Spinal Cord Form and Function

Functions of the Anterior Spinothalamic Tract

- Crude mechanoreceptors to touch

Proprioception

- Is the mind's capacity to know where the body's extremities are in relation to space. - It is afferent information that is required for neuromuscular control.

Functions of the Lateral Spinothalamic Tract:

- Sensations of Pain - Sensations of Temperature

Dorsal Horns of the Gray Matter (R + L)

- They provide an entrance for the afferent neurons - Dorsal aspect of the dorsal horns provides entrance to somatic sensory neurons - Ventral aspect of dorsal horns provides entrance to visceral sensory neurons.

Ventral Horns of the gray matter (R + L)

- They provide an exit for the efferent neurons. - Ventral aspect of the ventral horns provides an exit to the somatic motor neurons. - Dorsal aspect of the ventral horns provides exit to​ the visceral motor neurons.

Fasciculus Cuneatus and Fasciculus Gracilis Neurons:

1st order from the origin in the PNS to the medulla. 2nd order from medulla to the thalamus. 3rd order from thalamus to the cerebral cortex.

Anterior Spinothalamic Tract Neurons

1st order neuron enters the dorsal horn of gray matter of spinal cord. 2nd order crosses the spinal cord to opposite aspect of the spinal white matter and proceeds to the thalamus. 3rd order from the thalamus to the cerebral cortex Function: Crude mechanoreceptors to touch

Posterior Spinocerebellar Tract Neurons:

1st order neuron enters the dorsal horn of the gray matter spinal cord. 2nd order neuron moves from the dorsal horn entering the ipsilateral spinal cord white matter and proceeds to the cerebellum.

Lateral Spinothalamic Tract Neurons:

1st order to the dorsal horn of gray matter of spinal cord. 2nd order crosses spinal cord to opposite side of the white matter and proceeds to the thalamus. 3rd order from thalamus to the cerebral cortex.

Fasciculus Cuneatus

A tract of nerves in the spinal cord that primarily transmits information from the arms.

Why is gray matter "gray"?

Because it lacks MYELIN

Ascending Pathway 1st order neurons:

Conduct impulses from the periphery receptor to the spinal cord or brain stem.

AP 2nd order neurons:

Conduct impulses to the thalamus or the cerebrum.

Functions of the Fasciculus Cuneatus and Fasciculus Gracilis

Conscious proprioception. - Cuneatus: Upper limbs - Gracilis: Lower limbs

Fasciculus Gracilis

Is a bundle of axon fibers in the posterior column-medial lemniscus pathway of the spinal cord and carries information from the middle thoracic and lower limbs of the body.

AP 3rd order neurons:

Relay impulses to the somatosensory cortex of the cerebrum.

Functions of the Posterior Spinocerebellar Tract

Subconscious proprioception

Gray matter location

The central region of the spinal cord

Shape of gray matter

it is shaped like an H