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## PREGUNTAS NICOLETTA 2023 ### Nicoletta 1. **Acera del tejido nervioso:** * The astrocytes are a type of neuron specialized in numerical cognition. * Neurons lack mitochondria. * Neurons usually store neurotransmitters but do not synthesize them. * Schwann cells form the myelin...

## PREGUNTAS NICOLETTA 2023 ### Nicoletta 1. **Acera del tejido nervioso:** * The astrocytes are a type of neuron specialized in numerical cognition. * Neurons lack mitochondria. * Neurons usually store neurotransmitters but do not synthesize them. * Schwann cells form the myelin sheath in the central nervous system. 2. **Acerca de las neuronas y sus prolongaciones:** * Axons present spines, and on these spines, numerous synaptic contacts are established. * Neuronal prolongations are of 3 types: axons, dendrites, and myofibrils. * Axons are usually the shortest prolongations of multipolar neurons. * In the gray matter, axons lack a myelin sheath. 3. **Con respecto al potencial de membrana:** * In normal conditions, ions cross the neuronal membrane through channels formed by proteins inserted in the membrane. * Some ionic channels open due to changes in the membrane electrical potential. * The sodium-potassium pump moves potassium to the extracellular space and sodium to the cell's interior. * Sodium ions diffuse freely through the lipid bilayer of the neuron membrane, that is, they do not need channels. 4. **Acerca del potencial de acción** * The amplitude of action potentials depends on the distance from the site where they were generated. The further away from the origin, the smaller the amplitude. * During the depolarization phase of the action potential, sodium ions enter the cell from the extracellular space. * The intensity of a stimulus is encoded by the amplitude of action potentials. * The repolarization phase of the action potential is due to the release of potassium ions outside the cell. 5. **Acerca de las sinapsis** * Excitatory synapses cause a depolarization of the postsynaptic membrane. * Electrical synapses can be functionally symmetrical. * In chemical synapses, neurotransmitter release occurs 0.5 ms before the action potential reaches the synaptic terminal. * Once released, neurotransmitters cross the synaptic cleft by diffusion. 6. **Sobre el sistema vestibular:** * The vestibular system plays a key role in maintaining balance. * Head rotation movements cause the endolymph in the semicircular canals to move. * The otoliths of the saccule and utricle participate in the signaling of posture with respect to gravity. * The ciliated cells of the semicircular canals are located in a structure called otoconia.