Topic_5

Sensory System

A portion of the nervous system composed of sensory receptors, nerve pathways conducting sensory information to the CNS, and brain parts that process sensory information.

Sensation

Conscious awareness of a stimulus, such as becoming aware of pain in a finger.

Perception

The understanding of the meaning of a sensation, such as realizing that pain in a finger is caused by a cut.

Receptor Potentials

Graded potentials generated by sensory receptors in response to stimuli that can initiate action potentials.

Adequate Stimulus

The type of energy to which a certain type of receptor responds best.

Mechanoreceptors

A class of sensory receptors that respond to mechanical stimuli.

Thermoreceptors

A class of sensory receptors that respond to temperature changes.

Photoreceptors

A class of sensory receptors that respond to light.

Chemoreceptors

A class of sensory receptors that respond to chemical stimuli.

Nociceptors

A class of sensory receptors that respond to painful stimuli.

Slowly Adapting Neurons

Neurons that reduce the frequency of action potentials gradually upon constant stimulus.

Rapidly Adapting Neurons

Neurons that cease firing quickly upon constant stimulus.

Primary Sensory Coding

The conversion of stimulus energy into signals that convey relevant sensory information to the CNS.

Sensory Unit

A single sensory neuron and its field of nerve endings.

Two-Point Discrimination

The ability to perceive two distinct points when contact is made with the skin.

Lateral Inhibition

A mechanism that enhances the localization of a stimulus by inhibiting signals from neurons at the periphery compared to those at the center.

Specific Pathways

Pathways that convey action potentials produced by specific stimuli to the appropriate regions of the brain.

Non-specific Pathways

Pathways activated by different adequate stimuli; indicate something is happening but do not differentiate stimulus types.

Association Cortex

Regions of the cerebral cortex that process sensory information with complexity, contributing to functions like arousal, attention, and memory.

Factors Affecting Perception

Elements such as sensory receptor adaptation, emotions, personality, experience, and drugs that influence how stimuli are perceived.

Threshold

The minimum stimulus intensity required to produce an action potential.

Receptive Field

The area of skin or sensory organ where the application of a stimulus will influence a particular sensory neuron's ability to respond.

Convergence

The degree to which sensory pathways combine inputs that can affect stimulus localization.

Neural Pathways

Chains of neurons forming afferent sensory pathways ascending to the CNS.

Tonic Receptors

Sensory receptors that respond and generate potentials as long as the stimulus is present.

Phasic Receptors

Sensory receptors that respond only briefly upon the initial application of a stimulus.