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Question 1
Correct
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An example of cholinergic autonomic neurons are:
Your Answer: Sympathetic postganglionic neurons that innervate sweat glands.
Explanation:All preganglionic neurons in both the sympathetic and parasympathetic nervous system secrete acetylcholine. The postganglionic neurotransmitter of the parasympathetic nervous system in all neurons is acetylcholine. Postganglionic fibers of the sympathetic nervous system mainly secrete Noradrenalin and Adrenalin but at sweat glands and erector pili muscles the postganglionic neurotransmitter is acetylcholine.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 2
Correct
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The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer: Purkinje
Explanation:The cerebellar cortex consist of 3 layers. The molecular layer, the granule cell layer and the Purkinje cell layer in the middle. The Purkinje cells project into the deep cerebellar nuclei. They are the only output cells of the cerebellar cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 3
Correct
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Cold receptors are likely to be active at the following temperatures except?
Your Answer: 39 °C
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is primarily responsible for the detection of temperatures ranging from 8-28 C. It is an ion channel which upon activation causes the influx of Na+ and Ca+ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 4
Correct
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The nucleus ambiguus:
Your Answer: Regulates swallowing, phonation and parasympathetic supply to the heart via CN IX, X and XI
Explanation:Nucleus Ambiguus is a group of large motor neurons found deep in the medullary reticular formation. It contains cell bodies of nerves that are responsible for the innervation of muscles of speech and swallowing which are located in the soft palate, pharynx and larynx. Additionally, it contains cholinergic preganglionic parasympathetic neurons of the heart via CN X, IX and XI
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This question is part of the following fields:
- Medicine
- Neurology
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Question 5
Incorrect
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Regarding taste threshold and intensity discrimination:
Your Answer: 10% change in concentration of substance tasted is necessary before an intensity difference can be detected
Correct Answer: 30% change in concentration of substance tasted is necessary before an intensity difference can be detected
Explanation:The ability of humans to differentiate differences in intensity of taste is poor. A 30% change in the concentration of the substance being tasted is required before an intensity difference is perceived.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 6
Correct
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In Argyll Robertson pupils…
Your Answer: All of the options given
Explanation:Argyll Robertson pupils are bilaterally small pupils that accommodate or reduce in size near an object but do not react to light. They do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis but may be seen in diabetic neuropathy as well.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 7
Correct
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What is the most abundant cell type in the central nervous system called?
Your Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 8
Correct
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Regarding the formation of CSF, which of the following is true?
Your Answer: Its composition resembles that of brain ECF
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of entire volume of cerebrospinal fluid a day is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has a different electrolyte level. About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells. The composition and rate of CSF generation depends on several factors and is influenced by hormones and the content and pressure of blood and CSF.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 9
Correct
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The small opening in the cochlea through which the upper scala vestibuli and lower scala tympani communicates is called the:
Your Answer: Helicotrema
Explanation:The helicotrema is the part of cochlear labyrinth where the scala tympani and the scala vestibuli meet.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 10
Correct
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In which cell would you find a Nissl body?
Your Answer: Bipolar neuron
Explanation:Nissl bodies are the structures of protein synthesis in neurones. They are granular bodies of Rough Endoplasmic Reticulum and ribosomes. Astrocytes, Microglia, Schwann cell, oligodendrocytes are collectively known as glia or supporting cells of the nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 11
Correct
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Endolymph in the inner ear is rich in:
Your Answer: K
Explanation:Cochlear fluids namely endolymph and perilymph have different compositions. Perilymph is a typical extracellular fluid, with ionic composition comparable to plasma or cerebrospinal fluid. The main cation is sodium. Endolymph is a totally unique extracellular fluid, with an ion composition unlike that which is found anywhere else in the body. The major cation in the endolymph is potassium and there is virtually no sodium.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 12
Correct
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Activation of the cool receptor (CMR-1), causes:
Your Answer: Influx of Ca++ & Na+
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is an ion channel which upon activation causes the influx of Na+ and Ca++ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 13
Correct
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What happens first during depolarisation of the membrane potential?
Your Answer: Gated Na channels open allowing the influx of Na
Explanation:Generation of an action potential in response to a stimulus is a result of a previously maintained resting membrane potential (RMP). Generation of resting membrane potential is mediated mainly by potassium ions. Several membrane proteins maintain RMP by transport of ions in and out of cell. Na+/K+ ATPase pump maintains a concentration gradient of Na+ and K+ ions. Na+ concentration in extracellular fluid is higher compared to intracellular fluid and K+ ion concentration is higher intracellularly. Generation of an action potential facilitates opening of Na+ ion channels which allow for Na+ to diffuse inside the cell according to the concentration gradient.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 14
Correct
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What is found in the posterior cavity of the eye?
Your Answer: Vitreous humor
Explanation:The eye ball contains an anterior cavity and a posterior cavity. The anterior cavity once again is divided into the anterior chamber and posterior chamber. The anterior cavity is filled with aqueous humor whereas the posterior cavity contains vitreous humor.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Correct
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The choroid plexus:
Your Answer: All are true
Explanation:The choroid plexus is a vascular structure found in all cerebral ventricles. The functional unit of the choroid plexus, composed of a capillary, enveloped by a layer of differentiated ependymal epithelium. Unlike the capillaries that form the blood-brain barrier, choroid plexus capillaries are fenestrated and have no tight junctions. The endothelium, therefore, does not form a barrier to the movement of small molecules. Instead, the blood-CSF barrier at the choroid plexus is formed by the epithelial cells and the tight junctions that link them.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 16
Correct
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Which one of the following nerve fibers has the fastest conduction velocity?
Your Answer: α fiber
Explanation:α nerve fibers are characterized by being highly myelinated, which confers them with fast conduction properties. They innervate extrafusal skeletal muscle fibers, and their conduction velocity is between 80-120 m/s.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 17
Correct
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Question 18
Correct
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Question 19
Correct
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Which receptor type is associated with the inhibition of pancreatic endocrine secretion?
Your Answer: Α2
Explanation:The activation of alpha 2-adrenergic receptors in pancreatic beta-cells works by inhibiting the secretion of insulin.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 20
Correct
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Question 21
Correct
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The nucleus tractus solitaries is medullary nucleus that processes the following inputs except:
Your Answer: Sensory input from the semi-circular canal (CN VIII)
Explanation:Located in the brain stem is a series of purely sensory nuclei known as tractus solitaries. Inputs of the nucleus tractus solitaries include:Taste information from the facial nerve (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis).Sensory information from the ear (auricular branch of the vagus nerve).Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve.Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 22
Correct
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Corticospinal tracts are located in the ___ of the white matter.
Your Answer: Anterior and lateral funiculi
Explanation:The corticospinal tract is a descending or a motor tract which projects nerve fibers from the cortex of the cerebrum down to different levels of the spinal cord. The descending corticospinal tract descends from the origin, through the corona radiata, posterior half of the lateral ventricle, and enters the midbrain through the cerebral peduncle. In the medulla they form the medullary pyramids on either side of midline as lateral and anterior fibers.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 23
Correct
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Which statement is incorrect regarding nociceptor C fibers…
Your Answer: They are thinly myelinated
Explanation:Group C nerve fibers are unmyelinated and have a small diameter, which means they conduct impulses at a low velocity. They carry sensory information and nociception.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 24
Incorrect
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Which of the following are exclusively innervated by parasympathetic nerves?
Your Answer: Parotid glands
Correct Answer: Circular muscle of iris
Explanation:Circular muscle of iris is exclusively supplied by the parasympathetic nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 25
Incorrect
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Visceral afferent fibers are found in the following areas except the…?
Your Answer: None of the above
Correct Answer: Trigeminal nerve
Explanation:The general visceral afferent (GVA) fibers carry impulses from viscera to the central nervous system. The cranial nerves that contain GVA fibers include the facial nerve, the glossopharyngeal nerve and the vagus nerve
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This question is part of the following fields:
- Medicine
- Neurology
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Question 26
Correct
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Regarding the innervation of the cerebral blood vessels, postganglionic sympathetic neurons have their cell bodies in the:
Your Answer: Superior cervical ganglia
Explanation:The superior cervical ganglion (SCG) is a part of autonomic system which plays a major role in maintaining homeostasis of the body. This ganglion innervates structures in the head and neck and is the largest and the most superiorly located ganglion. The SCG provides sympathetic innervation to structures within the head, including the pineal gland, the blood vessels in the cranial muscles and the brain, the choroid plexus, the eyes, the lacrimal glands, the carotid body, the salivary glands, and the thyroid gland. The postganglionic axons of the SCG innervate the internal carotid artery and form the internal carotid plexus. The internal carotid plexus carries the postganglionic axons of the SCG to the eye, lacrimal gland, mucous membranes of the mouth, nose, and pharynx, and numerous blood-vessels in the head.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 27
Correct
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Which receptor type is associated with bronchial muscle relaxation?
Your Answer: β2
Explanation:β2-adrenoceptors are widely distributed in the respiratory tract. When they are activated, an intracellular response induces the activation of cyclic AMP; this, in turn, produces airway relaxation through phosphorylation of muscle regulatory proteins and modification of cellular Ca2+concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Correct
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Question 29
Correct
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Which substance has the lowest taste threshold concentration, in other words which substance can be present in the lowest concentration before taste buds will respond?
Your Answer: Strychnine hydrochloride (bitter)
Explanation:The lowest concentration of a gustatory stimulus to which the taste buds respond is considered to be the threshold concentration for that substance. The threshold concentration for strychnine is 0.0001 mm; this is because it allows the body to detect potentially dangerous substances (bitter plant components) at lower concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 30
Correct
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Interruption of the left optic tract will result in which visual field defect?
Your Answer: Right homonymous hemianopia
Explanation:Right homonymous hemianopia is due to a lesion or pressure on the left optic tract. Total blindness of the left eye is due to a complete occlusion of the left optic nerve. Bipolar hemianopia is due to a midline chiasmal lesion. Left nasal hemianopia due to a lesion involving the left perichiasmal area. Right homonymous inferior quadrantanopia is due to involvement of the lower left optic radiations.
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This question is part of the following fields:
- Medicine
- Neurology
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