neurons within the brain and spinal cord

The axon shown here is covered by insulating sheaths of myelin. Processes can be diversified as dendrites which receive information or axon which carries information. the descending Pathways carry motor signals down the spinal cord and a generally divided into pyramidal or extrapyramidal tracts the pyramidal fibers travel through the medullary pyramids of the medulla oblongata which is why they are termed pyramidal these fibers originate in the cerebral cortex and are responsible for the voluntary control of the muscles of the body and the face there are two different tracks that make up the pyramidal tracts these are the corticospinal and corticobulbar tract the corticospinal tract responsible for the control of the body the cell bodies are found within the cerebral cortex with axons converging and passing through the internal capsule followed by the crus cerebri in the midbrain the pons and subsequently arriving into the medulla oblongata at this level around 75% the fibers will it to the other side of the spinal cord and continue down to sign ups with a lower motor neuron in the ventral horns at each level these fibers are known as the lateral corticospinal the other 25% of the fibers that remain on the ipsilateral side will continue as the anterior corticospinal tract and they will continue down ipsilateral e until the cervical and highest thoracic levels where they will decussate and sign ups with their motor neurons as for the corticobulbar tract this is the tract responsible for the voluntary control of the head the face and the neck similarly to the corticospinal tract they originated from the cerebral cortex and pass through the internal capsule however rather than descend into the spinal cord these neurons have their axons sign up sing to the lower motor neurons in the brain stem specifically on to the cranial nerve nuclei. The loss of mature neurons is the main cause of functional defects after SCI, and this is directly involved in the induction of programmed cell death (PCD) in neural cells, including apoptosis. Neurons have a soma (or cell body) and processes, which are extensions from the soma that receive or carry information.

Neurons within the brain and spinal cord