Somatosensation Flashcards
Labeled Lines
Brain recognized distinct senses because action potentials travel along separate nerve tracts
Sensory Transduction
Conversion of electrical energy from a stimulus to a change in membrane potential in receptor cell
Pacinian Corpuscle
Detects vibrations
Receptive Fields
Three parts
1) Center that’s excitatory
2) Surround that’s inhibitory
3) Outside that has no effect
Sensory Adaptation
Progressive decrease in receptors response to sustained stimulation
Phasic Receptors
Display adaptation by decreasing frequency of action potentials
Tonic Receptors
Show little or no decline in action potential frequency
Sensory Cortex
Highly organized
Primary and secondary sensory cortex for each modality
Nociceptors
Peripheral receptors in free nerve endings that respond to pain
Aspects of Pain
Sensory: discriminatory dimension
Motivational: discriminatory dimension
Overall Cognitive: evaluative dimension
Pain pathway
Spinothalamic transmits temperature and pain to brain
1) Nerves send axons into dorsal horns of spinal cord
2) Synapse onto spinal neurons that cross midline and go into thalamus
3) Glutamate and substance P released to boost signal
Nerve Fibers in Pain
A delta fibers: large myelinated axons that register pain quickly
C fibers: thin unmyelinated that conduct pain slowly
