BIO SCI 47 Lecture Notes - Lecture 20: Enkephalin, Cortisol, Nerve
4 Jun 2018
School
Department
Course
Professor
Stress Lecture 20
● Afferent fiber sends info toward brain
○ sensory
● Efferent fiber sends info from the brain to the body
○ Motor reactions
● Primary sensory afferents, motor neuron efferent, sympathetic postganglionic
● A beta carries light touch, A delta carries sharp pain
○ If you don’t have myelin you can’t feel these/ you feel them slower
● C fibers modulate A delta signal
● A beta fibers modulate signal that goes to brain
● Amount of pain you’re feeling can be modified with fibers
○ Ex, putting pressure on it
● Sensory info comes in, takes afferent pathway
● Efferent pathway comes from cortex and hypothalamus to spinal cord and
neurons modulate in spinal
● Why would you want to modulate pain to hurt more?
○ So you know to seek help
● You get a cut, modulatory signals send down to inflame the area around wound
○ Helps not damage already damaged site by causing pain all around that
spot
● Substance P is neurotransmitter that modifies pain by inflaming it and sending
blood flow
Document Summary
Efferent fiber sends info from the brain to the body. Primary sensory afferents, motor neuron efferent, sympathetic postganglionic. A beta carries light touch, a delta carries sharp pain. If you don"t have myelin you can"t feel these/ you feel them slower. A beta fibers modulate signal that goes to brain. Amount of pain you"re feeling can be modified with fibers. Sensory info comes in, takes afferent pathway. Efferent pathway comes from cortex and hypothalamus to spinal cord and neurons modulate in spinal. You get a cut, modulatory signals send down to inflame the area around wound. Helps not damage already damaged site by causing pain all around that spot. Substance p is neurotransmitter that modifies pain by inflaming it and sending blood flow. People in depression have higher levels of substance p. Pain can be modulated based on situation. Fast stress response you feel less pain. Rise in cortisol, release enkephalins, inhibit pain.
