naïve lymphocyte (nī-ĒV LIM-fŏ-sīts): Mature B or T cell that has not yet encountered antigen for the first time.

nasal cavity (NĀ-zăl KAV-ĭt-ē): The inside of your nose.

nasogastric (nā-zō-GĂS-trĭk): Pertaining to the nose and stomach.

nasolacrimal (nā-zō-LAK-rĭ-măl): Pertaining to the nose and the tear duct.

nasopharyngeal (nā-zō-FAR-in-JĒ-ăl): Pertaining to the nose and pharynx.

nasopharyngitis (nā-zō-făr-ĭn-JĪ-tĭs): Inflammation of the nose and pharynx.

nasopharynx (nā-zō-FAR-ingks): The nasopharynx serves as an airway and is continuous with the nasal cavity.

natal (NĀT-ăl): Pertaining to born.

natural killer cell (nk): Cytotoxic lymphocyte of innate immune response.

nausea (NAW-sē-ă, naw-zē-ă): Urge to vomit.

nebulizer (NEB-yŭ-lī-zĕr): Device that creates a mist for giving respiratory treatment or medication.

necrosis (nĕ-KRŌ-sĭs): Condition of death.

neonatal (nē-ō-NĀT-ăl): Pertaining to the newborn. For example neonatal record, neonatal unit.

neonate (NĒ-ō-nāt):  New born (infant from birth to four weeks of age).

neonatologist (nē-ō-nā-TŎL-ō-jĭst): Physician who studies and treats disorders of the new born.

neonatology (nē-ō-nā-TŎL-ō-jē): Study of the newborn.

nephrectomy (nĕ-FREK-tŏ-mē): Excision of the kidney.

nephritis (nĕ-FRĪT-ĭs): Inflammation of the kidney.

nephrography (nĕ-FRŎG-ră-fē): Radiographic imaging of the kidney.

nephrolithiasis (nef-rō-li-THĪ-ă-sĭs): Condition of stone(s) in the kidney.

nephrolithotripsy (nĕf-rō-LITH-ŏ-trip-sē): Surgical crushing of sone(s) in the kidney.

nephrolitotomy (nĕf-rō-lĭth-ŎT-ō-mē): Incision into the kidney to remove stone(s).

nephrologist (nĕ-FRŎ-lō-jĭst): Specialist who studies and treats disease and disorders of the kidney.

nephrology (nĕ-FRŎL-ă-jē): Study of the kidney.

nephrolysis (nĕ-frŏl-ĭ-sĭs): Separating the kidney (from body structures).

nephroma (nĕ-FRŌ-mă): Tumor of kidney.

nephromegaly (nĕf-rō-MĔG-ă-lē): Enlarged kidney.

nephropexy (NĔF-rō-pĕks-ē): Surgical fixation of the kidney.

nephroscopy (NĔF-ră-skō-pē): Process of viewing the kidney.

nephrosonography (nĕ-FRŎ-sō-NOG-ră-fē): Process of recording the kidney using sound.

nephrostomy (nĕ-FRŎS-tō-mē): Creation of an artificial opening into the kidney.

nerve (nĕrv): Cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system.

neurectomy (nū-RĔK-tō-mē): Excision of nerves.

neuritis (noo-RĪ-tĭs): Inflammation of the nerves.

neuroarthropathy (noo-rō-ar-THROP-ă-thē, nū): Disease of the nerves and joints.

neuroglia (noo-ROG-lē-ă): Supportive tissue of the nervous system, including the network of branched cells in the central nervous system (astrocytes, microglia, and oligodendrocytes) and the supporting cells of the peripheral nervous system (Schwann cells and satellite cells), also called glia.

neuroid (noo-rōyd): Resembling a nerve.

neurologist (nū-RŎL-ō-jĭst): Specialist who studies and treats the nervous system.

neurology (noo-ROL-ŏ-jē): Study of nerves.

neurolysis (noo-ro-LĬ-sĭs): Dissolution of nerve (for pain management).

neuroma (noor-Ō-mă): Tumor made up of nerve (cells).

neuron (NOOR-on): Neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system.

neuroplasty (NŪ-rō-plăs-tē): Surgical repair of a nerve.

neuropathy (noo-ROP-ă-thē): Disease of (peripheral) nerves.

neurorrhaphy (nū-ROR-ă-fē): Suturing of a nerve.

neurosensory (nū-rō-SĔN-sō-rē): Relating to afferent nerves.

neurotomy (nū-RŎT-ō-mē): Incision into a nerve.

neurotransmitter (noor-ō-trans-MIT-ĕr): Chemical that is released from a nerve cell, transmits an impulse from a nerve cell to another nerve, muscle, organ, or other tissue.

neutrophil (nū-trō-FĬL-ĭk): Phagocytic white blood cell recruited from the bloodstream to the site of infection via the bloodstream.

nevus (NĒ-vŭs): A pigmented skin blemish.

nociceptors (nō-sē-SEP-tŏrs): Sensory neurons that respond to pain.

nocturia (nŏk-TŪ-rē-ă): Night urination.

node of Ranvier (nōd of ron-vē-Ā): Gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon.

nodule (NOJ-ool): A small node-like structure.

non-stress test (nŭn stres test): Test conducted on the pregnant woman to assess the fetal heart rate (FHR).

norepinephrine (nor-ep-ĭ-NEF-rĭn): A natural chemical in the body that acts as both a stress hormone and neurotransmitter (a substance that sends signals between nerve cells). It’s released into the blood as a stress hormone when the brain perceives stress.

nosocomial infection (nos-ŏ-KŌ-mē-ăl in-FEK-shŏn): Infection acquired in hospital.

nucleus (NOO-klē-ŭs): In the nervous system, a localized collection of neuron cell bodies that are functionally related; a “center” of neural function.

nulligravida (nŭl-ĭ-GRĂV-ĭ-dă): A woman who has never been pregnant.

nullipara (nŭl-ĬP-ă-ră): No pregnancies a woman who has never been pregnant.