Medical and Healthy Living Glossary - P
This page of our online glossary of medical and healthy living is for medical and healthy living terms beginning with the letter 'P'.
- Palliative Care - Medical treatment which helps to reduce the symptoms of a disease, especially a terminal or chronic condition, but will not cure it. Palliative care usually involves giving
antibiotics, transfusions, pain-killing drugs, low-dose chemotherapy and psychological and social support to help the person and their family adjust to the illness.
- Pancreas - A gland with both endocrine and exocrine functions. It is located at the back of the body between the kidneys. The pancreas has two functions. The acini produce pancreatic juice that goes to the intestine via a system of ducts. This contains an alkaline mixture of salt and enzymes - trypsin and chymotrypsin to digest proteins, amylase to break down starch and lipase to aid digestion of fats. The second cell types are in the islets of langerhans. These produce two hormones, insulin and glucagon, secreted directly into the blood for control of sugar levels.
- Paracetamol (Acetaminophen) - Commonly used to relieve mild to moderate pain and reduce fever.
- Parasite - One organism that lives off another.
- Pasteurisation (Pasteurization) - The process for treating food by raising the temperature to a specific level and maintaining it for a set time to destroy bacteria. It is named after the French chemist and bacteriologist, Louis Pasteur. Pasteurisation is carried out by heating food for a short time at a lower temperature than that used for sterilisation: the two methods used are heating to 72°C for fifteen seconds (the high-temperature shorttime method) or to 65°C for half an hour, and then cooling rapidly. Pasteurisation will kill tuberculosis bacteria that may be present in milk.
- Pathogen - A microorganism that causes disease.
- Peristalsis - The process by which food is propelled through the digestive tract by waves of muscular contraction and relaxation along an organ such as the intestine or oesophagus.
- Persistence - The ability to remain in the environment for months or years without degrading into inert substances.
- pH - The measure of concentration of hydrogen ions in an aqueous solution which determines its acidity. pH factor is shown as a number. The scale of pH ranges from 1.0 (highly acidic), with decreasing acidity until pH 7.0 (neutral) and then increasing alkalinity to 14 (highly alkaline).
- Phagocytosis - The process by which some white blood cells engulf and destroy invading organisms, such as bacteria or a virus.
- Phytic Acid - Salts of phytic acid (phytates) are found in cereal grains and pulses. They bind with minerals such as calcium, iron and zinc, and make it more difficult for the body to absorb them. Too much bran (a concentrated source of phytic acid) can inhibit the body's absorption of these minerals.
- Phytochemicals - A group of compounds that occur naturally in all fruit and vegetables. They are now thought to offer a degree of protection against cancer, heart disease, arthritis, hypertension and other degenerative ailments. It has not yet been proven that these chemicals arrest cancer, but there is evidence that people who consume a diet rich in fruit and vegetables have a lower incidence of cancer. Beta carotene, indoles and isothiocyanates are all phytochemicals.
- Phytooestrogen - A substance obtained from cereals, legumes and seeds which has a similar effect to oestrogen. Phytooestrogen is being used increasingly as an alternative
to hormone replacement therapy.
- Pilates - A holistic form of exercise and postural therapy that develops the deep abdominal muscles to control body movement and protect the back.
- Pinna - The part of the ear which is outside the head and is connected by a passage to the eardrum.
- Pituitary Gland - The most important endocrine gland in the body, which is situated at the base of the brain. It secretes hormones that stimulate other glands. The pituitary gland hangs down from the base of the brain, inside the sphenoid bone, on a stalk which attaches it to the hypothalamus.
- Plasma - The yellowish fluid that makes up the main part of blood. Red and white blood cells and platelets are suspended in it. Plasma also carries thousands of other vital substances around the body, including proteins, glucose, vitamins, hormones and antibodies. If blood does not clot it separates into blood corpuscles and plasma, which is formed of water and proteins, including the clotting agent fibrinogen. If blood clots, the corpuscles separate from serum, which is a watery liquid similar to plasma, but not containing fibrinogen.
- Platelets - Small blood cells that release thromboplastin and which multiply rapidly after an injury, encouraging the coagulation of blood.
- Pleura (Pleural Membrane) - Sheet of tissue lining the inner surface of the chest cavity and the lung's outer surface.
- Poliomyelitis (Polio) or Infantile Paralysis - An infectious disease caused by a virus that attacks the central nervous system. In some cases the symptoms resemble a stomach upset or influenza; in others there is, in addition, some stiffness of muscles. Paralytic poliomyelitis is less common, resulting in muscle weakness and paralysis, while the most serious cases involve breathing, when the diaphragm and related muscles are affected (bulbar poliomyelitis). Immunization against poliomyelitis is highly effective, and the disease has almost been eradicated in most countries.
- Polyfhenols - A group of organic compounds (which includes the tannins) that are found in many foods such as tea, coffee and red wines. Polyfhenols combine with iron and can therefore hinder its absorption by the body.
- Polyps (Polypus) - Small tumours that form on a mucous membrane, most commonly in the nose and sinuses or throat. They are rarely malignant, but may need to be removed surgically to prevent discomfort or chronic infection. Polyps in the lower bowel can sometimes become cancerous.
- Polyunsaturated Fats (Polyunsaturated Fatty Acids) - A fatty acid which is capable of absorbing more hydrogen than most others. Polyunsaturated fats are found in high levels in corn oil, sunflower oil, huts, some margarines and oily fish such as mackerel. They include the two families of essential fatty acids that are necessary for health, so small quantities should be included in the diet. A diet high polyunsarurated fats and low in both trans and saturated fats will help to lower blood cholesterol levels and therefore reduces the risk of heart disease.
- Polyuria - The passing of a larger than normal quantity of urine, which is also usually pale in colour. It can be merely be the result of a large fluid intake or be caused by a condition such as diabetes or a kidney disorder.
- Protein - A large group of organic compounds which contain carbon, hydrogen, oxygen, sulphur and nitrogen, with individual molecules built up of amino acids in long polypeptide chains. Globular protein includes enzymes, antibodies, carrier proteins (e.g. haemoglobin and some hormones). Fibrous proteins have elasticity and strength and are found in muscle, connective tissue and also chromosomes. Proteins are vital to the body and are synthesized from their constituent amino acids, which are obtained from the digestion of dietary protein. Foods such as beans, meat, eggs, fish and milk are rich in protein.
- Psoriasis - A a common inflammatory skin disease where red patches of skin are covered with white scales. Psoriasis often runs in families and may be associated with anxiety, commencing usually in childhood or adolescence. Treatment consists of ointments and creams with some drugs and vitamin A.
- Pulmonary - Relating to the lungs, such as the pulmonary circulation and pulmonary artery.
- Purines - A group of organic compounds that includes caffeine and uric acid. Until quite recently, people suffering from kidney and bladder stones formed by the crystallisation of uric acid were forbidden foods rich in purines. Meats such as kidneys and liver and fish such as sardines and anchovies are rich in purines.
- Pupil - The central opening in the iris of the eye. Light passes through the pupil to reach the retina.
|
|
