Glossary P

P

P value

The p (probability) value is a calculation used in studies to determine if the results are caused by chance or not. The lower the p-value, the more likely it is that the difference between groups was caused by treatment. A p value less than 0.05 is statistically significant and indicates that the result is not due to chance.

Pain threshold

The point at which a person becomes aware of pain.

Palpation

Examination by pressing on the surface of the body to feel the organs or tissues underneath.

Parenteral nutrition

The slow infusion of a solution of nutrients into a vein through a catheter, which is surgically implanted. This may be partial, to supplement food and nutrient intake, or total (TPN, total parenteral nutrition), providing the sole source of energy and nutrient intake for the patient.

Pathogenesis

The origin and development of a disease or disorder.

Pathogens

Disease causing microorganisms.

Pathological

Disease related.

Pathology

The study of the fundamental nature, causes, and development of abnormal conditions and the structural and functional changes that result.

Pathophysiologic mechanisms

Processes involved with a particular function.

Pathophysiology

Changes or alterations in function that accompany a particular syndrome or disease, generally as distinguished from structural defects.

Pelvic

Having to do with the pelvis (the lower part of the abdomen located between the hip bones).

Peptic ulcer

A sore in the lining of the esophagus, stomach, or duodenum, usually caused by the bacterium Helicobacter pylori (H. pylori). An ulcer in the stomach is a gastric ulcer; an ulcer in the duodenum is a duodenal ulcer.

Perineum

The area of the body between the anus and the vulva in females, and between the anus and the scrotum in males.

Peristalsis

Synchronized or coordinated contraction of the muscles that propel food content through the gastrointestinal (GI) tract to facilitate normal digestion and the absorption of nutrients. Peristalsis is dependent upon the coordination between the muscles, nerves, and hormones in the digestive tract.

Pharmacokinetics

How the body handles a drug, including how it is absorbed, circulated, transformed, and eliminated.

Physiology

The study of how the body functions at the levels of organs, cells, and molecules.

Pilot study

The initial study examining a new method or treatment.

Placebo

A placebo is an effect, not merely a thing. It is more or less a component of all healing yet is poorly understood or studied. In clinical trials a placebo pill, device, or procedure acts as a control to ensure that the effect seen with the treatment is specific, not only the result of the placebo effect or the natural evolution of an illness that accompany every therapeutic encounter. (Thompson WG. What are placebos, IFFGD 2002; Fact Sheet No. 172)

Postprandial

After meals.

Prevalence

The proportion of people in the entire population who are found to be with a disease or disorder at a certain point in time (sometimes called a "cross section"), without regard to when they first got the disease.

Primary care

First contact medical care to patients.

Primary care physician

A doctor who manages a person's health care over time. A primary care doctor is able to give a wide range of care, including prevention and treatment, and can refer a patient to a specialist.

Primary lactase deficiency

When a person is born with the inability to digest lactose, a sugar found in milk and milk products. Lactose can't be digested because there is not enough of an enzyme, called lactase, in the body. Consuming milk and dairy products causes diarrhea, bloating, gas, and discomfort. This deficiency can also develop over time, as the amount of lactase in the body decreases with age.

Probiotics

Microbial cell preparations or components of microbial cells that have a beneficial effect on the health and well being of the host.

Proceedings

A collection of current research reports, usually presented as brief abstracts, from a scientific meeting.

Progressive muscle relaxation

Voluntary relaxation through systematic tensing and relaxing of different muscle groups.

Prokinetic

Drugs that enhance propulsion of contents through the gut.

Prospective study

A study that utilizes carefully defined protocols to determine an outcome that is unknown beforehand.

Protease

A protein that digests other proteins.

Protein

A large complex molecule made up of one or more chains of amino acids. Proteins perform a wide variety of activities in the cell.

Protocol

An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered.

Proton pump inhibitor (PPI)

A drug that limits acid secretion in the stomach.

Pseudo-obstruction (intestinal)

A motility disorder with symptoms like those of a bowel blockage, but with no physical evidence of blockage or obstruction. Symptoms may include cramps, stomach pain, nausea, vomiting, bloating, fewer bowel movements than usual, and loose stools. May be chronic or acute (Ogilvie's syndrome).