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Medial Olfactory Stria
The olfactory tract (olfactory peduncle or olfactory stalk) is a bilateral bundle of afferent nerve fibers from the mitral and tufted cells of the olfactory bulb that connects to several target regions in the brain, including the piriform cortex, amygdala, and entorhinal cortex. It is a narrow white band, triangular on coronal section, the apex being directed upward. The term olfactory tract is a misnomer, as the olfactory peduncle is actually made up of the juxtaposition of two tracts, the medial olfactory tract (giving the medial and intermediate olfactory stria) and the lateral olfactory tract (giving the lateral and intermediate olfactory stria). However, the existence of the medial olfactory tract (and consequently the medial stria) is controversial in primates (including humans). Structure The olfactory peduncle and olfactory bulb lie in the olfactory sulcus a sulcus formed by the medial orbital gyrus on the inferior surface of each frontal lobe. The olfactory peduncl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory System
The olfactory system, is the sensory nervous system, sensory system used for the sense of smell (olfaction). Olfaction is one of the special senses directly associated with specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system. The main olfactory system detects airborne substances, while the accessory system senses fluid-phase stimuli. The senses of smell and taste (gustatory system) are often referred to together as the chemosensory system, because they both give the brain information about the chemical composition of objects through a process called transduction (physiology), transduction. Structure Peripheral The peripheral olfactory system consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium (layers of thin tissue covered in mucus that line the nasal cavity). The primary components of the layers of epithelial tissue are the mucous membranes, olfactory glands, olfactory receptor neurons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prepyriform Area
Prepyriform area (or prepiriform cortex) is a portion of the rhinencephalon consisting of paleocortex. Some sources state that it is part of the primary olfactory cortex. Prepyriform Cortex along with Pyriform cortex And Cortical portion of amygdaloid nuclei constitute lateral olfactory area which send signal to almost all portion of limbic system The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ... such as hippocampus, which seem to be most important area for learning to like and dislike foods depending upon one's experience with them. References Cerebral cortex Olfactory system {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development (a ''de novo'' mutation), or it can be inherited from two parents who are carriers of a faulty gene ( autosomal recessive inheritance) or from a parent with the disorder (autosomal dominant inheritance). When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA (due to their size). There are well over 6,000 known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kallmann Syndrome
Kallmann syndrome (KS) is a hereditary, genetic disorder that prevents a person from starting or fully completing puberty. Kallmann syndrome is a form of a group of conditions termed hypogonadotropic hypogonadism. To distinguish it from other forms of hypogonadotropic hypogonadism, Kallmann syndrome has the additional symptom of a anosmia, total lack of sense of smell (anosmia) or a hyposmia, reduced sense of smell. If left untreated, people will have poorly defined secondary sexual characteristics, show signs of hypogonadism, almost invariably are infertile and are at increased risk of developing osteoporosis. A range of other physical symptoms affecting the face, hands and skeletal system can also occur. Cause & Diagnosis The underlying cause is due to the defective migration of gonadotropin-releasing hormone expressing neurons (GnRH neuron, GNRH neurons) from olfactory placode to hypothalamus, leading to congenital Gonadotropin-releasing hormone, GNRH deficiency. This leads ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyposmia
Hyposmia, or microsmia, is a reduced ability to smell and to detect odors. A related condition is anosmia, in which no odors can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma. In 2012 an estimated 9.8 million people aged 40 and older in the United States had hyposmia and an additional 3.4 million had anosmia/severe hyposmia. Hyposmia might be a very early sign of Parkinson's disease.Factor, Stewart A., & Weiner, William J., eds. (2008). ''Parkinson's Disease: Diagnosis and Clinical Management'', 2nd ed., pp. 72-73. New York: Demos Medical Publishing. Hyposmia is also an early and almost universal finding in Alzheimer's disease and dementia with Lewy bodies. Lifelong hyposmia could be caused by or comorbid with Kallmann syndrome or autism. Along with other chemosensory disturbances, hyposmia can be a key indicator of COVID-19. Epidemiology The National Health and Nutrition Examination Survey ( NHANES) collect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anosmia
Anosmia, also known as smell blindness, is the lack of ability to detect one or more smells. Anosmia may be temporary or permanent. It differs from hyposmia, which is a decreased sensitivity to some or all smells. Anosmia can be categorized into acquired anosmia and congenital anosmia. Acquired anosmia develops later in life due to various causes, such as upper respiratory infections, head trauma, or neurodegenerative diseases. In contrast, congenital anosmia is present from birth and is typically caused by genetic factors or developmental abnormalities of the olfactory system. While acquired anosmia may have potential treatments depending on the underlying cause, such as medications or surgery, congenital anosmia currently has no known cure, and management focuses on safety precautions and coping strategies. Anosmia can be due to a number of factors, including inflammation of the nasal mucosa, blockage of nasal passages, or destruction of temporal lobular tissue. Anosmia s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parahippocampal Gyrus
The parahippocampal gyrus (or hippocampal gyrus') is a grey matter cortical region, a gyrus of the brain that surrounds the hippocampus and is part of the limbic system. The region plays an important role in memory encoding and retrieval. It has been involved in some cases of hippocampal sclerosis. Asymmetry has been observed in schizophrenia. Structure The anterior part of the gyrus includes the perirhinal and entorhinal cortices. The term parahippocampal cortex is used to refer to an area that encompasses both the posterior parahippocampal gyrus and the medial portion of the fusiform gyrus. Function Scene recognition The parahippocampal place area (PPA) is a sub-region of the parahippocampal cortex that lies medially in the inferior temporo-occipital cortex. PPA plays an important role in the encoding and recognition of environmental scenes (rather than faces). fMRI studies indicate that this region of the brain becomes highly active when human subjects view topograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncus
The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a sulcus called the rhinal sulcus. Although superficially continuous with the hippocampal gyrus, the uncus forms morphologically a part of the rhinencephalon. An important landmark that crosses the inferior surface of the uncus is the band of Giacomini or ''tail'' of the dentate gyrus. The term comes from the Latin word uncus, meaning ''hook'', and it was coined by Félix Vicq-d'Azyr (1748–1794). Clinical significance The part of the olfactory cortex that is on the temporal lobe covers the area of the uncus, which leads into the two significant clinical aspects: herniations and seizures * Herniations of the brain can occur if increased intracranial pressure due to a tumor, hemorrhage, or edema pushes the uncus over the tentorial notch against the brainstem and related cranial nerves. This can compress the oculomotor nerve (CN III). This causes pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tenia Tecta
This page is a glossary of architecture. A B C The Caryatid Porch of the Athens.html" ;"title="Erechtheion, Athens">Erechtheion, Athens, 421–407 BC D E In historical gardening, an ''estrade'' plant was pruned and trained with the main stem bare in sections, to achieve an appearance often likened to a "wedding cake". Met Museum blog, 2009 F ...
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Subcallosal Gyrus
The subcallosal gyrus (paraterminal gyrus, peduncle of the corpus callosum) is a narrow lamina on the medial surface of the hemisphere in front of the lamina terminalis, behind the parolfactory area, and below the rostrum of the corpus callosum. It is continuous around the genu of the corpus callosum with the indusium griseum. It is also considered a part of limbic system The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ... of the brain. References External links * Limbic system Gyri {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parolfactory Area
The subcallosal area (parolfactory area of Broca) is a small triangular field on the medial surface of the hemisphere in front of the subcallosal gyrus, from which it is separated by the posterior parolfactory sulcus; it is continuous below with the olfactory trigone, and above and in front with the cingulate gyrus; it is limited anteriorly by the anterior parolfactory sulcus. The subcallosal area is also known as "Zuckerkandl's gyrus", for Emil Zuckerkandl. The parahippocampal gyrus, subcallosal area, and cingulate gyrus have been described together as the periarcheocortex. The "subcallosal area" and "parolfactory area" are considered equivalent in BrainInfo, but in Terminologia Anatomica ''Terminologia Anatomica'' (commonly abbreviated TA) is the international standard for human anatomy, human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology (FIPAT) a program of the Inter ... they are considered distinct structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Perforated Substance
The anterior perforated substance is a part of the brain. It is bilateral. It is irregular and quadrilateral. It lies in front of the optic tract and behind the olfactory trigone. Structure The anterior perforated substance is bilateral. It lies in front of the optic tract. It lies behind the olfactory trigone, separated by the fissure prima. Medially and in front, it is continuous with the subcallosal gyrus. Laterally, it is bounded by the lateral stria of the olfactory tract, and is continued into the uncus. Its gray substance is confluent above with that of the corpus striatum, and is perforated anteriorly by numerous small blood vessels that supply such areas as the internal capsule. The anterior cerebral artery arises just below the anterior perforated substance. The middle cerebral artery passes through its lateral two thirds. Blood supply The anterior perforated substance is supplied by lenticulostriate arteries, which branch from the middle cerebral arte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
