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The patient with acute neurological problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
The medulla oblongata contains the vasomotor centre, also called the cardiovascular centre. This regulates the heartbeat and controls the diameter of blood vessels, thereby controlling blood pressure. The medulla is also responsible for the rhythmical pattern of breathing. The medulla contains ascending sensory pathways and descending motor pathways connecting the spinal cord with other parts of the brain. The area where the medulla joins the spinal cord is where most of the ascending and descending pathways (tracts of axons within the CNS) cross over; as a result, each cerebral hemisphere is responsible for sensation and voluntary movement on the opposite side of the body.
Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Terminal hairs consist of a central portion, the medulla, which is poorly developed in humans. Surrounding the medulla is the cortex. This is the main constituent of the shaft. Cells in this layer are keratinized and carry the pigment of the hair. The outermost layer is the cuticle, which is also keratinized.217,219
Hair Types and Subtypes in the Laboratory Mouse
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
John P. Sundberg, Margaret E. Hogan
The medulla, when present, consists of cells containing structural proteins, vacuoles, and medullary granules. These cells are believed to desiccate as they rise above the epidermis, with the replacement of the vacuoles with air spaces, forming the characteristic septa seen with the light microscope. The septa have been used as a tool to classify medullary types. Five types have been recognized: (1) absent, (2) discontinuous (separate air cells), (3) intermediate (regular groupings of air cells), (4) continuous, and (5) fragmented (irregular groupings of air cells).1 Presence of the medulla appears to be dependent on the diameter of the hair shaft. Fine hairs (auchene, zigzag) may have a limited medulla, and course hair, such as guard hairs, will demonstrate an extensive medullary region. The medullary dependence on shaft thickness can be seen within a single hair as well. The apical and basal ends of a hair may have an absent medulla, and the wider, central portions may have a medullary region four cells thick.
Pro-nociceptive pain modulation profile in patients with acute and chronic shoulder pain: a hypothesis-generating topical review
Published in Physical Therapy Reviews, 2021
Rani Othman, Nicola Swain, Steve Tumilty, Prasath Jayakaran, Ramakrishnan Mani
Descending control mechanisms that influence the neuronal activity of the dorsal horn arises from several supra-spinal sites [61]. In particular, periaqueductal grey matter and nuclei of the rostral ventral medulla are the key midbrain structures that are interconnected with the higher brain centres and limbic areas, and they receive direct inputs from the spinomesencephalic tract [52, 59, 61, 62]. The periaqueductal grey matter project to rostral ventral medulla, which projects onto the dorsal horn of the spinal cord [61]. The descending facilitatory or inhibitory control mechanisms of the periaqueductal grey matter and rostral ventral medulla are mainly coordinated by the activities of the higher brain centres [52, 62]. One aspect of descending control is associated with diffuse noxious inhibitory controls [59, 61]. Diffuse noxious inhibitory controls is a phenomenon that refers to a reduction in the nociceptive inputs produced by supra-spinally generated inhibition of wide dynamic range neurons and nociceptive-specific neurons in the dorsal horn of the spinal cord [63–65]. On the contrary, it is also evident that periaqueductal grey matter and rostral ventral medulla projections can facilitate nociceptive inputs at the dorsal horn of the spinal cord [52, 61]. Evidence suggests that descending facilitation of spinal nociception is a major contributor to the development of central sensitization, a key contributing mechanism linked to the chronic pain experience [52, 61].
Fumarate exerted an antihypertensive effect and reduced kidney injury molecule (KIM)-1 expression in deoxycorticosterone acetate-salt hypertension
Published in Clinical and Experimental Hypertension, 2021
Osaze Edosuyi, Myung Choi, Ighodaro Igbe, Adebayo Oyekan
The reduction in blood pressure observed in this study had a mechanistic link to L-arginine metabolism. L-arginine metabolism as represented by arginase and NOS activities were also impacted by fumarate especially in the medulla of DOCA-salt hypertensive rats. The contradictory increase in arginase activity in the cortex of DOCA-rats may be ‘compensatory’ especially as arginase has a vital role of promoting cell growth and collagen production and thus enhance tissue repair (27) and this could ameliorate DOCA-salt hypertensive renal injury. However, there was a consistent reduction in arginase activity in the medulla of the DOCA-salt rats. This reduction in arginase activity increased L-arginine availability in the medulla of fumarate-treated DOCA-salt rats which translated to increase in NO production. This ability of fumarate to improve the perfusion of the cortex and medulla was highlighted by the significant increase in NO production in DOCA-salt hypertensive rats treated with fumarate. Although there was a significant increase in NO levels in both regions of the kidney, the significant effect in the medulla appears to underline the reduction in blood pressure observed in fumarate-treated rats. This effect becomes more pertinent when the role of the medulla in the regulation of blood pressure via the control of the pressure-natriuresis state is considered. Thus, in hypertension, TCA cycle products improve the function of the renal medulla.
Adam Politzer (1835-1920) and the cochlear nucleus
Published in Journal of the History of the Neurosciences, 2021
Albert Mudry, John Riddington Young
A generation later, in 1893, nucleus was defined more recognizably as a group of cells forming central termination of a nerve or bundle of nerve-fibers. The same year, in his Illustrated Encyclopæaedic Medical Dictionary, Foster was far more descriptive, informing us that a nucleus was, any one of the separate masses of gray matter in the medulla oblongata, the floor of the fourth ventricle, and the aqueduct of Sylvius that represent the gray cornua of the spinal cord in its intracranial portion. As applied to the central nervous system, a more or less clearly defined mass of cinerea, or gray or ganglionic matter. Instead of n(ucleus), the terms nidus, nidulus, nest corpus, locus, ganglion, and centre are sometimes used; and unless otherwise stated, these are usually symmetrical or paired, appearing on the two sides. Formerly, any circumscribed mass or bundle of medullary substance or alba, when seen in sections, was called a white or medullary n(ucleus). (Foster 1893, 2425)