Online Medical Dictionary

Letter P

Pacemaker (Artificial): A device that delivers electrical impulses to the heart in order to regulate the rhythm of its beating. The electrodes sent to the heart muscles cause the muscles to contract in time. Pacemakers may be implanted and programmed by a cardiologist to emit electrodes at the most optimal pace suited to the individual. Pacemakers are implanted when the natural pacemaker is deficient, or when dysfunctions in the body's natural electrical cardiac conduction system exist.
Palliative Care: Medical care focused on providing pain relief, comfort and reducing the symptoms of a critical illness when the disease itself cannot be treated, or there is no potential to cure or reduce the progression of the condition.
Palpitations: An abnormal beating of the heart, wherein the beating becomes pronounced to the individual. Inciters for heart palpitations span from coffee and alcohol to disease such as hyperthyroidism, panic or anemia.
Palsy: Paralysis, usually pertaining to the inability to control the movement or sense a particular body part. Bell's palsy, for example, refers to the paralysis of one side of the face.
Pancolitis: Inflammation of the large intestine (colon), indicative that ulcerative colitis has worsened. If left untreated, pancolitis may lend to the risk of developing colon cancer.
Pancreas: The endocrine and exocrine gland organ situated in the posterior of the abdomen, responsible for the secretion of several enzymes essential in the digestive process, and key regulator hormones such as somatostatin (growth hormone inhibitor), glucagon (inceases blood glucose) and insulin (decreases blood glucose).
Pancreatectomy: The surgical procedure conducted to remove a portion or the entirety of the pancreas organ. Pancreatectomy is only performed if painful, chronic inflammation due to pancreaitis, severe damage, pancreatic tumour, or pancreatic cancer is prevalent.
Pancreatic: Regarding the pancreas.
Pancreatic Cancer: Malignant neoplasm of the pancreas, the risk of which developing is believed to be increased by age (over 60), smoking, poor diets high in sugar and red meat, and diabetes mellitus.
Pancreatic Carcinoma: See Pancreatic Cancer.
Pancreatitis: Inflammation of the pancreas; acute (sudden onset) or chronic (associated with recurring pain in the abdomen, sometimes with diabetes mellitus). Pancreatitis is most commonly induced by inflammation of the common bile duct, caused by the passing of gallstones, as well as the excessive consumption of alcohol.
Pap Smear: A gynecological screening test in which a cell sample from the outer cervix is attained to examine for pre-cancerous cells or malignancies of the ectocervix. The pap smear should be conducted in females annually, in aim to prevent cervical cancer by locating and treating cells before they become malignant.
Pap Test: Abbreviation for Papanicolaou test. See Pap Smear.
Papillary Tumour: A mushroom-like epithelial tumour that may develop out of the inner lining of an organ.
Papilloma: A benign epithelial tumour, often associated with the wart-like symptom caused by contraction of the human papillomavirus (HPV).
Parathyroid Gland: Endocrine glands of the neck, responsible for regulating calcium levels in the blood and bones.
Parathyroidectomy: The surgical procedure conducted to remove one or more of the parathyroid glands in order to extricate a parathyroid tumour or to treat hyperplasia of a gland, which is inducing the overproduction of the parathyroid hormone.
Parkinson's Disease: A progressive disorder of the central nervous system, marked by rigidity, the slowing of cognitive processing and voluntary movement, and body tremor. Parkinson's disease is caused by the degeneration of a region of the basal ganglia, resulting in a decreased production of cells producing the neurotransmitter dopamine.
Patho-: Prefix defining a disease, such as in a pathogen. May also be used in suffix, such as in the term psychopath.
Pathogen: An infectious or disease causing agent.
Pathogenic: Possessing the ability to cause disease or infection.
Pathologist: A physician specialized in the identification and study of disease.
Pathology: The study of disease and their diagnosis.
Pediatrics: The field of medicine focused on the care of infants and youth from birth to adulthood (or the age of 18).
Pediatric Arthritis: Systemic-onset juvenile rheumatoid arthritis.
Pelvic Inflammatory Disease (PID): A term used to describe inflammation of the uterus or other parts of reproductive system, causing tissue scarring, usually induced by and referring to bacterial infection or a sexually transmitted infection (STI).
Penile Cancer: A malignancy, usually of a Squamous cell carcinoma, developed from the tissues of the penis. Though rare in North America and Europe, has some prevalence in cancers among men of South America and Africa. Treatments include circumcision of a cancerous foreskin, micro-surgical removal of affected cells, radiation therapy or chemotherapy. Cause is postulated at an association with infection of the human papillomavirus (HIV), smoking and smegma, among other factors.
Peptic Ulcer: A painful, usually acidic ulcer found in areas of the gastrointestinal tract, such as the esophagus, stomach and duodenum. Peptic ulcers are most often caused by an infection of the bacterium Helicobacter pylori or stress. Complications can include gastrointestinal bleeding or corrosion of the gastrointestinal wall. Treatment may include prescribed antacids or antibiotics to treat bacterial infection.
Peripheral Nervous System: The nerves and ganglion located outside of the brain and spinal chord which function to transmit communications between the limbs and torso of the body and the central nervous system.
pH: A measure of the acidity of a fluid. Solutions measuring under 7 are said to be acidic, while those measuring above 7 are said to be basic, with 7 indicating neutrality.
Phalanges: The bones of the fingers and toes.
Physical Therapy: A branch of therapy concentrated on the rehabilitation or training of movement and functioning skills, as well as the prevention of motor impeded conditions, through exercise, massage, education and other focused techniques. Physical therapy, or physiotherapy, specialties also include treatment and care in cardiopulmonary, neurological, orthopedic, pediatric, geratric and women's health.
Piles: See Hemorrhoid.
Pink Eye: Conjunctivitis. Inflammation of the eye's outer layer caused by viral or bacterial infection or allergens, resulting in a red, watery and swelled appearing eye. Most cases of pink eye do not necessitate treatment and can be flushed out with fluids.
Pituitary Gland: An endocrine gland situated at the bottom of the hypothalamus, functioning to regulate the secretions emitted by other glands and the hormones that help to regulate the body's blood pressure, growth, production of breast milk during nursing, metabolism, functioning of the thyroid gland, temperature and water absorption.
Placenta: An organ that begins developing when the blastocyst implants in the lining of the uterus wall, allowing the transfer and exchange of nutrients, gases and waste between the fetus and the bloodstream of the mother.
Plasma: The liquid component of blood, which keeps blood cells suspended.
Plasma Cell: White blood cells that originate from the bone marrow as B cells, undergo differentiation and are transported by blood plasma. Plasma cells produce large amounts of antibodies.
Pneumonectomy: The surgical removal of the entirety or a portion of a lung, usually conducted to extricate malignant lung tumours in the treatment of lung cancer.
Pneumonia: Inflammation of the lung, usually caused by bacteria or virus, but can be triggered by additional irritants, such as fungi or parasite. Most cases of pneumonia can be treated with antibiotics, though some, up to 1 in 5, will require hospitalized care treatment.
Podiatrist: A physician specialized in the examination, diagnosis and treatment of diseases or conditions of the foot, ankle and lower leg.
Polio: An infectious, highly contagious viral disease, most often transmitted fecal-orally. The polio vaccine is administered to guard against the virus in many countries. The majority of polio cases are asymptomatic, while just under 1 per cent develop into paralytic poliomyelitis.
Poliomyelitis: See Polio.
Pons: A brain structure, located on the brain stem, the nuclei of which are responsible for transmitting signals between the cerebellum and the forebrain, as well as playing a role in the functions of sleep, swallowing, hearing, facial sensation and expression, tasting and bladder control, among various others.
Positron Emission Tomography (PET scans): An imaging technique providing three-dimensional images of bodily process utilizing short-lived radionuclides. Images are more difficult to reconstruct using the data collected by PET. PET scans are often used in conjunction with CT scans or MRIs.
Postpartum: The period lapsing for roughly six weeks, directly following childbirth. Also called the postnatal or puerperium period.
Progesterone: A hormone vital in readying the uterus for gestation (pregnancy) and in regulating menstruation.
Prognosis: A term used to describe the foreseeable outcome of a condition, illness or disease.
Prostate Cancer: A malignancy developing from the tissues of the prostate gland, the exocrine gland of the male reproductive system responsible for producing and secreting a component of semen. Due to its proximity to the bladder, prostate cancer may cause difficulties in urination and pain. Prostate cancer may spread to other tissues, particularly lymph nodes and bone. Prostate cancer is the most common of cancers developed in men, but due to its often slow development, many men with colon cancer will live out the duration of their life undiagnosed. Prostate cancer develops most commonly in men over the age of 50. Treatment methods include radical prostatectomy surgery, external beam radiation therapy and hormonal therapy.
Prosthesis: An artificial device used to replace a surgically removed, absent or otherwise missing body part, usually both cosmetically and functionally.
Prosthetic: Referring to a prosthesis, as in a prosthetic limb, an artificial replacement for the absent limb.
Psoriasis: A chronic, autoimmune skin disease, believed to be genetic and/or immune-related, caused when the immune system erroneously transmits signals for skin cells to grow more rapidly, producing scaly patches of red and white colour on the epidermis (the top layer of the skin). Psoriasis may be induced by stress or other environmental factors.
Psychosis: An abnormal state of mind.
Ptosis: The drooping of a body part, such as the drooping of an eye or the breasts.
Pulmonary Artery: The arteries responsible for carrying blood from the heart to the lungs. Pulmonary hypertension increases the blood pressure in the pulmonary artery, causing breathing difficulties and dizziness, and can lead to heart failure.
Pulmonary Stenosis: Obstructed flow of blood from the right ventricle of the heart into the pulmonary artery, usually due to pulmonary valve obstruction. Pulmonary stenosis is most often diagnosed in children, and can be associated with a congenital heart disease.
PX: Prognosis.