membrane
Other forms: membranes
A membrane is a thin layer of something. For an example of a membrane, you don’t have to look far: your skin is a kind of membrane.
Membranes are thin and flexible, but usually still strong enough to protect what’s inside or underneath them. Biologists often study membranes, such as those that surround your cells and organs. There are also membranes that don’t have anything to do with biology. A high-tech jacket might have a waterproof membrane to keep you dry in the rain.
Definitions of membrane
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a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants
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synonyms:
tissue layer
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types:
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trophoblast
the membrane that forms the wall of the blastocyst in early development; aids implantation in the uterine wall
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chorioallantoic membrane, chorioallantois
the very vascular fetal membrane composed of the fused chorion and adjacent wall of the allantois
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web
membrane connecting the toes of some aquatic birds and mammals
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Bowman's capsule, capsula glomeruli, glomerular capsule
thin double membrane surrounding the glomerulus of a nephron
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axolemma
outer membrane covering an axon
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basilar membrane
a membrane in the cochlea that supports the organ of Corti
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fetal membrane
any membrane that functions for the protection or nourishment or respiration or excretion of a developing fetus
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choroid, choroid coat
a highly vascular membrane in the eye between the retina and the sclera; a dark pigmentation minimizes the scattering of light inside the eye
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ciliary body
the part of the tunic of the eye between the choroid coat and the iris
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cornea
the transparent dome-shaped anterior portion of the outer covering of the eye; it covers the iris and pupil and is continuous with the sclera
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diaphragm, midriff
(anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
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eardrum, myringa, tympanic membrane, tympanum
the membrane in the ear that vibrates to sound
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endocranium
membrane lining the inside of the skull
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endosteum
vascular membrane that lines the inner surface of long bones
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ependyma
thin epithelial membrane lining the ventricles of the brain and the spinal cord canal
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fertilization membrane
the membrane that forms around a fertilized ovum and prevents penetration by additional spermatozoon
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hyaloid, hyaloid membrane
the transparent membrane enveloping the vitreous humor of the eye and separating it from the retina
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intima
the innermost membrane of an organ (especially the inner lining of an artery or vein or lymphatic vessel)
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iris
muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye; it forms the colored portion of the eye
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lamella
a thin membrane that is one of the calcified layers that form bones
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meninges, meninx
a membrane (one of 3) that envelops the brain and spinal cord
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mucosa, mucous membrane
mucus-secreting membrane lining all body cavities or passages that communicate with the exterior
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periosteum
a dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles; contains nerves and blood vessels that nourish the enclosed bone
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perithelium
tissue layer around small blood vessels
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retina
the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve
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sarcolemma
an extensible membrane enclosing the contractile substance of a muscle fiber
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semipermeable membrane
a membrane (as a cell membrane) that allows some molecules to pass through but not others
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serosa, serous membrane
a thin membrane lining the closed cavities of the body; has two layers with a space between that is filled with serous fluid
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synovial membrane, synovium
a thin membrane in synovial (freely moving) joints that lines the joint capsule and secretes synovial fluid
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adventitia, tunic, tunica
an enveloping or covering membrane or layer of body tissue
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allantois
the vascular fetal membrane that lies below the chorion and develops from the hindgut in many embryonic higher vertebrates (reptiles, birds and mammals)
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caul, embryonic membrane, veil
the inner membrane of embryos in higher vertebrates (especially when covering the head at birth)
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cell membrane, cytomembrane, plasma membrane
a thin membrane (a double layer of lipids) enclosing the cytoplasm of a cell; proteins in the membrane control passage of ions (like sodium or potassium or calcium) in and out of the cell
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conjunctiva
a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid
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arcus, arcus senilis
a whitish deposit in the shape of an arc that is sometimes seen in the cornea
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perforated eardrum
an eardrum with a hole or tear in it; can interfere with normal hearing and cause other ear problems
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pleura
the thin serous membrane around the lungs and inner walls of the chest
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peritoneum
a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera
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endocardium
the membrane that lines the cavities of the heart and forms part of the heart valves
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pericardium
a serous membrane with two layers that surrounds the heart
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epicardium, visceral pericardium
the innermost of the two layers of the pericardium
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parietal pericardium
the tough outermost layer of the pericardium that is attached to the diaphragm and the sternum
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leptomeninges
the two innermost layers of the meninges; cerebrospinal fluid circulates between these innermost layers
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dura, dura mater
the outermost (and toughest) of the 3 meninges
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arachnoid, arachnoid membrane
the middle of the 3 meninges
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pia mater
the highly vascular innermost of the 3 meninges
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endometrium
(pregnancy) the mucous membrane that lines the uterus; thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation; if pregnancy occurs it is shed along with the placenta at parturition
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umbilical, umbilical cord
membranous duct connecting the fetus with the placenta
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hymen, maidenhead, virginal membrane
a fold of tissue that partly covers the entrance to the vagina of a virgin
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albuginea
whitish tunic
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type of:
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animal tissue
the tissue in the bodies of animals
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a thin pliable sheet of material
DISCLAIMER: These example sentences appear in various news sources and books to reflect the usage of the word ‘membrane'.
Views expressed in the examples do not represent the opinion of Vocabulary.com or its editors.
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