The crust is the outermost layer of the planet
Answer:
Neurons are in charge of receiving stimuli from the environment, transforming them into nervous excitations and transmitting them to the nerve centers, where they organize themselves to give a response.The cycle of depolarization and hyperpolarization of the membrane and return to the resting membrane potential is called the action potential, an all-or-nothing reaction that can occur at rates of up to 1,000 pulses / second. Membrane depolarization that occurs as voltage gate Na + channels open at one point on an axon passively spreads a short distance and triggers the opening of adjacent channels, resulting in the generation of another action potential. In this way the depolarization wave, or nerve impulse, is conducted along the axon.
Explanation:
Neurons are highly specialized cells whose central function consists in the generation and transmission of signals, in order to communicate with the other neurons of the nervous system and with the outside of the organism. They are made up of three parts: the cell body, the dendrites, and the axon. Dendrites are extensions of the cell body with short, tubular branches, through which each neuron receives signals from other neurons. These signals are added or averaged, and in the event that the total intensity of the received stimulus is greater than a certain threshold, the neuron will generate and emit an electrical response signal. This signal will be sent through the axon, which will transmit the information to other neurons through chemical exchange. The axon divides near the end into thin branches that contact other neurons. The point of contact is called the synapse. At the synapse, there is a gap between the two cells called the synaptic cleft. The synapse is produced by the release of chemicals from the presynaptic neuron that excites the postsynaptic, transmitting the informational code. The arrival of an impulse at the end of a nerve fiber causes a chemical compound, a transmitter substance, to be released, which excites the neighboring neuron. The same neuron may have inhibitory and excitatory connections with different neurons, for which it will need to produce different chemicals that act as transmitters. A neuron receives and integrates multiple stimulations through the synapses, those received by the dendrites are added to those received in the soma so that the electrical potential of the cell membrane ends up exceeding the threshold and originates a nerve impulse in the area of the axonal cone. Nerve impulses are electrical signals generated by the spike trigger sites (axon cones) of a neuron as a result of membrane depolarization, which are conducted along the axon to its termination. The transmission of impulses from the endings of a neuron to another neuron, a muscle cell or a gland occurs at the level of the synapses.
affinity maturation-
because antibodies can potentially be generated against millions of unique epitopes, the size of an organisim's genome would need to increase exponentially in order to every possible antigen- binding side.
