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Question 1
Incorrect
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During a neck dissection, a nerve is observed to pass behind the medial aspect of the second rib. Which nerve from the list below is the most probable?
Your Answer: Medial pectoral nerve
Correct Answer: Phrenic nerve
Explanation:The crucial aspect to note is that the phrenic nerve travels behind the inner side of the first rib. Towards the top, it is situated on the exterior of scalenus anterior.
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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This question is part of the following fields:
- Respiratory System
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Question 2
Correct
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A 27-year-old male admitted to the ICU after a car accident has a pneumothorax. Using a bedside spirometer, his inspiratory and expiratory volumes were measured. What is the typical tidal volume for a male of his age?
Your Answer: 500ml
Explanation:The amount of air that is normally breathed in and out without any extra effort is called tidal volume, which is 500ml in males and 350ml in females.
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.
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This question is part of the following fields:
- Respiratory System
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Question 3
Incorrect
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A 35-year-old pregnant woman undergoes an ABG test. What is the anticipated outcome for a healthy pregnant woman?
Your Answer: Compensated metabolic acidosis
Correct Answer: Compensated respiratory alkalosis
Explanation:During pregnancy, a woman’s increased tidal volume leads to a decrease in carbon dioxide levels, resulting in alkalosis. This is because carbon dioxide generates acid, and reduced levels of it lead to a decrease in acid. The kidneys eventually adapt to this change by reducing the amount of alkaline bicarbonate in the body. Therefore, pregnancy causes a compensated respiratory alkalosis.
If a woman’s bicarbonate levels remain normal, she would have simple respiratory alkalosis.
On the other hand, if a woman produces excess acid, she would have metabolic acidosis, which is the opposite of what occurs during pregnancy.
Arterial Blood Gas Interpretation: A 5-Step Approach
Arterial blood gas interpretation is a crucial aspect of patient care, particularly in critical care settings. The Resuscitation Council (UK) recommends a 5-step approach to interpreting arterial blood gas results. The first step is to assess the patient’s overall condition. The second step is to determine if the patient is hypoxaemic, with a PaO2 on air of less than 10 kPa. The third step is to assess if the patient is acidaemic (pH <7.35) or alkalaemic (pH >7.45).
The fourth step is to evaluate the respiratory component of the arterial blood gas results. A PaCO2 level greater than 6.0 kPa suggests respiratory acidosis, while a PaCO2 level less than 4.7 kPa suggests respiratory alkalosis. The fifth step is to assess the metabolic component of the arterial blood gas results. A bicarbonate level less than 22 mmol/l or a base excess less than -2mmol/l suggests metabolic acidosis, while a bicarbonate level greater than 26 mmol/l or a base excess greater than +2mmol/l suggests metabolic alkalosis.
To remember the relationship between pH, PaCO2, and bicarbonate, the acronym ROME can be used. Respiratory acidosis or alkalosis is opposite to the pH level, while metabolic acidosis or alkalosis is equal to the pH level. This 5-step approach and the ROME acronym can aid healthcare professionals in interpreting arterial blood gas results accurately and efficiently.
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This question is part of the following fields:
- Respiratory System
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Question 4
Correct
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A 57-year-old man comes to his GP complaining of worsening shortness of breath during physical activity over the past year. He has never smoked and reports no history of occupational exposure to asbestos, dust, or fumes. His BMI is calculated to be 40 kg/m². Upon examination, there is decreased chest expansion bilaterally, but the lungs are clear upon auscultation. The GP orders spirometry, which reveals a decreased expiratory reserve volume.
Can you provide the definition of this particular lung volume?Your Answer: Maximum volume of air that can be expired at the end of a normal tidal expiration
Explanation:The expiratory reserve volume refers to the maximum amount of air that can be exhaled after a normal breath out. It is important to note that this volume can be reduced in conditions that limit lung expansion, such as obesity and ascites. Obesity, in particular, can cause a restrictive pattern on spirometry, where the FEV1/FVC ratio is ≥0.8. Other restrictive lung conditions include idiopathic pulmonary fibrosis, pleural effusion, ascites, and neuromuscular disorders that limit chest expansion. On the other hand, obstructive disorders like asthma and COPD lead to a FEV1/FVC ratio of <0.7, limiting the amount of air that can be exhaled in one second. It is essential to understand the different lung volumes and capacities, including inspiratory reserve volume, tidal volume, expiratory reserve volume, residual volume, inspiratory capacity, vital capacity, functional residual capacity, and total lung 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.
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This question is part of the following fields:
- Respiratory System
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Question 5
Incorrect
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An 75-year-old woman presents to her GP with a 4-month history of dysphagia, weight loss, and a change in her voice tone. After a nasendoscopy, laryngeal carcinoma is confirmed. The surgical team plans her operation based on a head and neck CT scan. Which vertebrae are likely located posterior to the carcinoma?
Your Answer: C2-C4
Correct Answer: C3-C6
Explanation:The larynx is situated in the front of the neck, specifically at the level of the C3-C6 vertebrae. It is positioned below the pharynx and contains the vocal cords that produce sound. The C1-C3 vertebrae are located much higher than the larynx, while the C2-C4 vertebrae cover the area from the oropharynx to the first part of the larynx. The C6-T1 vertebrae are situated behind the larynx and the upper portions of the trachea and esophagus.
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.
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This question is part of the following fields:
- Respiratory System
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Question 6
Incorrect
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A senior woman with a history of chronic obstructive pulmonary disease (COPD) arrives at the hospital complaining of worsening shortness of breath and a productive cough. As part of the initial evaluation, a chest X-ray is requested.
What radiographic feature would you anticipate observing on her chest X-ray?Your Answer: Empyema
Correct Answer: Flattened diaphragm
Explanation:The diaphragm of patients with COPD often appears flattened on a chest X-ray due to the chronic expiratory airflow obstruction causing dynamic hyperinflation of the lungs. Pleural effusions are commonly associated with infection, malignancy, or heart failure, while empyema is a result of pus accumulation in the pleural space caused by an infection.
Understanding COPD: Symptoms and Diagnosis
Chronic obstructive pulmonary disease (COPD) is a common medical condition that includes chronic bronchitis and emphysema. Smoking is the leading cause of COPD, and patients with mild disease may only need occasional use of a bronchodilator, while severe cases may result in frequent hospital admissions due to exacerbations. Symptoms of COPD include a productive cough, dyspnea, wheezing, and in severe cases, right-sided heart failure leading to peripheral edema.
To diagnose COPD, doctors may recommend post-bronchodilator spirometry to demonstrate airflow obstruction, a chest x-ray to check for hyperinflation, bullae, and flat hemidiaphragm, and to exclude lung cancer. A full blood count may also be necessary to exclude secondary polycythemia, and body mass index (BMI) calculation is important. The severity of COPD is categorized using the FEV1, with a ratio of less than 70% indicating airflow obstruction. The grading system has changed following the 2010 NICE guidelines, with Stage 1 – mild now including patients with an FEV1 greater than 80% predicted but with a post-bronchodilator FEV1/FVC ratio of less than 0.7. Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
In summary, COPD is a common condition caused by smoking that can result in a range of symptoms and severity. Diagnosis involves various tests to check for airflow obstruction, exclude lung cancer, and determine the severity of the disease.
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This question is part of the following fields:
- Respiratory System
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Question 7
Incorrect
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Which one of the following does not cause a normal anion gap acidosis?
Your Answer: Ureteric diversion
Correct Answer: Uraemia
Explanation:Normal Gap Acidosis can be remembered using the acronym HARDUP, which stands for Hyperalimentation/hyperventilation, Acetazolamide, and R (which is currently blank).
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.
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This question is part of the following fields:
- Respiratory System
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Question 8
Correct
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A 70-year-old man visits his primary care physician with complaints of hearing difficulties. He states that he has been increasingly struggling to hear his wife's conversations for the past six months. He is concerned that this problem will worsen and eventually lead to complete hearing loss, making it difficult for him to communicate with his children over the phone. His wife is also distressed by the situation, as he frequently asks her to turn up the volume on the television. The man has no history of exposure to loud noises and has well-controlled hypertension. He is a retired police officer and currently resides with his wife. What is the primary pathology underlying this man's most likely diagnosis?
Your Answer: Degeneration of the cells at the cochlear base
Explanation:The patient has a gradual-onset hearing loss, which is most likely due to presbycusis, an aging-related sensorineural hearing loss. This condition has multiple causes, including environmental factors like noise pollution and biological factors like genetics and oxidative stress. Damage to the organ of Corti stereocilia from exposure to sudden loud noises can also cause hearing loss, which is typically sudden and associated with a history of exposure to loud noises. Other conditions that can cause hearing loss include cholesteatoma, which is due to the accumulation of keratin debris in the middle ear, and otosclerosis, which is characterized by the overgrowth of bone in the middle ear.
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.
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This question is part of the following fields:
- Respiratory System
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Question 9
Incorrect
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What is the anatomical level of the transpyloric plane?
Your Answer: L4
Correct Answer: L1
Explanation: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.
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This question is part of the following fields:
- Respiratory System
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Question 10
Incorrect
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A 20-year-old female presented to the hospital with a complaint of a sore throat. She reported having a high-grade fever and severe pain on the right side of her throat for the past four days. The patient also experienced difficulty in swallowing and had restricted mouth opening. Additionally, she complained of bilateral ear pain and headache. Despite receiving oral antibiotics, her symptoms had worsened.
Upon examination, the patient had a fever of 38.5ºC and prominent cervical lymphadenopathy. Swelling of the right soft palate was observed, and the uvula was deviated to the left.
What is the most probable diagnosis?Your Answer: Acute tonsillitis
Correct Answer: Peritonsillar abscess (quinsy)
Explanation:Trismus, which is difficulty in opening the mouth, is a common symptom of peritonsillar abscess (also known as quinsy). It is important to note that quinsy is a complication of tonsillitis, not acute tonsillitis itself. Epiglottitis may present with muffled voice, drooling, and difficulty in breathing, while infectious mononucleosis is associated with other symptoms such as weight loss, fatigue, and enlarged lymph nodes and organs.
Peritonsillar Abscess: Symptoms and Treatment
A peritonsillar abscess, also known as quinsy, is a complication that can arise from bacterial tonsillitis. This condition is characterized by severe throat pain that is localized to one side, along with difficulty opening the mouth and reduced neck mobility. Additionally, the uvula may be deviated to the unaffected side. It is important to seek urgent medical attention from an ENT specialist if these symptoms are present.
The treatment for a peritonsillar abscess typically involves needle aspiration or incision and drainage, along with intravenous antibiotics. In some cases, a tonsillectomy may be recommended to prevent recurrence of the abscess. It is important to follow the recommended treatment plan and attend all follow-up appointments to ensure proper healing and prevent complications.
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This question is part of the following fields:
- Respiratory System
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Question 11
Incorrect
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A 60-year-old man visits his GP with worries about his hearing in recent months. He has difficulty understanding conversations in noisy environments and his spouse has commented on his need for the television to be turned up to maximum volume.
During the examination, the GP conducts some basic tests and finds:
Rinne's Test - Air conduction > bone conduction in both ears
Weber's Test - Lateralises to the left ear
What can be inferred from these test results?Your Answer: Right conductive hearing loss
Correct Answer: Left sensorineural hearing loss
Explanation:The patient has left sensorineural hearing loss, as indicated by the normal Rinne result (air conduction > bone conduction bilaterally) and abnormal Weber result (lateralising to the unaffected ear). In contrast, if the patient had conductive hearing loss, Rinne’s test would show bone conduction > air conduction, and Weber’s test would localise to the worse ear in bilateral conductive hearing loss or the affected ear in unilateral conductive hearing loss. For right sensorineural hearing loss, Rinne’s test would be normal, but Weber’s test would localise to the left ear.
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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This question is part of the following fields:
- Respiratory System
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Question 12
Correct
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A 10-year-old boy comes to the clinic with his mother. He complained of ear pain during the night, but there is no discharge, hearing loss, or other symptoms. Upon examination, he has no fever. The pinna of his ear appears red and swollen, and pressing on the tragus causes pain. Otoscopy reveals a healthy tympanic membrane, but the external auditory canal is inflamed. The external auditory canal consists of a cartilaginous outer part and a bony inner part. Which bone does the bony external canal pass through?
Your Answer: Temporal bone
Explanation:The temporal bone is the correct answer. It contains the bony external auditory canal and middle ear, which are composed of a cartilaginous outer third and a bony inner two-thirds. The temporal bone articulates with the parietal, occipital, sphenoid, zygomatic, and mandible bones.
The sphenoid bone is a complex bone that articulates with 12 other bones. It is divided into four parts: the body, greater wings, lesser wings, and pterygoid plates.
The zygomatic bone is located on the anterior and lateral aspects of the face and articulates with the frontal, sphenoid, temporal, and maxilla bones.
The parietal bone forms the sides and roof of the cranium and articulates with the parietal on the opposite side, as well as the frontal, temporal, occipital, and sphenoid bones.
The occipital bone is situated at the rear of the cranium and articulates with the temporal, sphenoid, parietals, and the first cervical vertebrae.
The patient’s symptoms of ear pain, erythematous pinna and external auditory canal, and tender tragus on palpation are consistent with otitis externa, which has numerous possible causes. The patient is not febrile and has no loss of hearing or dizziness.
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.
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This question is part of the following fields:
- Respiratory System
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Question 13
Correct
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A 75-year-old man visits his doctor complaining of weight loss and feeling full quickly. During the abdominal examination, the doctor notices a swollen lymph node in the left supraclavicular region. The doctor suspects that this could be a sign of gastric cancer with the spread of tumor emboli through the thoracic duct as it ascends from the abdomen into the mediastinum. Can you name the two other structures that pass through the diaphragm along with the thoracic duct?
Your Answer: Aorta and azygous vein
Explanation:The point at which the aorta, thoracic duct, and azygous vein cross the diaphragm is at T12, specifically at the aortic opening. This is also where the oesophageal branches of the left gastric veins, the vagal trunk, and the oesophagus pass through the diaphragm, at the oesophageal opening located at T10. The left phrenic nerve and sympathetic trunk have their own separate openings in the diaphragm. A lymph node in the left supraclavicular fossa, known as Virchow’s node, is a characteristic sign of early gastric carcinoma.
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.
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This question is part of the following fields:
- Respiratory System
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Question 14
Incorrect
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A 75-year-old man presents with a 2-month history of progressive shortness of breath and a recent episode of coughing up blood in the morning. He has also experienced significant weight loss of over 12 lbs and loss of appetite. Upon physical examination, conjunctival pallor is noted. The patient has a 30 pack year history of smoking. A chest x-ray reveals a mediastinal mass and ipsilateral elevation of the right diaphragm. What structure is being compressed by the mediastinal mass to explain these findings?
Your Answer: Sympathetic chain
Correct Answer: Phrenic nerve
Explanation:Lung cancer can cause the hemidiaphragm on the same side to rise due to pressure on the phrenic nerve. Haemoptysis is a common symptom of lung cancer, along with significant weight loss and a history of smoking. A chest x-ray can confirm the presence of a mediastinal mass, which is likely to be lung cancer.
A rapidly expanding lung mass can cause compression of surrounding structures, leading to complications. For example, an apical tumor can compress the brachial plexus, causing sensory symptoms in the arms or Erb’s or Klumpke’s palsies. Compression of the cervical sympathetic chain can cause Horner’s syndrome, which includes meiosis, anhidrosis, ptosis, and enophthalmos.
A mediastinal mass can also compress the recurrent laryngeal nerve as it winds around the aortic arch, resulting in hoarseness of voice or aphonia. Superior vena caval syndrome is a medical emergency that can cause swelling of the face, neck, upper chest, and arms, as well as the development of collaterals on the chest wall. Malignancy is the most common cause, but non-malignant causes can include an aortic aneurysm, fibrosing mediastinitis, or iatrogenic factors.
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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This question is part of the following fields:
- Respiratory System
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Question 15
Incorrect
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A 25-year-old man is receiving an endotracheal intubation. At which vertebral level does the trachea originate?
Your Answer: C2
Correct Answer: C6
Explanation:The trachea starts at the sixth cervical vertebrae and ends at the fifth thoracic vertebrae (or sixth in individuals with a tall stature during deep inhalation).
Anatomy of the Trachea
The trachea, also known as the windpipe, is a tube-like structure that extends from the C6 vertebrae to the upper border of the T5 vertebrae where it bifurcates into the left and right bronchi. It is supplied by the inferior thyroid arteries and the thyroid venous plexus, and innervated by branches of the vagus, sympathetic, and recurrent nerves.
In the neck, the trachea is anterior to the isthmus of the thyroid gland, inferior thyroid veins, and anastomosing branches between the anterior jugular veins. It is also surrounded by the sternothyroid, sternohyoid, and cervical fascia. Posteriorly, it is related to the esophagus, while laterally, it is in close proximity to the common carotid arteries, right and left lobes of the thyroid gland, inferior thyroid arteries, and recurrent laryngeal nerves.
In the thorax, the trachea is anterior to the manubrium, the remains of the thymus, the aortic arch, left common carotid arteries, and the deep cardiac plexus. Laterally, it is related to the pleura and right vagus on the right side, and the left recurrent nerve, aortic arch, and left common carotid and subclavian arteries on the left side.
Overall, understanding the anatomy of the trachea is important for various medical procedures and interventions, such as intubation and tracheostomy.
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This question is part of the following fields:
- Respiratory System
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Question 16
Correct
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Which one of the following does not decrease the functional residual capacity?
Your Answer: Upright position
Explanation:When a patient is in an upright position, the functional residual capacity (FRC) can increase due to less pressure from the diaphragm and abdominal organs on the lung bases. This increase in FRC can also be caused by emphysema and asthma. On the other hand, factors such as abdominal swelling, pulmonary edema, reduced muscle tone of the diaphragm, and aging can lead to a decrease in FRC. Additionally, laparoscopic surgery, obesity, and muscle relaxants can also contribute to a reduction in FRC.
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.
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This question is part of the following fields:
- Respiratory System
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Question 17
Incorrect
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An anxious father brings his 6-month-old to the out of hours GP. The baby has been coughing persistently for the past 2 days and it seems to be getting worse. He also has a runny nose and an audible wheeze. The GP diagnoses bronchiolitis.
What is the most probable causative organism in this case?Your Answer: Adenoviruses
Correct Answer: Respiratory syncytial virus
Explanation:Understanding Bronchiolitis
Bronchiolitis is a condition that is characterized by inflammation of the bronchioles. It is a serious lower respiratory tract infection that is most common in children under the age of one year. The pathogen responsible for 75-80% of cases is respiratory syncytial virus (RSV), while other causes include mycoplasma and adenoviruses. Bronchiolitis is more serious in children with bronchopulmonary dysplasia, congenital heart disease, or cystic fibrosis.
The symptoms of bronchiolitis include coryzal symptoms, dry cough, increasing breathlessness, and wheezing. Fine inspiratory crackles may also be present. Children with bronchiolitis may experience feeding difficulties associated with increasing dyspnoea, which is often the reason for hospital admission.
Immediate referral to hospital is recommended if the child has apnoea, looks seriously unwell to a healthcare professional, has severe respiratory distress, central cyanosis, or persistent oxygen saturation of less than 92% when breathing air. Clinicians should consider referring to hospital if the child has a respiratory rate of over 60 breaths/minute, difficulty with breastfeeding or inadequate oral fluid intake, or clinical dehydration.
The investigation for bronchiolitis involves immunofluorescence of nasopharyngeal secretions, which may show RSV. Management of bronchiolitis is largely supportive, with humidified oxygen given via a head box if oxygen saturations are persistently < 92%. Nasogastric feeding may be needed if children cannot take enough fluid/feed by mouth, and suction is sometimes used for excessive upper airway secretions.
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This question is part of the following fields:
- Respiratory System
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Question 18
Incorrect
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A 59-year-old man comes to see his GP complaining of vertigo that has been going on for three days. He also reports experiencing left-sided ear pain and a change in his sense of taste, as well as constant ringing in his left ear. He took paracetamol on his own, but the vertigo persisted, so he decided to seek medical attention.
During the examination, the doctor observes that the man has a drooping left face with involvement of the forehead. Upon otoscopic examination, vesicles are seen in the external auditory canal of the left ear. A neurological examination is performed, which is normal except for the left facial paralysis.
What is the appropriate treatment for this man's condition?Your Answer: Amoxicillin
Correct Answer: Oral acyclovir and corticosteroids
Explanation:Ramsay Hunt syndrome is treated with a combination of oral acyclovir and corticosteroids. This condition is caused by the varicella zoster virus, as evidenced by the presence of vesicles on the left ear and involvement of the seventh and eighth cranial nerves. Symptoms include facial paralysis and hearing impairments. Treatment typically involves a seven to ten day course of oral acyclovir and a five day course of corticosteroids, such as prednisolone.
It is important to note that oseltamivir (tamiflu) is an antiviral used for influenzae, while chloroquine is typically used for malaria. Amoxicillin is an antibiotic and is not effective in treating viral infections. While corticosteroids can provide relief from inflammation, they are not the primary treatment for Ramsay Hunt syndrome when used alone.
Understanding Ramsay Hunt Syndrome
Ramsay Hunt syndrome, also known as herpes zoster oticus, is a condition that occurs when the varicella zoster virus reactivates in the geniculate ganglion of the seventh cranial nerve. The first symptom of this syndrome is often auricular pain, followed by facial nerve palsy and a vesicular rash around the ear. Other symptoms may include vertigo and tinnitus.
To manage Ramsay Hunt syndrome, doctors typically prescribe oral acyclovir and corticosteroids. These medications can help reduce the severity of symptoms and prevent complications.
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This question is part of the following fields:
- Respiratory System
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Question 19
Incorrect
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A 56-year-old woman comes to the clinic complaining of a persistent cough and increased production of sputum over the past year. She also reports feeling fatigued and experiencing shortness of breath. The patient mentions having had four chest infections in the last 12 months, all of which were treated with antibiotics. She has no personal or family history of lung issues and has never smoked.
The healthcare provider suspects that bronchiectasis may be the underlying cause of her symptoms and orders appropriate tests.
Which test is most likely to provide a definitive diagnosis?Your Answer: Sputum culture
Correct Answer: High-resolution computerised tomography
Explanation:Bronchiectasis can be diagnosed through various methods, including chest radiography, histopathology, and pulmonary function tests.
Chest radiography can reveal thickened bronchial walls, cystic lesions with fluid levels, collapsed areas with crowded pulmonary vasculature, and scarring, which are characteristic features of bronchiectasis.
Histopathology, which is a more invasive investigation often done through autopsy or surgery, can show irreversible dilation of bronchial airways and bronchial wall thickening.
However, high-resolution computerised tomography is a more favorable imaging technique as it is less invasive than histopathology.
Pulmonary function tests are commonly used to diagnose bronchiectasis, but they should be used in conjunction with other investigations as they are not sensitive or specific enough to provide sufficient diagnostic evidence on their own. An obstructive pattern is the most common pattern encountered, but a restrictive pattern is also possible.
Understanding the Causes of Bronchiectasis
Bronchiectasis is a condition characterized by the permanent dilation of the airways due to chronic inflammation or infection. There are various factors that can lead to this condition, including post-infective causes such as tuberculosis, measles, pertussis, and pneumonia. Cystic fibrosis, bronchial obstruction caused by lung cancer or foreign bodies, and immune deficiencies like selective IgA and hypogammaglobulinaemia can also contribute to bronchiectasis. Additionally, allergic bronchopulmonary aspergillosis (ABPA), ciliary dyskinetic syndromes like Kartagener’s syndrome and Young’s syndrome, and yellow nail syndrome are other potential causes. Understanding the underlying causes of bronchiectasis is crucial in developing effective treatment plans for patients.
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This question is part of the following fields:
- Respiratory System
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Question 20
Incorrect
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A father brings his 5-year-old daughter to the GP with a 72-hour history of left ear pain. She has had a cough with coryzal symptoms for the past four days. She has no past medical history, allergies or current medications, and she is up-to-date with her vaccinations. Her temperature is 38.5ºC. No abnormality is detected on examination of the oral cavity. Following otoscopy, what is the most likely causative pathogen for her diagnosis of otitis media?
Your Answer: Rhinovirus
Correct Answer: Streptococcus pneumoniae
Explanation:Otitis media is primarily caused by bacteria, with viral URTIs often preceding the infection. The majority of cases are secondary to bacterial infections, with the most common culprit being…
Acute otitis media is a common condition in young children, often caused by bacterial infections following viral upper respiratory tract infections. Symptoms include ear pain, fever, and hearing loss, and diagnosis is based on criteria such as the presence of a middle ear effusion and inflammation of the tympanic membrane. Antibiotics may be prescribed in certain cases, and complications can include perforation of the tympanic membrane, hearing loss, and more serious conditions such as meningitis and brain abscess.
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This question is part of the following fields:
- Respiratory System
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Question 21
Incorrect
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A 26-year-old man presents to the emergency department with a feeling of food stuck in his throat. He experienced this sensation 2 hours ago after consuming fish at a nearby seafood restaurant. The patient reports no breathing difficulties. Upon laryngoscopy, a fish bone is found lodged in the left piriform recess. While removing the fish bone, a nerve located deep to the mucosa covering the recess is damaged.
Which function is most likely to be affected in this individual?Your Answer: Pharyngeal reflex
Correct Answer: Cough reflex
Explanation:Foreign objects lodged in the piriform recess can cause damage to the internal laryngeal nerve, which is located just beneath a thin layer of mucosa covering the recess. This nerve plays a crucial role in the cough reflex, as it carries sensory information from the area above the vocal cords. Attempts to remove foreign objects from the piriform recess can also lead to nerve damage.
Other functions, such as mastication, the pharyngeal reflex, salivation, and taste sensation, are mediated by different nerves and are not directly related to the piriform recess or the internal laryngeal nerve.
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.
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This question is part of the following fields:
- Respiratory System
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Question 22
Incorrect
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A 25-year-old man comes to the doctor complaining of frequent urination, unquenchable thirst, and recent weight loss of around 5 kilograms in the last 2 months. The patient reports feeling extremely tired, although he acknowledges that work has been stressful lately, and his eating habits have been poor. The patient has a medical history of cystic fibrosis, with a Pseudomonas aeruginosa flare-up last year that required a brief hospital stay.
What could be the probable reason for this patient's clinical presentation?Your Answer: Diabetes insipidus
Correct Answer: Diabetes mellitus
Explanation:Cystic fibrosis can lead to the development of a unique type of diabetes mellitus known as cystic fibrosis-related diabetes mellitus. This is caused by the destruction of pancreatic islets due to abnormal chloride channel function, which leads to thickened bodily secretions that damage the exocrine pancreas over time. As a result, there is a gradual reduction in islet cell function and relative insulin deficiency, which can cause symptoms such as polydipsia, polyuria, fatigue, and weight loss.
It is important to note that this type of diabetes is distinct from type 1 or type 2 diabetes. Additionally, it is not associated with other conditions such as diabetes insipidus, primary hyperparathyroidism, or prostatitis, which have their own unique symptoms and causes.
Understanding Cystic Fibrosis: Symptoms and Other Features
Cystic fibrosis is a genetic disorder that affects various organs in the body, particularly the lungs and digestive system. The symptoms of cystic fibrosis can vary from person to person, but some common presenting features include recurrent chest infections, malabsorption, and liver disease. In some cases, infants may experience meconium ileus or prolonged jaundice. It is important to note that while many patients are diagnosed during newborn screening or early childhood, some may not be diagnosed until adulthood.
Aside from the presenting features, there are other symptoms and features associated with cystic fibrosis. These include short stature, diabetes mellitus, delayed puberty, rectal prolapse, nasal polyps, and infertility. It is important for individuals with cystic fibrosis to receive proper medical care and management to address these symptoms and improve their quality of life.
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This question is part of the following fields:
- Respiratory System
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Question 23
Correct
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A 24-year-old female arrives at the emergency department in a state of panic following a recent breakup with her partner. She complains of chest tightness and dizziness, fearing that she may be experiencing a heart attack. Upon examination, her vital signs are stable except for a respiratory rate of 34 breaths per minute. What compensatory mechanism is expected in response to the change in her oxyhaemoglobin dissociation curve, and what is the underlying cause?
Your Answer: Left shift, respiratory alkalosis
Explanation:The patient’s oxygen dissociation curve has shifted to the left, indicating respiratory alkalosis. This is likely due to the patient experiencing a panic attack and hyperventilating, leading to a decrease in carbon dioxide levels and an increase in the affinity of haemoglobin for oxygen. Respiratory acidosis, hypercapnia, and a right shift of the curve are not appropriate explanations for this patient’s condition.
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.
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This question is part of the following fields:
- Respiratory System
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Question 24
Incorrect
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A 55-year-old woman comes to the clinic complaining of a persistent cough and increased production of sputum over the past year. She also reports feeling fatigued and experiencing shortness of breath. The patient mentions having had four chest infections in the last 12 months, all of which were treated with antibiotics. She has no medical or family history and has never smoked.
The healthcare provider suspects that bronchiectasis may be the underlying cause of her symptoms and orders appropriate tests, including a sputum sample.
What is the most likely organism to be identified?Your Answer: Haemophilus influenzae
Correct Answer:
Explanation:Bronchiectasis patients may have various bacteria present in their respiratory system, with Haemophilus influenzae and Pseudomonas aeruginosa being the most common. Staphylococcus aureus has also been found but not as frequently. Respiratory syncytial virus has not been detected in acute exacerbations of bronchiectasis. It is crucial to identify the specific bacteria causing exacerbations as antibiotic sensitivity patterns differ, and sputum culture results can impact the effectiveness of treatment. These findings are outlined in the British Thoracic Society’s guideline for non-CF bronchiectasis and a study by Metaxas et al. on the role of atypical bacteria and respiratory syncytial virus in bronchiectasis exacerbations.
Bronchiectasis is a condition where the airways become permanently dilated due to chronic inflammation or infection. Before treatment, it is important to identify any underlying causes that can be addressed, such as immune deficiencies. Management of bronchiectasis includes physical training, such as inspiratory muscle training, which has been shown to be effective for patients without cystic fibrosis. Postural drainage, antibiotics for exacerbations, and long-term rotating antibiotics for severe cases are also recommended. Bronchodilators may be used in selected cases, and immunizations are important to prevent infections. Surgery may be considered for localized disease. The most common organisms isolated from patients with bronchiectasis include Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella spp., and Streptococcus pneumoniae.
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This question is part of the following fields:
- Respiratory System
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Question 25
Correct
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A premature baby is born and the anaesthetists are struggling to ventilate the lungs because of insufficient surfactant. How does Laplace's law explain the force pushing inwards on the walls of the alveolus caused by surface tension between two static fluids, such as air and water in the alveolus?
Your Answer: Inversely proportional to the radius of the alveolus
Explanation:The Relationship between Alveolar Size and Surface Tension in Respiratory Physiology
In respiratory physiology, the alveolus is often represented as a perfect sphere to apply Laplace’s law. According to this law, there is an inverse relationship between the size of the alveolus and the surface tension. This means that smaller alveoli experience greater force than larger alveoli for a given surface tension, and they will collapse first. This phenomenon explains why, when two balloons are attached together by their ends, the smaller balloon will empty into the bigger balloon.
In the lungs, this same principle applies to lung units, causing atelectasis and collapse when surfactant is not present. Surfactant is a substance that reduces surface tension, making it easier to expand the alveoli and preventing smaller alveoli from collapsing. Therefore, surfactant plays a crucial role in maintaining the proper functioning of the lungs and preventing respiratory distress. the relationship between alveolar size and surface tension is essential in respiratory physiology and can help in the development of treatments for lung diseases.
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This question is part of the following fields:
- Respiratory System
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Question 26
Incorrect
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A 67-year-old man has been diagnosed with stage III lung cancer and is concerned about potential complications. What are the risks he may face?
Your Answer: Pulmonary fibrosis
Correct Answer: Pneumothorax
Explanation:Pneumothorax is more likely to occur in individuals with lung cancer.
Pneumothorax: Characteristics and Risk Factors
Pneumothorax is a medical condition characterized by the presence of air in the pleural cavity, which is the space between the lungs and the chest wall. This condition can occur spontaneously or as a result of trauma or medical procedures. There are several risk factors associated with pneumothorax, including pre-existing lung diseases such as COPD, asthma, cystic fibrosis, lung cancer, and Pneumocystis pneumonia. Connective tissue diseases like Marfan’s syndrome and rheumatoid arthritis can also increase the risk of pneumothorax. Ventilation, including non-invasive ventilation, can also be a risk factor.
Symptoms of pneumothorax tend to come on suddenly and can include dyspnoea, chest pain (often pleuritic), sweating, tachypnoea, and tachycardia. In some cases, catamenial pneumothorax can be the cause of spontaneous pneumothoraces occurring in menstruating women. This type of pneumothorax is thought to be caused by endometriosis within the thorax. Early diagnosis and treatment of pneumothorax are crucial to prevent complications and improve outcomes.
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This question is part of the following fields:
- Respiratory System
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Question 27
Incorrect
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A middle-aged woman who is obese comes in with complaints of polyuria. She has a history of squamous cell lung carcinoma. What could be the possible reason for her polyuria?
Your Answer: Type 2 diabetes mellitus
Correct Answer: Hyperparathyroidism
Explanation:Polyuria is caused by all the options listed above, except for syndrome of inappropriate ADH secretion. However, the patient’s age does not match the typical onset of type 1 diabetes, which usually occurs in young individuals. Furthermore, squamous cell lung carcinoma is commonly associated with a paraneoplastic syndrome that results in the release of excess parathyroid hormone by the tumor, leading to hypercalcemia and subsequent polyuria, along with other symptoms such as renal and biliary stones, bone pain, abdominal discomfort, nausea, vomiting, depression, and anxiety.
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.
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This question is part of the following fields:
- Respiratory System
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Question 28
Incorrect
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A 78-year-old man comes to the emergency department complaining of increasing difficulty in breathing over the past two days. He has a medical history of squamous cell lung cancer.
Upon examination, the trachea is observed to have shifted towards the left side, with dull percussion and absence of breath sounds throughout the left chest.
What is the probable diagnosis?Your Answer: Right pneumothorax
Correct Answer: Left lung collapse
Explanation:When a lung collapses, it can cause the trachea to shift towards the affected side, and there may be dullness on percussion and reduced breath sounds throughout the lung field. This is because the decrease in pressure on the affected side causes the mediastinum and trachea to move towards it.
A massive pleural effusion, on the other hand, would cause widespread dullness and absent breath sounds, but it would push the trachea away from the affected side due to increased pressure.
Pneumonia typically only affects one lung zone, so there would not be widespread dullness or absent breath sounds throughout the hemithorax. It also does not usually affect the position of the mediastinum or trachea.
Pneumothorax would be hyperresonant on percussion, not dull, and it may push the trachea away from the affected side in severe cases, but this is more common in tension pneumothoraces that occur after trauma.
A lobectomy may cause the trachea to shift towards the same side as the surgery due to decreased pressure, but it would not cause dullness or absent breath sounds throughout the lung fields.
Understanding White Lung Lesions on Chest X-Rays
When examining a chest x-ray, white shadowing in the lungs can indicate a variety of conditions. These may include consolidation, pleural effusion, collapse, pneumonectomy, specific lesions such as tumors, or fluid accumulation such as pulmonary edema. In cases where there is a complete white-out of one side of the chest, it is important to assess the position of the trachea. If the trachea is pulled towards the side of the white-out, it may indicate pneumonectomy, lung collapse, or pulmonary hypoplasia. If the trachea is pushed away from the white-out, it may indicate pleural effusion, a large thoracic mass, or a diaphragmatic hernia. Other signs of a positive mass effect may include leftward bowing of the azygo-oesophageal recess and splaying of the ribs on the affected side. Understanding the potential causes of white lung lesions on chest x-rays can aid in accurate diagnosis and treatment.
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This question is part of the following fields:
- Respiratory System
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Question 29
Correct
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A 32-year-old woman arrives at the emergency department complaining of sudden shortness of breath and a sharp pain on the right side of her chest that worsens with inspiration. Upon examination, the doctor observes hyper-resonance and reduced breath sounds on the right side of her chest.
What is a risk factor for this condition, considering the probable diagnosis?Your Answer: Cystic fibrosis
Explanation:Pneumothorax can be identified by reduced breath sounds and a hyper-resonant chest on the same side as the pain. Cystic fibrosis is a significant risk factor for pneumothorax due to the frequent chest infections, lung remodeling, and air trapping associated with the disease. While tall, male smokers are also at increased risk, Marfan’s syndrome, not Turner syndrome, is a known risk factor.
Pneumothorax: Characteristics and Risk Factors
Pneumothorax is a medical condition characterized by the presence of air in the pleural cavity, which is the space between the lungs and the chest wall. This condition can occur spontaneously or as a result of trauma or medical procedures. There are several risk factors associated with pneumothorax, including pre-existing lung diseases such as COPD, asthma, cystic fibrosis, lung cancer, and Pneumocystis pneumonia. Connective tissue diseases like Marfan’s syndrome and rheumatoid arthritis can also increase the risk of pneumothorax. Ventilation, including non-invasive ventilation, can also be a risk factor.
Symptoms of pneumothorax tend to come on suddenly and can include dyspnoea, chest pain (often pleuritic), sweating, tachypnoea, and tachycardia. In some cases, catamenial pneumothorax can be the cause of spontaneous pneumothoraces occurring in menstruating women. This type of pneumothorax is thought to be caused by endometriosis within the thorax. Early diagnosis and treatment of pneumothorax are crucial to prevent complications and improve outcomes.
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This question is part of the following fields:
- Respiratory System
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Question 30
Correct
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Which one of the following is not found in the anterior mediastinum?
Your 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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This question is part of the following fields:
- Respiratory System
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