Bruch's membrane


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Related to Bruch's membrane: Drusen, choriocapillaris, Retinal pigment epithelium

membrane

 [mem´brān]
a thin layer of tissue that covers a surface, lines a cavity, or divides a space or organ. adj., adj mem´branous.
alveolar-capillary membrane (alveolocapillary membrane) a thin tissue barrier through which gases are exchanged between the alveolar air and the blood in the pulmonary capillaries. Called also blood-air barrier and blood-gas barrier.
alveolodental membrane periodontium.
arachnoid membrane arachnoid.
basement membrane a sheet of amorphous extracellular material upon which the basal surfaces of epithelial cells rest; it is also associated with muscle cells, Schwann cells, fat cells, and capillaries, interposed between the cellular elements and the underlying connective tissue. It comprises two layers, the basal lamina and the reticular lamina, and is composed of Type IV collagen (which is unique to basement membranes), laminin, fibronectin, and heparan sulfate proteoglycans.
basilar membrane the lower boundary of the scala media of the ear.
Bowman's membrane a thin layer of basement membrane between the outer layer of stratified epithelium and the substantia propria of the cornea.
Bruch's membrane the inner layer of the choroid, separating it from the pigmented layer of the retina.
cell membrane plasma membrane.
decidual m's (deciduous m's) decidua.
Descemet's membrane the posterior lining membrane of the cornea; it is a thin hyaline membrane between the substantia propria and the endothelial layer of the cornea.
diphtheritic membrane the peculiar false membrane characteristic of diphtheria, formed by coagulation necrosis.
drum membrane tympanic membrane.
epiretinal membrane a pathologic membrane partially covering the surface of the retina, probably originating chiefly from the retinal pigment epithelial and glial cells; membranes peripheral to the macula are generally asymptomatic, while those involving the macula or adjacent to it may cause reduction in vision, visual distortion, and diplopia.
extraembryonic m's those that protect the embryo or fetus and provide for its nutrition, respiration, and excretion; the yolk sac (umbilical vesicle), allantois, amnion, chorion, decidua, and placenta. Called also fetal membranes.
false membrane a membranous exudate, such as the diphtheritic membrane; called also neomembrane.
fenestrated membrane one of the perforated elastic sheets of the tunica intima and tunica media of arteries.
hemodialyzer membrane the semipermeable membrane that filters the blood in a hemodialyzer, commonly made of cuprophane, cellulose acetate, polyacrylonitrile, polymethyl methacrylate, or polysulfone.
Henle's membrane fenestrated membrane.
high efficiency membrane a hemodialyzer membrane that has clearance characteristics that increase progressively with increases in dialysis blood flow rates; this usually implies that the membrane is not a high flux membrane.
high flux membrane a hemodialyzer membrane that has a high permeability to fluids and solutes and thus a high rate of clearance of fluids and solutes composed of large molecules.
hyaline membrane
1. a membrane between the outer root sheath and inner fibrous layer of a hair follicle.
3. a homogeneous eosinophilic membrane lining alveolar ducts and alveoli, frequently found at autopsy of infants that were preterm. See also hyaline membrane disease.
hyoglossal membrane a fibrous lamina connecting the undersurface of the tongue with the hyoid bone.
impaired oral mucous membrane a nursing diagnosis approved by the North American Nursing Diagnosis Association, defined as disruptions of the lips and soft tissue of the oral cavity. Changes in the integrity and health of the oral mucous membrane can occur as a characteristic of such medical disorders as periodontal disease, uncontrolled diabetes mellitus, oral cancer, and infection with herpes. Chemical irritants such as alcohol and tobacco can also adversely affect the oral mucous membrane, as can mechanical trauma due to broken teeth, poorly fitting dentures, and endotracheal intubation. Other etiologic factors include dehydration, mouth breathing, poor oral hygiene, radiation to the head or neck, and antineoplastic agents.

Preventive measures that can help maintain the health and integrity of the oral mucosa will depend on the cause. Routinely brushing and flossing the teeth during the day and at bedtime can help avoid dental caries and periodontal disease. Some patients may need instruction in the proper procedure for cleaning the teeth and removing debris and plaque, or they may need assistance in devising ways to cope with physical disabilities that make good oral hygiene difficult for them. Patients who are unconscious or unable to perform self-care activities should have mouth care as often as needed to keep the mouth clean and moist and avoid aspiration of debris and infectious microorganisms. Adequate hydration and a lip lubricant can help avoid alterations in the oral mucosa and promote comfort.
limiting membrane one that constitutes the border of some tissue or structure.
mucous membrane the membrane covered with epithelium that lines the tubular organs of the body.
Nasmyth's membrane primary cuticle.
nuclear membrane
1. either of the membranes, inner and outer, comprising the nuclear envelope.
olfactory membrane the olfactory portion of the mucous membrane lining the nasal fossa.
placental membrane the membrane that separates the fetal from the maternal blood in the placenta.
plasma membrane the membrane that encloses a cell; it is composed of phospholipids, glycolipids, cholesterol, and proteins. The primary structure is a lipid bilayer. Phospholipid molecules have an electrically charged “head” that attracts water and a hydrocarbon “tail” that repels water; they line up side by side in two opposing layers with their heads on the inner or outer surface of the membrane and their tails in the core, from which water is excluded. The other lipids affect the structural properties of the membrane. Proteins embedded in the membrane transport specific molecules across the membrane, act as hormone receptors, or perform other functions.
Reissner's membrane the thin anterior wall of the cochlear duct, separating it from the scala vestibuli.
membrane of round window secondary tympanic membrane.
Scarpa's membrane tympanic membrane, secondary.
semipermeable membrane one permitting passage through it of some but not all substances.
serous membrane the membrane lining the walls of the body cavities and enclosing the contained organs; it consists of mesothelium lying upon a connective tissue layer and it secretes a watery fluid.
synovial membrane the inner of the two layers of the articular capsule of a synovial joint; composed of loose connective tissue and having a free smooth surface that lines the joint cavity.
tympanic membrane see tympanic membrane.
tympanic membrane, secondary the membrane enclosing the round window; called also Scarpa's membrane.
unit membrane the trilaminar structure of all cellular membranes (such as the plasma membrane, nuclear membranes, mitochondrial membranes, endoplasmic reticulum, lysosomes) as they appear in electron micrographs. The biochemical structure is a lipid bilayer.
virginal membrane hymen.
vitelline membrane the external envelope of an ovum.
vitreous membrane
2. hyaline membrane (def. 1).
4. a delicate boundary layer investing the vitreous body.

Bruch's membrane

The innermost layer of the choroid. The retinal pigment epithelium transports metabolic waste from the photoreceptors across Bruch's membrane to the choroid. Bruch's membrane thickens with age slowing the transport of metabolites, which may lead to the formation of drusen in age-related macular degeneration; there is also a build-up of deposits (Basal Linear Deposits, or BLinD, and Basal Lamellar Deposits, or BLamD) on and within the membrane. This build-up seems to fragment the membrane; inflammatory and neovascular mediators can then invite choroidal vessels to grow into and beyond the fragmented membrane. This neovascular membrane destroys the architecture of the outer retina and leads to sudden loss of central vision (wet age-related macular degeneration).

Pseudoxanthoma elasticum, myopia and trauma can also cause defects in Bruch's membrane, which may lead to choroidal neovascularisation; Alport's Syndrome, a genetic disorder affecting the alpha (IV) collagen chains, can also lead to defects in the Bruch membrane, such as “dot and fleck” retinopathy.

Bruch's membrane layers
(1) Basement membrane of the retinal pigment epithelium.
(2) Inner collagenous zone.
(3) Central band of elastic fibres.
(4) Outer collagenous zone.
(5) Basement membrane of the choriocapillaris.

Bruch's membrane

An insulating membrane that separates the RETINA from the underlying CHOROID. In older people, Bruch's membrane is liable to develop splits or cracks through which blood vessels branching from the choroidal fine vessels may pass. This can lead to AGE-RELATED MACULAR DEGENERATION.

Bruch's membrane

A membrane in the eye between the choroid membrane and the retina.

Bruch's membrane

the complex basal lamina separating the choroid from the retinal pigment epithelium.
References in periodicals archive ?
Retinal pigment epithelium wound healing on human Bruch's membrane explants.
Type IV collagen and laminin in Bruch's membrane and basal linear deposit in the human macula.
Ultrastructural localization of extracellular matrix components in human retinal vessels and Bruch's membrane.
Angioid streaks are full thickness breaks in calcified and thickened Bruch's membrane.
As discussed in a previous article (OT November 25, 2011), wet AMD develops where Bruch's membrane is compromised (mostly by dry AMD) and is penetrated by blood vessels growing from the choroid to underlie the retina and macula.
The common factor with these conditions is compromise of Bruch's membrane and this is what allows new vessels to grow into a sub-retinal position.
Wet AMD starts with the growth of new, fragile vessels from the choroidal circulation, which penetrate through breaks in Bruch's membrane to proliferate beneath the RPE.
Age-related lipofuscin deposits in Bruch's membrane are called:
a decrease in the number of collagen cross-links in Bruch's membrane
The basal end of each RPE cell rests on a basement membrane that forms part of Bruch's membrane, and the apical end have multiple microvilli measuring 5-7[micro]m that project between the outer segments of the rods and cones.
If the RPE is not able to phagocytose the photoreceptor outer segments completely, then remnants of the outer segments accumulate on the inner collagenous layer of Bruch's membrane (68).
They result from the accumulation of insoluble, lipophilic material between Bruch's membrane and the RPE.