Bruch's membrane

Layers and cell types of the mammalian retina, RPE: retinal pigment epithelium, OS: outer segments of the photoreceptor cells, IS: inner segments of the photoreceptor cells, ONL: outer nuclear layer, OPL: outer plexiform layer, INL: inner nuclear layer, IPL: inner plexiform layer, GC: ganglion cell layer . P: pigment epithelial cell, BM: Bruch's membrane, R: rods, C: cones, H: horizontal cell, Bi: bipolar cell, M: Müller cell, A: amacrine cell, G: ganglion cell, Ax: axons, arrow: Membrane limitans externa.
The direction of incidence of the light is from below to above

The Bruch's membrane is a border membrane between the choroid and the retinal pigment epithelium (RPE) of the eye and thus forms an extension of the blood-brain barrier. It is the "antagonist" of the ciliary muscle in the ciliary body during accommodation and mediates the transport of nutrients and fluids between the RPE and the vascular layer of the choroid ( choriocapillaris ).

Bruch's membrane separates the retinal pigment epithelium from the choriocapillaris and serves as the gateway through the blood-brain barrier

It was named after its discoverer Carl Bruch (1819-1884).

structure

The Bruch membrane is made up of five layers (from outside to inside):

• Basement membrane of the vessels of the choriocapillaris
• Outer collagen fiber layer
• Layer of elastic fibers
• Inner collagen fiber layer
• Basement membrane of the retinal pigment epithelial cells

Pathophysiology

The Bruch's membrane changes in the course of physiological aging. There is a change in the protein composition and a thickening of the membrane, which also leads to a change in permeability by a factor of 10. It is assumed that this is why deposits of "drusen" ( basal laminar deposits ) occur in the border area between the pigment epithelial layer and the Bruch's membrane, as accumulations of photoreceptor residues that have not been removed. These changes are likely to be involved in the development of age-related retinal diseases (AMD - age related macular degeneration ).

literature

• Michael Schünke, Erik Schulte, Udo Schumacher: Prometheus. LernAtlas der Anatomie. Head, Neck and Neuroanatomy. 2nd, revised and expanded edition. Thieme, Stuttgart et al. 2009, ISBN 978-3-13-139542-9 .

Individual evidence

1. ^ DJ Moore, GM Clover: The effect of age on the macromolecular permeability of human Bruch's membrane . In: Investigative Ophthalmology & Visual Science . tape 42 , no. 12 , November 1, 2001, ISSN  0146-0404 , p. 2970-2975 , PMID 11687544 .