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Encyclopedia > Medial reticular formation
Brain: Medial reticular formation
Taken from "The Brainstem Reticular Formation and its Significance for Autonomic and Affective Behavior". The above diagram illustrates the reticular nuclei in the brainstem in a tiered fashion

Surrounding the previously discussed ridge of serotonergic cells, the medial reticular formation has many roles and functions. The medial reticular formation is filled with a mixture of large and small neurons. Image File history File links Download high-resolution version (750x931, 668 KB)a nice look at the nuclei involved in the reticular formation The copyright status of this work is undetermined and may be difficult or impossible to determine. ... Serotonergic means related to, capable of producing, altering, or releasing serotonin, a neurotransmitter, and can refer to the following classes of chemicals: Selective serotonin reuptake inhibitor - A common class of serotonergic antidepressants Noradrenergic and specific serotonergic antidepressant - Another class of serotonergic antidepressants serotonergic psychedelics - The serotonergic hallucinogenic drugs This is... Neurons (also called nerve cells) are the primary cells of the nervous system. ...

The most famous and prominent cells in this region are the giant neurons, located mostly within the medial RF.

These neurons have long axons in both the ascending and descending directions. An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ...

Through their projections, this portion of the RF has been known to mediate posture, movement, pain, autonomic function and arousal. While not moving, a human can be in one of the following main positions. ... Look up movement in Wiktionary, the free dictionary The term Movement has a variety of different meanings related to motion: Physical movement between points in space (A to B). The amount of movement is called distance. ... Look up Pain in Wiktionary, the free dictionary. ... Anatomy and Physiology of the A.N.S. In contrast to the voluntary nervous system, the involuntary or autonomic nervous system is responsible for homeostasis, maintaining a relatively constant internal environment by controlling such involuntary functions as digestion, respiration, and metabolism, and by modulating energy needed to cope with stressful... Arousal is a physiological and psychological state involving the activation of the reticular activating system in the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of alertness and readiness to respond. ...

The nuclei of the medial reticular formation are:

These two columns have been the subject of much speculation and mystery because their intricate parts are so interwoven and specific.

In fact it has taken decades to unravel them to this point, and there are still far more mysteries to unravel for future neural scientists. (Above in figure one can be seen a color diagram of the lateral and medial reticular formation, separated into nuclei, which blend into one another).

Three out of the four nuclei mainly involved in mediating expiration and inspiration are located in the medial RF and should be discussed. Expiration (2003) is an independent feature film directed by Gavin Heffernan In respiration, expiration is initiated by a decrease in volume and positive pressure exerted upon the intrapleural space upon diaphragm relaxation. ... Ä· Look up inspiration in Wiktionary, the free dictionary. ...

Respiration has an autorhythmia, thought to be mediated by the dorsal reticular formation.

Even when all afferent stimuli are eliminated, the respiration rhythm continues on.

Expiration is mediated by the nucleus reticularis parvocellularis and the dorsorostral portion of the gigantocellularis.

The nuclei which mediate inspiration are the rostral portion of the ventral reticular nucleus and part of the lateral RN.

The efferent fibers for the inspiration nuclei follow the motor path of the glossopharyngeal nerve and the vagus nerve. The glossopharyngeal nerve is the ninth of twelve cranial nerves. ... The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the abdomen. ...

This exhalation process takes place when the aforementioned nuclei inhibit the nuclei responsible for inspiration.

In order for this to take place there must be inhibitory connections from the expiring neurons to the inspiring neurons.



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