RECEPTOR PHYSIOLOGY
• Definition of receptor
• Types of receptors
• Adaptations in receptors
• Properties of receptors
• Receptor potential
DEFINITION
• Receptors are trasducers , they convert stimuli into electrical
impulse.
• Sensory receptors are specialized epithelial cells or neurons
that transduce environmental signals in to neuronal signals.
FUNCTIONS OF RECEPTORS
1. Transduction
2. Amplification
3. Transmission
4. Integration
, SENSORY RECEPTORS
1. Sensory Transduction
• Conversion of stimulus energy into membrane potential •
of receptor cell
• Begins by a change in membrane permeability
• results in “graded” change in membrane potential
“RECEPTOR POTENTIAL”
• Is graded: proportional to strength of stimulus can be
due to change in ion permeability :
1. as gated ion channels respond to receptor
molecule
(a ligand binds to)
2. or due to actual stretching of membrane in
response to pressure.
SENSORY RCEPTORS
2. AMPLIFICATION - strengthening of a stimulus too
weak to be carried into nervous system • Direct -
Complex organ, ear: sound waves
• magnified 20X
, • Part of transduction in eye: 100,000X of action
potential in signal to brain from eye, vs. few
photons of light energy trigger process
SENSORY RECEPTORS
3. TRANSMISSION - conducting impulses to CNS
• Some cases, pain receptor, is a sensory neuron that
conducts signal
• other receptors transmit chemical signals (neurotransmitters)
across a synapse to a sensory neuron
• •Stimulus does not turn on/off production of action potential
but controls the frequency with which they are
generated…
• can detect a change in stimulus intensity,
• not just presence or abscence of stimuli.
SENSORY RECEPTORS
• 4. Integration - processing of information > begins
immediately integration via summation of graded
potentials.
• Definition of receptor
• Types of receptors
• Adaptations in receptors
• Properties of receptors
• Receptor potential
DEFINITION
• Receptors are trasducers , they convert stimuli into electrical
impulse.
• Sensory receptors are specialized epithelial cells or neurons
that transduce environmental signals in to neuronal signals.
FUNCTIONS OF RECEPTORS
1. Transduction
2. Amplification
3. Transmission
4. Integration
, SENSORY RECEPTORS
1. Sensory Transduction
• Conversion of stimulus energy into membrane potential •
of receptor cell
• Begins by a change in membrane permeability
• results in “graded” change in membrane potential
“RECEPTOR POTENTIAL”
• Is graded: proportional to strength of stimulus can be
due to change in ion permeability :
1. as gated ion channels respond to receptor
molecule
(a ligand binds to)
2. or due to actual stretching of membrane in
response to pressure.
SENSORY RCEPTORS
2. AMPLIFICATION - strengthening of a stimulus too
weak to be carried into nervous system • Direct -
Complex organ, ear: sound waves
• magnified 20X
, • Part of transduction in eye: 100,000X of action
potential in signal to brain from eye, vs. few
photons of light energy trigger process
SENSORY RECEPTORS
3. TRANSMISSION - conducting impulses to CNS
• Some cases, pain receptor, is a sensory neuron that
conducts signal
• other receptors transmit chemical signals (neurotransmitters)
across a synapse to a sensory neuron
• •Stimulus does not turn on/off production of action potential
but controls the frequency with which they are
generated…
• can detect a change in stimulus intensity,
• not just presence or abscence of stimuli.
SENSORY RECEPTORS
• 4. Integration - processing of information > begins
immediately integration via summation of graded
potentials.
