Changes

==Pain==

==Pain==

*"Painful stimuli" can range from itches, to nausea, to being in agony.

Painful stimuli can result in responses ranging from itches, to nausea, to simply being in agony. Painful stimuli may be transmitted to the brain by one of two pathways: the [[Sensory Pathways - Anatomy & Physiology#Spinothalamic Tract|Spinothalamic Tract]] or the the [[Sensory Pathways - Anatomy & Physiology#Ascending Reticular Formation|Ascending Reticular Formation]].

*Painful stimuli may be transmitted to the brain by one of two pathways:

::[[Sensory Pathways - Anatomy & Physiology#Spinothalamic Tract|Spinothalamic Tract]]

::[[Sensory Pathways - Anatomy & Physiology#Ascending Reticular Formation|Ascending Reticular Formation]]

'''Spinothalamic Tract'''

===Spinothalamic Tract===

*Fast, initial pinprick is detected by free [[PNS Structure - Anatomy & Physiology#Nerve Fibres|nerve]] endings

This fast, initial pinprick is detected by free [[PNS Structure - Anatomy & Physiology#Nerve Fibres|nerve]] endings and causes an impulse along large, myelinated fibres. The pain sensation is localised, and ends quickly.

*Causes an impulse along large, myelinated fibres

*Pain sensation is localised, and ends quickly

'''Ascending Reticular Formation'''

===Ascending Reticular Formation===

*A painful sensation is detected by free [[PNS Structure - Anatomy & Physiology#Nerve Fibres|nerve]] endings

This pain sensation is detected by free [[PNS Structure - Anatomy & Physiology#Nerve Fibres|nerve]] endings which causes an impulse along small, unmyelinated fibres. This results in a delayed perception of the sensation of pain, and that pain is often less localised but more persistent.

*Causes an impulse along small, unmyelinated fibres

*A delayed sensation of pain is percieved, that is less localised, persistent.

'''Clinical Relevance'''

'''Clinical Relevance'''