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Reissner's Fiber
Reissner's fiber ''(named after Ernst Reissner)'' is a fibrous aggregation of secreted molecules extending from the subcommissural organ (SCO) through the ventricular system and central canal to the terminal ventricle, a small ventricle-like structure near the end of the spinal cord. In vertebrates, Reissner's fiber is formed by secretions of SCO-spondin from the subcommissural organ into the ventricular cerebrospinal fluid. Reissner's fiber is highly conserved, and present in the central canal of all chordates A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five .... In cephalochordates, Reissner's fiber is produced by the ventral infundibular organ, as opposed to the dorsal SCO. Structure Reissner’s fiber (RF) is a complex and dynamic structure present in the third and fourth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Reissner
Ernst Reissner (; 24 September 1824 – 16 September 1878) was a Baltic provinces, Baltic German anatomist from Riga, Livonia. In 1851 he received his medical degree at the University of Dorpat (now known as the University of Tartu), and in 1855 became a professor of anatomy at Dorpat. In 1875, he retired from teaching for health reasons. Reissner is remembered for his anatomical studies of the ear, particularly research concerning the formation of the inner ear. By studying the embryos of birds and farm animals, he was able to determine individual stages involving the formation of the inner ears' labyrinth (inner ear), labyrinth. From this research he was therefore able to conceptualize formation of the labyrinth in humans. Today, his name is lent to Reissner's membrane, a Biological membrane, membrane inside the cochlea of the inner ear. Another anatomical structure that is named after him is Reissner's fiber, a long, fibrous aggregation of glycoproteins secreted by the subc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subcommissural Organ
The subcommissural organ (SCO) is one of the circumventricular organs of the brain. It is a small glandular structure that is located in the posterior region of the third ventricle, near the entrance of the cerebral aqueduct. The name of the SCO comes from its location beneath the posterior commissure, a bundle of nerve fibers interconnecting parts of the two hemispheres of the brain. The SCO is one of the first differentiated brain structures to develop. Although it is evolutionarily an ancient structure that is present throughout the chordate phylum, its arrangement varies somewhat among species. Functions of the SCO are unknown; some evidence indicates it may participate in clearance of certain compounds from the cerebrospinal fluid, and possibly in morphogenetic mechanisms, such as development of the posterior commissure. Structure Cells of the subcommissural organ, which are specialized in the secretion of glycoproteins (see below), are arranged into two layers: a super ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventricular System
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 fluid can flow. Ventric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Canal
The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it receives cerebrospinal fluid, and shares the same ependymal lining. The central canal helps to transport nutrients to the spinal cord as well as protect it by cushioning the impact of a force when the spine is affected. The central canal represents the adult remainder of the central cavity of the neural tube. It generally occludes (closes off) with age. Structure The central canal below at the ventricular system of the brain, beginning at a region called the obex where the fourth ventricle, a cavity present in the brainstem, narrows. The central canal is located in the third of the spinal cord in the cervical and thoracic regions. In the lumbar spine it enlarges and is located more centrally. At the conus medullaris, where the spinal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Ventricle
The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it receives cerebrospinal fluid, and shares the same ependymal lining. The central canal helps to transport nutrients to the spinal cord as well as protect it by cushioning the impact of a force when the spine is affected. The central canal represents the adult remainder of the central cavity of the neural tube. It generally occludes (closes off) with age. Structure The central canal below at the ventricular system of the brain, beginning at a region called the obex where the fourth ventricle, a cavity present in the brainstem, narrows. The central canal is located in the third of the spinal cord in the cervical and thoracic regions. In the lumbar spine it enlarges and is located more centrally. At the conus medullaris, where the spinal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and second lumbar vertebrae, where it ends. The enclosing bony vertebral column protects the relatively shorter spinal cord. It is around long in adult men and around long in adult women. The diameter of the spinal cord ranges from in the cervical and lumbar regions to in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCO-spondin
SCO-spondin is a protein that in humans is encoded by the ''SSPO'' gene. SCO-spondin is secreted by the subcommissural organ, and contributes to commissural axon growth and the formation of Reissner's fiber Reissner's fiber ''(named after Ernst Reissner)'' is a fibrous aggregation of secreted molecules extending from the subcommissural organ (SCO) through the ventricular system and central canal to the terminal ventricle, a small ventricle-like str ..., a fibrous aggregation of secreted molecules extending from the subcommissural organ to the end of the spinal cord. References Further reading * * * * * * * {{protein-stub Extracellular matrix proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebrospinal Fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the brain, and absorbed in the arachnoid granulations. 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 immunological protection to the brain inside the 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 the brain and spinal cord. It fills the ventricles of the brain, cisterns, and sulci, as well as the central canal of the spinal cord. There is also a connection from the subarachnoid space to the bony labyrinth of the inner ear via the perilymphat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordates
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit metameric segmentation. In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cephalochordates. These CSIs prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalochordates
A cephalochordate (from Greek: κεφαλή ''kephalé'', "head" and χορδή ''khordé'', "chord") is an animal in the chordate subphylum, Cephalochordata. They are commonly called lancelets. Cephalochordates possess 5 synapomorphies, or primary characteristics, that all chordates have at some point during their larval or adulthood stages. These 5 synapomorphies include a notochord, dorsal hollow nerve cord, endostyle, pharyngeal slits, and a post-anal tail (see chordate for descriptions of each). The fine structure of the cephalochordate notochord is best known for the Bahamas lancelet, ''Asymmetron lucayanum''. Cephalochordates are represented in modern oceans by the Amphioxiformes and are commonly found in warm temperate and tropical seas worldwide. With the presence of a notochord, adult amphioxus are able to swim and tolerate the tides of coastal environments, but they are most likely to be found within the sediment of these communities. Cephalochordates are segmented mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infundibular Organ
An infundibulum (Latin for ''funnel''; plural, ''infundibula'') is a funnel-shaped cavity or organ. Anatomy * Brain: the pituitary stalk, also known as the ''infundibulum'' and ''infundibular stalk'', is the connection between the hypothalamus and the posterior pituitary. * Hair follicle: the infundibulum is the cup or funnel in which a hair follicle grows. * Infundibulum (heart): The infundibulum of the heart, or conus arteriosus, is the outflow portion of the right ventricle. * Lung: The alveolar sacs of the lungs, from which the air chambers (alveoli) open, are also called ''infundibula''. * Sinus (anatomy): The ethmoidal infundibulum is the most important of three infundibula of the nose: the frontal infundibulum and the maxillary infundibulum flow into it. * Infundibulum of uterine tube: the funnel-like end of the mammal oviduct nearest to the ovary. * Gallbladder: The Infundibulum of the gallbladder (also known as the "neck" of the gallbladder) is the end of nearest to the cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
