10/02/2015 Flashcards
What does the anterior spinothalamic tract do?
Takes signals about crude touch and pressure to the brain
What does the lateral spinothalamic tract do?
Takes signals about pain and temperature sensation to the brain
Describe the course of the nerves of the spinothalamic tract
Nerve 1: from sensory receptor in end organ, enters spine dorsally, synapses at the SPINAL CORD, one or two levels above where it entered.
Nerve 2: immediately decussates in the spinal cord and the travels up to synapse at the thalamus
Nerve 3: from the thalamus to the cortex
What does the posterior column medial lemniscus pathway do?
(Also known as PCML or dorsal column medial lemniscus)
Why is it named this way?
The PCML takes signals about fine touch and vibration sensation to the brain.
It is named after it’s main structures: the posterior (dorsal) columns are the structures in the spinal cord that are formed by nerve fibres of the PCML. The medial lemniscus is the structure deep in the medulla of the brain stem formed by the decussation of fibres from the posterior columns.
Describe the course of the nerves in the posterior column medial lemniscus pathway.
First order neurone: from the receptor at the end organ, enters the spinal cord dorsally, travels up and synapses at the medulla.
Second order neurone: decussates at the medulla in the medial lemniscus, travels up and synapses at the thalamus.
Third order neurone: from the thalamus to the cortex.
What does the corticospinal tract do?
One of the pyramidal tracts. The other one is corticobulbar
It carries signals regarding voluntary movement from the motor cortex to effector organs.
Describe the course of the nerves in the corticospinal tract.
(One of the pyramidal tracts. The other one is corticobulbar)
Upper motor neurone: from the motor cortex, decussates at the medulla then carries on down to synapse with the LMN at the anterior horn of the spinal cord at the required level.
Lower motor neurone: from the anterior horn of the spinal cord out to the effector organ.
