Peak temperatures in December in Hawaii can reach levels of up to 26Â°C on average. However, in 1988, Hawaii recorded its highest ever temperature in December, where the thermometer reached an incredible 31Â°C. There is no chance of a white Christmas on the beaches in Hawaii, unless you include the whiteness of the sand.
2) Synaptic Cleft: This is the narrow gap between the axon terminal of the presynaptic neuron, and the post-synaptic membrane of another excitable cell. It is filled with extracellular fluid. 3) Postsynaptic membrane: The membrane across the synaptic cleft is called the postsynaptic membrane.) A nerve impulse reaches the axon terminal of a presynaptic neuron; the membrane is depolarised by an action potential. 2) Depolarisation of the axon terminal during the action potential causes voltage sensitive calcium ion channels to open in the terminal knob.
The axon is wrapped in myelin, which ensheathes some sections but leaves sections of the axon bare between the sheathed portions. At its far end, the axon splits up into many axon terminal. Each forms a synapse with a dendrite or cell body of another neuron. The cell to which the axon terminal belongs (sending cell) is called the presynaptic cell, while the cell to which the dendrite or cell body belongs (receiving cell) is called the postsynaptic cell. There is a space between the two cells, across which they communicate.