3. Central Nervous System
(spinal cord)
grey matter
(the butterfly
shape; consist central canal
of cell bodies (contains
of neurones) cerebrospinal
fluid brings
white matter nutrients to
(consists of spinal cord)
nerve fibers)
The opposite arrangement is found in the
cortex of the brain.
4.
5. Spinal cord and spinal nerves
pg.261
- contains only sensory neurones
- aggregation - contains nerve
relay of cell bodies fibres from both
of sensory dorsal and ventral
neurones roots
- contains only motor neurones
6. Reflex actions
An 1immediate response to a 2specific
stimulus 3without conscious control
e.g. knee jerk, withdrawal of hand from hot
object
Simplest form of response
Classified under
– spinal reflex actions (controlled by spinal
cord)
- cranial reflexes (controlled by brain but not
will; in head region)
8. Reflex arc
Consists of
1. Receptor or sense organ
2. Sensory neurone
3. Reflex centre (spinal cord or brain)
4. Motor neurone
5. Effector (muscle/gland)
9. Conditioned reflex
a reflex action acquired from past
experiences or learning with a stimulus
which is originally ineffective in
producing the response
e.g Pavlov’s experiment
10. Pavlov’s Experiment
The dog's salivation to meat powder is an unconditional reflex
(no learning is involved)
Over time, however, the dog comes to salivate at the sounding of
the tone alone. When this occurs, a conditional reflex has
developed