Glossary (M-P)



Any of the many forms of mononuclear phagocytes found in the tissues. (Dorland, 28th ed)

Macrophages, Alveolar

Macrophages, Peritoneal
Mononuclear phagocytes derived from bone marrow precursors but resident in the peritoneum.

Magnetic Resonance Imaging (MRI)
A special imaging technique to examine the body using powerful magnetic fields and radiowaves. A computer is then used to produce the pictures of the internal organs of the body. MRI provides highly detailed information through visualization of soft tissues and highly detailed information. In many cases, MRI provides more useful images than CT scanning or ultrasound. MRI is done in a diagnostic clinic, radiology lab or hospital. A radiologist (a doctor who specialized in using x-rays, ultrasound, CT, MRI and other scans to aid in diagnosis) or qualified radiology technologist performs the procedure. The radiologist or other medical specialist will interpret the results. MRI takes about 30 to 90 minutes and is a painless, non-invasive test. Some people find the noise and being still and confined in a narrow space upsetting.

Malignant Pleural Effusions
Fluid built up in the pleural space (space around the lungs) due to cancer. More common cancers that cause this are breast and lung.

Marek's Disease
A Iymphoproliferative disease of fowl caused by a herpes virus. Lymphoid cell infiltrations are most common in the peripheral nerves and gonads, but widespread infiltrations may also be found in any of the visceral organs, skin, muscle, and the iris of the eye. The location of the lesions dictates the clinical signs, such as paralysis, general depression, and blindness. (Dorland, 27th ed)

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Mast Cells
A connective tissue cell whose specific physiologic function remains unknown. (Dorland, 28th ed)

Maxillary Sinus
One of the paired paranasal sinuses, located in the body of the maxilla, communicating with the middle meatus of the nasal cavity.

Maxillary Sinus Neoplasms
Neoplasms or tumors of the maxillary sinus. The majority of paranasal sinus neoplasms arise here. They develop silently when confined to the sinus and produce symptoms on extension through the walls.

Maxillary Sinusitis
Inflammation of the maxillary sinus. In most cases it is the result of infection by the bacteria haemophilus influenzae, streptococcus pneumoniae, and staphylococcus aureus. This condition may be acute or chronic.

Meconium Aspiration
Syndrome caused by sucking of thick meconium into the lungs, usually by term or post-term infants (often small for gestational age) either in utero or with first breath. The resultant small airway obstruction may produce respiratory distress, tachypnea, cyanosis, pneumothorax, and/or pneumomediastinum.

Metered Dose Inhaler (MDI)
A hand held canister that is used to inhale medication in measured amounts. The number of sprays a canister gives can be tracked.

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Middle Lobe Syndrome
Atelectasis of the right middle pulmonary lobe, with chronic pneumonitis. (Dorland, 27th ed)

Milk Hypersensitivity
Allergic reaction to milk (usually cow's milk) or milk products. In infants the hypersensitivity is manifested by colic, vomiting, diarrhea, rhinitis, wheezing, etc. Milk hypersensitivity should be differentiated from lactose intolerance, an intolerance to milk as a result of congenital deficiency of lactase.

Monoclonal Gammopathies, Benign
Conditions characterized by the presence of a monoclonal serum (or urine) protein without clinical manifestations of plasma cell dyscrasia.


Monocytes, Activated Killer
Monocytes made cytotoxic by ex vivo incubation with cytokines, especially interferon-gamma. AKM cells are used for adoptive immunotherapy in cancer patients.

Mouth Breathing

See "Magnetic Resonance Imaging".

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Relating to mucus or a mucous membrane.

A thick, clear fluid found in the airways. Also known as phlegm, or sputum.

Multiple Chemical Sensitivity

Multiple Myeloma
A malignant tumor of plasma cells usually arising in the bone marrow; characterized by diffuse involvement of the skeletal system, hyperglobulinemia, Bence-Jones proteinuria, and anemia.

Multiple Sclerosis
A disease in which there are foci of demyelination of various sizes throughout the white matter of the central nervous system, sometimes extending into the gray matter. Typically, the symptoms of lesions of the white matter are weakness, incoordination, paresthesias, speech disturbances, and visual complaints. The course of the disease is usually prolonged, so that the term multiple also refers to remissions and relapses that occur over a period of many years. The etiology is unknown. (Dorland, 28th ed)

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Myasthenia Gravis
A disorder of neuromuscular function due to the presence of antibodies to acetylcholine receptors at the neuromuscular junction. Clinically there is fatigue and exhaustion of the muscular system with a tendency to fluctuate in severity and without sensory disturbance or atrophy. The disorder may be restricted to a muscle group or become generalized with severe weakness and, in some cases, ventilatory insufficiency. (Dorland, 27th ed)

Mycosis Fungoides
A chronic malignant T -cell lymphoma of the skin. In the late stages the lymph nodes and viscera are affected.


Nasal Bone
Either of two small elongated rectangular bones that together form the bridge of the nose

Nasal Cavity
The proximal portion of the respiratory passages on either side of the nasal septum, lined with ciliated mucosa, extending from the nares to the pharynx.

Nasal Mucosa
The mucous membrane lining the nasal cavity.

Nasal Obstruction
Any hindrance to the passage of air into and out of the nose. The obstruction may be in the nasal vestibule, fossae, or other areas of the nasal cavity.

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Nasal Polyps
Focal accumulations of edema fluid in the nasal mucosa accompanied by hyperplasia of the associated submucosal connective tissue. Polyps may be neoplasms, foci of inflammation, degenerative lesions, or malformations.

Nasal Septum
The partition separating the two nasal cavities in the midplane, composed of cartilaginous, membranous and bony parts.

Neuritis, Experimental Allergic
An autoimmune demyelinating disorder of peripheral nerves produced by injection of peripheral nerve tissue protein.


A specialized structure that serves as an organ of the sense of smell as well as part of the respiratory system; the term includes both the extemal nose and the nasal cavity.

Nose Deformities, Acquired
Deformities of the nose acquired after birth from injury or disease.

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Nose Diseases
Disorders of the nose, general or unspecified.

Nose Neoplasms
Neoplasms or tumors of the nose.

Nutritional Intake
The amount of food you eat, usually measured in calories.


Olfactory Mucosa
That portion of the nasal mucosa containing the sensory endings for olfaction; the organ of smell.

Olfactory Receptor Neurons
Neurons in the olfactory epithelium with proteins that bind, and thus detect, odorants. Olfactory receptor neurons are bipolar. They send to the surface of the epithelium apical dendrites with non-motile cilia from which project odorant receptor molecules. Their unmyelinated axons synapse in the olfactory bulb of the brain. Unlike other neurons, they can be generated from precursor cells in adults.

Ophthalmia, Sympathetic

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An individual, living thing.

Loss of calcium in the bones.

A colorless, odorless and tasteless gas needed for life. After air is inhaled, oxygen is sent to the blood and to the cells for energy in the process of cellular respiration.


Palliative Care
Palliative care refers to medical care provided by doctors and other members of the healthcare team that is aimed at providing maximum comfort and relief of disease symptoms for a patient. The focus of care is no longer cure, disease control, or prolonging life but instead to assist the patient and family in achieving the best quality of life for the remainder of the patient's life.

Pancoast's Syndrome

Paranasal Sinus Diseases
Diseases affecting or involving the PARANASAL SINUSES and generally manifesting as inflammation, abscesses, cysts, or tumors.

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Paranasal Sinus Neoplasms
Neoplasms or tumors of the paranasal sinuses. Malignant neoplasms are rare, comprising 3% of all head and neck neoplasms. The majority arise in the maxillary sinus, with malignancies of the ethmoid sinus constituting virtually all the remaining tumors.

Paranasal Sinuses
Air-filled extensions of the respiratory part of the nasal cavity into the frontal, ethmoid, sphenoid, and maxillary cranial bones. They vary in size and form in different individuals and are lined by the ciliated mucous membranes of the nasal cavity.


Parietal Pleura
The portion of the pleural membrane that lines the thoracic (chest) cavity.

Peak Expiratory Flow Rate (PERF)
The fastest rate a person can expel air from their lungs after taking in as big a breath as possible.

Peak Flow Meter
A small device which measures one's peak expiratory flow rate.

Please see "Positive End Expiratory Pressure"

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Pemphigoid, Bullous

Group of chronic blistering diseases characterized histologically by acantholysis and blister formation within the epidermis.

Pemphigus, Benign Familial
Rare hereditary disease characterized by recurrent eruptions of vesicles and bullae mainly on the neck, axillae, and groin. It exhibits autosomal dominant inheritance and is unrelated to pemphigus vulgaris though it closely resembles that disease.

Please see "Peak Expiratory Flow Rate".

Perfusion Scan
A test to determine the status of blood flow to an organ.

Peritonsillar Abscess

Peyer's Patches
Lymphoid tissue on the mucosa of the small intestine.

Phagocyte Bactericidal Dysfunction
Disorders in which phagocytic cells cannot kill ingested bacteria; characterized by frequent recurring infection with formulation of granulomas.

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Any cell capable of ingesting particulate matter. (Dorland, 28th ed)

Inflammation of the throat.

The thick sticky mucus that is secreted in the respiratory passages usually as a result of infection, inflammation or irritation of the airways. It is coughed up and discharged through the mouth.

Pickwickian Syndrome

Plasma Cells


The thin serous membrane enveloping the lungs and lining the thoracic (chest) cavity.

Pleural Cavity
The chest cavity. It houses the heart and lungs.

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Pleural Diseases
Disorders of the pleural space, general or unspecified.

Pleural Effusion

Pleural Effusion, Malignant

Pleural Membranes
The lung is surrounded by a membrane that has two closely opposed layers known as the pleura. The visceral pleura (inside layer) lines the lungs. The parietal pleura (outside layer) lines the chest cavity. The two layers are separated by a thin film of lubricating fluid that helps the smooth sliding of one surface over another during breathing movements.

Pleural Neoplasms

Pleural Procedure
A medical or surgical procedure involving pleura (lining of the lung).

Pleural Space
The tiny fluid-filled "space" between the visceral and parietal pleura; if air should enter this normally non-communicating space, a pneumothorax will result

Inflammation of the pleura, with exudation into its cavity and upon its surface. It may occur as either an acute or chronic process. (Dorland, 28th ed)

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Pleurisy complicated with pneumonia. (Dorland, 27th ed)

Condition characterized by permanent deposition of substantial amounts of particulate matter in the lungs, usually of occupational or environmental origin, and by the tissue reaction to its presence.

Inflammation of the lungs with consolidation and exudation

Pneumonia, Aspiration

Pneumonia, Bacterial
Pneumonia caused by various species of bacteria. Bacterial pneumonia commonly results from bronchogenic spread of infection following microaspiration of secretions. The largest category of this disease arises from community-acquired pneumonias.

Pneumonia, Lipid

Pneumonia, Mycoplasma
Interstitial pneumonia caused by extensive infection of the lungs and bronchi, particularly the lower lobes of the lungs, by mycoplasma pneumoniae.

Pneumonia, Pneumococcal
A febrile disease caused by streptococcus pneumoniae. This condition is characterized by inflammation of one or more lobes of the lungs, and symptoms include chills, fever, rapid breathing, and cough.

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Pneumonia, Pneumocystis Carinii
A pulmonary disease occurring in immunodeficient or malnourished patients or infants, characterized by dyspnea, tachypnea, and hypoxemia. Pneumocystis carinii pneumonia is a frequently seen opportunistic infection in AIDS. It is caused by the fungus Pneumocystis carinii.

Pneumonia, Rickettsial
Pneumonia caused by infection with bacteria of the family Rickettsiaceae.

Pneumonia, Staphylococcal
Pneumonia caused by staphlyococcus aureus. This condition is a frequent complication of viral influenza.

Pneumonia, Viral
Pneumonia caused by a virus. (Dorland, 28th ed)

The resection of the most functionless areas of the lungs in emphysema to relieve the symptoms of COPD.

An accumulation of air or gas in the pleural space, which may occur spontaneously or as a result of trauma or a pathological process and results in partial or complete collapse of the lung. The air needs to be drained from the space it occupies. Usually, a tube, called a chest tube, is inserted into the space and left in place until the air is expelled and the lung re-expands.

POEMS Syndrome
A chronic, progressive multisystem disorder of obscure etiology characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes.

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The opposite of anemia. In this condition there are too many red blood cells. Polycythemia exists when the haemoglobin, red blood cell count, and total RBC volume are all above normal.

Polyendocrinopathies, Autoimmune
Autoimmune disease affecting multiple endocrine organs. Type I is characterized by childhood onset and mucocutaneous candidiasis, while type II exhibits any combination of adrenal insufficiency (ADDISON'S DISEASE), lymphocytic thyroiditis, hypoparathyroidism, and gonadal failure. In both types organ-specific antibodies against a variety of endocrine glands have been detected. The type II syndrome differs from type I in that it is associated with HLA-A1 and 88 haplotypes, onset is usually in adulthood, and candidiasis is not present.

Positive End Expiratory Pressure (PEEP)

Positive-Pressure Respiration, Intrinsic

Primary Immune Deficiency
An immune deficiency that you are born with.

A class of chemicals found in the body that includes antibodies.

Pulmonary Alveolar Proteinosis
A chronic lung disease characterized by dyspnea, productive cough, chest pain, weakness, weight loss, and hemoptysis, and by the filling of the distal alveoli with a bland, eosinophilic, proteinaceous material that prevents ventilation of affected areas. (Dorland, 28th ed)

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Pulmonary Alveoli

Pulmonary Edema
Abnormal, diffuse, extravascular accumulation of fluid in the pulmonary tissues and air spaces due to changes in hydrostatic forces in the capillaries or to increased capillary permeability. (Dorland, 28th ed)

Pulmonary Embolism
Embolism in the pulmonary artery or one of its branches.

Pulmonary Emphysema
Condition of the lungs characterized by increase beyond normal in the size of air spaces distal to the terminal bronchioles, either from dilatation of the alveoli or from destruction of their walls.

Pulmonary Eosinophilia
A disease characterized by pulmonary infiltrations of eosinophils and blood eosinophilia.

Pulmonary Fibrosis

Pulmonary Nodules
A round or oval-shaped, small abnormality in the lungs.

Pulmonary Vena-Occlusive Disease
Obstruction of the small- and medium-sized pulmonary veins by fibrous proliferation of the intima and media or by thrombosis or a combination of both.

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Pulmonary Function Tests (PFT)
A set of teats that studies lung volumes and capacities to evaluate the mechanical properties of the lung. The test measures:

  • TCL (Total Lung Capacity -is the volume of air in the lungs after a maximal inspiration
  • RV (Residual Volume -is the volume of air remaining in the lungs after a maximum expiration)
  • VT (Tidal Volume -is the volume of air that enters the lungs during inspiration and leaves the lungs during expiration)
  • FRC (Functional Residual Capacity -is the volume of air that remains in the lungs at the end of a normal expiration)
  • VC (Vital Capacity -is the maximum volume of air that can be exhaled form the lungs after a maximum inspiration)
  • FEF (Forced Expiratory Flow)
  • FVC (Forced Vital Capacity -after taking in as deep a breath as possible, the air is breathed out as forcibly as possible until no more can be breathed out)
  • FEV1 (Forced Expiratory Volume in 1 second -is the maximum amount of air that can be breathed out in the first second during a forced expiration)
  • DLCa (Lung Diffusion Capacity -provides an estimate of how well a gas is able to move from your lungs into your blood)

Purpura, Schoenlein-Henoch
A form of nonthrombocytopenic purpura due to a hypersensitivity vasculitis associated with a variety of clinical symptoms including urticaria and erythema, arthropathy and arthritis, gastrointestinal symptoms, and renal involvement.

Purpura, Thrombocytopenic

Purpura, Thrombocytopenic, Idiopathic
Thrombocytopenia occurring in the absence of toxic exposure or a disease associated with decreased platelets. It is mediated by immune mechanisms, in most cases IgG autoantibodies which attach to platelets and subsequently undergo destruction by macrophages. The disease is seen in acute (affecting children) and chronic (adult) forms.

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