🧠 Nervous System🟢 BasicSensory Receptors

Sensory Receptors and Transduction

Specialised nerve endings that detect a stimulus such as touch, heat or light and convert it into electrical signals the nervous system can read.

Key points

A sensory receptor changes one form of energy (the stimulus) into electrical signals, a process called transduction, producing a graded receptor (generator) potential.
Receptors are grouped by the stimulus they detect: mechanoreceptors (touch, pressure, stretch), thermoreceptors (temperature), nociceptors (pain), photoreceptors (light) and chemoreceptors (taste, smell, blood gases).
Within a receptor's working range, a larger stimulus gives a larger receptor potential, coded as a higher frequency of action potentials, so stimulus strength becomes firing rate.
Each sensory modality has its own dedicated pathway (the labelled-line principle), so the brain reads the type of sensation from which pathway is active rather than from the signal itself.
Many receptors adapt: fast-adapting ones (such as touch) fire mainly when a stimulus changes, while slow-adapting ones (such as some pain and pressure receptors) keep firing while it lasts.
The smallest stimulus that can be felt is the threshold, and a receptor's receptive field is the area over which a stimulus will excite it.

Memory trick

Different energies, one currency: receptors transduce their stimulus into a receptor potential, then code its strength as firing rate along a labelled line.

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🧠 Nervous System🟢 BasicSensory Receptors

Sensory Receptors and Transduction

Specialised nerve endings that detect a stimulus such as touch, heat or light and convert it into electrical signals the nervous system can read.

Key points

A sensory receptor changes one form of energy (the stimulus) into electrical signals, a process called transduction, producing a graded receptor (generator) potential.
Receptors are grouped by the stimulus they detect: mechanoreceptors (touch, pressure, stretch), thermoreceptors (temperature), nociceptors (pain), photoreceptors (light) and chemoreceptors (taste, smell, blood gases).
Within a receptor's working range, a larger stimulus gives a larger receptor potential, coded as a higher frequency of action potentials, so stimulus strength becomes firing rate.
Each sensory modality has its own dedicated pathway (the labelled-line principle), so the brain reads the type of sensation from which pathway is active rather than from the signal itself.
Many receptors adapt: fast-adapting ones (such as touch) fire mainly when a stimulus changes, while slow-adapting ones (such as some pain and pressure receptors) keep firing while it lasts.
The smallest stimulus that can be felt is the threshold, and a receptor's receptive field is the area over which a stimulus will excite it.

Memory trick

Different energies, one currency: receptors transduce their stimulus into a receptor potential, then code its strength as firing rate along a labelled line.

All of Physiology More Nervous System