Alzheimer's disease

A progressive deterioration of the brain, most common in elderly people, that results in a loss of memory and a general breakdown in mental and physical health.

atom

A basic particle of matter. All substances are made of atoms, which are often combined to make larger units called molecules. Inside each atom are smaller particles known as protons, neutrons, and electrons.

blood transfusion

The replacement of blood lost by a patient by other blood of the same type or a compatible type.

CAT

The technique of computerized axial tomography, which directs a series of X-ray beams through the body to produce detailed cross sections.

cataract

A cloudiness of the lens of the eye, which can lead to blindness. It is common in old age and may also result from an illness such as diabetes.

cochlea

The spiral-shaped structure in the inner ear in which sound vibrations of different frequencies are turned into nerve impulses before being sent to the brain.

cornea

The transparent, protective outer covering of the center of the eye.

defibrillator

A device that can be used to restart the heart by producing a strong electric shock across a patient's chest.

digital images

Pictures built up from many separate points, each point representing an item of data that has been collected by an instrument and stored as a number inside a computer.

Doppler scanning

A scanning technique that uses ultrasound to measure the speed of moving objects, for example, the blood inside the body.

electrode

A conducting part, usually made of metal, by which an electric current leaves or enters a device.

endoscope

A long, flexible device equipped with a light, a lens, and various instruments that can be used to look inside the body and carry out certain types of surgery.

fetus

An unborn child from the end of the eighth week of pregnancy to the moment of birth. Before the eighth week the unborn child is known as an embryo.

forceps

Pincers used by surgeons for a variety of purposes, such as holding back tissues or pinching off several blood vessels to prevent bleeding.

frequency

When applied to waves such sound waves, light waves, or radio waves, it is the number of vibrations, or waves, that pass a point in one second.

glaucoma

A disease in which the pressure of the liquid inside the eyeball increases above normal. Unless treated in time, the disease causes irreparable damage to a person's sight

hydrogen atom

The smallest particle of hydrogen. Hydrogen atoms are very common in many substances and tissues in the human body.

immune system

The body's chemical defense system, which is used to identify and destroy foreign invaders, such as viruses.

implant

An artificial part or device that is placed inside the human body to take the place of a natural part that has been damaged by accident or disease.

infrared light

Light similar to ordinary light but invisible and consisting of waves of lower frequency. We experience infrared light as heat waves.

keyhole surgery

Surgery that is carried out through small cuts and openings about the size of a thumbnail.

magnetic field

The region around a magnet where the effects of the magnet are exerted.

memory chip

A microchip that is used to store information for use by a computer.

microchip

A complex circuit made from microscopic components, laid down on a single crystal of a substance called silicon, that can store r process information.

microprocessor

A microchip that works as the processing section of a computer.

microsurgery

Surgery so delicate that it requires the use of a surgical microscope and miniature instruments.

minimum-intervention

A term used to describe surgery that attempts to treat the patient while causing as little damage to the body as possible.

MRI

The technique of magnetic resonance imaging. A patient in an MRI scanner is surrounded by a strong magnetic and exposed to high-frequency radio waves. This causes the nuclei of hydrogen atoms to give off radio waves at a certain frequency that the scanner is set up to detect.

nucleus

The central part of an atom, which contains most of its mass. The nucleus consists of protons and (except for atoms of ordinary hydrogen) neutrons.

optical fiber

A fine, bendable strand of specially made glass or plastic in which light can easily travel.

organ

A part of the body, built up from various types of tissue, that performs a unique, important task. Examples of organs include the heart, the brain, the lungs, the stomach, and the kidneys.

percutaneous surgery

A new type of surgical procedure that involves operating through needle-sized holes.

PET

The technique of positron emission tomography. This involves injecting a patient with a radioactive sugar solution and then using a PET scanner to measure how much of the sugar has been absorbed by different parts of the patient's brain.

proton

A very small positively charged particle found within the nuclei of atoms.

radioactive

Emitting penetrating rays and particles of several types due to the breakup of the nuclei of certain atoms.

retina

The layer at the back of the eye that senses the intensity and color of light.

retractor

A tool used in surgery to hold back parts, such as bones and muscles, that would otherwise get in the way of the operation.

scalpel

A very sharp, lightweight knife used in surgery.

signal processor

A device used to distinguish and separate the different parts that make up a sound or other kind of signal.

tissue

A group of similar cells that perform a specific and common function. For example, a section of muscle, a section of skin, and a part of an organ are tissues.

transplant

The replacement of a diseased or defective organ, or part of an organ, with a healthy organ taken from another person.

tumor

An abnormal growth in some part of the body.

ultrasound

Sound consisting of waves of very high frequency.

X-rays

High-frequency electromagnetic waves that can be used to take pictures of structures inside the body.

 

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