Please enable JavaScript.
Coggle requires JavaScript to display documents.
8c properties of reflex arc - Coggle Diagram
8c
properties of reflex arc
Adequate stimulus
The reflex activity is stereotyped and specific in terms of both the stimulus and the response.
Therefore, a particular stimulus produces a particular response.
the receptors respond maximally only when an appropriate specific stimulus is applied
likewise, the stimulus that produces a reflex is very precise and is called the adequate stimulus for the particular reflex
bell megendie law
not in imp list
the principle is that in the SC
the dorsal or posterior roots entering yhe SC is -sensory
& the ventral or anterior roots emerging frm the SC is- motor
this is known as the Bell-megendie law
Final common pathway
The ‘α-motor neurons’ that supply the extrafusal muscle fibers in the skeletal muscles
are the final common pathway over which the neural control system coordinates the activity of skeletal muscle fibers.
All neural influences (excitatory and inhibitory) affecting muscular contraction ultimately funnel through them to the muscles.
If an α-motor neuron is stimulated,
skeletal muscle fibers contract;
if the α-motor neuron is not stimulated,
the skeletal muscle fibers relax.
Central excitatory and inhibitory states
The spinal cord shows prolonged changes in excitability because of activity in reverberating circuits or prolonged effects of synaptic mediators.
The prolonged state in which excitatory influences exceed inhibitory influences is called central excitatory state
conversely, if inhibitory state dominates, it is called central inhibitory state.
Habituation and Sensitization of reflex responses
Though the reflex responses are stereotyped, still they can be modified by experience. Therefore,
If the stimulus is benign and repeated at frequent intervals, the response declines and disappears, a phenomenon called ‘habituation’.
Opposite response i.e. prolonged facilitation of synaptic conduction in a reflex can be produced by noxious stimulus,
this phenomenon is called ‘sensitization’ which can last from hours to days.