Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «M»:
Mitochondrial cytopathy, Kearns-Sayre type
Mitochondrial cytopathy, Kearns-Sayre type: See: Kearns-Sayre syndrome....
Mitochondrial disease: Mutations (changes) in the
mitochondrial chromosome are responsible for a number of disorders
including, for example:
An eye disease called Leber's hereditary optic
A type of epilepsy called MERRF
which stands for Myoclonus Epilepsy with Ragged Red Fibers;...
Mitochondrial DNA: Mitochondrial DNA (mtDNA) is the DNA of the mitochondrion, a structure situated in the cytoplasm of the cell rather than in the nucleus (where all the other chromosomes are located).
All mtDNA is inherited from the mother. There are 2 to 10 copies of the mtDNA genome in each mito...
Mitochondrial encephalopathy, MELAS
Mitochondrial encephalopathy, MELAS: MELAS is the acronym for Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes.
MELAS is a form of dementia. It is caused by mutations in the genetic material (DNA) in the mitochondria. While most of our DNA is in the chromosomes in the cell nuc...
Mitochondrial genome: All of the genetic information contained in the chromosome of the mitochondrion, a structure located in the cytoplasm outside the nucleus of the cell. The nucleus houses the better known chromosomal genome, our complement of chromosomes.
The mitochondrial genome consists of mit...
Mitochondrial inheritance: The inheritance of a trait encoded in the
mitochondrial genome. Because of the oddities of mitochondria, mitochondrial
inheritance does not obey the classic rules of genetics. Persons with a
mitochondrial disease may be male or female but they are always related in the...
Mitochondrial myopathy: A group of neuromuscular diseases caused by damage to the mitochondria, energy-producing structures in cells that serve as power plants. Nerve and muscle cells require a great deal of energy and are particularly impaired by mitochondrial dysfunction.
Some of the more common...
Mitochondrion: Singular of mitochondria. The mitochondria are normal
structures called organelles in cells. They are located in the cell's cytoplasm
outside the nucleus.
The mitochondria are responsible for energy production. They consist of two
sets of membranes, a smooth continuous outer coat ...
Mitosis: Ordinary division of a body cell (a somatic cell) to form two daughter cells, each with the same chromosome complement as the parent cell. ...
Mitotic: Pertaining to mitosis. ...
Mitotic nondisjunction: The failure in mitosis for the two members of a chromosome pair to separate (to disjoin) normally so that both chromosomes go to one daughter cell while none go to the other daughter cell....
Mitral insufficiency: Incomplete closure of the mitral valve resulting in the backflow of blood from the left ventricle to the left atrium of the heart. ...
Mitral prolapse: Drooping down or abnormal bulging of the mitral
valve cusps during the contraction of the heart. ...
Mitral regurgitation: Backflow of blood from the left ventricle to the left atrium of the heart due to mitral insufficiency from incomplete closure of the mitral valve....
Mitral valve: A valve in the heart situated between the left atrium and the left ventricle that permits blood to flow from the left atrium into the left ventricle but not in the reverse direction.
The mitral valve has two flaps (cusps). It is called "mitral" because it looks like a bishop's miter ...