outer+surface
71layer — A sheet of one substance lying on another and distinguished from it by a difference in texture or color or by not being continuous with it. SEE ALSO: stratum, lamina. SYN: panniculus. ameloblastic l. the internal l. of the enamel organ. SYN: enam …
72ear, human — ▪ anatomy Introduction organ of hearing and equilibrium that detects and analyzes noises by transduction (or the conversion of sound waves into electrochemical impulses) and maintains the sense of balance (equilibrium). The human ear, like …
73Muscle — is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart… …
74Nature — This article is about the physical universe. For other uses, see Nature (disambiguation). Natural and Natural World redirect here. For other uses, see Natural (disambiguation). See also: Natural environment Hopetoun Falls, Australia …
75nervous system, human — ▪ anatomy Introduction system that conducts stimuli from sensory receptors to the brain and spinal cord and that conducts impulses back to other parts of the body. As with other higher vertebrates, the human nervous system has two main… …
76joint — /joynt/, n. 1. the place at which two things, or separate parts of one thing, are joined or united, either rigidly or in such a way as to permit motion; juncture. 2. a connection between pieces of wood, metal, or the like, often reinforced with… …
77skin — skinlike, adj. /skin/, n., v., skinned, skinning, adj. n. 1. the external covering or integument of an animal body, esp. when soft and flexible. 2. such an integument stripped from the body of an animal, esp. a small animal; pelt: a beaver skin.… …
78digestive system, human — Introduction the system used in the human body for the process of digestion. The human digestive system consists primarily of the digestive tract (alimentary canal), or the series of structures and organs through which food and liquids pass… …
79Lyme disease microbiology — Lyme disease, or borreliosis, is caused by Gram negative spirochetal bacteria from the genus Borrelia , which has at least 37 known species, 12 of which are Lyme related, and an unknown number of genomic strains. Borrelia species known to cause… …
80earthquake — /errth kwayk /, n. 1. a series of vibrations induced in the earth s crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating. 2. something that is severely disruptive; upheaval. [1300 50; ME erthequake …
