Transcript The Reflex Arc

The Reflex Arc
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Reflexes are an automatic and rapid response
to a particular stimulation
If the command centre for the reflex is located
in the brain – cerebral reflex
If the command centre for the reflex is located
in the spinal cord – spinal reflex
Autonomic and Somatic Reflexes
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Autonomic reflexes are mediated by the
autonomic division of the nervous system
Involve activation of smooth and cardiac
muscles as well as glands
Regulate bodily functions such as digestion,
elimination, blood pressure, salivation, and
sweating
Somatic Reflexes involve stimulation of
skeletal muscles
The Reflex Arc
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The name given to
the pathway along
which the initial
stimulus and the
corresponding
response message
travel
There are 5 parts to a reflex arc:
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1. Receptor: receives the initial stimulus i.e. A
loud noise, pinprick to the skin)
2. Sensory nerve: carries the impulse to the
spinal column or brain (aka afferent nerve)
3. Intermediate nerve fibre: interprets the
signal and issues and appropriate response
Cont...
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4. Motor nerve: carries the response message
from the spinal cord to the muscle or organ (aka
efferent nerve)
5. Effector organ: carries out the response
(i.e. Skeletal muscle – moving your hand away
from danger)