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Area Postrema
The area postrema, a paired structure in the medulla oblongata of the brainstem, is a circumventricular organ having permeable capillaries and sensory neurons that enable its role to detect circulating chemical messengers in the blood and transduce them into neural signals and networks. Its position adjacent to the bilateral nuclei of the solitary tract and role as a sensory transducer allow it to integrate blood-to-brain autonomic functions. Such roles of the area postrema include its detection of circulating hormones involved in vomiting, thirst, hunger, and blood pressure control. Structure The area postrema is a paired protuberance found at the inferoposterior limit of the fourth ventricle. Specialized ependymal cells are found within the area postrema. These cells differ slightly from the majority of ependymal cells (ependymocytes), forming a unicellular epithelial lining of the ventricles and central canal. The area postrema is separated from the vagal trigone by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medulla Oblongata
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. 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. The medulla contains the cardiovascular center, the respiratory center, vomiting and vasomotor centers, responsible for the autonomic functions of breathing, heart rate and blood pressure as well as the sleep–wake cycle. "Medulla" is from Latin, ‘pith or marrow’. And "oblongata" is from Latin, ‘lengthened or longish or elongated'. During embryonic development, the medulla oblongata develops from the myelencephalon. The myelencephalon is a secondary brain vesicle which forms during the maturation of the rhombencephalon, also referred to as the hindbrain. The bulb is an archaic term for the medulla oblongata. In modern clinical usage, the word bulbar (as in bulbar palsy) is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ependymal Cells
The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous system (CNS). It is involved in the production of cerebrospinal fluid (CSF), and is shown to serve as a reservoir for neuroregeneration. Structure The ependyma is made up of ependymal cells called ependymocytes, a type of glial cell. These cells line the ventricles in the brain and the central canal of the spinal cord, which become filled with cerebrospinal fluid. These are nervous tissue cells with simple columnar shape, much like that of some mucosal epithelial cells. Early monociliated ependymal cells are differentiated to multiciliated ependymal cells for their function in circulating cerebrospinal fluid. The basal membranes of these cells are characterized by tentacle-like extensions that attach to astrocytes. The apical side is cov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Terminolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (anatomy)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedrich Bur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventricular System
In neuroanatomy, the ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is continuous with the central canal of the spinal cord from the fourth ventricle, allowing for the flow of CSF to circulate. All of the ventricular system and the central canal of the spinal cord are lined with ependyma, a specialised form of epithelium connected by tight junctions that make up the blood–cerebrospinal fluid barrier. Structure The system comprises four ventricles: * lateral ventricles right and left (one for each hemisphere) * third ventricle * fourth ventricle There are several foramina, openings acting as channels, that connect the ventricles. The interventricular foramina (also called the foramina of Monro) connect the lateral ventricles to the third ventricle through which the cerebrospinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebrospinal Fluid
Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ventricles of the brain. CSF is mostly produced by specialized Ependyma, ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations. It is also produced by ependymal cells in the lining of the ventricles. In humans, there is about 125 mL of CSF at any one time, and about 500 mL is generated every day. CSF acts as a shock absorber, cushion or buffer, providing basic mechanical and immune system, immunological protection to the brain inside the Human skull, skull. CSF also serves a vital function in the cerebral autoregulation of cerebral blood flow. CSF occupies the subarachnoid space (between the arachnoid mater and the pia mater) and the ventricular system around and inside t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurochemical
A neurochemical is a small organic molecule or peptide that participates in neural activity. The science of neurochemistry studies the functions of neurochemicals. Prominent neurochemicals Neurotransmitters and neuromodulators *Glutamate is the most common neurotransmitter. Most neurons secrete with glutamate or GABA. Glutamate is excitatory, meaning that the release of glutamate by one cell usually causes adjacent cells to fire an action potential. (Note: Glutamate is chemically identical to the MSG commonly used to flavor food.) *GABA is an example of an inhibitory neurotransmitter. * Monoamine neurotransmitters: **Dopamine is a monoamine neurotransmitter. It plays a key role in the functioning of the limbic system, which is involved in emotional function and control. It also is involved in cognitive processes associated with movement, arousal, executive function, body temperature regulation, and pleasure and reward, and other processes. **Norepinephrine, also known as norad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanycytes
Tanycytes are highly specialized ependymal cells found in the third ventricle of the brain, and on the floor of the fourth ventricle. Each tanycyte has a long basal process that extends deep into the hypothalamus. It is possible that their function is to transfer chemical signals from the cerebrospinal fluid to the central nervous system. The term ''tanycyte'' comes from the Greek word tanus which means elongated. Structure Tanycytes are highly specialized ependymal cells (also called ependymoglial cells) with long basal processes. Tanycytes in adult mammals are found in the ventricular system, and the median eminence, a circumventricular organ. They are most numerous in the third ventricle of the brain, are also found in the fourth ventricle, and can also be seen in the spinal cord radiating from the central canal (also known as the ependymal canal), to the spinal cord surface. The long processes extend through the layer of astrocytes to cross the median eminence and form end-fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ependyma
The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous system (CNS). It is involved in the production of cerebrospinal fluid (CSF), and is shown to serve as a reservoir for neuroregeneration. Structure The ependyma is made up of ependymal cells called ependymocytes, a type of glial cell. These cells line the ventricles in the brain and the central canal of the spinal cord, which become filled with cerebrospinal fluid. These are nervous tissue cells with simple columnar shape, much like that of some mucosal epithelial cells. Early monociliated ependymal cells are differentiated to multiciliated ependymal cells for their function in circulating cerebrospinal fluid. The basal membranes of these cells are characterized by tentacle-like extensions that attach to astrocytes. The apical side i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obex
The obex () is the point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord. Cerebrospinal fluid can flow from the fourth ventricle into the obex. In anatomical studies, the obex has been found to occur approximately 10–12 mm above the level of the foramen magnum. In patients with low tonsillar position, the obex has been found at or below the plane of the foramen magnum. The obex occurs in the caudal medulla. The decussation of sensory fibers happens at this point. Clinical significance Lesions at the location can result in obstructive hydrocephalus. The most common lesion at this location is a subependymoma, a benign tumor. Hemangioblastoma has been observed in this location. Detection of prions Immunohistochemistry (IHC) to test brain, lymph, and neuroendocrine tissues for the presence of the abnormal prion protein to diagnose wasting diseases like chronic wasting disease in deer A deer (: deer) or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhomboid Fossa
The rhomboid fossa is a rhombus-shaped depression that is the anterior part of the fourth ventricle. Its anterior wall, formed by the back of the pons and the medulla oblongata, constitutes the floor of the fourth ventricle. It is covered by a thin layer of grey matter continuous with that of the spinal cord; superficial to this is a thin lamina of neuroglia which constitutes the ependyma of the Ventricular system, ventricle and supports a layer of ciliated epithelium. Parts The fossa consists of three parts, superior, intermediate, and inferior: ;The superior part :The superior part is triangular in shape and limited laterally by the superior cerebellar peduncle; its apex, directed upward, is continuous with the cerebral aqueduct; its base is represented by an imaginary line at the level of the upper ends of the superior foveae. ;The intermediate part :The intermediate part extends from this level to that of the horizontal portions of the Taenia of fourth ventricle, taeniae of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Vagal Nucleus
The dorsal nucleus of vagus nerve (or posterior nucleus of vagus nerve or dorsal vagal nucleus or nucleus dorsalis nervi vagi or nucleus posterior nervi vagi) is a cranial nerve nucleus of the vagus nerve (CN X) situated in the medulla oblongata of the brainstem ventral to the floor of the fourth ventricle. It contains nerve cell bodies of parasympathetic neurons of CN X that provide parasympathetic innervation to the gastrointestinal tract and lungs as well as other thoracic and abdominal organs. These functions include, among others, bronchoconstriction and gland secretion. Cell bodies of pre-ganglionic parasympathetic neurons of CN X that innervate the heart meanwhile reside in the nucleus ambiguus, and additional cell bodies of the nucleus ambiguus give rise to the branchial efferent motor fibers of the vagus nerve (CN X) terminating in the laryngeal, and pharyngeal muscles, and musculus uvulae muscle. Additional images File:Gray694.png, Section of the medulla oblongata at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
