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  • Question 1 - Which drug is the least likely to trigger an episode of acute intermittent...

    Incorrect

    • Which drug is the least likely to trigger an episode of acute intermittent porphyria?

      Your Answer: Diazepam

      Correct Answer: Penicillin

      Explanation:

      Drugs to Avoid and Use in Acute Intermittent Porphyria

      Acute intermittent porphyria (AIP) is a genetic disorder that affects the production of haem. It is characterized by abdominal and neuropsychiatric symptoms and is more common in females. AIP is caused by a defect in the porphobilinogen deaminase enzyme. Certain drugs can trigger an attack in individuals with AIP, including barbiturates, halothane, benzodiazepines, alcohol, oral contraceptive pills, and sulphonamides. Therefore, it is important to avoid these drugs in individuals with AIP. However, there are some drugs that are considered safe to use, such as paracetamol, aspirin, codeine, morphine, chlorpromazine, beta-blockers, penicillin, and metformin.

    • This question is part of the following fields:

      • General Principles
      26.1
      Seconds
  • Question 2 - A 25-year-old female visits her doctor with concerns about her drinking habits and...

    Correct

    • A 25-year-old female visits her doctor with concerns about her drinking habits and a desire to quit. She acknowledges that alcohol provides a temporary sense of relief but acknowledges its harmful effects. She also inquires about the mechanism by which alcohol produces this sensation.

      The doctor informs her that alcohol imitates the impact of the primary inhibitory neurotransmitters that operate on the spinal cord and central nervous system.

      What is the primary inhibitory neurotransmitter in the spinal cord?

      Your Answer: Glycine

      Explanation:

      The Role of Glycine in the Body

      Glycine is an amino acid that is essential for the production of proteins in the body. While it is not considered an essential amino acid, as it can be synthesized from serine, it plays a crucial role in the body’s functions. Glycine is the primary inhibitory neurotransmitter in the spinal cord and brainstem, where it prevents glutamate-mediated depolarization of the postsynaptic terminal via NMDA receptors. It is also used as an intermediate in the synthesis of porphyrins and purines.

      The glycine cleavage system is the major pathway for glycine breakdown, which largely occurs in the liver. However, a defect in this system can lead to glycine encephalopathy, a rare autosomal recessive disorder characterized by myoclonic seizures soon after birth. This disorder is caused by high levels of glycine in the blood and cerebrospinal fluid. While glycine is usually only found in small amounts in proteins, it makes up 35% of collagen. Overall, glycine plays a vital role in the body’s functions and is necessary for maintaining proper health.

    • This question is part of the following fields:

      • General Principles
      58.9
      Seconds
  • Question 3 - A 63-year-old man arrives at the emergency department with difficulty speaking and weakness...

    Correct

    • A 63-year-old man arrives at the emergency department with difficulty speaking and weakness on his right side. The symptoms appeared suddenly, and he did not experience any trauma or pain. During the examination, you observe weakness in his right upper limb. Although he comprehends your inquiries, he struggles to find the right words to respond. There are no alterations in his sensation. You suspect that he has suffered a stroke. Which region of the brain is responsible for expressive dysphasia?

      Your Answer: Broca's area

      Explanation:

      Broca’s area, located in the inferior posterior frontal lobe, is associated with expressive dysphasia, which is characterized by difficulty producing language and non-fluent speech. This condition is sometimes referred to as Broca’s dysphasia. On the other hand, the primary motor cortex, located in the posterior frontal lobe, is responsible for motor control, and lesions in this area can result in motor deficits affecting the opposite side of the body.

      Wernicke’s area, another brain region involved in speech, is primarily responsible for language comprehension and understanding. Lesions in this area can lead to receptive dysphasia, which is characterized by a lack of comprehension and understanding of language. Patients with receptive dysphasia may speak fluently, but their sentences may not make sense and may include neologisms.

      The occipital lobe, located at the back of the brain, is responsible for visual processing. Lesions in this area can result in homonymous hemianopia (with sparing of the macula), agnosias, and cortical blindness.

      Finally, the primary sensory cortex, located in the anterior region of the parietal lobe, receives sensory innervation. Lesions in this area can lead to loss of sensation, proprioception, fine touch, and vibration sense on the opposite side of the body.

      Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.

      In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.

    • This question is part of the following fields:

      • Neurological System
      35.3
      Seconds
  • Question 4 - You are designing a research project looking at the complement system, in-particular the...

    Correct

    • You are designing a research project looking at the complement system, in-particular the alternative complement pathway. As your dependent variable you choose the time taken to reduce levels of different strains of Salmonella bacteria to undetectable levels in vitro.

      What will you choose as your independent variable?

      Your Answer: Polysaccharides

      Explanation:

      The activation of the alternative complement pathway is triggered by polysaccharides found on pathogens, such as gram negative bacteria. The research study is focused on evaluating the effectiveness of this pathway, making polysaccharides the suitable dependent variable to measure. On the other hand, the classical complement pathway is activated by the formation of antigen-antibody complexes, specifically IgM/IgG. Th1 lymphocytes play a role in the cell-mediated response, while Th2 lymphocytes are involved in the humoral or antibody response.

      Overview of Complement Pathways

      Complement pathways are a group of proteins that play a crucial role in the body’s immune and inflammatory response. These proteins are involved in various processes such as chemotaxis, cell lysis, and opsonisation. There are two main complement pathways: classical and alternative.

      The classical pathway is initiated by antigen-antibody complexes, specifically IgM and IgG. The proteins involved in this pathway include C1qrs, C2, and C4. On the other hand, the alternative pathway is initiated by polysaccharides found in Gram-negative bacteria and IgA. The proteins involved in this pathway are C3, factor B, and properdin.

      Understanding the complement pathways is important in the diagnosis and treatment of various diseases. Dysregulation of these pathways can lead to autoimmune disorders, infections, and other inflammatory conditions. By identifying the specific complement pathway involved in a disease, targeted therapies can be developed to effectively treat the condition.

    • This question is part of the following fields:

      • General Principles
      32.6
      Seconds
  • Question 5 - A 30-year-old man visits the GP complaining of weakness in his right foot...

    Correct

    • A 30-year-old man visits the GP complaining of weakness in his right foot muscles. The GP observes difficulty with inversion and suspects weakness in the posterior leg muscles.

      Which muscle is responsible for this movement?

      Your Answer: Tibialis posterior

      Explanation:

      The muscles located in the deep posterior compartment are:

      Muscular Compartments of the Lower Limb

      The lower limb is composed of different muscular compartments that perform various actions. The anterior compartment includes the tibialis anterior, extensor digitorum longus, peroneus tertius, and extensor hallucis longus muscles. These muscles are innervated by the deep peroneal nerve and are responsible for dorsiflexing the ankle joint, inverting and evert the foot, and extending the toes.

      The peroneal compartment, on the other hand, consists of the peroneus longus and peroneus brevis muscles, which are innervated by the superficial peroneal nerve. These muscles are responsible for eversion of the foot and plantar flexion of the ankle joint.

      The superficial posterior compartment includes the gastrocnemius and soleus muscles, which are innervated by the tibial nerve. These muscles are responsible for plantar flexion of the foot and may also flex the knee.

      Lastly, the deep posterior compartment includes the flexor digitorum longus, flexor hallucis longus, and tibialis posterior muscles, which are innervated by the tibial nerve. These muscles are responsible for flexing the toes, flexing the great toe, and plantar flexion and inversion of the foot, respectively.

      Understanding the muscular compartments of the lower limb is important in diagnosing and treating injuries and conditions that affect these muscles. Proper identification and management of these conditions can help improve mobility and function of the lower limb.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
      41.9
      Seconds
  • Question 6 - A 65-year-old male arrives at the emergency department with alterations in his vision....

    Incorrect

    • A 65-year-old male arrives at the emergency department with alterations in his vision. During the conversation, he uses nonsensical words such as 'I went for a walk this morning and saw the tree lights shining'. However, he can communicate fluently. The possibility of a brain lesion is high.

      Which specific region of the brain is likely to be impacted?

      Your Answer: Occipital lobe

      Correct Answer: Temporal lobe

      Explanation:

      Fluent speech may still be present despite neologisms and word substitution resulting from temporal lobe lesions. Superior homonymous quadrantanopia may also occur. Apraxia can be caused by lesions in the parietal lobe, while changes to vision may result from lesions in the occipital lobe. Non-fluent speech can be caused by lesions in the frontal lobe, while ataxia, intention tremor, and dysdiadochokinesia may result from lesions in the cerebellum.

      Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.

      In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.

    • This question is part of the following fields:

      • Neurological System
      23.4
      Seconds
  • Question 7 - You are a medical student on an endocrine ward. There is a 65-year-old...

    Correct

    • You are a medical student on an endocrine ward. There is a 65-year-old patient on the ward suffering from hypopituitarism. One of the junior doctors explains to you that the patient's pituitary gland was damaged when they received radiation therapy for a successfully treated brain tumour last year. He shows you a CT scan and demonstrates that only the anterior pituitary gland is damaged, with the posterior pituitary gland unaffected.

      Which of the following hormones is unlikely to be affected?

      Your Answer: antidiuretic hormone

      Explanation:

      The pituitary gland is a small gland located within the sella turcica in the sphenoid bone of the middle cranial fossa. It weighs approximately 0.5g and is covered by a dural fold. The gland is attached to the hypothalamus by the infundibulum and receives hormonal stimuli from the hypothalamus through the hypothalamo-pituitary portal system. The anterior pituitary, which develops from a depression in the wall of the pharynx known as Rathkes pouch, secretes hormones such as ACTH, TSH, FSH, LH, GH, and prolactin. GH and prolactin are secreted by acidophilic cells, while ACTH, TSH, FSH, and LH are secreted by basophilic cells. On the other hand, the posterior pituitary, which is derived from neuroectoderm, secretes ADH and oxytocin. Both hormones are produced in the hypothalamus before being transported by the hypothalamo-hypophyseal portal system.

    • This question is part of the following fields:

      • Neurological System
      29.6
      Seconds
  • Question 8 - Can you provide a definition for pseudostratified epithelium? ...

    Correct

    • Can you provide a definition for pseudostratified epithelium?

      Your Answer: A single layer of epithelial cells with nuclei at different height

      Explanation:

      Types of Epithelial Tissue

      Epithelial tissue is a type of tissue that lines the surfaces of organs, glands, and body cavities. There are different types of epithelial tissue, including simple, stratified, and transitional epithelium. Pseudostratified epithelium is a type of simple epithelium that appears to be several cells deep due to the nuclei being at different heights. This gives the illusion of a stratified epithelium. The lining of the conducting airways, up to the respiratory bronchioles, is lined by ciliated, pseudostratified columnar epithelium.

      A simple epithelium is a single layer of epithelial cells with nuclei at the same height, while a stratified epithelium is multiple layers of epithelial cells upon each other, usually stratified squamous. The skin is an example of a stratified epithelium. A transitional epithelium is multiple layers of epithelial cells that stretch over each other. This type of epithelium is found in the ureters and bladder. When contracted, the epithelium is stratified, but when stretched, the epithelial cells slide to give a simple epithelium. This allows for expansion with a minimal increase in wall pressure.

    • This question is part of the following fields:

      • Clinical Sciences
      6.4
      Seconds
  • Question 9 - A 68-year-old woman visits her doctor reporting a burning and stabbing pain that...

    Incorrect

    • A 68-year-old woman visits her doctor reporting a burning and stabbing pain that has been present for a few days across her left breast, extending to her back. She also mentions a new rash in the same area. The patient states that she has been feeling generally unwell since the onset of the pain and rash. During the physical examination, a vesicular rash with an erythematous base is observed on her left breast and around the left side of her back in a straight line, without crossing the midline. Which nerve root is likely to be affected in this case?

      Your Answer: T3

      Correct Answer: T5

      Explanation:

      The most probable nerve root to be affected in shingles, which causes a rash to follow straight lines along dermatomes without crossing the midline, is T4-T6. This is because the breast is innervated by intercostal nerve branches from these nerve roots.

      The breast is situated on a layer of pectoral fascia and is surrounded by the pectoralis major, serratus anterior, and external oblique muscles. The nerve supply to the breast comes from branches of intercostal nerves from T4-T6, while the arterial supply comes from the internal mammary (thoracic) artery, external mammary artery (laterally), anterior intercostal arteries, and thoraco-acromial artery. The breast’s venous drainage is through a superficial venous plexus to subclavian, axillary, and intercostal veins. Lymphatic drainage occurs through the axillary nodes, internal mammary chain, and other lymphatic sites such as deep cervical and supraclavicular fossa (later in disease).

      The preparation for lactation involves the hormones oestrogen, progesterone, and human placental lactogen. Oestrogen promotes duct development in high concentrations, while high levels of progesterone stimulate the formation of lobules. Human placental lactogen prepares the mammary glands for lactation. The two hormones involved in stimulating lactation are prolactin and oxytocin. Prolactin causes milk secretion, while oxytocin causes contraction of the myoepithelial cells surrounding the mammary alveoli to result in milk ejection from the breast. Suckling of the baby stimulates the mechanoreceptors in the nipple, resulting in the release of both prolactin and oxytocin from the pituitary gland (anterior and posterior parts respectively).

    • This question is part of the following fields:

      • Reproductive System
      68.5
      Seconds
  • Question 10 - Which is least likely to cause hyperuricaemia? ...

    Incorrect

    • Which is least likely to cause hyperuricaemia?

      Your Answer: Lesch-Nyhan syndrome

      Correct Answer: Amiodarone

      Explanation:

      The drugs that cause hyperuricaemia due to reduced urate excretion can be remembered using the mnemonic Can’t leap, which stands for Ciclosporin, Alcohol, Nicotinic acid, Thiazides, Loop diuretics, Ethambutol, Aspirin, and Pyrazinamide. Additionally, decreased tubular secretion of urate can occur in patients with acidosis, such as those with diabetic ketoacidosis, ethanol or salicylate intoxication, or starvation ketosis, as the organic acids that accumulate in these conditions compete with urate for tubular secretion.

      Understanding Hyperuricaemia

      Hyperuricaemia is a condition characterized by elevated levels of uric acid in the blood. This can be caused by an increase in cell turnover or a decrease in the excretion of uric acid by the kidneys. While some individuals with hyperuricaemia may not experience any symptoms, it can be associated with other health conditions such as hyperlipidaemia, hypertension, and the metabolic syndrome.

      There are several factors that can contribute to the development of hyperuricaemia. Increased synthesis of uric acid can occur in conditions such as Lesch-Nyhan disease, myeloproliferative disorders, and with a diet rich in purines. On the other hand, decreased excretion of uric acid can be caused by drugs like low-dose aspirin, diuretics, and pyrazinamide, as well as pre-eclampsia, alcohol consumption, renal failure, and lead exposure.

      It is important to understand the underlying causes of hyperuricaemia in order to properly manage and treat the condition. Regular monitoring of uric acid levels and addressing any contributing factors can help prevent complications such as gout and kidney stones.

    • This question is part of the following fields:

      • Renal System
      30.6
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

General Principles (2/3) 67%
Neurological System (2/3) 67%
Musculoskeletal System And Skin (1/1) 100%
Clinical Sciences (1/1) 100%
Reproductive System (0/1) 0%
Renal System (0/1) 0%
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