TwoOldGuys Study Guides
Animal Physiology 3
support Life functions
response to stimulus
Traditional definitions of stimulus and response are circular.
stimulus = "any thing that triggers a response"
response = "what an organism does when it encounters a stimulus"
In other words, stimulus = (see response); response = (see stimulus)
- non-circular definition
- response =
action taken by an organism after detecting a stimulus
- stimulus =
any environmental condition which exceeds the "normal" range for that factor
- sensory cells continually moniter homeostatic status
- when stimulus detected, nerve impulse transmitted via axon
- interneuron routes signal appropriately
- reflex, simple
signal sent to motor neuron
- reflex, complex
signal sent to other interneurons, then to ultimate destinations
- muscles/ muscle groups
- endocrine glands
- instinctive behavior
signal sent to medulla [primitive brain]
- learned behavior, intellectual response
signal sent to cerebrum
Response is rapid, but of short duration.
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© 2004-2005 TwoOldGuys
revised 19 aug 2006