Lecture 4 - Ascending Tracts, ANS Flashcards
what sensations does the spinothalamic tract carry?
pain, temperature, light touch, pressure
what is the route of the spinothalamic tract?
- primary neuron from receptor into posterior root of spinal nerve to cell bodies in posterior root ganglion and synapse with secondary neuron in posterior horn of spinal cord
- secondary neuron crosses to opposite side in spinal cord -> enters spinothalamic tract and ascends to thalamus to synapse with tertiary neuron
- tertiary neuron leaves thalamus through internal capsule to somatic sensory cortex
what sensations does the dorsal column (medial lemniscal tract) carry?
proprioception, pressure and vibration
what is the route of the medial lemniscal tract?
- primary neuron from receptor to posterior root of spinal nerve to cell bodies in posterior root ganglion -> axons enter spinal cord and ascend in same side of spinal cord to medulla oblongata -> synapse with secondary neurons
- secondary neuron axons cross midline in medulla oblongata and ascend to thalamus synapse with tertiary neuron
- tertiary neuron from thalamus through internal capsule to somatic sensory cortex
what is the internal capsule?
projection fibres, tracts linking cerebral cortex with brain stem and spinal cord
where does the ANS innervate?
smooth muscle, cardiac muscle and glands
what smooth muscle functions does ANS regulate?
digestion and urination
what cardiac muscle functions does the ANS regulate?
heart rate and blood pressure
what is a ganglion?
group of nerve cell bodies where one neuron passes on nerve impulses to another neuron
preganglionic neuron
spinal cord -> ganglion
postganglionic neuron
ganglion -> organ
how does the ANS decline with age?
- constipation due to reduce mobility of GI tract
- dry eyes due to reduced tear formation
