Nervous System I
> nervous system overview
• controls skeletal muscle movement
pain - unpleasant sensory and emotional
>
-
• regulates cardiac and smooth muscle activity
experience associated with actual and potential
tissue damage
• integration of sensory info
• more heavily influenced by reaction to pain
• adjusts to changing external environment
than intensity
↳ mechanism
>
- neuron - functional unit of nervous sysstem
• action potential - electrical charge along axon • tissue injury - burn
• Na+ in soma depolarizes • inflammation - swelling, redness, pain
• K+ efflux repolarizes • mediator release - prostoglandins,
serotonin, acetylcholine
• afferent (sensory) - carry info to CNS • nociceptor - percieves pain
• efferent (motor) - carry info from CNS to efferent organs • to spinal cord, thalamus
> central nervous system (CNS)
-
• to somatosensory cortex
• brain and spinal cord - protected by skull and vertebral • pain is percieved
column
acute vs. chronic
• computational and control functions - acute
peripheral nervous system (PNS)
>
• recent onset, short duration
• outside CNS structures • autonomic responses
• relay info to CNS and output messages that control effector - increased HR, SV, BP, muscle tension
organs - decreased gut motility, salivary flow
↳ chronic
↳autonomic nervous system (ANS)
• constinous, intermittent for 6 months or
• regulate, adjust vital visceral functions more
- blood pressure and flow • absence of autonomic response
- body temp • psychological
- respiration - irritable, depression, withdrawal, decreased
- digestion sleep, appetite
- metabolism
> types of pain
-
- elimination • nociceptive - pain receptors activated due
↳ • sympathetic - internal and peripheral actions
to actual or impending tissue injury
- vital functions • neuropathic - direct injury to nerves
- critcal threat to integrity (ie. fight or flight) • cutaneous - skin or subcutaneous tissues,
- break down glucose for energy, GI slows, HR increase sharp burning pain
↳• parasympathetic - internal actions • deep somatic - diffuse and throbbing, in
- conservation of energy, resource replenishment body structures
- organ function during inactivity (ie. rest and digest) • visceral - diffuse and poorly defined,
stretching, distension, ischemia of tissues
- somatosensory nervous system • referred - percieved as originating at part
• awarness of body sensations - touch, temp, limb position, of body innvervated by same segment of
pain NS
• discrete nerve endings in skin and body tissues
• first order - receptor to spinal column
• second order - ascending to thalamus
• third order - to somatosensory cortex
> nervous system overview
• controls skeletal muscle movement
pain - unpleasant sensory and emotional
>
-
• regulates cardiac and smooth muscle activity
experience associated with actual and potential
tissue damage
• integration of sensory info
• more heavily influenced by reaction to pain
• adjusts to changing external environment
than intensity
↳ mechanism
>
- neuron - functional unit of nervous sysstem
• action potential - electrical charge along axon • tissue injury - burn
• Na+ in soma depolarizes • inflammation - swelling, redness, pain
• K+ efflux repolarizes • mediator release - prostoglandins,
serotonin, acetylcholine
• afferent (sensory) - carry info to CNS • nociceptor - percieves pain
• efferent (motor) - carry info from CNS to efferent organs • to spinal cord, thalamus
> central nervous system (CNS)
-
• to somatosensory cortex
• brain and spinal cord - protected by skull and vertebral • pain is percieved
column
acute vs. chronic
• computational and control functions - acute
peripheral nervous system (PNS)
>
• recent onset, short duration
• outside CNS structures • autonomic responses
• relay info to CNS and output messages that control effector - increased HR, SV, BP, muscle tension
organs - decreased gut motility, salivary flow
↳ chronic
↳autonomic nervous system (ANS)
• constinous, intermittent for 6 months or
• regulate, adjust vital visceral functions more
- blood pressure and flow • absence of autonomic response
- body temp • psychological
- respiration - irritable, depression, withdrawal, decreased
- digestion sleep, appetite
- metabolism
> types of pain
-
- elimination • nociceptive - pain receptors activated due
↳ • sympathetic - internal and peripheral actions
to actual or impending tissue injury
- vital functions • neuropathic - direct injury to nerves
- critcal threat to integrity (ie. fight or flight) • cutaneous - skin or subcutaneous tissues,
- break down glucose for energy, GI slows, HR increase sharp burning pain
↳• parasympathetic - internal actions • deep somatic - diffuse and throbbing, in
- conservation of energy, resource replenishment body structures
- organ function during inactivity (ie. rest and digest) • visceral - diffuse and poorly defined,
stretching, distension, ischemia of tissues
- somatosensory nervous system • referred - percieved as originating at part
• awarness of body sensations - touch, temp, limb position, of body innvervated by same segment of
pain NS
• discrete nerve endings in skin and body tissues
• first order - receptor to spinal column
• second order - ascending to thalamus
• third order - to somatosensory cortex
