44.
A pyramidal motor pathway is primarily concerned with volitional (voluntary)
control of body parts, particularly the fine movements of hands. These pathways
are called pyramidal because their neuron processes help to make up structures in
the base of the brain called pyramids. (para 11-20a)
45.
An extrapyramidal pathway is primarily concerned with automatic (nonvolitional)
control of body parts for purposes of coordination. (para 11-20b)
46.
Examples of general senses are:
a.
Pain.
b.
Temperature (warm and cold).
c.
Touch (light and deep).
d.
Proprioception ("body sense"). (para 11-21c)
47.
Examples of special senses are:
a.
Smell (olfaction).
b.
Taste (gustation).
c.
Vision.
d.
Hearing (auditory).
e.
Equilibrium. (para 11-21d)
48.
The general sensory pathway is from the receptor organ, via the PNS nerves, to
the CNS. This general pathway then ascends fiber tracts in the neuraxis. The
pathway ends in the central area of the opposite cerebral hemisphere.
49.
The receptors for the sense of smell are special hair cells called chemoreceptors.
These are found in the olfactory epithelium, high in the nasal chambers in the
head. The information received is transmitted by way of the olfactory nerves to the
olfactory bulbs and then into the opposite cerebral hemisphere.
50.
Special hair cells (chemoreceptors) are found in the taste buds, scattered over the
tongue and the rear of the mouth. These cells, which react to dispersed or
dissolved food molecules, are the sensory receptors for the special sense of taste.
The information received is transmitted to the opposite side of the brain by three
cranial nerves. (paras 11-24, 11-25)
51.
The eyeball is the sense organ containing the receptor tissues for the special
sense of vision. The eyeball is shaped like a bulb (or sphere).
MD0006
11-57
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