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However, current advances in physiology usually depend on carefully designed laboratory experiments that reveal the functions of the many structures and chemical compounds that make up the human body.
Like anatomists, physiologists typically specialize in a particular branch of physiology.
This is a micrograph of nerve cells from the brain. (credit a: “Writer Hound”/Wikimedia Commons; credit b: Micrograph provided by the Regents of University of Michigan Medical School © 2012) Anatomists take two general approaches to the study of the body’s structures: regional and systemic.
Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen.
Macro- means “large,” thus, gross anatomy is also referred to as macroscopic anatomy.
In contrast, micro- means “small,” and microscopic anatomy is the study of structures that can be observed only with the use of a microscope or other magnification devices (Figure 1b).
At the microscopic level, the arrangement and function of the nerves and muscles that serve the eyelid allow for its quick action and retreat.
At a smaller level of analysis, the function of these nerves and muscles likewise relies on the interactions of specific molecules and ions.