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Glossary - L

Displaying glossary terms beginning with the letter L: 1 - 50 of 79 in total
labile hypertension
Blood pressure that frequently fluctuates between normal and abnormal during the course of a day, often within only a few minutes.
labyrinth
The inner ear. It contains the cochlea, which is responsible for hearing, as well as structures that are needed for balance.
laceration
A tear in the skin.
lacrimal gland
The gland that produces tears.
lactase
An enzyme that breaks down milk sugar (lactose) in the body.
lactic acidosis
A rare but potentially lethal condition in which blood lactic acid levels increase.
lactose
A sugar found in milk and dairy products.
lactose intolerance
The inability of the body to easily digest lactose, a sugar found in milk and dairy products.
lacunar stroke
A small ischemic stroke caused by the blockage of one of the smaller blood vessels in the brain; the most common effect is weakness or disability on one side of the body.
lamellar bone
Hard, dense tissue that forms the outer shell of bones. Also called compact bone.
lamina
One of the two thin, plate-like parts of each vertebra.
laminectomy
An operation in which all or part of one or both laminae is removed.
Langerhans cells
Cells of the immune system that work in the skin to fight infection.
lanugo hair
Fine, soft hair that grows all over the body of a fetus and is typically shed before birth.
laparoscopy
A surgical procedure carried out with tiny instruments inserted through small openings in the skin.
Related health topics: Prostate Cancer
laser
A concentrated beam of light; lasers are used in certain surgeries and other medical procedures.
laser assisted uvula-palatoplasty (LAUP)
A surgical procedure to ease snoring by removing or reshaping some of the tissues in the mouth (usually the uvula and soft palate) that vibrate and cause the noise of snoring.
laser hair removal
Permanent hair removal technique that uses a laser to target and heat melanin in the hair shaft, which damages the hair follicle.
laser photocoagulation
Surgery that uses a laser to seal off blood vessels in the eye; used to treat a number of eye diseases.
laser prostatectomy
A surgical technique for treating an enlarged prostate (benign prostatic hyperplasia). It uses a high-energy laser to remove large amounts of prostate tissue with little bleeding.
latex allergy
An allergic reaction to the proteins found in natural rubber.
laxative
A drug or substance that induces bowel movements or makes the stool softer and looser.
Related health topics: Anorexia Nervosa , Bulimia
LDL
Abbreviation for low-density lipoprotein. This so-called bad cholesterol can build up on artery walls, narrowing the artery and making a heart attack or stroke more likely.
learned insomnia
When fear of not sleeping develops after a short period of not sleeping well, and this anxiety causes ongoing trouble falling or staying asleep.
LED photomodulation
Use of a panel of bright lights (LEDs) to stimulate skin cells and improve the look of the skin.
left anterior descending coronary artery
One of the main arteries that supplies blood to the heart; It runs down the front surface of the heart.
left atrium
The left upper chamber of the heart.
Related health topics: Marfan's Syndrome, Stroke Overview
left circumflex coronary artery
One of the main arteries that supplies blood to the heart; it curves around the back of the heart.
left ventricle
The left lower chamber of the heart. It pumps blood out of the heart to other organs in the body.
left ventricular hypertrophy
A thickening of the wall of the lower left chamber of the heart, which is responsible for pumping blood to organs throughout the body.
left-ventricular assist device (LVAD)
A surgically implanted pump that augments the pumping action of the left ventricle.
lensometer
A device used to check the prescription of eyeglasses.
leptin
A hormone produced by fat cells that acts on the brain to suppress appetite and burn stored fat.
lesion
An infected, diseased, or wounded area of tissue.
leukotriene blockers
Asthma medications that work by blocking leukotrienes, chemicals made in the body as part of an allergic reaction.
leukotriene modifiers
Asthma medications that work by blocking the production or action of leukotrienes, chemicals made in the body as part of an allergic reaction.
leukotrienes
Chemicals that cause airways to swell when an allergic reaction occurs or in diseases like asthma.
levothyroxine sodium
A man-made version of the thyroid hormone thyroxine.
libido
Sexual desire.
lice (Pediculus humanus capitis)
A blood-sucking parasite that can cause an itchy scalp; infestations are highly contagious and especially common in school-age children.
ligament
A band of tissue that connects bones.
Related health topics: Endometriosis, Marfan's Syndrome
ligature
Any material that is tied around a blood vessel to stop it from bleeding.
lignans
Antioxidant chemicals found in seeds like flax and sesame, as well as some fruits, vegetables, and grains.
limbic system
A group of structures in the brain that help control memory, emotions, sexual arousal, and motivation.
limbus
The border between the cornea and the white of the eye.
liothyronine sodium
A man-made version of the thyroid hormone triiodothyronine.
lipase
An enzyme secreted by the pancreas that helps the body break down fats.
Related health topics: Acute Pancreatitis
lipids
Fats, oils, and waxes that serve as building blocks for cells or as energy sources. Lipids are also capable of accumulating in the artery walls to form plaque.
lipoatrophy
Dents or depressions in the skin that are caused by a loss of fatty tissue.
lipohypertrophy
A buildup of fatty tissue.