Thursday 30 April 2020
Describe the adaptations of the nervous system to its functions
The central nervous system consists of the
brain; and the spinal cord; and nerve fibres; that serve the sensory organs ;
and the effector organs and glands; the brain is a collection of
millions/billions/109 neurones; that form the biggest ganglion; it
is highly convoluted; to provide a large surface area for impulse reception,
processing and transmission; the brain and the spinal cord are protected by the
meninges; the brain and the spinal cord have spaces/canals and ventricles;
filled with a cerebrospinal fluid; which acts as a bridge/supply medium for
oxygen and nutrients; and the removal of metabolic waste; the brain has centres
for the storage; retrieval and processing of impulses; the cerebrum processes
and stores information; the cerebellum; sends impulses to joints and muscles;
to correct balance; the medulla oblongata sends impulses to the cardiovascular;
and breathing/ventilation systems; to regulate them; the brain has the
hypothalamus that secretes a neurosecretion to influence a pituitary gland that
secretes hormones; involved in reproduction; and homeostatic functions; the
hypothalamus; detects changes in temperature; and osmotic pressure; and sends
impulses to relevant effector organs for their regulation; the thalamus;
receives majority of the impulses and channels them to the relevant areas of
the brain; both the brain and the spinal cord have regions of the grey matter;
that enable very rapid processing/transmission of impulses; the nervous system
has neurones (relay/intermediate, motor and sensory); that transmit impulses at
a very rapid note/speed (100 ms-1) to and from the central nervous
system to effect suitable responses; there exists in the central nervous system
an electrochemical gradient/concentration gradient; that allows for the
generation of electrical impulses; they have numerous mitochondria; for
generating energy for the function of the sodium pump; which enables
polarization and repolarisation; during impulse transmission and
refractory/recovery periods; the spinal cord has no integration/association
functions and is therefore suited for reflex actions; needed in emergencies;
the spinal cord is long; and connects nerve fibres of the peripheral nerves
with the brain for storage of information; the spinal cord has a dorsal root
for sensory fibres/neurones; and a ventral root; for motor neurones/fibres;
Accept any other correct
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