Intro to Sensory Flashcards
Functions of a Sensory System
Collect, Convey, Integrate information
Conscious
Unconscious
Modulatory
Collaterals
Axon branches can have multiple targets
Ex. Pressure neuron axon can have synapse for modulation, for reflex, and for cortex
Stimuli - Receptor - Modality
Photon - photoreceptor - vision
Molecules - chemoreceptor - taste, smell
Mechanical - mechanoreceptor - touch, hearing, proprioception
Temperature - thermoreceptor - Temperature
Tissue Damage - Nociceptor - Pain
Adequate Stimulus
The form of energy a particular receptor is designed to sense
Sensory Transduction
Process of converting the energy of a stimulus into an action potential
Receptor deformed by energy
- > membrane permeability altered
- > receptor potential generated
- > action potential generated
Properties of Stimulus
Modality
Intensity
Duration
Location
Modality
Type of sense
Conveyed to CNS by labeled lines
Intensity
Larger stimulus
- > more receptors activated
- > larger depolarization
- > more AP
Encoded by FREQUENCY of AP
Adaption
Response of a receptor to a constantly applied stimulus diminishes with time
Can be fast or slow
Duration
Conveyed by ADAPTION
What adapts?
Cell receptors can adapt
Organs surrounding receptor adapt (ex pac Corp)
Thalamus (higher centers) adapt
Location
Conveyed by RECEPTIVE FIELDS
Receptive Field
Area of skin within which the receptor is stimulated
I.e. Receptor distribution
Classifying Axons
2 schemes
- ABC Group
- conduction velocity
- A is fastest - I, II, III, Group
- diameter
- I is fastest
Axon Speed
Larger faster
Mylenated faster
Pain, temp, itch are slowest
Muscles and proprioception fastest
(Conditions affecting myelin affect balance and movement)
