A free, self-paced textbook in 8 chapters. Read a chapter, then drill it with the 53 companion flashcards using spaced repetition.
To introduce anatomy, all descriptions begin from the standard anatomical position: a person standing upright with feet together and parallel, arms at the sides with palms facing f...
The skeletal system provides the rigid framework on which the body is built. Its 206 adult bones serve multiple functions: they support soft tissues, protect vital organs like the...
Muscle tissue exists in three forms, each tailored to its location and function. Skeletal muscle is voluntary and striated, attached to bones and controlled consciously to produce...
The nervous system is organized into two main divisions that work together to sense, integrate, and respond to information. The central nervous system (CNS) consists of the brain a...
The cardiovascular system delivers oxygen and nutrients while removing metabolic wastes through a muscular pump and a network of vessels. The heart wall is composed of three layers...
The digestive system breaks food into absorbable nutrients through a muscular tube called the alimentary canal and several accessory organs that aid digestion. The stomach prepares...
The reproductive systems differ markedly between the sexes but share the purpose of producing gametes, supporting fertilization, and in females, nurturing developing offspring. In...
The eye is a roughly spherical organ whose anterior cornea provides initial refraction of light, while the iris controls the size of the pupil to regulate light entry. Behind the p...