Peripheral Nervous System: Sensory Integration

Flashcards covering the divisions of the peripheral nervous system, the levels of sensory integration, and the mechanics of sensory transduction and pain perception.

Sensory afferent division

A branch of the peripheral nervous system consisting of neurons that carry sensory information from the body toward the central nervous system.

Motor efferent division

A major branch of the peripheral nervous system that includes somatic and visceral motor neurons going to muscles and viscera.

Somatic afferent neurons

Sensory neurons that carry information from the skin, skeletal muscles, and joints.

Visceral sensory afferent neurons

Sensory neurons that carry information from internal organs, such as the heart, lungs, and intestines.

Generator potential

A type of graded potential, also called a receptor potential, that is a transmembrane potential produced by the activation of a sensory receptor.

Sensory transduction

The process of converting a sensory signal, such as a cold stimulus, into an electrical signal through a depolarizing event.

Receptor level

The first level of sensory integration involving sensory reception and transmission to the central nervous system via receptors like free nerve endings or muscle spindles.

Circuit level

The second level of sensory integration where information is processed in ascending pathways at synapses in the spinal cord, brainstem, thalamus, and cerebellum.

Perceptual level

The third level of sensory integration occurring in the sensory cortex where sensory input is processed to give meaning to the stimulus and provide awareness.

Adaptation

A decrease in the sensitivity of a receptor in response to a constant stimulus, resulting in a lower frequency of action potentials.

Phasic receptors

Receptors that adapt to stimuli, such as those for pressure, touch, and smell, by firing a burst of action potentials initially and then decreasing the rate.

Divergence

A circuit pattern where neurons split to send information to multiple other neurons, advancing in the same pathway.

Magnitude estimation

An aspect of sensory perception where the intensity of a stimulus is coded by the frequency of action potentials arriving at the cortical sensory center.

Spatial discrimination

The ability to identify exactly where a stimulus originated on the body, often represented by the sensory homunculus.

Substance p

A neurotransmitter released by pain-carrying sensory afferent neurons at their synapse with second-order neurons.

Referred pain

Pain perceived at a location other than the site of the actual tissue damage, such as heart pain felt in the left arm or gallbladder pain felt in the right shoulder.

First order sensory neuron

The initial neuron in a sensory pathway that detects a stimulus with its dendrites and carries the signal to the spinal cord.

Tracks

Bundles of axons within the central nervous system that carry information, such as pain or temperature, up to the thalamus.