dead space (VD) is calculated by multiplying tidal volume by the difference between arterial carbon dioxide pressure (PaCO2) and end-tidal carbon dioxide pressure (PeCO2) and then dividing the result by PaCO2.

    • This question is part of the following fields:

      • Respiratory System
      18.9
      Seconds
  • Question 8 - A 44-year-old male singer visits his GP complaining of a hoarse voice that...

    Correct

    • A 44-year-old male singer visits his GP complaining of a hoarse voice that has persisted for a few weeks. He first noticed it after his thyroidectomy. Upon reviewing his post-thyroidectomy report, it was noted that he experienced a complication related to external laryngeal nerve injury. Which muscle's loss of innervation could be responsible for this patient's symptoms?

      Your Answer: Cricothyroid

      Explanation:

      The external laryngeal nerve is responsible for innervating the cricothyroid muscle. If this nerve is injured, it can result in paralysis of the cricothyroid muscle, which is often referred to as the tuning fork of the larynx. This can cause hoarseness in the patient. However, over time, the other muscles will compensate for the paralysis, and the hoarseness will improve. It is important to note that the recurrent laryngeal nerve is responsible for innervating the rest of the muscles.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      15.5
      Seconds
  • Question 9 - A 55-year-old woman comes to your clinic seeking help to quit smoking. She...

    Correct

    • A 55-year-old woman comes to your clinic seeking help to quit smoking. She has been using nicotine patches for 6 months but has not been successful in her attempts. You decide to prescribe bupropion.

      What is a typical side effect of bupropion?

      Your Answer: Gastrointestinal disturbance

      Explanation:

      Side Effects of Buproprion

      Buproprion is a medication that can cause aggression and hallucination in some patients. However, the more common side effects are gastrointestinal disturbances such as diarrhoea, nausea, and dry mouth. These side effects are often experienced by patients taking buproprion. It is important to be aware of the potential side effects of any medication and to speak with a healthcare provider if any concerns arise. Additional information on buproprion and its potential side effects can be found in the electronic Medicines Compendium and Medicines Complete.

    • This question is part of the following fields:

      • Respiratory System
      11.1
      Seconds
  • Question 10 - A 29-year-old man comes to the clinic with a complaint of ear pain....

    Correct

    • A 29-year-old man comes to the clinic with a complaint of ear pain. He mentions that the pain started yesterday and has been preventing him from working. He also reports experiencing dizziness and muffled sounds on the affected side. During the examination, you notice that he has a fever and a bulging tympanic membrane with visible fluid. Based on these symptoms, you suspect that he has a middle ear infection. Now, you wonder which ossicle the tensor tympani muscle inserts into.

      Which ossicle does the tensor tympani muscle insert into?

      Your Answer: Malleus

      Explanation:

      The tensor tympani muscle is located in a bony canal above the pharyngotympanic tube and originates from the cartilaginous portion of the tube, the bony canal, and the greater wing of the sphenoid bone. Its function is to reduce the magnitude of vibrations transmitted into the middle ear by pulling the handle of the malleus medially when contracted. This muscle is innervated by the nerve to tensor tympani, which arises from the mandibular nerve.

      The middle ear contains three ossicles, which are the malleus, incus, and stapes. The malleus is the most lateral and attaches to the tympanic membrane, while the incus lies between and articulates with the other two ossicles. The stapes is the most medial and is connected to the oval window of the cochlea. The stapedius muscle is associated with the stapes. The lunate and trapezium are not bones of the middle ear but are carpal bones.

      A patient with ear pain, difficulty hearing, dizziness, and fever may have otitis media, which is confirmed on otoscopy by a bulging tympanic membrane and visible fluid level.

      Anatomy of the Ear

      The ear is divided into three distinct regions: the external ear, middle ear, and internal ear. The external ear consists of the auricle and external auditory meatus, which are innervated by the greater auricular nerve and auriculotemporal branch of the trigeminal nerve. The middle ear is the space between the tympanic membrane and cochlea, and is connected to the nasopharynx by the eustachian tube. The tympanic membrane is composed of three layers and is approximately 1 cm in diameter. The middle ear is innervated by the glossopharyngeal nerve. The ossicles, consisting of the malleus, incus, and stapes, transmit sound vibrations from the tympanic membrane to the inner ear. The internal ear contains the cochlea, which houses the organ of corti, the sense organ of hearing. The vestibule accommodates the utricule and saccule, which contain endolymph and are surrounded by perilymph. The semicircular canals, which share a common opening into the vestibule, lie at various angles to the petrous temporal bone.

    • This question is part of the following fields:

      • Respiratory System
      15.3
      Seconds
  • Question 11 - A 67-year-old female smoker with a two-month history of worsening shortness of breath...

    Correct

    • A 67-year-old female smoker with a two-month history of worsening shortness of breath presents for evaluation. On examination, she appears comfortable at rest with a regular pulse of 72 bpm, respiratory rate of 16/min, and blood pressure of 128/82 mmHg. Physical findings include reduced expansion on the left lower zone, dullness to percussion over this area, and absent breath sounds over the left lower zone with bronchial breath sounds just above this region. What is the likely clinical diagnosis?

      Your Answer: Pleural effusion

      Explanation:

      Pleural Effusion and its Investigation

      Pleural effusion is a condition where there is an abnormal accumulation of fluid in the pleural space, which is the space between the lungs and the chest wall. This can be caused by various factors such as post-infection, carcinoma, or emboli. To determine the cause of the pleural effusion, a pleural tap is the most appropriate investigation. The sample obtained from the pleural tap is sent for cytology, protein concentration, and culture.

      A normal pleural tap would have clear appearance, pH of 7.60-7.64, protein concentration of less than 2%, white blood cells count of less than 1000/mm³, glucose level similar to that of plasma, LDH level of less than 50% of plasma concentration, amylase level of 30-110 U/L, triglycerides level of less than 2 mmol/l, and cholesterol level of 3.5-6.5 mmol/l.

      A transudative tap is associated with conditions such as congestive heart failure, liver cirrhosis, severe hypoalbuminemia, and nephrotic syndrome. On the other hand, an exudative tap is associated with malignancy, infection (such as empyema due to bacterial pneumonia), trauma, pulmonary infarction, and pulmonary embolism.

      In summary, pleural effusion can be caused by various factors and a pleural tap is the most appropriate investigation to determine the cause. The results of the pleural tap can help differentiate between transudative and exudative effusions, which can provide important information for diagnosis and treatment.

    • This question is part of the following fields:

      • Respiratory System
      20.1
      Seconds
  • Question 12 - A 29-year-old cyclist is brought to the emergency department by air ambulance following...

    Correct

    • A 29-year-old cyclist is brought to the emergency department by air ambulance following a car collision. She was intubated at the scene and currently has a Glasgow Coma Score of 8. Where is the control and regulation of the respiratory centers located?

      Your Answer: Brainstem

      Explanation:

      The brainstem houses the respiratory centres, which are responsible for regulating various aspects of breathing. These centres are located in the upper pons, lower pons and medulla oblongata.

      The thalamus plays a role in sensory, motor and cognitive functions, and its axons connect with the cerebral cortex. The cerebellum coordinates voluntary movements and helps maintain balance and posture. The parietal lobe processes sensory information, including discrimination and body orientation. The primary visual cortex is located in the occipital lobe.

      The Control of Ventilation in the Human Body

      The control of ventilation in the human body is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration. The respiratory centres, chemoreceptors, lung receptors, and muscles all play a role in this process. The automatic, involuntary control of respiration occurs from the medulla, which is responsible for controlling the respiratory rate and depth of respiration.

      The respiratory centres consist of the medullary respiratory centre, apneustic centre, and pneumotaxic centre. The medullary respiratory centre has two groups of neurons, the ventral group, which controls forced voluntary expiration, and the dorsal group, which controls inspiration. The apneustic centre, located in the lower pons, stimulates inspiration and activates and prolongs inhalation. The pneumotaxic centre, located in the upper pons, inhibits inspiration at a certain point and fine-tunes the respiratory rate.

      Ventilatory variables, such as the levels of pCO2, are the most important factors in ventilation control, while levels of O2 are less important. Peripheral chemoreceptors, located in the bifurcation of carotid arteries and arch of the aorta, respond to changes in reduced pO2, increased H+, and increased pCO2 in arterial blood. Central chemoreceptors, located in the medulla, respond to increased H+ in brain interstitial fluid to increase ventilation. It is important to note that the central receptors are not influenced by O2 levels.

      Lung receptors also play a role in the control of ventilation. Stretch receptors respond to lung stretching, causing a reduced respiratory rate, while irritant receptors respond to smoke, causing bronchospasm. J (juxtacapillary) receptors are also involved in the control of ventilation. Overall, the control of ventilation is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration.

    • This question is part of the following fields:

      • Respiratory System
      12.3
      Seconds
  • Question 13 - A 44-year-old woman is scheduled for a thyroidectomy due to symptomatic tracheal compression....

    Incorrect

    • A 44-year-old woman is scheduled for a thyroidectomy due to symptomatic tracheal compression. She has a history of hyperthyroidism that was controlled with carbimazole. However, she was deemed a suitable candidate for thyroidectomy after presenting to the emergency department with dyspnoea and stridor.

      As a surgical resident assisting the ENT surgeon, you need to ligate the superior thyroid artery before removing the thyroid glands to prevent excessive bleeding. However, the superior laryngeal artery, a branch of the superior thyroid artery, is closely related to a structure that, if injured, can lead to loss of sensation in the laryngeal mucosa.

      What is the correct identification of this structure?

      Your Answer: Right recurrent laryngeal nerve

      Correct Answer: Internal laryngeal nerve

      Explanation:

      The internal laryngeal nerve and the superior laryngeal artery are closely associated with each other. The superior laryngeal artery travels alongside the internal laryngeal branch of the superior laryngeal nerve, beneath the thyrohyoid muscle. It originates from the superior thyroid artery near its separation from the external carotid artery.

      If the internal laryngeal nerve is damaged, it can result in a loss of sensation to the laryngeal mucosa. The nerve is situated beneath the mucous membrane of the piriform recess, making it vulnerable to injury from sharp objects like fish and chicken bones that may become stuck in the recess.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      56
      Seconds
  • Question 14 - Which one of the following is not a typical feature of central chemoreceptors...

    Incorrect

    • Which one of the following is not a typical feature of central chemoreceptors in the regulation of respiration?

      Your Answer: During acute hypercapnia the carotid receptors will be stimulated first

      Correct Answer: They are stimulated primarily by venous hypercapnia

      Explanation:

      Arterial carbon dioxide stimulates them, but it takes longer to reach equilibrium compared to the carotid peripheral chemoreceptors. They are not as responsive to acidity because of the blood-brain barrier.

      The Control of Ventilation in the Human Body

      The control of ventilation in the human body is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration. The respiratory centres, chemoreceptors, lung receptors, and muscles all play a role in this process. The automatic, involuntary control of respiration occurs from the medulla, which is responsible for controlling the respiratory rate and depth of respiration.

      The respiratory centres consist of the medullary respiratory centre, apneustic centre, and pneumotaxic centre. The medullary respiratory centre has two groups of neurons, the ventral group, which controls forced voluntary expiration, and the dorsal group, which controls inspiration. The apneustic centre, located in the lower pons, stimulates inspiration and activates and prolongs inhalation. The pneumotaxic centre, located in the upper pons, inhibits inspiration at a certain point and fine-tunes the respiratory rate.

      Ventilatory variables, such as the levels of pCO2, are the most important factors in ventilation control, while levels of O2 are less important. Peripheral chemoreceptors, located in the bifurcation of carotid arteries and arch of the aorta, respond to changes in reduced pO2, increased H+, and increased pCO2 in arterial blood. Central chemoreceptors, located in the medulla, respond to increased H+ in brain interstitial fluid to increase ventilation. It is important to note that the central receptors are not influenced by O2 levels.

      Lung receptors also play a role in the control of ventilation. Stretch receptors respond to lung stretching, causing a reduced respiratory rate, while irritant receptors respond to smoke, causing bronchospasm. J (juxtacapillary) receptors are also involved in the control of ventilation. Overall, the control of ventilation is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration.

    • This question is part of the following fields:

      • Respiratory System
      35.7
      Seconds
  • Question 15 - A respiratory specialist is conducting a bronchoscopy to determine a suitable biopsy for...

    Correct

    • A respiratory specialist is conducting a bronchoscopy to determine a suitable biopsy for histological evaluation of suspected bronchial carcinoma in a pediatric patient.

      While performing the procedure, the bronchoscope is erroneously inserted through the diaphragm at the T10 level.

      Which structure is at the highest risk of being harmed as a result of this error?

      Your Answer: Oesophagus

      Explanation:

      The oesophagus passes through the diaphragm at the level of T10 along with the vagal trunk, which is the most likely structure to have been damaged. The aorta, on the other hand, perforates the diaphragm at T12 and supplies oxygenated blood to the lower body, while the azygous vein also perforates the diaphragm at T12 and drains the right side of the thorax into the superior vena cava.

      Structures Perforating the Diaphragm

      The diaphragm is a dome-shaped muscle that separates the thoracic and abdominal cavities. It plays a crucial role in breathing by contracting and relaxing to create negative pressure in the lungs. However, there are certain structures that perforate the diaphragm, allowing them to pass through from the thoracic to the abdominal cavity. These structures include the inferior vena cava at the level of T8, the esophagus and vagal trunk at T10, and the aorta, thoracic duct, and azygous vein at T12.

      To remember these structures and their corresponding levels, a helpful mnemonic is I 8(ate) 10 EGGS AT 12. This means that the inferior vena cava is at T8, the esophagus and vagal trunk are at T10, and the aorta, thoracic duct, and azygous vein are at T12. Knowing these structures and their locations is important for medical professionals, as they may need to access or treat them during surgical procedures or diagnose issues related to them.

    • This question is part of the following fields:

      • Respiratory System
      17.1
      Seconds
  • Question 16 - A 48-year-old male presents for a preoperative evaluation for an inguinal hernia repair....

    Correct

    • A 48-year-old male presents for a preoperative evaluation for an inguinal hernia repair. During the assessment, you observe a loculated left pleural effusion on his chest x-ray. Upon further inquiry, the patient discloses that he worked as a builder three decades ago. What is the probable reason for the effusion?

      Your Answer: Mesothelioma

      Explanation:

      Due to his profession as a builder, this individual is at risk of being exposed to asbestos. Given the 30-year latent period and the presence of a complex effusion, it is highly probable that the underlying cause is mesothelioma.

      Understanding Mesothelioma

      Mesothelioma is a type of cancer that affects the mesothelial layer of the pleural cavity, which is commonly linked to asbestos exposure. Although it is rare, other mesothelial layers in the abdomen may also be affected. Symptoms of mesothelioma include dyspnoea, weight loss, chest wall pain, and clubbing. In some cases, patients may present with painless pleural effusion. It is important to note that only 20% of patients have pre-existing asbestosis, but 85-90% have a history of asbestos exposure, with a latent period of 30-40 years.

      Diagnosis of mesothelioma is typically made through a chest x-ray, which may show pleural effusion or pleural thickening. A pleural CT is then performed to confirm the diagnosis. If a pleural effusion is present, fluid is sent for MC&S, biochemistry, and cytology. However, cytology is only helpful in 20-30% of cases. Local anaesthetic thoracoscopy is increasingly used to investigate cytology negative exudative effusions as it has a high diagnostic yield of around 95%. If an area of pleural nodularity is seen on CT, an image-guided pleural biopsy may be used.

      Management of mesothelioma is mainly symptomatic, with industrial compensation available for those who have been exposed to asbestos. Chemotherapy and surgery may be options for those who are operable. Unfortunately, the prognosis for mesothelioma is poor, with a median survival of only 12 months.

    • This question is part of the following fields:

      • Respiratory System
      16.4
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  • Question 17 - Which of the following laryngeal tumors is unlikely to spread to the cervical...

    Correct

    • Which of the following laryngeal tumors is unlikely to spread to the cervical lymph nodes?

      Your Answer: Glottic

      Explanation:

      The area of the vocal cords lacks lymphatic drainage, making it a lymphatic boundary. The upper portion above the vocal cords drains to the deep cervical nodes through vessels that penetrate the thyrohyoid membrane. The lower portion below the vocal cords drains to the pre-laryngeal, pre-tracheal, and inferior deep cervical nodes. The aryepiglottic and vestibular folds have a significant lymphatic drainage and are prone to early metastasis.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      5.8
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  • Question 18 - A patient with a body mass index (BMI) of 40kg/m² presents to the...

    Incorrect

    • A patient with a body mass index (BMI) of 40kg/m² presents to the GP describing apnoeic episodes during sleep. He is referred to the hospital's respiratory team where he receives an initial spirometry test which is shown below.

      Forced expiratory volume in 1 sec (FEV1) 2.00 48% of predicted
      Vital capacity (VC) 2.35 43% of predicted
      Total lung capacity (TLC) 4.09 51% of predicted
      Residual volume (RV) 1.74 75% of predicted
      Total lung coefficient (TLCO) 5.37 47% of predicted
      Transfer coefficient (KCO) 1.83 120% of predicted

      What type of lung disease pattern is shown in a patient with a body mass index (BMI) of 30kg/m² who presents to the GP with similar symptoms?

      Your Answer: Intrapulmonary

      Correct Answer: Extrapulmonary

      Explanation:

      Understanding Pulmonary Function Tests

      Pulmonary function tests are a useful tool in determining whether a respiratory disease is obstructive or restrictive. These tests measure various aspects of lung function, such as forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). By analyzing the results of these tests, doctors can diagnose and monitor conditions such as asthma, COPD, pulmonary fibrosis, and neuromuscular disorders.

      In obstructive lung diseases, such as asthma and COPD, the FEV1 is significantly reduced, while the FVC may be reduced or normal. The FEV1% (FEV1/FVC) is also reduced. On the other hand, in restrictive lung diseases, such as pulmonary fibrosis and asbestosis, the FEV1 is reduced, but the FVC is significantly reduced. The FEV1% (FEV1/FVC) may be normal or increased.

      It is important to note that there are many conditions that can affect lung function, and pulmonary function tests are just one tool in diagnosing and managing respiratory diseases. However, understanding the results of these tests can provide valuable information for both patients and healthcare providers.

    • This question is part of the following fields:

      • Respiratory System
      34.6
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  • Question 19 - A 75-year-old man is having a left pneumonectomy for bronchial carcinoma. When the...

    Correct

    • A 75-year-old man is having a left pneumonectomy for bronchial carcinoma. When the surgeons reach the root of the lung, which structure will be the most anterior in the anatomical plane?

      Your Answer: Phrenic nerve

      Explanation:

      The lung root contains two nerves, with the phrenic nerve positioned in the most anterior location and the vagus nerve situated in the most posterior location.

      Anatomy of the Lungs

      The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.

    • This question is part of the following fields:

      • Respiratory System
      64.6
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  • Question 20 - A 25-year-old man is shot in the chest during a robbery. The right...

    Correct

    • A 25-year-old man is shot in the chest during a robbery. The right lung is lacerated and is bleeding. An emergency thoracotomy is performed. The surgeons place a clamp over the hilum of the right lung. Which one of the following structures lies most anteriorly at this level?

      Your Answer: Phrenic nerve

      Explanation:

      At this location, the phrenic nerve is situated in front. The vagus nerve runs in front and then curves backwards just above the base of the left bronchus, releasing the recurrent laryngeal nerve as it curves.

      Anatomy of the Lungs

      The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.

    • This question is part of the following fields:

      • Respiratory System
      9
      Seconds
  • Question 21 - A 55-year-old Caucasian man presents to the ENT clinic with complaints of gradual...

    Correct

    • A 55-year-old Caucasian man presents to the ENT clinic with complaints of gradual hearing loss over the past year. He reports having to turn up the volume on his television to the maximum to hear it comfortably. There are no associated symptoms such as tinnitus or dizziness, and the patient has no significant medical history.

      Upon examination, a Weber and Rinne test reveal conductive hearing loss in the left ear. Otoscope examination shows no signs of middle ear effusion or tympanic membrane involvement in either ear. A pure tone audiometry confirms conductive hearing loss in the left ear, with a Carhart's notch present.

      The physician diagnoses the patient with otosclerosis and discusses treatment options.

      What is the underlying pathology of otosclerosis?

      Your Answer: Replacement of normal bone by vascular spongy bone

      Explanation:

      Otosclerosis is a condition where normal bone is replaced by spongy bone with a high vascularity. This leads to progressive conductive hearing loss, without any other neurological impairments. The replacement of the normal endochondral layer of the bony labyrinth by spongy bone affects the ability of the stapes to act as a piston, resulting in the conduction of sound from the middle ear to the inner ear being affected. Caucasians are most commonly affected by this condition.

      Benign paroxysmal positional vertigo (BPPV) is caused by the dislodgement of otoliths into the semicircular canals. This condition results in vertiginous dizziness upon positional changes, but does not affect auditory function.

      Meniere’s disease is caused by endolymphatic hydrops, which is the accumulation of fluid in the inner ear. The pathophysiology of this condition is not well understood, but it leads to vertigo, tinnitus, hearing loss, and aural fullness.

      Cholesteatoma is caused by the accumulation of desquamated, stratified squamous epithelium. This leads to the formation of a mass that can gradually enlarge and erode the ossicle chain, resulting in conductive hearing loss.

      Presbycusis is a type of sensorineural hearing loss that occurs as a result of aging. The degeneration of the organ of Corti is one of the underlying pathological mechanisms that causes this condition. This leads to the destruction of outer hair cells and a decrease in hearing sensitivity.

      Understanding Otosclerosis: A Progressive Conductive Deafness

      Otosclerosis is a medical condition that occurs when normal bone is replaced by vascular spongy bone. This condition leads to a progressive conductive deafness due to the fixation of the stapes at the oval window. It is an autosomal dominant condition that typically affects young adults, with onset usually occurring between the ages of 20-40 years.

      The main features of otosclerosis include conductive deafness, tinnitus, a normal tympanic membrane, and a positive family history. In some cases, patients may also experience a flamingo tinge, which is caused by hyperemia and affects around 10% of patients.

      Management of otosclerosis typically involves the use of a hearing aid or stapedectomy. A hearing aid can help to improve hearing, while a stapedectomy involves the surgical removal of the stapes bone and replacement with a prosthesis.

      Overall, understanding otosclerosis is important for individuals who may be at risk of developing this condition. Early diagnosis and management can help to improve hearing and prevent further complications.

    • This question is part of the following fields:

      • Respiratory System
      18
      Seconds
  • Question 22 - John, a 55-year-old man, arrives at the emergency department complaining of chest pain...

    Incorrect

    • John, a 55-year-old man, arrives at the emergency department complaining of chest pain that is relieved by leaning forward. He also mentions that the pain spreads to his left shoulder. The diagnosis is pericarditis.

      Which nerve is accountable for the referred pain in this case?

      Your Answer: Vagus nerve

      Correct Answer: Phrenic nerve

      Explanation:

      The phrenic nerve provides motor innervation to the diaphragm and sensory innervation to the pleura and pericardium. Pericarditis can cause referred pain to the shoulder due to the supraclavicular nerves originating at C3-4. It is important to note that there are no pericardial nerves. The spinal accessory nerve innervates the trapezius and sternocleidomastoid muscles, while the trochlear nerve supplies the superior oblique muscle. Although the vagus nerve has various functions, it does not supply the pericardium.

      The Phrenic Nerve: Origin, Path, and Supplies

      The phrenic nerve is a crucial nerve that originates from the cervical spinal nerves C3, C4, and C5. It supplies the diaphragm and provides sensation to the central diaphragm and pericardium. The nerve passes with the internal jugular vein across scalenus anterior and deep to the prevertebral fascia of the deep cervical fascia.

      The right phrenic nerve runs anterior to the first part of the subclavian artery in the superior mediastinum and laterally to the superior vena cava. In the middle mediastinum, it is located to the right of the pericardium and passes over the right atrium to exit the diaphragm at T8. On the other hand, the left phrenic nerve passes lateral to the left subclavian artery, aortic arch, and left ventricle. It passes anterior to the root of the lung and pierces the diaphragm alone.

      Understanding the origin, path, and supplies of the phrenic nerve is essential in diagnosing and treating conditions that affect the diaphragm and pericardium.

    • This question is part of the following fields:

      • Respiratory System
      14.5
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  • Question 23 - An 87-year-old man with a history of interstitial lung disease is admitted with...

    Incorrect

    • An 87-year-old man with a history of interstitial lung disease is admitted with fever, productive cough, and difficulty breathing. His inflammatory markers are elevated, and a chest x-ray reveals focal patchy consolidation in the right lung. He requires oxygen supplementation as his oxygen saturation level is 87% on room air. What factor causes a decrease in haemoglobin's affinity for oxygen?

      Your Answer: Decrease in temperature

      Correct Answer: Increase in temperature

      Explanation:

      What effect does pyrexia have on the oxygen dissociation curve?

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

    • This question is part of the following fields:

      • Respiratory System
      22
      Seconds
  • Question 24 - A 55-year-old man is admitted to the ICU after emergency surgery for an...

    Incorrect

    • A 55-year-old man is admitted to the ICU after emergency surgery for an abdominal aortic aneurysm. He presents with abdominal pain and diarrhea and is in a critical condition. Despite the absence of peritonism, which of the following arterial blood gas patterns is most likely to be observed?

      Your Answer: pH 7.29, pO2 8.9, pCO2 5.9, Base excess -4, Lactate 3

      Correct Answer: pH 7.20, pO2 9.0, pCO2 3.5, Base excess -10, Lactate 8

      Explanation:

      It is probable that this individual is experiencing metabolic acidosis as a result of a mesenteric infarction.

      Disorders of Acid-Base Balance

      The acid-base nomogram is a useful tool for categorizing the various disorders of acid-base balance. Metabolic acidosis is the most common surgical acid-base disorder, characterized by a reduction in plasma bicarbonate levels. This can be caused by a gain of strong acid or loss of base, and is classified according to the anion gap. A normal anion gap indicates hyperchloraemic metabolic acidosis, which can be caused by gastrointestinal bicarbonate loss, renal tubular acidosis, drugs, or Addison’s disease. A raised anion gap indicates lactate, ketones, urate, or acid poisoning. Metabolic alkalosis, on the other hand, is usually caused by a rise in plasma bicarbonate levels due to a loss of hydrogen ions or a gain of bicarbonate. It is mainly caused by problems of the kidney or gastrointestinal tract. Respiratory acidosis is characterized by a rise in carbon dioxide levels due to alveolar hypoventilation, while respiratory alkalosis is caused by hyperventilation resulting in excess loss of carbon dioxide. These disorders have various causes, such as COPD, sedative drugs, anxiety, hypoxia, and pregnancy.

    • This question is part of the following fields:

      • Respiratory System
      22.3
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  • Question 25 - A father brings his 9-year-old daughter to your general practice, as he is...

    Incorrect

    • A father brings his 9-year-old daughter to your general practice, as he is worried about her hearing. He notices that he has to repeat himself when talking to her, and thinks she is often 'in her own little world'. During the examination, the Rinne test is positive on the left and negative on the right. What conclusions can be drawn from this?

      Your Answer: Conductive hearing loss on the right.

      Correct Answer: Can not tell if both sides are affected.

      Explanation:

      The Rinne and Weber tests are used to diagnose hearing loss. The Rinne test involves comparing air and bone conduction, with a positive result indicating a healthy or sensorineural loss and a negative result indicating a conductive loss. The Weber test involves placing a tuning fork on the forehead and determining if the sound is symmetrical or louder on one side, with a conductive loss resulting in louder sound on the affected side and a sensorineural loss resulting in louder sound on the non-affected side. When used together, these tests can provide more information about the type and affected side of hearing loss.

      Rinne’s and Weber’s Test for Differentiating Conductive and Sensorineural Deafness

      Rinne’s and Weber’s tests are used to differentiate between conductive and sensorineural deafness. Rinne’s test involves placing a tuning fork over the mastoid process until the sound is no longer heard, then repositioning it just over the external acoustic meatus. A positive test indicates that air conduction (AC) is better than bone conduction (BC), while a negative test indicates that BC is better than AC, suggesting conductive deafness.

      Weber’s test involves placing a tuning fork in the middle of the forehead equidistant from the patient’s ears and asking the patient which side is loudest. In unilateral sensorineural deafness, sound is localized to the unaffected side, while in unilateral conductive deafness, sound is localized to the affected side.

      The table below summarizes the interpretation of Rinne and Weber tests. A normal result indicates that AC is greater than BC bilaterally and the sound is midline. Conductive hearing loss is indicated by BC being greater than AC in the affected ear and AC being greater than BC in the unaffected ear, with the sound lateralizing to the affected ear. Sensorineural hearing loss is indicated by AC being greater than BC bilaterally, with the sound lateralizing to the unaffected ear.

      Overall, Rinne’s and Weber’s tests are useful tools for differentiating between conductive and sensorineural deafness, allowing for appropriate management and treatment.

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      • Respiratory System
      22.6
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  • Question 26 - A 38-year-old male presents to the hospital with recurrent nose bleeds, joint pain,...

    Incorrect

    • A 38-year-old male presents to the hospital with recurrent nose bleeds, joint pain, chronic sinusitis, and haemoptysis for the past 3 days. During the examination, the doctor observes a saddle-shaped nose and a necrotic, purpuric, and blistering plaque on his wrist. The patient reports that he had a small blister a few weeks ago, which has now progressed to this. The blood test results suggest a possible diagnosis of granulomatosis with polyangiitis, and the patient is referred for a renal biopsy. What biopsy findings would confirm the suspected diagnosis?

      Your Answer: Diffuse increase in mesangial cells

      Correct Answer: Epithelial crescents in Bowman's capsule

      Explanation:

      Glomerulonephritis is a condition that affects the kidneys and can present with various pathological changes. In rapidly progressive glomerulonephritis, patients may present with respiratory tract symptoms and cutaneous manifestations of vasculitis. Renal biopsy will show epithelial crescents in Bowman’s capsule, indicating severe glomerular injury. Mesangioproliferative glomerulonephritis is characterized by a diffuse increase in mesangial cells and is not associated with respiratory tract symptoms or cutaneous manifestations of vasculitis. Membranoproliferative glomerulonephritis involves deposits in the intraglomerular mesangium and is associated with activation of the complement pathway and glomerular damage. It is unlikely to be the diagnosis in the scenario as it is not associated with vasculitis symptoms. A normal nephron architecture would not explain the patient’s symptoms and is an incorrect answer.

      Granulomatosis with Polyangiitis: An Autoimmune Condition

      Granulomatosis with polyangiitis, previously known as Wegener’s granulomatosis, is an autoimmune condition that affects the upper and lower respiratory tract as well as the kidneys. It is characterized by a necrotizing granulomatous vasculitis. The condition presents with various symptoms such as epistaxis, sinusitis, nasal crusting, dyspnoea, haemoptysis, and rapidly progressive glomerulonephritis. Other symptoms include a saddle-shape nose deformity, vasculitic rash, eye involvement, and cranial nerve lesions.

      To diagnose granulomatosis with polyangiitis, doctors perform various investigations such as cANCA and pANCA tests, chest x-rays, and renal biopsies. The cANCA test is positive in more than 90% of cases, while the pANCA test is positive in 25% of cases. Chest x-rays show a wide variety of presentations, including cavitating lesions. Renal biopsies reveal epithelial crescents in Bowman’s capsule.

      The management of granulomatosis with polyangiitis involves the use of steroids, cyclophosphamide, and plasma exchange. Cyclophosphamide has a 90% response rate. The median survival rate for patients with this condition is 8-9 years.

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      • Respiratory System
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  • Question 27 - A 72-year-old male has unfortunately been diagnosed with lung cancer after a brief...

    Correct

    • A 72-year-old male has unfortunately been diagnosed with lung cancer after a brief illness during which he visited his GP with a cough and loss of weight. The GP has received the histology report after a recent bronchoscopy, which revealed a squamous cell carcinoma. What symptoms would you anticipate in this patient based on the diagnosis?

      Your Answer: Clubbing

      Explanation:

      Hypertrophic pulmonary osteoarthropathy (HPOA) is linked to squamous cell carcinoma, while small cell carcinoma of the lung is associated with excessive secretion of ADH and may also cause hypertension, hyperglycemia, and hypokalemia due to excessive ACTH secretion (although this is not typical). Lambert-Eaton syndrome is also linked to small cell carcinoma, while adenocarcinoma of the lung is associated with gynecomastia.

      Lung cancer can present with paraneoplastic features, which are symptoms caused by the cancer but not directly related to the tumor itself. Small cell lung cancer can cause the secretion of ADH and, less commonly, ACTH, which can lead to hypertension, hyperglycemia, hypokalemia, alkalosis, and muscle weakness. Lambert-Eaton syndrome is also associated with small cell lung cancer. Squamous cell lung cancer can cause the secretion of parathyroid hormone-related protein, leading to hypercalcemia, as well as clubbing and hypertrophic pulmonary osteoarthropathy. Adenocarcinoma can cause gynecomastia and hypertrophic pulmonary osteoarthropathy. Hypertrophic pulmonary osteoarthropathy is a painful condition involving the proliferation of periosteum in the long bones. Although traditionally associated with squamous cell carcinoma, some studies suggest that adenocarcinoma is the most common cause.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 28 - Which one of the following is not found in the anterior mediastinum? ...

    Incorrect

    • Which one of the following is not found in the anterior mediastinum?

      Your Answer: Arch of the azygos vein

      Correct Answer: Thoracic duct

      Explanation:

      The posterior and superior mediastinum contain the thoracic duct.

      The mediastinum is the area located between the two pulmonary cavities and is covered by the mediastinal pleura. It extends from the thoracic inlet at the top to the diaphragm at the bottom. The mediastinum is divided into four regions: the superior mediastinum, middle mediastinum, posterior mediastinum, and anterior mediastinum.

      The superior mediastinum is the area between the manubriosternal angle and T4/5. It contains important structures such as the superior vena cava, brachiocephalic veins, arch of aorta, thoracic duct, trachea, oesophagus, thymus, vagus nerve, left recurrent laryngeal nerve, and phrenic nerve. The anterior mediastinum contains thymic remnants, lymph nodes, and fat. The middle mediastinum contains the pericardium, heart, aortic root, arch of azygos vein, and main bronchi. The posterior mediastinum contains the oesophagus, thoracic aorta, azygos vein, thoracic duct, vagus nerve, sympathetic nerve trunks, and splanchnic nerves.

      In summary, the mediastinum is a crucial area in the thorax that contains many important structures and is divided into four regions. Each region contains different structures that are essential for the proper functioning of the body.

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      • Respiratory System
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  • Question 29 - A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain,...

    Correct

    • A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain, nausea, vomiting, and a decreased level of consciousness. Upon examination, the patient exhibits Kussmaul respiration and an acetone-like breath odor.

      What type of metabolic disturbance is most consistent with the symptoms and presentation of this patient?

      Your Answer: Metabolic acidosis, oxygen dissociation curve shifts to the right

      Explanation:

      The correct answer is that metabolic acidosis shifts the oxygen dissociation curve to the right. This is seen in the condition described in the question, diabetic ketoacidosis, which is associated with metabolic acidosis. Acidosis causes more oxygen to be unloaded from haemoglobin, leading to a rightward shift in the curve. The other answer options are incorrect, as they either describe a different type of acidosis or an incorrect direction of the curve shift.

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

    • This question is part of the following fields:

      • Respiratory System
      11.1
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  • Question 30 - A 35-year-old man comes to the clinic complaining of worsening retrosternal chest pain...

    Correct

    • A 35-year-old man comes to the clinic complaining of worsening retrosternal chest pain that radiates to the neck and shoulders and is pleuritic in nature. During examination, a pericardial friction rub is heard at the end of expiration. The diagnosis is pericarditis. What nerve supplies this area?

      Your Answer: Phrenic nerve

      Explanation:

      The correct answer is the phrenic nerve, which provides sensory innervation to the pericardium, the central part of the diaphragm, and the mediastinal part of the parietal pleura. It also supplies motor function to the diaphragm. The long thoracic nerve, medial pectoral nerve, thoracodorsal nerve, and vagus nerve are all incorrect answers.

      The Phrenic Nerve: Origin, Path, and Supplies

      The phrenic nerve is a crucial nerve that originates from the cervical spinal nerves C3, C4, and C5. It supplies the diaphragm and provides sensation to the central diaphragm and pericardium. The nerve passes with the internal jugular vein across scalenus anterior and deep to the prevertebral fascia of the deep cervical fascia.

      The right phrenic nerve runs anterior to the first part of the subclavian artery in the superior mediastinum and laterally to the superior vena cava. In the middle mediastinum, it is located to the right of the pericardium and passes over the right atrium to exit the diaphragm at T8. On the other hand, the left phrenic nerve passes lateral to the left subclavian artery, aortic arch, and left ventricle. It passes anterior to the root of the lung and pierces the diaphragm alone.

      Understanding the origin, path, and supplies of the phrenic nerve is essential in diagnosing and treating conditions that affect the diaphragm and pericardium.

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      • Respiratory System
      12.4
      Seconds

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Respiratory System (15/30) 50%
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