a pliable sheet-like structure acting as a boundary, lining, or partition in an organism
the semipermeable membrane surrounding the cytoplasm of a cell
a lipoprotein membrane which encloses many cells and cell organelles and is composed of two electron-dense layers enclosing a less dense layer
an epithelial tissue which secretes mucus, and lines many body cavities and tubular organs including the gut and respiratory passages
a microscopic membrane of lipids and proteins which forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and regulates the passage of molecules in and out of the cytoplasm
a mesothelial tissue which lines certain internal cavities of the body, forming a smooth, transparent, two-layered membrane lubricated by a fluid derived from serum. The peritoneum, pericardium, and pleura are serous membranes
a thin, delicate membrane of protein fibres and mucopolysaccharides separating an epithelium from underlying tissue
a thin transparent membrane enveloping the vitreous humour of the eye
a membrane forming part of the organ of hearing, which vibrates in response to sound waves. In humans and other higher vertebrates it forms the eardrum, between the outer and middle ear
a transparent membrane surrounding and secreted by the fertilized ovum, preventing the entry of further spermatozoa
a whitish or translucent membrane that forms an inner eyelid in birds, reptiles, and some mammals. It can be drawn across the eye to protect it from dust and keep it moist
a condition in newborn babies in which the lungs are deficient in surfactant, which prevents their proper expansion and causes the formation of hyaline material in the lung spaces
a fine, delicate membrane, the middle one of the three membranes or meninges that surround the brain and spinal cord, situated between the dura mater and the pia mater