Olfactory receptor cells may be considered specialized, primitive-type, bipolar neurons. Their nuclei are located at the base of the epithelial layer. Basal stem cells located along the basement membrane differentiate…

TROCHLEAR NERVE The trochlear nerve is slender, and its nucleus of origin is located in the midbrain just caudal to the oculomotor nuclei. The trochlear fibers curve posterolaterally and slightly…

Pontine reticulospinal fibers project to the spinal cord via the medial reticulospinal tract only. This tract traverses the anterior funiculus ipsilaterally and extends along the entire length of the spinal…

DISORDERS Proximal spinal accessory nerve lesions cause weakness of the sternocleidomastoid and the trapezius muscles. Damage within the posterior triangle of the neck spares the sternocleidomastoid, resulting in trapezius weakness….

The known output pathways from the vestibular nuclei include projections to the spinal cord, oculomotor nuclei, cerebellum and reticular formation. Vestibular activity also reaches the thalamus, superior colliculus and other…

The central (sulcocommissural) branches of the anterior spinal artery pass back into the anterior median fissure to supply the central parts of the spinal cord. At the anterior commissure, the…

Below its inferior ganglion, the vagus nerve descends within a homolateral carotid sheath, shared with the internal jugular vein and carotid artery, to the thoracic inlet. The vagus nerve intercommunicates…

RETINA The retina has several distinct layers. Rods and cones form synaptic connections with bipolar and horizontal cells. Bipolar cells are relay neurons that transmit visual signals from the inner…

The dorsal vagal nucleus is a mixed nucleus that represents fused visceral afferent and efferent columns of neurons. It consists of a longitudinal column of cells lying beneath the vagal…