Peristaltic Movements (Gr. περί, round, and στέλλω, to send). The slow, wave-like movements of the stomach and intestines.
Peritoneum (Gr. περιτείνω, to stretch around). The investing membrane of the stomach, intestines, and other abdominal organs.
Perspiration (Lat. perspiro, to breathe through). The sweat.
Petrous (Gr. πέτρα, a rock). The name of the hard portion of the temporal bone, in which are situated the drum of the ear and labyrinth.
Phalanges (Gr. φάλαγξ, a body of soldiers closely arranged in ranks and files). The bones of the fingers and toes.
Pharynx (Gr. φάρμγξ, the throat). The cavity between the back of the mouth and the gullet.
Physiology (Gr. φύσις, nature, and λόγος, a discourse). The science of the functions of living, organized beings.
Pia Mater (Lat.). Literally, the tender mother; the innermost of the three coverings of the brain. It is thin and delicate; hence the name.
Pinna (Lat. a feather or wing). External cartilaginous flap of the ear.
Plasma (Gr. πλάσσω, to mould). Anything formed or moulded. The liquid part of the blood.