Arachnoid Membrane: From 1 Different Sources
One of the membranes covering the brain and spinal cord (see BRAIN). Arachnoiditis is the name applied to in?ammation of this membrane.
The general name given to the membrane which lines many of the hollow organs of the body. These membranes vary widely in structure in di?erent sites, but all have the common character of being lubricated by MUCUS – derived in some cases from isolated cells on the surface of the membrane, but more generally from de?nite glands placed beneath the membrane, and opening here and there through it by ducts. The air passages, the gastrointestinal tract and the ducts of glands which open into it, and also the urinary passages, are all lined by mucous membrane.... mucous membrane
The ear-drum, which separates the external and middle ear. (See EAR.)... tympanic membrane
See TEETH.... periodontal membrane
Membranes that line many internal organs and cavities, secreting a thin, lymph-like fluid, that lubricates and slowly circulates.... serous membranes
This forms the lining of the soft parts that enclose the cavity of a joint. (See JOINTS.)... synovial membrane
A layer of tissue that covers or lines a body surface or forms a barrier.... membrane
See BRAIN; CROUP; DIPHTHERIA; labour (under PREGNANCY AND LABOUR).... membranes
The mucus-secreting skin that lines (and protects against the environment) all openings, cavities or entrances into the body, such as the intestinal tract, lungs, urinary tract, sinuses, vagina, etc.... mucous membranes (mucosa)
The membrane that lines and isolates abcesses.... pyogenic membrane
The middle of the 3 layers of membrane (meninges) that cover the brain.... arachnoid mater
See amniotomy.... artificial rupture of membrane
(arachnoid mater) n. the middle of the three membranes covering the brain and spinal cord (see meninges), which has a fine, almost cobweb-like, texture. Between it and the pia mater within lies the subarachnoid space, containing cerebrospinal fluid and large blood vessels; the membrane itself has no blood supply.... arachnoid
one of the thin-walled projections outwards of the arachnoid membrane into the blood-filled sinuses of the dura, acting as a one-way valve for the flow of cerebrospinal fluid from the subarachnoid space into the bloodstream. Large villi, known as arachnoid granulations (or Pacchionian bodies), are found in the region of the superior sagittal sinus. They may be so distended as to cause pitting of the adjacent bone.... arachnoid villus
(ARM) see amniotomy.... artificial rupture of membranes
the thin delicate membrane that lies at the base of an *epithelium. It is composed of mucopolysaccharide and fibres of protein.... basement membrane
a membrane in the *cochlea of the ear that separates two of the three channels (scalae) that run the length of the spiral cochlea. The organ of Corti is situated on the basilar membrane, inside the scala media.... basilar membrane
the transparent innermost layer of the *choroid, which is in contact with the retinal pigment epithelium (see retina). [K. W. L. Bruch (1819–84), German anatomist]... bruch’s membrane
the fibrous tissue in the anterior aspect of the neck between the lower border of the *thyroid cartilage (the ‘Adam’s apple’) and the upper border of the *cricoid cartilage, lying immediately below it. It is the site where certain emergency airway devices can be inserted.... cricothyroid membrane
the membrane that forms the deepest layer of the *stroma of the cornea of the eye. The endothelium lies between it and the aqueous humour. [J. Descemet (1732–1810), French anatomist]... descemet’s membrane
(cellophane maculopathy) a transparent membrane that forms on the retina, over the *macula. Contraction of this causes wrinkling of the retina (macular pucker) and hence distorted vision.... epiretinal membrane
(ECMO) a technique that is accepted as a rescue treatment for otherwise fatal respiratory failure in newborn babies or infants due to prematurity or overwhelming septicaemia (e.g. meningitis). It involves modified prolonged *cardiopulmonary bypass to support gas exchange, which allows the lungs to rest and recover. ECMO is only available in selected high-technology centres.... extracorporeal membrane oxygenation
the membranous structures that surround the embryo and contribute to the placenta and umbilical cord. They include the *amnion, *chorion, *allantois, and *yolk sac. In humans the allantois is always very small and by the end of pregnancy the amnion and chorion have fused into a single membrane and the yolk sac has disappeared.... extraembryonic membranes
the transparent membrane that surrounds the *vitreous humour of the eye, separating it from the retina.... hyaloid membrane
a bone that develops in connective tissue by direct *ossification, without cartilage being formed first. The bones of the face and skull are membrane bones.... membrane bone
see PROM; PPROM; labour.... premature rupture of membranes
the membrane that separates the scala vestibuli and the scala media of the *cochlea of the ear. [E. Reissner (1824–78), German anatomist]... reissner’s membrane
a membrane that allows the passage of some molecules but not others. Cell membranes (see cell) are semipermeable. Semipermeable membranes are used clinically in *haemodialysis for patients with kidney failure.... semipermeable membrane
(serosa) a smooth transparent membrane, consisting of *mesothelium and underlying elastic fibrous connective tissue, lining certain large cavities of the body. The *peritoneum of the abdomen, *pleura of the chest, and *pericardium of the heart are all serous membranes. Each consists of two portions: the parietal portion lines the walls of the cavity, and the visceral portion covers the organs concerned. The two are continuous, forming a closed sac with the organs essentially outside the sac. The inner surface of the sac is moistened by a thin fluid derived from blood serum, which allows frictionless movement of organs within their cavities. Compare mucous membrane.... serous membrane
an inherited disease of the kidneys in which the glomerular basement membrane, which filters waste material from the blood, is too thin, allowing small amounts of blood to pass across it. This can be a cause of benign familial haematuria and thin membrane disease is a common finding in renal biopsy series where the procedure has been carried out as part of the investigation of *haematuria. Thin membranes are also found in other conditions, e.g. in some cases of *Alport’s syndrome and *Berger’s nephropathy.... thin membrane disease
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