Medical terms - Letter M (page 8) | MedicalVocabulary.org

Mediterranean Fever

Fever: A inherited disorder of unknown cause featuring short recurring bouts of fever together with pain in the joints, chest or abdomen. Also called Familial Mediterranean Fever (FMF). Between attacks, the patient…
Mediterranean-style diet

See: Mediterranean diet
Medium-chain acyl-CoA dehydrogenase

An enzyme abbreviated as MCAD. See: MCAD deficiency
Medium-chain acyl-CoA dehydrogenase deficiency

See: MCAD deficiency
MEDLARS

MEDLARS® is an acronym that stands for Medical Literature Analysis and Retrieval System. It is a computer-based system of the U.S. National Library of Medicine (NLM) that allows rapid access to NLM's store of biomedical…
MEDLINE

MEDLINE® is the best known database of the U.S. National Library of Medicine (NLM). MEDLINE enables anyone to query the NLM computer's store of journal article references on specific topics. It currently contains 9…
Medulla

The innermost part. The adrenal medulla is the innermost part of that gland. The renal medulla is the inner part of the kidney. The spinal medulla is the part of the spinal cord that is lodged within the vertebral canal
Medulla oblongata

The base of the brain, which is formed by the enlarged top of the spinal cord. This part of the brain directly controls breathing, blood flow, and other essential functions
Medulla, adrenal

The inner portion of adrenal gland. (The outer portion is the adrenal cortex). The adrenal medulla makes epinephrine (adrenaline) and norepinephrine (noradrenaline). Epinephrine is secreted in response to low blood…
Medullary cystic kidney disease, recessive

Ssive type: A childhood genetic kidney disease in which there is progressive symmetrical destruction of the kidneys involving both the tubules and glomeruli, characteristically resulting in anemia, polyuria, polydipsia…
Medulloblastoma

A type of brain tumor that tends to occur in children, arise in the cerebellum (in the lower part of the brain), and spread along the spine. Medulloblastoma is the most common type of primary brain tumor in childhood…
MEDVAC

Acronym for medical evacuation. MEDVAC typically refers to a team that is organized with the skills for the purpose of proper medical evacuation in situations of emergency
MEF2A

A transcription factor that participates in vascular development. MEF2A is a member of the myocyte enhancer factor-2 (MEF2) family of transcription factors. Messenger RNA (mRNA) from MEF2A has been detected in blood…
Mega- (prefix)

The combining form 'mega-' comes from the Greek 'megas', great or big and means abnormally large. Megalocephaly is too large a head. Megacardia is too large a heart. Megacolon is too large a colon.
Megabase

Unit of length for DNA fragments that is equal to 1 million nucleotides. A megabase (Mb) is roughly equal to 1 centiMorgan (cM)
Megacolon

An abnormally enlarged colon.
Megakaryocyte

A giant cell in the bone marrow that is the ancestor of blood platelets.
Megalencephaly

Also called macrencephaly, a condition in which there is an abnormally large, heavy, and usually malfunctioning brain. By definition, the brain weight is greater than average for the age and gender of the child. Head…
Megrim

Migraine. Usually periodic attacks of headaches on one or both sides of the head. Megrim (migraine) may be accompanied by nausea, vomiting, increased sensitivity of the eyes to light (photophobia), increased sensitivity…
Meibomian cyst

A cyst of the little glands called Meibomian glands that are located in the eyelids and make a lubricant they discharge through their tiny openings in the edges of the lids. The lubricant is a fatty substance called…
Meibomian gland

One of the little glands in the eyelids that make a lubricant called sebum which they discharge through their tiny openings in the edges of the lids. The meibomian glands can become inflamed, a condition termed…
Meibomianitis

Inflammation of the little glands called Meibomian glands located in the eyelids that make a lubricant which they discharge through their tiny openings in the edges of the lids. The lubricant is a fatty substance called…
Meibomitis

See: Meibomianitis
Meiosis

The process of germ cell formation. During meiosis, each chromosome pairs with the other chromosome in the pair and they exchange segments of genetic material. In both women and men, the autosomes (non-sex chromosomes)…
Meiotic

Pertaining to meiosis (the process of germ cell formation).
Meiotic drive

Preferential selection during meiosis (germ cell production). In meiotic drive there is preferential production of certain gametes. This alters the segregation of genes from the Mendelian expectations. Meiotic drive is…
Meiotic nondisjunction

Failure of two members of a chromosome pair to separate (disjoin) during meiosis so that both go to one daughter cell and none to the other. This mechanism is responsible for the extra chromosome 21 in trisomy 21 (Down…
Melan- (prefix)

Prefix meaning dark or black. It comes from the Greek 'melas', black. Examples of terms containing melan- include melancholia, melanin, melanocytes, melanoma and melena
Melancholia

Old term for depression.
Melanin

A skin pigment (substance that gives the skin its color). Dark-skinned people have more melanin than light- skinned people. Melanin also acts as a sunscreen and protects the skin from ultraviolet light. Melanin is…
Melanocyte

A pigment-producing cell in the skin, hair and eye that determines their color. The pigment that melanocytes make is called melanin. The major determinant of color is not the number but rather the activity of the…
Melanoderma

Increased skin pigmentation, darkening of the skin. This is directly due to an increased amount of melanin pigment in the skin when there is increased production of melanin by the melanocytes (the cells that make…
Melanoma

Melanoma: The most dangerous form of skin cancer, a malignancy of the melanocyte, the cell that produces pigment in the skin. Melanoma is most common in people with fair skin, but can occur in people with all skin…
Melanoma of the eye

See: Intraocular melanoma
Melanoma thickness

A method for determining the prognosis (outlook) with melanoma. The thickness of a melanoma is related to the 5-year survival rate after surgical removal of the tumor. Also called Breslow thickness. Named for the…
Melanoma vaccine

A cancer vaccine prepared from human melanoma cancer cells. It may be used alone or with other therapy in treating melanoma.
Melanoma, acral-lentiginous

One of the four clinical types of malignant melanoma, uncommon in whites but the most common type in nonwhites. It starts as an irregular enlarging black flat spot (macule), most often on the palm and sole, less often…
Melanoma, amelanotic

A form of melanoma in which the malignant cells (melanocytes) do not make the pigment melanin. Amelanotic melanomas may be pink, red, or have light brown, tan, or gray at the edges and are usually detectable only on…
Melanoma, benign

A tumor of the melanocytes that is not cancerous
Melanoma, choroidal

Malignant melanoma that arises in the eye. See ocular melanoma
Melanoma, ciliary body

See: Intraocular melanoma
Melanoma, conjunctival

An uncommon eye cancer that arises in the conjunctiva, the clear membrane that covers the outer surface of the eye and the inner part of the eyelids. Conjunctival melanoma accounts for 2% of all eye malignancies and…
Melanoma, eye

See: Intraocular melanoma
Melanoma, intraocular

See: Intraocular melanoma
Melanoma, iris

See: Intraocular melanoma
Melanoma, juvenile

Melanoma, juvenile: A benign raised pink or red scaly area typically seen on a preadolescent child's skin, usually on the cheek. Also called a benign compound nevus or a spindle and epithelioid cell nevus.
Melanoma, lentigo maligna

One of the four clinical types of malignant melanoma and the slowest growing one. It typically begins as a patch of mottled pigmentation that is dark brown, tan, or black on sun-exposed skin, such as on the face
Melanoma, malignant

See: Melanoma
Melanoma, nodular

One of the four clinical types of malignant melanoma, typically presents as a raised, distinct, bluish-black tumor that may be encircled by particularly pale skin, most often in middle-aged or older adults
Melanoma, ocular

A malignant melanoma arising from a structure within the eye. The most common sites of origin are the choroid, ciliary body, and iris. It tends to occur after age 40. The tumor may metastasize from the eye. The most…