Medical and Healthy Living Glossary - N
This page of our online glossary of medical and healthy living is for medical and healthy living terms beginning with the letter 'N'.
- Nematodes - Wormlike organisms that live in the ground. They may also be a parasite on fish.
- Nephron - A tiny filter in the kidneys which filters fluid. A nephron is formed out of a series of tubules, the loop of Henle, Bowman’s capsule and a glomerulus. Blood enters the nephron from the renal artery, and waste materials are filtered out by the Bowman’s capsule. Some substances return to the bloodstream by reabsorption in the tubules.
- Neurons (Nerve Cells) - Nerve cells in the nervous system that can carry electrical impulses.
- Neurotransmitters - Chemical messengers released from nerve endings which transmit
nerve impulses from one neurone to another.
- Neurotoxins - Chemicals that affect the bodies' nervous system. Severe reactions can include visual problems, muscle twitching, weakness, abnormalities of brain function, and behavioral changes.
- Nitrates - Chemical compounds containing nitrogen that occur naturally in certain foods and which are sometimes added to meat and meat products as preservatives. Nitrates are widely used in agriculture as a fertiliser, and can leach from the soil into rivers and reservoirs that provide domestic water supplies.
- Nitrites - Like the chemically related nitrates, nitrites are added to meats such as bacon to help preserve them. They may also be produced within the body, through the action of bacteria in the stomach on nitrates contained in food or drinking water.
- Non-Haem Iron - The form of iron which is found in vegetables. It is less efficiently absorbed than the haem iron in meat. However, vitamin C for example, from a glass of orange juice when taken with a meal - aids in the absorption of the non-haem.
- Noradrenaline (Norepinephrine) - This hormone is closely related to adrenaline and has a similar action. It is released by the adrenal gland and is also released as a neurotransmitter by nerve endings. Noradrenaline helps to maintain blood pressure in shock, haemorrhage or hypotension.
- Nucleus - The central control region of the cell.
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