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Cerebral Aqueduct
The cerebral aqueduct (aqueduct of the midbrain, aqueduct of Sylvius, Sylvian aqueduct, mesencephalic duct) is a small, narrow tube connecting the third and fourth ventricles of the brain. The cerebral aqueduct is a midline structure that passes through the midbrain. It extends rostrocaudally through the entirety of the more posterior part of the midbrain. It is surrounded by the periaqueductal gray (central gray), a layer of gray matter. Congenital stenosis of the cerebral aqueduct is a cause of congenital hydrocephalus. It is named for Franciscus Sylvius. Anatomy The cerebral aqueduct is roughly circular in transverse section, and measures 1-2 mm in diameter. It is 15 mm long and is commonly subdivided into a pars anterior antrum, and pars posterior. Relations Rostrally, it is continuous with the third ventricle, commencing just inferior to the posterior commissure. Caudally, it is continuous with the fourth ventricle at the junction of the mesencephalon and pons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Colliculus
In neuroanatomy, the superior colliculus () is a structure lying on the tectum, roof of the mammalian midbrain. In non-mammalian vertebrates, the Homology (biology), homologous structure is known as the optic tectum or optic lobe. The adjective form ''tectum, tectal'' is commonly used for both structures. In mammals, the superior colliculus forms a major component of the midbrain. It is a paired structure and together with the paired inferior colliculi forms the corpora quadrigemina. The superior colliculus is a layered structure, with a pattern that is similar in all mammals. The layers can be grouped into the superficial layers (retinal nerve fiber layer, stratum opticum and above) and the deeper remaining layers. Neurons in the superficial layers receive direct input from the retina and respond almost exclusively to visual stimuli. Many neurons in the deeper layers also respond to other modalities, and some respond to stimuli in multiple modalities. The deeper layers also conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Colliculus
The inferior colliculus (IC) (Latin for ''lower hill'') is the principal midbrain nucleus of the Auditory system, auditory pathway and receives input from several peripheral brainstem nuclei in the auditory pathway, as well as inputs from the auditory cortex.Shore, S. E.: ''Auditory/Somatosensory Interactions''. In: Squire (Ed.): ''Encyclopedia of Neuroscience'', Academic Press, 2009, pp. 691–695 The inferior colliculus has three subdivisions: the central nucleus, a dorsal cortex by which it is surrounded, and an external cortex which is located laterally. Its bimodal neurons are implicated in auditory-Somatosensory system, somatosensory interaction, receiving projections from Somatosensory system, somatosensory nuclei. This multisensory integration may underlie a filtering of self-effected sounds from vocalization, chewing, or respiration activities. The inferior colliculi together with the superior colliculi form the eminences of the corpora quadrigemina, and also part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-brain
The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, motor control, sleep and wakefulness, arousal ( alertness), and temperature regulation.Breedlove, Watson, & Rosenzweig. Biological Psychology, 6th Edition, 2010, pp. 45-46 The name ''mesencephalon'' comes from the Greek ''mesos'', "middle", and ''enkephalos'', "brain". Structure The midbrain is the shortest segment of the brainstem, measuring less than 2cm in length. It is situated mostly in the posterior cranial fossa, with its superior part extending above the tentorial notch. The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while caudally it adjoins the hindbrain (pon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliosis
Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes. In its most extreme form, the proliferation associated with gliosis leads to the formation of a glial scar. The process of gliosis involves a series of cellular and molecular events that occur over several days. Typically, the first response to injury is the migration of macrophages and local microglia to the injury site. This process, which constitutes a form of gliosis known as microgliosis, begins within hours of the initial CNS injury. Later, after 3–5 days, oligodendrocyte precursor cells are also recruited to the site and may contribute to remyelination. The final component of gliosis is astrogliosis, the proliferation of surrounding astrocytes, which are the main constituents of the glial sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinealoblastoma
Pineoblastoma is a malignant tumor of the pineal gland. A pineoblastoma is a supratentorial midline primitive neuroectodermal tumor. Pineoblastoma can present at any age, but is most common in young children. They account for 0.001% of all primary CNS neoplasms. Epidemiology Pineoblastomas typically occur at very young ages. One study found the average age of presentation to be 4.3 years, with peaks at age 3 and 8. Another cites cases to more commonly occur in patients under 2 years of age. Rates of occurrence for males and females are similar, but may be slightly more common in females. One study found incidence of pineoblastoma to be increased in black patients compared to white patients by around 71%. This difference was most apparent in patients aged 5 to 9 years old. Pathophysiology The pineal gland is a small organ in the center of the brain that is responsible for controlling melatonin secretion. Several tumors can occur in the area of the pineal gland, with the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, which may be called a tumour or tumor.'' ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology. Prior to the abnormal growth of tissue, such as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia and can occur in other conditions as well. The word neoplasm is from Ancient Greek 'new' and 'formation, creation'. Types A neopla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital
A birth defect is an abnormal condition that is present at childbirth, birth, regardless of its cause. Birth defects may result in disability, disabilities that may be physical disability, physical, intellectual disability, intellectual, or developmental disability, developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic disorder, metabolic and degenerative disease, degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic disorder, genetic or chromosome abnormality, chromosomal disorders, exposure to certain medications or chemicals, or certain vertically transmitted infection, infections during pregnancy. Risk factors include folate deficiency, alcohol drink, d ... [...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] |
Aqueductal Stenosis
Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus. The aqueduct of Sylvius is the channel which connects the third ventricle to the fourth ventricle and is the narrowest part of the CSF pathway with a mean cross-sectional area of 0.5 mm2 in children and 0.8 mm2 in adults. Because of its small size, the aqueduct is the most likely place for a blockage of CSF in the ventricular system. This blockage causes ventricle volume to increase because the CSF cannot flow out of the ventricles and cannot be effectively absorbed by the surrounding tissue of the ventricles. Increased volume of the ventricles will result in higher pressure within the ventricles, and cause higher pressure in the cerebral cortex, cortex from it being pushed into the skull. A person may hav ... [...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] |
Canal (anatomy)
{{notability, date=April 2024 In anatomy, a canal (or ''canalis'' in Latin) is a tubular passage or channel which connects different regions of the body. Examples Cranial region * Alveolar canals * Carotid canal * Facial canal * Greater palatine canal * Incisive canals * Infraorbital canal * Mandibular canal * Optic canal * Palatovaginal canal * Pterygoid canal Abdominal region * Inguinal canal Pelvic region * Anal canal * Cervical canal * Pudendal canal Upper extremities * Suprascapular canal * Carpal canal * Ulnar canal * Radial canal Lower extremities * Adductor canal * Femoral canal * Obturator canal See also * Foramen In anatomy and osteology, a foramen (; : foramina, or foramens ; ) is an opening or enclosed gap within the dense connective tissue (bones and deep fasciae) of extant and extinct amniote animals, typically to allow passage of nerves, artery, ... References *''Dorland's Illustrated Medical Dictionary'', 27th ed. 1988 W.B. Saunders Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
