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Glossary - P

Displaying glossary terms beginning with the letter P: 1 - 50 of 201 in total
pacemaker (artificial)
A small electronic device generally placed in the chest to correct an irregular heartbeat. It generates small electrical pulses that prompt the heart to beat at a normal pace.
pacemaker, artificial
An electrical device that regulates the speed and rhythm of the heart when the heart can no longer do that itself.
Related health topics: Cardiomyopathy , Muscular Dystrophy
pacemaker, natural
A specialized cluster of cells called the sinoatrial node in the top of the right atrium. The pacemaker produces a steady flow of beat now signals that flash across the atria and then pass through the atrioventricular node to the ventricles.
painkillers
Drugs that relieve pain.
palate
The tissues that make up the roof of the mouth.
palliative care
Treatment that relieves the symptoms of a serious illness, but does not cure the disease itself.
palpate
To examine a part of the body by touching it carefully.
Related health topics: Gallbladder and bile duct cancer
palpitation
Pounding or racing of the heart.
palpitations
A sensation that the heart is beating rapidly or irregularly.
palsy
Paralysis in part of the body, often with loss of sensation and uncontrolled body movements.
pancreas
A gland in the abdomen that produces digestive enzymes and hormones.
pandemic
A disease outbreak affecting large populations or a whole region, country, or continent.
pannus
An abnormal layer of tissue that forms over joints or the cornea of the eye.
papillary muscles
Threads of muscle that pull the heart valves between the upper and lower chambers of the heart closed during heart contractions.
paraplegia
Paralysis of the legs and lower part of the body.
parasomnias
Sleep disorders, such as night terrors or sleep walking, that periodically interfere with sleep.
parasympathetic nervous system
Part of the nervous system that calms body systems excited by the stress hormones.
parathyroid glands
Glands responsible for releasing a hormone that controls calcium levels and influences bone loss and growth.
parathyroid hormone (PTH)
A hormone that controls levels of calcium and phosphorous in the blood and influences bone loss and growth.
parietal lobe
Part of the brain. It plays a role in sensory processes, like pain and touch, and language.
Related health topics: Osteoporosis
Parkinson's disease
A brain disorder that causes movement problems, including shaking, difficulty walking, and rigidity in muscles.
paroxysm
A sudden, violent attack or convulsion; or the worsening of symptoms or recurrence of disease.
paroxysmal hemicrania
A rare form of headache. Sufferers experience a severe throbbing, drilling pain on one side of the face or behind the eye.
passive immunity
Immunity that is conferred by another, such as a mother's antibodies protecting her baby during gestation and shortly after birth.
patch test
A test used to diagnose whether a rash was caused by a reaction to certain allergens, such as poison ivy or a cosmetic ingredient, or an irritant such as soap.
patella
The thick bone that protects the knee joint; also known as the kneecap.
Related health topics: Eczema
pathogen
A tiny organism such as a virus, bacterium, or parasite that can invade the body and produce disease.
pathology
The underlying abnormalities that contribute to or are characteristic of a disease.
patient-controlled analgesia (PCA)
A method that allows a person to control, within limits, the amount and timing of pain medication he or she receives. It is usually done by pressing a button to release the medication from a computerized pump into an IV.
Related health topics: Small Cell Lung Cancer
pattern-recognition receptors (PRRs)
Proteins that recognize classes of pathogens and stimulate the innate immune system to signal the adaptive immune system.
PDE5 inhibitors
Drugs that block phosphodiesterase type 5 (PDE5), an enzyme that breaks down erection-producing chemicals. These drugs can help a man achieve and maintain an erection.
peak bone mass
The greatest amount of bone tissue that a person has during his or her life.
peak flow
A measure of how fast a person can blow air out of the lungs.
peak flow meter
A device to assess lung function, often used to diagnose and monitor asthma.
pellagra
A rare disease brought on by severe niacin deficiency that causes diarrhea, dermatitis, and dementia.
pelvic floor
The sling of muscles that support the intestines and bladder, as well as the uterus in women. Weak or damaged pelvic floor muscles can cause incontinence or diminished sexual pleasure, among other problems.
penile prosthesis
An inflatable or bendable device that is implanted in the penis to allow a man with erectile dysfunction to have erections when he wishes.
pepsin
Enzymes secreted by the stomach to break down protein.
peptic ulcer
A raw, crater-like sore in the lining of the stomach or duodenum that causes burning stomach pain.
percutaneous diskectomy
Surgical removal of part of a spinal disk that is bulging out abnormally and pressing on a nerve root or the spinal column.
percutaneous electrical nerve stimulation (PENS)
A pain relief therapy that uses needles to deliver low-voltage electrical current under the skin to stop pain signals from reaching the brain.
percutaneous transluminal coronary angioplasty (PTCA)
A procedure used to open blocked coronary arteries. A small, thin tube with a tiny balloon at its tip is inserted into a narrowed coronary artery. The balloon is then inflated to widen the narrowed area. A stent may be put in place to hold the artery open. PTCA is also known as balloon angioplasty.
perforation
A hole, such as an ulcer, in an organ or tissue.
performance anxiety
Concern about sexual performance that is so severe that it leads to sexual dysfunction.
perfusion
Passage of a fluid through a specific organ or an area of the body.
perfusion defect
A test result that indicates abnormal blood flow or areas of damaged or dead heart muscle.
pericarditis
Inflammation of the pericardium, the heart's sac-like covering.
pericardium
The fibrous sac that surrounds the heart and the roots of the major blood vessels.
perimenopause
The transition time in a woman's life that begins when ovaries produce less estrogen and menstruation becomes less frequent, and ends when the ovaries no longer produce eggs and menstruation stops.
perineum
The area of skin between the vagina and anus in women, and between the scrotum and anus in men.