What are Receptor Organs?
Distinguish the functions of sensory receptor classes (mechanoreceptors, chemical receptors, photoreceptors, nociceptors)
Indicate three general mechanisms for accurately communicating the magnitude or degree of the stimulus (analog data) to the CNS through action potential (digital signals) and classify the mechanisms in sensory systems, for instance
Explain, compare and contrast the recognition, transmission, and perception of sensations related to touch, sound, sight, taste, smell, and pain
Compare and contrast the visual and vestibular mechanisms between the various animal lines.
Sensory Receptor Cells:
⦁ Specialized cells (a neuron is also a receptor cell)
⦁ Specialized neuronic cells (the receptors secrete neurotransmitters to induce changes in the membrane potential of the synapsed neuron)
The sensory system detects and expresses information from the outside world to the body through the nervous system. The sensory system relies on sensory receptor cells specialized in modifying membrane potential.
If the changes in membrane potential are necessary to cause a potential for action, then neurons in the adjacent PNS division are transmitted to the CNS for data processing.
The CNS integrates the inbound signals and interprets them in an effective division of the PNS, to react to their body systems.
Sensorial receptor cells include Mechanoreceptors: respond by mechanical energy or pressure to physical deformation of the cell membrane, including touch, stretch, move, or sound.
⦁ Chemoreceptors: React to some, frequently dissolved molecules in a specific medium.
⦁ Photoreceptors: reacting to the radiation intensity (in most vertebrate’s visible light; in many insects both visible and UV light)
Harmful: react to “noxious” stimuli and essentially to anything that damages the tissue.
Thermoconceptors: Heat or cold reaction All two-way symmetrical animals have sensory systems and natural selection has driven the development of sensory systems of any type; sensory systems differ according to species’ history. For instance, the shiver is electrosensitive to the electric fields of other organisms produced in its environment, in comparison to the majority of fish predators.
