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Question 1
Incorrect
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What is the most prevalent type of primary brain tumor found in adults?
Your Answer: Meningioma
Correct Answer: Glioblastoma multiforme
Explanation:Cerebral Tumours
The most common brain tumours in adults, listed in order of frequency, are metastatic tumours, glioblastoma multiforme, anaplastic astrocytoma, and meningioma. On the other hand, the most common brain tumours in children, listed in order of frequency, are astrocytoma, medulloblastoma, and ependymoma.
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This question is part of the following fields:
- Neurosciences
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Question 2
Incorrect
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Which cranial nerve is solely responsible for sensory functions?
Your Answer: Trigeminal
Correct Answer: Vestibulocochlear
Explanation:Overview of Cranial Nerves and Their Functions
The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.
The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.
The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.
The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.
The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.
The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.
The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.
The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.
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This question is part of the following fields:
- Neurosciences
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Question 3
Correct
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What is the main component of pick bodies?
Your Answer: Tau
Explanation:Pyramidal cell neurons known as Betz cells are situated in the grey matter of the motor cortex.
Frontotemporal Lobar Degeneration (FTLD) is a pathological term that refers to a group of neurodegenerative disorders that affect the frontal and temporal lobes of the brain. FTLD is classified into several subtypes based on the main protein component of neuronal and glial abnormal inclusions and their distribution. The three main proteins associated with FTLD are Tau, TDP-43, and FUS. Each FTD clinical phenotype has been associated with different proportions of these proteins. Macroscopic changes in FTLD include atrophy of the frontal and temporal lobes, with focal gyral atrophy that resembles knives. Microscopic changes in FTLD-Tau include neuronal and glial tau aggregation, with further sub-classification based on the existence of different isoforms of tau protein. FTLD-TDP is characterized by cytoplasmic inclusions of TDP-43 in neurons, while FTLD-FUS is characterized by cytoplasmic inclusions of FUS.
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This question is part of the following fields:
- Neurosciences
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Question 4
Incorrect
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What condition has been associated with decreased small interneurons in cortical layer II of the prefrontal cortex, which are believed to be related to the GABA system?
Your Answer: Narcolepsy
Correct Answer: Schizophrenia
Explanation:The key to answering this question is identifying that it pertains to the prefrontal cortex, which is strongly linked to schizophrenia. Other conditions that are associated with abnormalities in this region include ADHD and bipolar disorder. Schizophrenia is characterized by changes in GABA function, including both release and uptake. Additionally, a decrease in small interneurons in cortical layer II of the prefrontal cortex is believed to contribute to these alterations. Sedvall’s 2002 work on the pathophysiological mechanisms of schizophrenia provides further insight into these issues.
Schizophrenia is a pathology that is characterized by a number of structural and functional brain alterations. Structural alterations include enlargement of the ventricles, reductions in total brain and gray matter volume, and regional reductions in the amygdala, parahippocampal gyrus, and temporal lobes. Antipsychotic treatment may be associated with gray matter loss over time, and even drug-naïve patients show volume reductions. Cerebral asymmetry is also reduced in affected individuals and healthy relatives. Functional alterations include diminished activation of frontal regions during cognitive tasks and increased activation of temporal regions during hallucinations. These findings suggest that schizophrenia is associated with both macroscopic and functional changes in the brain.
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This question is part of the following fields:
- Neurosciences
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Question 5
Correct
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Which of the following do not describe the features of REM sleep?
Your Answer: K complexes on the EEG
Explanation:During REM sleep, the EEG patterns resemble those observed during wakefulness, characterized by numerous beta-rhythms that are fast.
Sleep Stages
Sleep is divided into two distinct states called rapid eye movement (REM) and non-rapid eye movement (NREM). NREM is subdivided into four stages.
Sleep stage
Approx % of time spent in stage
EEG findings
CommentI
5%
Theta waves (4-7 Hz)
The dozing off stage. Characterized by hypnic jerks: spontaneous myoclonic contractions associated with a sensation of twitching of falling.II
45%
Theta waves, K complexes and sleep spindles (short bursts of 12-14 Hz activity)
Body enters a more subdued state including a drop in temperature, relaxed muscles, and slowed breathing and heart rate. At the same time, brain waves show a new pattern and eye movement stops.III
15%
Delta waves (0-4 Hz)
Deepest stage of sleep (high waking threshold). The length of stage 3 decreases over the course of the night.IV
15%
Mixed, predominantly beta
High dream activity.The percentage of REM sleep decreases with age.
It takes the average person 15-20 minutes to fall asleep, this is called sleep latency (characterised by the onset of stage I sleep). Once asleep one descends through stages I-II and then III-IV (deep stages). After about 90 minutes of sleep one enters REM. The rest of the sleep comprises of cycles through the stages. As the sleep progresses the periods of REM become greater and the periods of NREM become less. During an average night’s sleep one spends 25% of the sleep in REM and 75% in NREM.
REM sleep has certain characteristics that separate it from NREM
Characteristics of REM sleep
– Autonomic instability (variability in heart rate, respiratory rate, and BP)
– Loss of muscle tone
– Dreaming
– Rapid eye movements
– Penile erectionDeafness:
(No information provided on deafness in relation to sleep stages)
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This question is part of the following fields:
- Neurosciences
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Question 6
Incorrect
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What is the structure that divides which parts of the brain?
Your Answer: The cerebellar hemispheres
Correct Answer: The lateral ventricles
Explanation:The septum pellucidum is a thin layer that divides the front sections of the left and right lateral ventricles in the brain. It extends as a flat structure from the corpus callosum to the fornix.
Dementia Pugilistica: A Neurodegenerative Condition Resulting from Neurotrauma
Dementia pugilistica, also known as chronic traumatic encephalopathy (CTE), is a neurodegenerative condition that results from neurotrauma. It is commonly seen in boxers and NFL players, but can also occur in anyone with neurotrauma. The condition is characterized by symptoms such as gait ataxia, slurred speech, impaired hearing, tremors, disequilibrium, neurobehavioral disturbances, and progressive cognitive decline.
Most cases of dementia pugilistica present with early onset cognitive deficits, and behavioral signs exhibited by patients include aggression, suspiciousness, paranoia, childishness, hypersexuality, depression, and restlessness. The progression of the condition leads to more prominent behavioral symptoms such as difficulty with impulse control, irritability, inappropriateness, and explosive outbursts of aggression.
Neuropathological abnormalities have been identified in CTE, with the most unique feature being the abnormal accumulation of tau in neurons and glia in an irregular, focal, perivascular distribution and at the depths of cortical sulci. Abnormalities of the septum pellucidum, such as cavum and fenestration, are also a common feature.
While the condition has become increasingly rare due to the progressive improvement in sports safety, it is important to recognize the potential long-term consequences of repeated head injuries and take steps to prevent them.
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This question is part of the following fields:
- Neurosciences
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Question 7
Correct
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What is the name of the dural reflection that acts as a boundary between the cerebellum and the occipital lobes of the cerebrum?
Your Answer: Tentorium cerebelli
Explanation:Dura Mater
The dura mater is one of the three membranes, known as meninges, that cover the brain and spinal cord. It is the outermost and most fibrous layer, with the pia mater and arachnoid mater making up the remaining layers. The pia mater is the innermost layer.
The dura mater is folded at certain points, including the falx cerebri, which separates the two cerebral hemispheres of the brain, the tentorium cerebelli, which separates the cerebellum from the cerebrum, the falx cerebelli, which separates the cerebellar hemispheres, and the sellar diaphragm, which covers the pituitary gland and forms a roof over the hypophyseal fossa.
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This question is part of the following fields:
- Neurosciences
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Question 8
Correct
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Which of the following is not an example of glial cells?
Your Answer: Purkinje cells
Explanation:The initial exam question erroneously included neurons as a potential answer instead of Purkinje cells. However, this was deemed too simplistic and was subsequently revised. It is important to note that glial cells serve as support cells for neurons, whereas Purkinje cells are a specific type of neuron and therefore cannot be classified as glial cells.
Glial Cells: The Support System of the Central Nervous System
The central nervous system is composed of two basic cell types: neurons and glial cells. Glial cells, also known as support cells, play a crucial role in maintaining the health and function of neurons. There are several types of glial cells, including macroglia (astrocytes and oligodendrocytes), ependymal cells, and microglia.
Astrocytes are the most abundant type of glial cell and have numerous functions, such as providing structural support, repairing nervous tissue, nourishing neurons, contributing to the blood-brain barrier, and regulating neurotransmission and blood flow. There are two main types of astrocytes: protoplasmic and fibrous.
Oligodendrocytes are responsible for the formation of myelin sheaths, which insulate and protect axons, allowing for faster and more efficient transmission of nerve impulses.
Ependymal cells line the ventricular system and are involved in the circulation of cerebrospinal fluid (CSF) and fluid homeostasis in the brain. Specialized ependymal cells called choroid plexus cells produce CSF.
Microglia are the immune cells of the CNS and play a crucial role in protecting the brain from infection and injury. They also contribute to the maintenance of neuronal health and function.
In summary, glial cells are essential for the proper functioning of the central nervous system. They provide structural support, nourishment, insulation, and immune defense to neurons, ensuring the health and well-being of the brain and spinal cord.
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This question is part of the following fields:
- Neurosciences
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Question 9
Correct
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What brain structures are responsible for regulating breathing and heart rate?
Your Answer: Medulla
Explanation:The medulla governs the rhythm of the heart and respiration. The amygdala regulates emotional reactions and the ability to perceive the emotions of others. The midbrain is linked to vision, hearing, motor coordination, sleep patterns, alertness, and temperature regulation. The cerebellum manages voluntary movement and balance. The thalamus transmits sensory and motor signals to the cerebral cortex.
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This question is part of the following fields:
- Neurosciences
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Question 10
Correct
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What type of tissue in the central nervous system is categorized as white matter?
Your Answer: Internal capsule
Explanation:White matter is the cabling that links different parts of the CNS together. There are three types of white matter cables: projection tracts, commissural tracts, and association tracts. Projection tracts connect higher centers of the brain with lower centers, commissural tracts connect the two hemispheres together, and association tracts connect regions of the same hemisphere. Some common tracts include the corticospinal tract, which connects the motor cortex to the brainstem and spinal cord, and the corpus callosum, which is the largest white matter fiber bundle connecting corresponding areas of cortex between the hemispheres. Other tracts include the cingulum, superior and inferior occipitofrontal fasciculi, and the superior and inferior longitudinal fasciculi.
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This question is part of the following fields:
- Neurosciences
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