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NeurOn Glossary of Terms

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z


Afferent is a general term applied to nerves or blood vessels that means nerve signals or blood are traveling from the peripheral to the center of the body.

Relating to the science of plant and animal structures

A wasting away of the body or an organ

Autonomic Nervous System (ANS)
The autonomic nervous system is the part of the nervous system that supplies stimulation to the involuntary muscles, like the heartbeat and the glands. The autonomic nervous system is controlled principally by parts of the brain stem and the hypothalamus (a part of the brain).


The study of the biological and chemical interactions of living things

Blood pressure
Blood pressure is the pressure exerted by the flow of blood through the arteries of the body. This pressure is greatest during the contraction of the ventricles of the heart (systolic pressure), which forces blood into the arterial system. Pressure falls to its lowest level when the heart is filling with blood (diastolic pressure).


Cardiovascular means pertaining to the heart and the blood vessels.

Central Nervous System (CNS)
The Central Nervous System consists of the brain and the spinal cord; the CNS is responsible for the integration of all nervous activities.

Circadian means being, having, characterized by, or occurring in approximately 24 hour periods or cycles; in relation to sleep cycles.

Relating to perception, judgment, memory and reasoning.


Dynamics refers to the forces in a system (such as everyday life on Earth) that drive the system (such as gravity).


Efferent means conducting (fluid or a nerve impulse) outward from a given organ or part thereof, e.g. the efferent connections of a group of nerve cells, efferent blood vessels, or the excretory duct of an organ.

A state of rest or balance.


Homeostatic means relating to homeostasis, which is the physiological process by which the internal systems of the body (e.g. blood pressure, body temperature, acid-base balance) are maintained at equilibrium despite variations in the external conditions.


Kinematics refers to the study of pure motion without thinking about the forces causing the motion.


Melatonin is a substance secreted by the pineal gland that passes by way of the blood or through the fluid of the third ventricle to the anterior pituitary gland to control gonadotropic hormone secretion; melatonin can be manufactured artificially and is showing several possible beneficial medical uses.

A nerve that carries impulses from the receptor and the brain

Metabolism is the sum of all the chemical and physical changes that take place within the body and enable its continued growth and functioning.

A metabolite is a substance that takes part in the process of metabolism, which involves the breakdown of complex organic constituents of the body with the liberation of energy for use in bodily functioning. The various compounds that take part in or are formed by these reactions are called metabolites.

A state where the gravity is reduced to almost negligible levels. illustration

Microgravity Sciences
A research program which studies fundamental science, combustion science, materials science and biotechnology in the space environment in order to better understand gravity dependent physical phenomena.

Motor plasticity
Motor plasticity refers to the capability of that which imparts movement, i.e., the muscles, to be formed or molded, i.e. the quality of being plastic.


Neuromuscular means of or relating to nerves and the muscles they stimulate.

A neuron is a nerve cell, one of the basic functional units of the nervous system; it is specialized to transmit electrical nerve impulses and so carry information from one part of the body to another.

Neuroscience is any one of the various branches of science concerned with growth, development and function of the nervous system.

A chemical that communicates information between neurons by movement across the synapse. illustration


Optokinetic refers to the occurrence of intermittent rotation of the eye when the subject looks at moving objects. In other words, when the visual scene continually moves before the eyes, such as when a person is riding in a car or turning around, the eyes fix on one highlight after another in the visual field, jumping from one to the next at a rate of two to three jumps per second. The jumps are called saccades and the movements a are called optokinetic movements.

Orthostatic intolerance
When astronauts come back to Earth after they become adapted to space and weightlessness, they tend to faint when they stand because their blood pressure falls.

An otolith (or otoconium) is one of the small particles of calcium carbonate in the saccule or utricle of the inner ear. Pressure of the otoliths on the hair cells of the macula provide sensory inputs about acceleration and gravity.


Physiological means of or relating to physiology, the science that studies the function of the body and the vital processes of living things, whether animal or plant.

A placebo is a substance, made to look like medicine, that actually does nothing. Its purpose is to control a study of a real medicine.

Plasma volume
Plasma volume is the measure of the volume of plasma in the blood. Plasma is the liquid portion of blood; the solid portion of blood is composed of cells. Plasma consists of a solution of various inorganic salts, such as sodium, potassium, calcium, protein, and other blood volume is about 5 liters.


The receptor is the ending of a nerve where an impulse starts. This ending is usually on the skin or near the surface and is the cause of "pain" as we know it.


Spacelab is a reusable laboratory that contains space flight hardware carried in the Space Shuttle's payload bay. Most life sciences experiments are conducted in the Spacelab. Equipment is mounted along the walls and floor of the pressurized cylindrical Spacelab module. Crewmembers float into the Spacelab through a tunnel adapter that transits from the airlock in the Shuttle middeck to the Spacelab.

Spatial orientation
Spatial orientation refers to the process of aligning or positioning in a three-dimensional space with respect to a specific direction or reference system.

Stimuli (plural form of stimulus) are things that cause an organism to perform an activity or start a reaction.

Sympathetic means relating to the actions of the sympathetic nervous system, one of the two divisions of the autonomic nervous system. Its nerves are distributed to the blood vessels, sweat glands, salivary

A place where nerve signals are sent across a gap.


Growing and/or living on land


A hollow part of the body connected to another hollow part, an example is the area leading to the cochlea, found in the inner ear.

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