Glossary

Medical and scientific terms

Please see below a list of medical and scientific words from the Wings for Life website and their definitions.

A

Abdominal

The part of the body that lies between the thorax and the pelvis and encloses the stomach, intestines, liver, spleen, and pancreas.

Ascending pathways

Nerve pathways that go upward from the spinal cord towards the brain and carry sensory information from the body.

Astrocytes

The largest and most common of the supporting, or glial, cells in the brain and spinal cord. Astrocytes (meaning "star cells" because of their shape) help regulate the chemical environment around cells, respond to injury, and release regulatory substances that influence nerve cells.

Autonomic dysreflexia

Dysregulation of the autonomous nervous system can result in a potentially life-threatening increase in blood pressure, sweating, and other autonomic reflexes in reaction to bowel impaction or some other stimulus.

Apoptosis

Programmed cell death, or "cell suicide"; a form of cell death in which a controlled sequence of events (or programme) leads to the elimination of cells without releasing harmful substances to the surrounding area.

Autonomous Nervous System

The autonomous nervous system comprises all the neurons and nerves through which the visceral organs, the glands and the involuntary muscles, such as the intrinsic muscles of the eye and those associated with the hair follicle, are innervated. Functions like the heart rate, the blood pressure or sweating are controlled by the autonomous nervous system.

Axon

Long nerve cell fibres that conduct electrical impulses. Axons contact other nerve, muscle, and gland cells by synapses (cell connections, see below) and the release of neurotransmitters that influence those cells.

C

Conduction

The transmission of an electric impulse from the cell body of the neuron to the synapse via the axon.

Central nervous system (CNS)

The brain and spinal cord.

Contusion

A bruising injury, spinal cord contusion results in tissue damage followed by a cavity or hole in the center of the spinal cord (cyst).

Corticospinal tracts

The nerve fibres that carry signals from motor control areas of the brain to the spinal cord (also called the pyramidal tract).

Cyst

A fluid-filled cavity that forms where cells have died. The cyst is often surrounded by a glial scar.

D

Dura mater

The outermost and toughest of the three membranes covering the brain and spinal cord.

Descending pathways

Nerve pathways that conduct nerve impulses from the brain to the spinal cord and thereby allow the brain to control movement of the body below the head.

E

Epidural

Situated on or outside the dura mater.

Excitotoxicity

Excessive release of neurotransmitters/molecules causing damage to nerve and glial cells.

Extended re-growth

Re-growth of the cut axons through and below the injury site, ideally having a reconnection with appropriate target cells

Extra-cellular matrix

Any material produced by cells and secreted into the surrounding medium, but usually applied to the non-cellular portion of tissues. The supporting structure to which cells adhere.

F

Free radicals

Highly reactive chemicals that attack and destroy molecules crucial for cell function by capturing electrons and, thus, modifying chemical structures. Free radicals are common by-products of normal chemical reactions occurring in cells. The body has several mechanisms to deactivate free radicals.

G

Glia

Supporting cells of the nervous system. Glial cells in the brain and spinal cord by far outnumber nerve cells. Not only do they provide physical support, but they also respond to injury, regulate the chemical composition surrounding cells, form the myelin insulation of nervous pathways, and help guide neuronal migration during development. The three major types of glial cells in the CNS are astrocytes, oligodendrocytes and microglia.

Glial scar

Cluster of activated glial cells which form a physical barrier to axonal growth. When injured, the glial cells also release or display substances that inhibit axonal growth.

Glutamate

Excitatory neurotransmitter of the brain.

Grey matter

The parts of the brain and spinal cord composed mainly of cell bodies and dendrites. The grey matter of the spinal cord lies in a butterfly-shaped region in the centre of the cord.

I

Impulse conduction

The capacity of neuronal cells to conduct electrical signals.

Inflammation

A localised inflammatory response that involves a complex series of events elicited by injury or destruction of tissues, which serves to destroy, dilute or wall off (sequester) both the injurious agent and the injured tissue.

M

Microglia

A type of glial cell that are "resident" immune cells found in the CNS. Microglia are scavengers that engulf dead cells and other debris.

Motor cortex

The region of the brain that instructs motor movements.

Myelin

Electrically insulating coating around axons that gives white matter its whitish appearance. Myelin is essential for the speed and reliability of signal transmission along nerve fibres. In the CNS, oligodendrocytes (a type of glial cell) wrap myelin around axons. In the PNS, schwann cells generate myelin.

N

Neurofunctional recovery

A recovery of the nervous system that leads to a regaining of motor activity and/or sensation.

Neuron

A nerve cell.

Neuroregeneration

Regeneration is the ability to restore lost or damaged tissues and their functions. The term neuroregeneration refers to the regeneration of the nervous system.

Neurotransmitter

Chemicals released by nerve cells at synapses that influence the activity of other cells. Nerve cells communicate via the neurotransmitter. Neurotransmitters may excite, inhibit, or otherwise influence the activity of cells.

O

Oligodendrocytes

A type of glial cell in the brain and spinal cord. Oligodendrocytes wrap axons with myelin, which improves the speed and reliability of impulse conduction. These cells also produce substances that inhibit the regeneration of axons in the adult CNS.

P

Paraplegia

Complete or partial impairment of sensation and motor activity of the lower part of the body (legs).

Peripheral nervous system (PNS)

All the nerves in the body that are outside the brain and spinal cord (the central nervous system), i.e. the nerves that extend from the spinal cord to the muscles and skin. It carries messages from all over the body to the central nervous system and vice versa.

Pressure sores

An area of skin that has died due to prolonged pressure, cutting off its normal blood supply. The pressure is usually due to long periods of immobility and lack of pressure relief. The sores can be painful and slow to heal.

R

Respiratory infection

Results in pneumonia perhaps due to malventilation and/or immune suppression.

S

Subcutaneous

Located or placed just beneath the skin.

Secondary damage

Damage that continues in the hours and days following the initial trauma, extending the size of the injury. Secondary damage is caused by the reactive processes in the tissue.

Spasticity

A state of increased muscular tone in which abnormal stretch reflexes intensify muscle resistance to passive movements.

Spinal cord segments

Divisions of the spinal cord along its length. Each spinal segment sends a pair of spinal nerves to the body.

Spinal nerve

Spinal nerve extends from the spinal cord to the body (muscles, skin, etc .) Spinal nerves carry afferent sensory axons and efferent motor axons. Humans have 31 left-right pairs of spinal nerves. The spinal nerves are part of the peripheral nervous system (PNS).

Synapse

The functional connecting structure between a nerve cell axon and target cells, which may be other nerve cells, muscle cells, or gland cells. At the synapse, the axon releases a chemical neurotransmitter that diffuses across a tiny gap and binds to receptors (molecules on the surface of the target cell) that then change the target cell's behavior

T

Tetraplegia

Complete or partial impairment of sensation and motor activity of both the upper and lower part of the body.

U

Urinary infection

Inflammation caused by pathogens of the urinary tract (urethra, bladder). The infection can "spread" and induce infection of the kidney.

V

Vertebra

One of the bone segments of the spinal column. The spinal column consists of 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, sacrum and tailbone.