How Do Neurons Become Excited?

How Do Neurons Become Excited?
Neurons become excited in response to a stimulus. Sensory neurons
are sensitive to specific stimuli in their surrounding environment. For
example, sensory neurons found in human skin are sensitive to touch,
pain, and change in temperature outside of the body. Meanwhile, sensory
neurons located inside the body are sensitive to pain and changes in tem-
perature inside the body. Sensory receptors in the ears, eyes, nose, and
mouth register sound, light, smell, and taste, respectively. Once these
neurons are excited by a stimulus, the excitability or impulse moves along
that neuron toward the brain, where it is interpreted. Our brain initiates
impulses as well. Some of these impulses travel throughout the brain for
thinking processes and memory recall. Or these impulses may travel away
from the brain toward destinations outside the central nervous system
such as skeletal muscle, the heart, and other organs.

Energy Is Everything

Energy Is Everything
What Is Energy?
Energy may be best understood as a potential or presence that allows for
some type of work to be performed. Some of energy's more recognizable
forms are heat, light, mechanical, chemical, and electrical energy. Without
energy we simply would not exist. The universe, if it existed at all, would
be a frigid, barren, motionless void.
   Energy is neither created nor destroyed, however it can be converted
from one form to another. This means that while the total amount of
energy in the universe remains constant, the quantity of the different
forms can change relative to one another. For instance, you are probably
reading this site by the light of a nearby lamp. The light bulb has a thin
filament inside, which transforms the electrical energy running from the
wall socket and through the cord to the filament in the bulb where it
is converted into two other forms of energy—light and heat. As the fila-
ment illuminates, there is a reduction in electrical energy and an increase
in light and heat energies. So energy is not lost but transformed to other
forms.
   A little bit closer to nutrition, food contains chemical energy in the form
of carbohydrates, proteins, fats, and alcohol. Once inside our body the
chemical energy of these substances can be transformed into mechanical
energy to power muscular movement and other activities as well as heat
to maintain our body temperature. Furthermore, we can store these
energy molecules when we cannot immediately use them.