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The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. [1] It is anterior and partially inferior to the cerebellum . It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions, ranging from vomiting to sneezing . [ 2 ]
In the medulla oblongata, the arcuate nucleus is a group of neurons located on the anterior surface of the medullary pyramids. These nuclei are the extension of the pontine nuclei. [1] They receive afferents from the corticospinal tract. [citation needed] They in turn project efferents into the cerebellum through the inferior cerebellar ...
As well as motor neurons, the nucleus ambiguus contains preganglionic parasympathetic neurons which innervate postganglionic parasympathetic neurons in the heart. [ 2 ] It is a region of histologically disparate cells located just dorsal ( posterior ) to the inferior olivary nucleus in the lateral portion of the upper ( rostral ) medulla .
The ventral portion of the medulla oblongata contains the medullary pyramids. These two ridge-like structures travel along the length of the medulla oblongata and are bordered medially by the anterior median fissure. They each have an anterolateral sulcus along their lateral borders, where the hypoglossal nerve emerges from.
The lateral corticospinal tract is a descending motor pathway that begins in the cerebral cortex, decussates in the pyramids of the lower medulla [1] (also known as the medulla oblongata or the cervicomedullary junction, which is the most posterior division of the brain [2]) and proceeds down the contralateral side of the spinal cord.
The medulla oblongata, often just referred to as the medulla, is the lower half of the brainstem continuous with the spinal cord. Its upper part is continuous with the pons. [11]: 1121 The medulla contains the cardiac, dorsal and ventral respiratory groups, and vasomotor centres, dealing with heart rate, breathing and blood pressure.
The inferior olivary nucleus (ION) is a structure found in the medulla oblongata underneath the superior olivary nucleus. [1] In vertebrates, the ION is known to coordinate signals from the spinal cord to the cerebellum to regulate motor coordination and learning. [ 2 ]
The olive consists of two parts: The inferior olivary nucleus (or 'complex'), which is a part of the olivo-cerebellar system and is mainly involved in cerebellar motor-learning and function. The superior olivary nucleus, considered part of the pons and part of the auditory system, aiding the perception of sound.