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Resting Nerve Membrane Potentials

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Multiple Choice Questions in Neurology: What is the value of normal resting nerve action potential? -30 mv -40 mv -50 mv -70 mv Resting Nerve Membrane Potentials At the resting state of the neurons: More sodium ions are outside More potassium ions are inside The inside of the neuron is negative relative to the outside In the resting state, the outside of the nerve cell (extracellular) has zero potential so the resting membrane potential is equal to the voltage inside the cell (intracellular). The normal resting membrane potential of a neuron is -70 mV. Remember, the negative (-) means the inside of the neuron is 70 mV less than the outside. The resting nerve membrane potential is because of potassium (K) ions. Reference(s): Hodgkin, A. L., and A. F. Huxley. “Resting and Action Potentials in Single Nerve Fibres.” The Journal of Physiology, vol. 104, no. 2, 1945, pp. 176–95, doi:https://doi.org/10.1113/jphysiol.1945.sp004114. [Answer is 4. -70 mv] Multiple Choice Questions in Neurol

Gerstmann's Syndrome

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Multiple Choice Questions in Neurology: Characteristic feature(s) of Gerstmann's syndrome: Alexia Acalculia Anomia Right and left confusion Finger anomia Dyscalculia Alexia Difficulty in reading or understanding the written words Acalculia / Dyscalculia Acquired disorder of calculation abilities Inability to perform known arithmetic functions Anomia Difficulty in word finding Impairment of retrieving known words Intact comprehension Intact word repetition Agnosia Inability to retrieve known sensory information Auditory agnosia: inability to recognize or differentiate between sounds Visual agnosia: inability to recognize objects Finger agnosia: inability to name, distinguish or recognize the own or others fingers Prosopagnosia Facial agnosia Inability to recognize known or familiar faces Simultanagnosia Disorder of visual attention Ability to visualize a single object of a whole scene Unable to visualize more than a single object at a time Unable to visualize the overall meaning of

Anterior Cerebral Artery

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Multiple Choice Questions in Neurology: Anterior communicating artery (ACom) originates from which part of the anterior cerebral artery (ACA)? A3 - segment A1 - segment A2 - segment A4 - segment Anterior Cerebral Artery   Anterior Communicating Artery (ACom) It is about 4 mm in length. The anterior communicating artery is an anastomosis between the left & right anterior cerebral artery circulation. It originates from the anterior cerebral artery - A1 segment. Applied Anatomy Anterior communicating artery (ACom) is the most common site for intracranial aneurysm. Anterior communicating artery (ACom) aneurysm may cause bitemporal heteronymous hemianopia. Anterior Cerebral Artery Anterior cerebral artery arises from the internal carotid artery. It is divided into five segments. A1: Pre-communicating segment Medial lenticulostriate arteries Anterior communicating artery A2: Post-communicating segment Recurrent artery of Heubner Orbitofrontal artery Frontopolar artery A3: Pre-callosal se

Tuberous Sclerosis

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Multiple Choice Questions in Neurology: What are the triads of Tuberous sclerosis? Seizure Focal cortical atrophy Mental retardation Adenoma sebaceum Port wine nevus Tuberous Sclerosis Tuberous sclerosis is also known as Bourneville disease Inheritance Autosomal dominant inheritance Tuberous sclerosis 1 (TSC1): HAMARTIN (chromosome 9q32-34) Tuberous sclerosis 2 (TSC2): TUBERIN (chromosome 16p13.3): Most common Clinical Features Childhood onset Multiple Ectodermal Benign Tumours Skin: sebaceous glands Eyes: retina Nervous system: brain, spinal cord Mental retardation, learning difficulty, attention deficit hyperactivity disorder (ADHD) are common. Multiple hamartomas Brain histopathology shows disorganized cortical lamination with indistinct gray and white matter junction. Cardiac rhabdomyomas are multiple hamartomas that usually regress over time. Cardiac rhabdomyoma (benign tumors) may present in 50% of patients. The incidence in the newborn may be as high as 90% and in adults as low

Kennedy Disease

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Multiple Choice Questions in Neurology: True and False statements about Kennedy Syndrome: CAG repeat Gynecomastia Testicular atrophy Peripheral neuropathy Ocular muscle involvement Kennedy's Disease Inheritance X-linked recessive disorder Trinucleotide repeat: CAG gene Clinical Features Slowly progressive limb-girdle type muscle weakness Slowly progressive bulbar dysfunction Early tremor Muscle cramps Fasciculations Marked abnormal sensory nerve conduction study Degeneration of both motor and sensory neurons Lower motor neurons signs Elevated serum creatine kinase Abnormal sex hormone levels Gynecomastia Testicular atrophy Diabetes mellitus Note: Extraocular muscles are spared. References: Fischbeck, K. H. "Kennedy disease." Journal of inherited metabolic disease 20.2 (1997): 152-158. Sperfeld, Anne D., et al. "X-linked bulbospinal neuronopathy: Kennedy disease." Archives of Neurology 59.12 (2002): 1921-1926. [Answers are A. CAG repeat-True, B. Gynecomastia-True

Genomic Imprinting Disorders

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Multiple Choice Questions in Neurology: Somatic cells form by two copies of alleles during the fertilization, one copy inherited from each parent. However, if gene expression occurs from only one allele i.e. one parent, is called genomic imprinting. Which of the following is/are associated with genomic imprinting disorders? Fragile X Syndrome Angelman Syndrome Myotonic Dystrophy Prader Willi Syndrome Huntington's Disorder Genomic Imprinting Disorders Normally, somatic cells form by two copies of alleles during the fertilization, one copy inherited from each parent. However, if gene expression occurs from only one allele i.e. one parent, is called genomic imprinting. Epigenetic phenomena do not involve alterations in the DNA sequence. It usually affects functional activity and expression of genes. Genomic imprinting is an epigenetic phenomena. Imprinted alleles/genes of the parent are silent. Only non-imprinted alleles/genes of parents are expressed in children. Imprinted alleles/ge