Medical terms - Letter L (page 5) | MedicalVocabulary.org

Lens, intraocular

See: Intraocular lens
Lens, objective

In a microscope, the objective lens is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece). The light microscope today is usually binocular (with one…
Lens, ocular

In a microscope, the lens closest to the eye is termed the ocular (the eyepiece) whereas the objective (also called the objective lens) is the lens nearest to the object being examined. The light microscope today is…
Lentigines

When there is one lentigo, there are usually more lentigines
Lentiginosis profusa syndrome

See: LEOPARD syndrome
Lentigo

A type of freckle that is a small tan, brown, or black spot which tends to be darker than the usual (ephelis-type) freckle and which do not fade in the winter. This kind of spot is referred to as lentigo simplex…
Lentigo maligna melanoma

See: Melanoma, lentigo maligna
Lentigo, senile

See: Senile lentigo
Lenz microphthalmia syndrome

A genetic disorder characterized by microphthalmia (small eye) or anopthalmia (no eye) associated with malformation of the ears, teeth, fingers, skeleton, and genitourinary system. About half of patients have…
Leon virus

Type 3 poliovirus. Named after the patient in California from whom this virus was first isolated. There are two other strains of poliovirus: Type 1 (known as the Brunhilde virus) and Type 2 (known as the Lansing virus)…
Leonardo da Vinci

Architect, engineer, inventor, painter and the father of anatomic art. Leonardo da Vinci first became interested when he was asked by a Veronese anatomist named Marc Antonia Della Torre to do the illustrations for a…
LEOPARD syndrome

A genetic syndrome transmitted in an autosomal dominant manner that is named for its characteristic features: > >L -- lentigines (dark freckles) on the head and neck >E -- electrocardiogram (EKG) abnormalities >O --…
Leper

1. Someone with leprosy (Hansen disease). The term leper is now in disfavor. 2. By extension, a pariah. A person who is avoided or shunned by society.From the French lepre, from the Greek lepros meaning scaly, referring…
Lepra

1. Leprosy (Hansen disease) 2. Before the mid 19th century, psoriasis.The acronym LEPRA stands for the Leprosy Relief Association
Leprosy

See: Hansen disease
Leptin

A hormone that has a central role in fat metabolism. Leptin was originally thought to be a signal to lose weight but it may, instead, be a signal to the brain that there is fat on the body. Hugely obese children have…
Leptomeningeal

Having to do with the leptomeninges, the two innermost layers of tissues that cover the brain and spinal cord. Leptomeningeal metastasis refers to cancer that has spread from the original (primary) tumor to the…
Leptomeninges

The two innermost layers of tissues that cover the brain and spinal cord. The two layers are called the arachnoid mater and pia mater
Leptospirosis

Leptospirosis: An infectious disease caused by a particular type of bacteria called a spirochete transmitted by rats as well as by skunks, opossums, raccoons, foxes, and other vermin. Leptospirosis occurs worldwide but…
Lesbian

Female homosexual. The name 'lesbian' comes from the Greek island of Lesbos in the Aegian Sea where in antiquity the women were said to be homosexual. The poet Sappho who lived on Lesbos (circa 600 BC) was a lesbian in…
Lesbian suicide risk

High rates of suicide have consistently been reported among homosexuals, particularly among adolescents and young adults. A 1989 report concluded that 'gay youth are 2 to 3 times more likely to attempt suicide than…
Lesbianism

Female homosexuality. Also called sapphism (after the lesbian poet Sappho)
Lesion

Pronounced 'lee-sion' with the emphasis on the 'lee,' a lesion can be almost any abnormality involving any tissue or organ due to any disease or any injury. There are, not surprisingly, many types of lesions. There are…
Let down reflex

An involuntary reflex during breastfeeding which causes the milk to flow freely
Lethal

Deadly, fatal, capable of causing death, death-dealing. The word 'lethal' comes from the Latin 'letum' meaning 'death or destruction.
Lethal gene, zygotic

A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic…
Lethargy

1. Abnormal drowsiness, stupor. 2. A state of indifference.From the Greek lethargia, drowsiness
Letrozole

Letrozole: An oral antiestrogen. Letrozole inhibits the enzyme aromatase in the adrenal glands that produces the estrogens (estradiol and estrone) and thereby lowers their levels. The brand name of letrozole is Femara…
Leu

Leucine. See also: Amino acid symbols
Leucemia

A different spelling of leukemia, cancer of the blood cells. The growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes)…
Leucine

An amino acid, one of the 20 building blocks of protein. A dietary essential amino acid, leucine is needed for optimal growth in childhood. It is one of the three branched-chain amino acids. Symbol: Leu
Leucovorin

Folinic acid, the active form of folic acid in the body. Used as an antidote to protect normal cells from high doses of the anticancer drug methotrexate and to increase the antitumor effects of fluorouracil (5-FU) and…
Leuk-

Prefix meaning white, as in leukemia. Leuk-and leuko-, the form used before a consonant, come from the Greek 'leukos' meaning white
Leukemia

Leukemia: Cancer of the blood cells. The growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes) but in practice it can…
Leukemia, accelerated phase of

Leukemia, accelerated phase of: Refers to chronic myelogenous leukemia (CML) that is progressing. The number of immature, abnormal white blood cells in the bone marrow and blood is higher than in the chronic phase but…
Leukemia, acute

Cancer of the blood cells (leukemia) that progresses rapidly, as opposed to chronic leukemia which progresses slowly. The two major types of acute leukemia are acute lymphoblastic leukemia (ALL) and acute myelocytic…
Leukemia, acute lymphoblastic

See: Acute lymphoblastic leukemia.
Leukemia, acute lymphocytic

Abbreviated AML. Also called acute myeloid leukemia or acute nonlymphocytic leukemia (ANLL). A quickly progressive malignant disease in which there are too many immature blood-forming cells in the blood and bone marrow…
Leukemia, acute myelogenous

Leukemia, acute myelogenous: Abbreviated AML. Also called acute myeloid leukemia or acute nonlymphocytic leukemia (ANLL). A quickly progressive malignant disease in which there are too many immature blood-forming cells…
Leukemia, acute myeloid

Leukemia, acute myeloid: A quickly progressive malignant disease in which there are too many immature blood-forming cells in the blood and bone marrow, the cells being specifically those destined to give rise to the…
Leukemia, acute nonlymphocytic

Leukemia, acute nonlymphocytic: Abbreviated ANLL. More commonly called acute myeloid leukemia (AML). A quickly progressive malignant disease in which there are too many immature blood-forming cells in the blood and bone…
Leukemia, blastic phase of

Leukemia, blastic phase of: A stage in which 30 percent or more of the cells in the bone marrow or blood are blast cells, which may form tumors
Leukemia, chronic lymphocytic

The most common form of leukemia in adults, in which the lymphocytes may look fairly normal but are not fully mature and do not deal effectively with infection. The malignant cells are found in the blood and bone…
Leukemia, chronic phase of

Leukemia, chronic phase of: A stage in which there are few blast cells in the blood or bone marrow, and few if any symptoms
Leukemia, hairy cell

See: Hairy cell leukemia
Leukemia, hairy-cell

See: Hairy cell leukemia
Leukemia, juvenile myelomonocytic leukemia

See: Juvenile myelomonocytic leukemia
Leukemia, lymphocytic

A form of leukemia that has a sudden onset, lymphocytic leukemia starts in the bone marrow but often spreads to the lymphatic and nervous system. With aggressive treatment, which may include chemotherapy, radiation…
Leukemia, myelogenous

Condition in which the bone marrow makes too many white blood cells. Early symptoms include fatigue and night sweats. Treatment may be by radiation, chemotherapy, biological therapy, or bone- marrow transplant. Also…
Leukemia, refractory

Leukemia in which the high level of white blood cells is not decreasing in response to treatment