anaphy: the human organism

• The human body is a magnificent, complex, and prolific system
• If a person's intestines were stretched out, they would be as tall as a three-story building
• By the time a person reaches old age, they will have produced enough saliva to fill more than one swimming pool
• A person loses about two-thirds of a kilogram every year in dead skin cells, and will lose more than 50 kilograms of them in their lifetime
• Anatomy


  The study of the structure and relationships between body parts
• Physiology


  The science of how body parts come together to function and keep the body alive
• Anatomy and physiology draw on other disciplines like chemistry and physics
• Anatomy and physiology are about understanding why we are alive, how we came to be alive, how disease harms us, and how our body recovers from illness and injury
• Anatomy and physiology are also about understanding processes like death, sex, eating, sleeping, and thinking
• For centuries, the dissection of human bodies was taboo in many societies, so the study of anatomy followed a long, slow, and often creepy road
• Today, students of anatomy and physiology still use educational cadavers to learn, in person and hands-on, what's inside a human body by dissecting them
• Complementarity of structure and function


  The basic idea that what a structure can do depends on its specific form
• The human body is made up of about 7 octillion atoms
• Cells


  The smallest units of living things, which vary widely in size and shape depending on their purpose
• Tissues


  Groups of similar cells that perform specific functions
• Organs


  Combinations of two or more tissue types that perform specific functions
• Organ systems


  Organs working together to get things done
• Organism


  The highest level of organization, made up of trillions of cells in nearly constant activity
• Homeostasis


  The ability of all living systems to maintain stable, internal conditions no matter what changes are occurring outside the body
• Everyone's ultimate cause of death is the extreme and irreversible loss of homeostasis
• Anatomical position


  The standard position of a person standing erect and facing straight ahead, with arms at the sides and palms forward
• Planes of the body

  Sagittal (left-right), parasagittal, coronal (front-back), and transverse (top-bottom)
• Axial and appendicular parts

  Axial (head, neck, trunk) and appendicular (arms, legs)
• Directional terms


  Anterior/ventral, posterior/dorsal, superior/cranial, inferior/caudal, medial, lateral, proximal, distal
• Anatomical language can help doctors and surgeons communicate precisely about the location of an issue within the body