Without our Nervous System, our life would be very, very
different. For a start, we simply wouldn’t be able to feel pain. Take a candle
for example, if we couldn’t feel pain then we would just leave our hand far too
close to the flame but because we do have a very advanced Nervous System we’re
able to take our hand away as quickly as possible without becoming too burnt!
Your body is home to a network of neurones and passages
which send messages all over your body – all to keep you out of harm’s way. Your
nervous system is one huge evolutionary product – the first nervous tissue
actually came about in wormlike organisms 550 to 600 million years ago.
Your nervous system is made up of two components - the CNS
(Central Nervous System) and the PNS (Peripheral Nervous System).
The CNS – This contains the brain and spinal cord. Most of your
central nervous system is enclosed within your body that is apart from
something called the “olfactory epithelium”. It’s a specialised area of tissue
inside the nasal cavity involved in smell. Scientists say that because it is
exposed this might be a potential avenue for further treatments relating to
your CNS.
The PNS – This mainly consists of nerves, pairs of nerves
that originate from the brain, enclosed in bundles of long fibres. It connects
the CNS to every other part of the body.
Surprisingly your nervous system controls your heart rate.
The job of which is done by chemoreceptors. These are found in the walls of
your carotid arteries. They detect changes in pH as a result of a change in CO2
concentration. When your blood CO2 concentration is too low, your
chemoreceptors detect a pH drop. They then send impulses to the section of the
medulla oblongata ( a region of the brain) responsible for increasing heart
rate. This section of the brain then sends impulses to a node in your heart.
Your heart rate is now faster and the pH can return to normal.
Christmas Countdown: 21 sleeps to go!
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