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Clinical Neuroanatomy
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The receptor cells are derived from ectoderm and are unique in being replaced from stem cells every 30–50 days. They also enter the central nervous system (CNS) as very thin (0.1–0.4 ¼m), non-myelinated axons without synapse. These axons become grouped and ensheathed by Schwann cells forming some 20 fasciculi which are invested by pia and arachnoid mater, and pass through the orifices of the cribriform plate to enter the olfactory bulbs lying each side of the crista galli in the floor of the anterior cranial fossa. These axons synapse with dendrites of the large mitral cells of the olfactory glomeruli and each glomerulus receives axons from a wide area of the epithelium. There seems to be no functional grouping of axons. This arrangement allows a relatively small number of receptor cells to distinguish a large number of different odours. The axons of the mitral cells form the bulk of the olfactory tract but centrifugal axons of uncertain origin also pass to the olfactory bulb and undoubtedly modify activity in the olfactory glomeruli, perhaps having both inhibitory and facilitatory actions. The olfactory tracts pass posteriorly and slightly laterally crossing the floor of the anterior cranial fossa, the optic nerves and immediately above the optic chiasm. Just in front of the anterior perforated substance, each divides into medial, intermediate and lateral olfactory striae.
Anatomy for neurotrauma
Published in Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor, Essentials of Anesthesia for Neurotrauma, 2018
Vasudha Singhal, Sarabpreet Singh
The basal vein (of Rosenthal) is formed by the union of the anterior and deep middle cerebral veins, beneath the anterior perforated substance. It also receives tributaries from the interpeduncular fossa, inferior horn of the lateral ventricle, parahippocampal gyrus, and midbrain.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Crosby, Humphrey, and Lauer’s somewhat atypical inclusions—the medial part of the anterior perforated substance in the “medial olfactory area” and the lateral part of the anterior perforated substance in the “lateral olfactory area” (see above for citations)—may result from their not describing an “intermediate olfactory area.” Barr and Kiernan (1983, p. 261) and Afifi and Bergman (1986, p. 309), on the other hand, do describe an intermediate olfactory area, which they consider equivalent to gray matter in the anterior perforated substance. Romero-Sierra (1986) also describes “remnants” of an “intermediate olfactory stria” in man, which penetrate the anterior perforated substance (p. 132); but he does not mention an “intermediate olfactory area” (p. 131–132, 317–321).
Investigational drugs for the treatment of olfactory dysfunction
Published in Expert Opinion on Investigational Drugs, 2022
Arianna Di Stadio, Cinzia Severini, Andrea Colizza, Marco De Vincentiis, Ignazio La Mantia
The neuroepithelium is connected through the axons of the ORN to the olfactory bulb, which contains glomerulus, mitral cells and tufted relay neurons. The axons converge in the glomerulus to form the first cranial nerve (olfactory nerve). The glomerulus is connected by synapses to the mitral cells; the latter together with the tufted relay neurons forms the olfactory tract. This structure bifurcates in the medial and lateral olfactory stria (y inverted-shaped). The olfactory stimulus is conducted through these structures up to the piriform cortex, the periamygdaloid cortex, the olfactory tuberculosis and the anterior olfactory nucleus. The primary olfactory cortex is formed by the medial and lateral olfactory stria and the anterior perforated substance. The lateral olfactory stria is extended posteriorly giving origin to the entorhinal area which, together with the uncus, forms the secondary olfactory cortex, also known as the orbitofrontal cortex (Figure 2). This area is straightly related to memory. The primary cortex is responsible for the active perception of the sense of smell, while the secondary one is the portion where the smell perception is integrated with emotions and memory.