Neurological System Part II (Exam Mode) By Rnpedia.Com

Multiple sclerosis is a disease that attacks the myelin sheaths of neurons in the central nervous system (CNS). The myelin sheaths are protective coverings that surround and insulate the axons of neurons, allowing for efficient transmission of nerve impulses. When these myelin sheaths are damaged or destroyed, it disrupts the normal flow of electrical signals in the CNS, leading to the various symptoms and complications associated with multiple sclerosis.

Myasthenia gravis is an autoimmune disorder where antibodies attack and destroy acetylcholine receptors at the neuromuscular junction. Acetylcholine is a neurotransmitter responsible for transmitting signals between nerve cells and muscle cells. When the receptors are blocked and destroyed, the communication between the nerves and muscles is disrupted, leading to muscle weakness and fatigue. Therefore, the correct answer is Acetylcholine.

Adenosine is not considered a monoamine because it is not derived from an amino acid and does not contain an amino group. Monoamines are neurotransmitters that are derived from amino acids and contain an amino group.

Oligodendrocytes are a type of glial cell that is responsible for producing and maintaining the myelin sheath in the central nervous system (CNS). The myelin sheath is a fatty substance that wraps around nerve fibers, allowing for faster and more efficient transmission of electrical signals. Therefore, oligodendrocytes are primarily found in the CNS, where they play a crucial role in supporting and protecting nerve cells.

Glutamic acid can function as a neurotransmitter in the central nervous system (CNS). It is an excitatory neurotransmitter that plays a crucial role in synaptic transmission and is involved in various cognitive processes such as learning and memory. Glutamic acid is released from presynaptic neurons and binds to specific receptors on postsynaptic neurons, allowing for the transmission of signals between neurons. It is one of the most abundant neurotransmitters in the brain and is involved in numerous neurological disorders when its levels are dysregulated.

The correct answer is Neuroglia. Neuroglia refers to the supporting cells located within the central nervous system (CNS). These cells play a crucial role in supporting and protecting the neurons. They provide structural support, regulate the extracellular environment, and help in the repair of damaged neural tissue. Neuroglia includes various types of cells such as astrocytes, oligodendrocytes, microglia, and ependymal cells.

Schwann cells are located in the PNS (Peripheral Nervous System). These cells are responsible for producing the myelin sheath, which wraps around and insulates nerve fibers in the peripheral nerves. This myelin sheath helps in the transmission of nerve impulses and promotes faster conduction of signals. In contrast, the CNS (Central Nervous System) is made up of the brain and spinal cord, where other types of glial cells, such as oligodendrocytes, are responsible for myelination.

Serotonin is not considered a catecholamine because it is derived from the amino acid tryptophan, whereas catecholamines are derived from the amino acid tyrosine. Catecholamines include dopamine, norepinephrine, and epinephrine, which are all involved in the regulation of various physiological processes in the body. Serotonin, on the other hand, is primarily known for its role in mood regulation, sleep, and appetite.

Huntington's chorea, a genetic disorder that affects the brain, has been linked with a deficiency in the amino acid GABA. GABA (gamma-aminobutyric acid) is an important neurotransmitter that helps regulate brain activity and plays a role in controlling movement. A deficiency in GABA can disrupt the normal functioning of the brain, leading to symptoms such as involuntary movements, cognitive decline, and behavioral changes, which are characteristic of Huntington's chorea.

Prozac is a selective serotonin reuptake inhibitor (SSRI) drug that blocks the reuptake of serotonin into presynaptic axons. This means that Prozac prevents the reabsorption of serotonin by the nerve cells that released it, allowing more serotonin to remain in the synapse and continue transmitting signals between neurons. This can help to alleviate symptoms of depression and other mood disorders, as serotonin is involved in regulating mood, emotions, and overall well-being.

Valium, also known as diazepam, is a medication that belongs to the benzodiazepine class. It acts by enhancing the effects of gamma-aminobutyric acid (GABA), a neurotransmitter in the brain that inhibits neural transmission. By increasing GABA activity, Valium helps to reduce anxiety, promote relaxation, and induce sedation. Therefore, the correct answer is GABA.

Tetrodotoxin is the correct answer because it is a potent neurotoxin that blocks sodium channels. Sodium channels are responsible for the generation and propagation of action potentials in neurons. By blocking these channels, tetrodotoxin inhibits the normal function of neurons, leading to paralysis and potentially death. Strychnine, neostigmine, and curare do not block sodium channels and have different mechanisms of action.

Saltatory conduction refers to the process of a nerve impulse jumping or "leaping" from one node of Ranvier to the next along a myelinated axon. This allows for faster and more efficient transmission of the nerve impulse compared to unmyelinated conduction. The myelin sheath insulates the axon, forcing the electrical signal to "skip" from one exposed node to another, reducing the energy required and increasing the speed of transmission. Therefore, saltatory conduction is the correct term for the progression of a nerve impulse with the nodes of Ranvier.

Endopeptidases are enzymes that break down proteins by cleaving peptide bonds within the protein chain. Clostridium botulinum, a bacterium that causes botulism, releases endopeptidases. These enzymes specifically target peptide bonds, resulting in the destruction of the protein structure. Amylase is an enzyme that breaks down starches, not proteins. Exopeptidases are enzymes that cleave peptide bonds at the ends of protein chains. Protein kinase is an enzyme involved in the regulation of protein function through phosphorylation, not protein degradation.

Denoaxonic is not considered a type of synapse. The other options listed (dendrodendritic, axosomatic, and axoaxonic) are all recognized types of synapses. A synapse is a structure that allows for communication between neurons, and it typically involves the transmission of electrical or chemical signals. However, denoaxonic does not fit into any established category of synapses.

Ependymal cells are the correct answer because they are specialized cells that line the ventricles of the brain and the central canal of the spinal cord. These cells play a crucial role in the production and circulation of cerebrospinal fluid, which helps to protect and nourish the brain and spinal cord. Additionally, ependymal cells have cilia on their surface that help to move the cerebrospinal fluid throughout the ventricles and spinal cord.

Astrocytes are the most common type of cells in the central nervous system (CNS). They are star-shaped cells that provide support and nourishment to neurons. Astrocytes also play a crucial role in maintaining the blood-brain barrier, regulating the chemical environment of the brain, and repairing damaged neural tissue. They are involved in various functions such as regulating neurotransmitter levels, controlling blood flow, and providing structural support. Overall, astrocytes are essential for the proper functioning of the CNS.

Cocaine primarily affects the nervous system by blocking the re-uptake of monoamines. Monoamines are a group of neurotransmitters that include dopamine, norepinephrine, and serotonin. By blocking their re-uptake, cocaine increases the levels of these neurotransmitters in the synapse, leading to an intensified and prolonged stimulation of the nervous system. This can result in increased alertness, euphoria, and heightened energy levels.

Excessive polarization due to GABA is created due to the opening of Cl- channels. GABA is an inhibitory neurotransmitter that causes hyperpolarization of the postsynaptic membrane, making it less likely for an action potential to occur. The opening of Cl- channels allows Cl- ions to enter the cell, resulting in an influx of negative charge and further hyperpolarization. This inhibitory effect helps to regulate and balance neuronal activity in the brain.

Calmodulin is a regulatory protein in the cytoplasm that plays a crucial role in various processes at the synapse. It is involved in the regulation of calcium levels and acts as a calcium sensor, binding to calcium ions and undergoing conformational changes. These changes allow calmodulin to interact with and regulate the activity of various target proteins, including enzymes, ion channels, and other signaling molecules. By modulating the activity of these proteins, calmodulin helps to regulate synaptic transmission and plasticity, thereby influencing the overall function of the synapse.