Answer:
A theory.
Explanation:
A scientific theory is the product of related observations supported by evidence acquired through scientific investigation. An example of a theory includes the theory of evolution (which explains observations in the fossil record, phylogenetic patterns observed in species, and these results have been aquired through scientific investgation and analysis of things like the genome of species, and archeaological evidence)
Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.
Answer:
1. The presynaptic neuron reaches the synaptic knob and the terminal is depolarized.
2. The electrical voltage gated calcium channels in the presynaptic knob opens.
3. The calcium ions enters through the calcium channel, this calcium ions cause the fusion of the synaptic vesicles to the presynaptic membrane, the cell membrane of an axon terminal that faces the receiving cell.
4. There is neurotransmitter release by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron e.g. acetylcholine by exocytosis.
5. Acetylcholine diffuses across the synaptic cleft and bind to receptors on the postsynaptic neuron, that is a neuron to the cell body or dendrite of which an electrical impulse is transmitted across a synaptic cleft by the release of a chemical neurotransmitter from the axon terminal of a presynaptic neuron.
6. This causes sodium ion channels in the postsynaptic neuron to open, and sodium ions diffuse in.
7. Excitatory (excited neurons) postsynaptic potentials are created, and if these generator potentials are sufficient then the postsynaptic terminal reaches threshold potential and there is propagation.
Explanation: The nervous system is made up of billions of specialized cells called neurons, it is crucial to have an efficient communication between neurons for normal functioning of the central and peripheral nervous systems. The presynaptic action potential refers to an action potential of neuron before synapse. The above is the sequence of event during the transmission of information across the synaptic cleft