This article is the second part to the medical terminology article A-M. This article contains information on medical terms N-V.

Neurotransmitters- Chemical messengers the provide communication between the brain cells.

Neurovascular- Involving the nerves and blood vessels.

Nicotine- Stimulant found in tobacco products that can trigger a migraine headache.

Non-steroidal anti-inflammatory drugs- also known as NSAIDs, are used to treat headaches. These are more commonly referred to as Ibuprofen and Naproxen.

Over the counter- Refers to medications that are available without a prescription. Aspirin, acetaminophen, and ibuprofen are examples.

Phonophobia- sensitivity to sound.

Photophobia- sensitivity to light.

Preventive medications- Prescription medications that are taken on a daily basis to prevent the onset of a headache or migraine.

Primary headache- headache that are not the result of another medical condition.

Secondary headache- headache that are a result of another medical condition such as allergies or head trauma.

Serotonin- a chemical messenger that communicates with the brain when to close or expand blood vessels.

Sinuses- air-filled spaces located in your forehead, cheekbones and behind your nose. When these are areas are inflamed the pain is similar to that of a headache.

Symptomatic relief medications- used to relieve symptoms associated with headaches. This can include not only the pain itself but nausea or vomiting as well.

Transformed migraines- coexisting migraine with a tension headache. These tend to be chronic daily occurrences with a vascular quality.

Trigger- the factor that will be the onset of the headache or migraine. Some examples of headache and migraine triggers are stress, diet, weather changes, certain smells, caffeine.

Tyramine- a natural substance is foods that are formed as proteins breakdown with age. Cheese, red wine and processed meats are examples of foods high in tyramine. This has been known to trigger migraines in some people.

Vasoconstriction- the narrowing or closing of a blood vessel.

Vasodilation- the swelling or opening of a blood vessel.