Anterolateral System Flashcards
What laminae does the indirect spinothalamic tract synapse in?
Laminae 2 & 3
What type of fibres are used in the direct pathway and what is there function?
A- Delta fibres. Thinly myelinated fibres and conduct short-term, sharp easily located pain.
where does the 3rd order neuron synapse in the Paleo Spinothalamic and spinoreticular indirect pathway?
Come from the reticular formation and goes to the Thalamus -Intra laminae thalamic Nucleus - this is due to non-localising pain.
Where does the 2 order neuron for the Paleo Spinothalamic and spinorectular pathway go to?
From the Dorsolateral Fasciculus to the reticular formation.
What are the two sub groups of the spinothalamic tract?
The direct pathway and the indirect pathway
There is a 4th order neuron in the indirect Paleo Spinothalamic pathway. Where does it go?
Cingulate Nucleus (Cerebral cortex)
Lymbic system
Hypothalamus
Insular cortex
What sensation does the Spinothelamic tract collect?
Pain, temp, crude touch and simple tactile sensations
What does the Periaqueductal Grey activate and get released?
Endogenous Opioids - inhibition of the pain signal in the spinal cord - the spinomesenchephilc tract goes here.
What sensations travel on the direct pathway?
Pain, temp and simple tactile sensations
Where does the 3rd order neuron of the Spinomesencephalic pathway arise and terminate?
Midbrain –> amygdala via para brachial nuclei
What tracts are in the indirect pathway?
Paleo Spinothelamic, spinoreticular and spinomesencephalic
What sensations is the indirect pathway involved in?
Automatic, endocrine, motor and arousal components of pain, temp and crude touch.
Involved in activation of pain inhibiting mechanisms
What laminae does the direct spinothalamic tract synapse in?
Laminae 1 & 5
What type of fibres are used in the indirect pathway and what is there function
C- fibres. Unmyelinated fibres - relay dull, persistent and poorly localised pain.
What is the spinoreticular tract function?
Changes in the level of attention response to pain
What tracts are within the anterolateral system?
Spinothalamic tract, Spinoreticular tract and Spinomesencephalic tract
The indirect pathways decussate differently. How?
Some fibres decussate at the point of the spinal cord and travel contralaterally others don’t and travel ipsilaterally. This is known as bilaterally.
What sensations travel on the direct pathway?
Pain - sharp, localised,
Where is the 1st synapse of the anterolateral system?
Dorsolateral Fasciculus - grey matter
What sensations is the indirect pathway involved in?
Dull pain - Automatic, endocrine, motor and arousal components, temp and crude touch.
Involved in activation of pain-inhibiting mechanisms such as Endogenous Opioids
What receptors does the spinothalamic tract use to detect pain?
Nociceptors
