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Ectoderm
Ectoderm One of the three primary germ cell layers (the other two being the mesoderm and endoderm) that make up the very early embryo. The ectoderm is the outermost of the three layers. It differentiates to give rise to many important tissues and structures including the outer layer of the skin and its appendages (the sweat glands, hair, and nails), the teeth, the lens of the eye, parts of the inner ear, the nerves, brain, and spinal cord. This much is classic human embryology. Stem cell research, however, has shown that some cells within ectodermal structures retain their ability to differentiate into other tissues. For example, some cells in brain (ectoderm) can become bone marrow (mesoderm).
RELATED TERMS--------------------------------------
Germ
A disease-causing microorganism.
Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.
Mesoderm
The middle layer of cells in an embryo, from which the muscular, skeletal, vascular, connective etc. tissues develop.
Embryo
The early stages of development before an organism becomes self supporting.
Ectoderm
One of the three primary germ cell layers (the other two being the mesoderm and endoderm) that make up the very early embryo. The ectoderm is the outermost of the three layers. It differentiates to give rise to many important tissues and structures including the outer layer of the skin and its appendages (the sweat glands, hair, and nails), the teeth, the lens of the eye, parts of the inner ear, the nerves, brain, and spinal cord. This much is classic human embryology. Stem cell research, however, has shown that some cells within ectodermal structures retain their ability to differentiate into other tissues. For example, some cells in brain (ectoderm) can become bone marrow (mesoderm).
Skin
Skin is an organ of the integumentary system; which is composed of a layer of tissues that protect underlying muscles and organs. Skin is used for insulation, vitamin D production, sensation, and excretion (through sweat).
Lens
The lens of the eye is like an adjustable lens of a camera and focuses light rays on to the retina for sharp images. A condition called presbyopia occurs when the lens is no longer able to adjust for objects at different distances.
Eye
The organ of sight. The eye has a number of components. These components include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous.
Ear
The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain.
Brain
"That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called ""hemispheres."" "
Cord
1. In anatomy, a long ropelike structure. 2. Short for the spinal cord or the umbilical cord.
Ectodermal
Pertaining to the ectoderm or to tissues derived from the ectoderm, one of the three primary germ cell layers that make up the very early embryo. The ectoderm is the outermost of the three layers.
Differentiate
The process cells undergo as they mature into normal cells. Differentiated cells have distinctive characteristics, perform specific functions, and are less likely to divide. See dedifferentiate, undifferentiated.
Bone
Bone refers either to a hardened connective tissue or to one of the individual structures, or organs, into which it is formed, found in many animals. Bones support body structures, protect internal organs, and (in conjunction with muscles) facilitate movement; are also involved with cell formation, calcium metabolism, and mineral storage. The bones of an animal are, collectively, known as the skeleton.
Marrow
The tissue which fills the cavities of most bones; the medulla. In the larger cavities it is commonly very fatty, but in the smaller cavities it is much less fatty, and red or reddish in color.
SIMILAR TERMS--------------------------------------
Ectodermal
Pertaining to the ectoderm or to tissues derived from the ectoderm, one of the three primary germ cell layers that make up the very early embryo. The ectoderm is the outermost of the three layers.
Ectodermal dysplasia
A genetic disorder in which there is abnormal development of the skin and associated structures (the hair, nails, teeth, and sweat glands). The most dangerous problem occurs in cases with decreased sweating due to absence of the sweat glands. Affected persons have trouble controlling fevers and being in a warm environment. The hair may also be absent or sparse. The skin tends to be thin and light in color. Problems with the lining inside the nose predispose to chronic nasal infections. The teeth may be notably absent or develop abnormally. There are a number of different types of ectodermal dysplasia. X-linked anhidrotic (non-sweating) ectodermal dysplasia is most common. As an X-linked trait, it mainly affects males. There is also an autosomal dominant form affecting males and females alike. The term "ectodermal dysplasia" refers to the abnormal development (dysplasia) of structures derived from the ectoderm, one of the germ cell layers in the embryo.
Ectomy
A surgical suffix referring to the removal of something. For example, a lumpectomy is the surgical excision of a lump which may be benign or not, tonsillectomy is the removal of the tonsils, a partial colectomy is removal of part of the colon, an appendectomy is removal of the appendix, etc.
Ectoparasite
A parasite that lives on or in the skin but not within the body. Fleas and lice are ectoparasites. Infestation with an ectoparasite is called an ectoparasitosis.
Ectoparasitosis
Infestation with an ectoparasite, a parasite that lives on or in the skin. The four major ectoparasitoses are pediculosis, scabies, cutaneous larva migrans and tungiasis (sand-flea disease).
Ectopia cordis
A type of birth defect in the heart is abnormally located. In ectopia cordis, the heart usually protrudes outside the chest.
Ectopic
Out of place. An ectopic heart beat originates in an abnormal location of the heart.
Ectopic pregnancy
Pregnancy that develops outside the uterus, usually in one of the fallopian tubes.
PREVIOUS AND NEXT TERMS--------------------------------------
ECoG
Electrocochleography.
Ecogenetics
The interaction of genetics with the environment. The genetic disease PKU (phenylketonuria) provides an illustration of ecogenetics. Persons with PKU lack an enzyme to process an amino acid (phenylalanine) and so require a special environment: a diet low in phenylalanine.
Economy class syndrome
The formation of blood clots in veins deep within the legs -- deep vein thrombosis -- occurring during (or just after) a long airplane flight, especially in economy class (tourist class) where there is the least space allotted per passenger and ones legs tend especially to be immobilized for lack of leg room.
Ecstatic
Pertaining to ecstasy, a state of rapture and trancelike elation.
ECT
Electroconvulsive therapy.
Ectoderm
Ectodermal
Pertaining to the ectoderm or to tissues derived from the ectoderm, one of the three primary germ cell layers that make up the very early embryo. The ectoderm is the outermost of the three layers.
Ectodermal dysplasia
A genetic disorder in which there is abnormal development of the skin and associated structures (the hair, nails, teeth, and sweat glands). The most dangerous problem occurs in cases with decreased sweating due to absence of the sweat glands. Affected persons have trouble controlling fevers and being in a warm environment. The hair may also be absent or sparse. The skin tends to be thin and light in color. Problems with the lining inside the nose predispose to chronic nasal infections. The teeth may be notably absent or develop abnormally. There are a number of different types of ectodermal dysplasia. X-linked anhidrotic (non-sweating) ectodermal dysplasia is most common. As an X-linked trait, it mainly affects males. There is also an autosomal dominant form affecting males and females alike. The term "ectodermal dysplasia" refers to the abnormal development (dysplasia) of structures derived from the ectoderm, one of the germ cell layers in the embryo.
Ectomy
A surgical suffix referring to the removal of something. For example, a lumpectomy is the surgical excision of a lump which may be benign or not, tonsillectomy is the removal of the tonsils, a partial colectomy is removal of part of the colon, an appendectomy is removal of the appendix, etc.
Ectoparasite
A parasite that lives on or in the skin but not within the body. Fleas and lice are ectoparasites. Infestation with an ectoparasite is called an ectoparasitosis.
Ectoparasitosis
Infestation with an ectoparasite, a parasite that lives on or in the skin. The four major ectoparasitoses are pediculosis, scabies, cutaneous larva migrans and tungiasis (sand-flea disease).
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