Medulla Flashcards
What is the inferior olivary nucleus?
It is a group of neuronal cell bodies that function as a relay center in the coordination of information between the cerebral cortex and the cerebellum to ensure synchrony of movements.
Where is the inferior olivary nucelus?
Immediately lateral to the pyramids on the central surface of the medulla
What are the pyramids?
The medullary pyramids form bulbous projections on the ventral surface of the medulla. They contain axons from neuronal cell bodies in the motor cortex which participate in teh regulation of lower motor neurons of cranial nerve nuclei in the brain stem and of the ventral horn of the spinal cord.
What is the route from the inferior olivary nucleus to the cerebellum?
Across the midline and through the contralateral inferior cerebellar peduncle to synapse in the cerebellum.
What are the secnodary neurons in the dorsal/posterior columns?
Nuclei gracilis and cuneatus
Where and to what does the dorsal column cross the midline?
The nuclei gracilis and cuneatus axons cross in the lower medulla to form the contralateral medial lemniscus.
How is the spinothalamic tract localized in the medulla?
Same is spinal cord since the fbers decussate in teh spinal cord
What is the cuneocerebellar tract?
These fibers carry unconscious proprioception and enter the spinal cord superior to Clark’s nucleus.
What is the course of the cuneocerebellar tract?
The fibers ascend in the posterior columns to the level of the accessory cuneate nucleus located in the medulla (near the cuneate nucleus). They synapse with neurons in the accessory cuneate nucleus and those axons form the cuneocerebella tract which go through the ipsiateral inferior cerebellar peduncle to the cerebellum.
What is the inferior cerebellar peduncle?
IT is located dorsolaterally in the rostral medulla and is the major comunication cable between the medulla dn the cerebellum.
What is the sulcus limitans?
It separates sensory deribative from motor derivatives. Visceral information is closest to it.
Hypoglossal Nucleus?
It is present in the midline of the medulla. This group of neurons send ther fibers out of the brainstem just lateral to the pyramids.
What does the hypoglossal nucleus innervate?
It innervates the tnogue and when lesioned, it produces lower motor neuron symptoms. Its upper motor neuron is in the cortex.It tavels with the corticospinal fibers and leave the pyramids to synapse in the hypoglossal nucleus.
What is the nucleus ambiguus?
A “lower” motor neuron which innervates the muscle s of the larynx and pharynx and soft palate via cranial nerves IX, X and XI The rootlets leave the brainstem lateral to the olive on the ventral surface
Visceral motor nuclei?
Parasympathetic preganglionic neurons right next to the somatic motor column. The dorsal motor nucleus of the vagus is the principal parasympatetic nucleus and fibers travel to thoracic and abdominal viscera.
