Definitions beginning with the
Word P

• Palliative Care
  Palliative care is any form of medical care or treatment that concentrates on reducing the severity of disease symptoms, rather than striving to halt, delay, or reverse progression of the disease itself or provide a cure. The goal is to prevent and relieve suffering and to improve quality of life for people facing serious, complex illness. Non-hospice palliative care is not dependent on prognosis and is offered in conjunction with curative and all other appropriate forms of medical treatment.
• Pathogenesis
  The term pathogenesis means step by step development of a disease and the chain of events leading to that disease due to a series of changes in the structure and /or function of a cell/tissue/organ being caused by a microbial, chemical or physical agent. The pathogenesis of a disease is the mechanism by which an etiological factor causes the disease. The term can also be used to describe the development of the disease, such as acute, chronic and recurrent.
• Pathology
  Pathology is the study and diagnosis of disease through examination of organs, tissues, bodily fluids, and whole bodies (autopsies).
• Phagocytes
  Phagocytes are the white blood cells that protect the body by ingesting (phagocytosing) harmful foreign particles, bacteria, and dead or dying cells. They are essential for fighting infections and for subsequent immunity. Phagocytes are important throughout the animal kingdom and are highly developed in vertebrates. One litre of human blood contains about six billion phagocytes.
• Phagocytosis
  Phagocytosis is the cellular process of phagocytes and protists of engulfing solid particles by the cell membrane to form an internal phagosome. Phagocytosis is a specific form of endocytosis involving the vesicular internalization of solid particles, such as bacteria, and is therefore distinct from other forms of endocytosis such as the vesicular internalization of various liquids. Phagocytosis is involved in the acquisition of nutrients for some cells, and in the immune system it is a major mechanism used to remove pathogens and cell debris. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytosed.
• Phenotype
  A phenotype is any observable characteristic or trait of an organism: such as its morphology, development, biochemical or physiological properties, or behavior. Phenotypes result from the expression of an organism genes as well as the influence of environmental factors and possible interactions between the two. The genotype of an organism is the inherited instructions it carries within its genetic code. Not all organisms with the same genotype look or act the same way because appearance and behavior are modified by environmental and developmental conditions. Similarly, not all organisms that look alike necessarily have the same genotype. This genotype-phenotype distinction was proposed by Wilhelm Johannsen in 1911 to make clear the difference between an organism heredity and what that heredity produces. The distinction is similar to that proposed by August Weismann, who distinguished between germ plasm (heredity) and somatic cells (the body). A more modern version is Francis Crick Central dogma of molecular biology.