Anatomy chapt. 16-17

• These tracts are paired bilaterally & symetically along the spinal cord.
• The axons within each tract are grouped according to body region innervated.
• Processing occurs at several points along the way
• All tracts involve the brain & spinal cord.

A continous flow of information among the brain, spinal cord and peripheral nerves

Millions of sensory neurons are delievering information to processing centers in the CNS

Millions of motor neurons are controlling or adjusting the activites or the peripheral effectors.

To cross over to the opposite side.

The axon of either the 1st, or 2nd order neuron decussates to the opposite side of the spinal cord or brain stem as it decends.

A sensory neuron that delivers information to the CNS. It's cell body is in the dorsal root ganglion or a cranial nerve ganglion.

Interneuron upon which the axon of the first order neuron synapses. The second order neuron's cell body may be located in either the spinal cord or the brain stem.

In pathways ending at the cerebral cortex, the 2nd-order neuron synapses on a 3rd-order neuron in the thalamus. The axon of the 3rd-order neuron carries sensory information from the thalamus to the appropiate sensory area of the cerebral cortex.

When stimulated a receptor passes information to the form of action potentials in an afferent (sensory) fiber.

Carries proprioceptive information concerning the position of muscles, tendons, & joints to the cerebellum.

Fine coordination of body movements

Carries sensations of pain, temperature & "crude" sensations of touch & pressure.

Highly localized information from the skin & muscular skeleton system about proprioceptive. Fine touch, pressure, vibration sensations. Carries information about the type of stimulus the exact site of stimulation, & when the stimulus starts & stops.