The Study of Anatomy

Human anatomy is the scientific study of the body’s structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope. Other larger structures can readily be seen, manipulated, measured, and weighed. The word “anatomy” comes from a Greek root that means “to cut apart”. Human anatomy was first studied by observing the exterior of the body and observing the wounds of soldiers and other injuries. Later, physicians were allowed to dissect bodies of the dead to augment their knowledge. When a body is dissected, its structures are cut apart in order to observe their physical attributes and their relationships to one another. Dissection is still used in medical schools, anatomy courses, and in pathology labs. In order to observe structures in living people, however, a number of imaging techniques have been developed. These techniques allow clinicians to visualize structures inside the living body such as a cancerous tumor or a fractured bone.

Specialized Areas of Anatomy

Gross anatomy is the study of the larger structures of the body, those visible without the aid of magnification. Macro- means “large”, therefore gross anatomy is also referred to as macroscopic anatomy.

Gross Anatomy: Nerve Tissue

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. Microscopic anatomy includes cytology (study of cells) and histology (study of tissues). As the technology of microscopes has advanced, anatomists have been able to observe smaller and smaller structures of the body, from slices of large structures like the heart to the three-dimensional structures of large molecules in the body.

Microanatomy: Nerve Tissue

Approaches to Anatomy

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. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region.

In contrast, systemic anatomy is the study of the structures that make up a discrete body system (or organ systems). There are 11 body systems, and each is made up of structures that work together to perform a unique body function. For example, the circulatory system (or cardiovascular system) consists of the heart, blood, and blood vessels and functions to circulate gases, nutrients, hormones, and waste products.

The Study of Physiology

Whereas anatomy is about structure, physiology is about function. Human physiology is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life. Much of the study of physiology centers on the body’s tendency toward homeostasis. Homeostasis is the state of steady internal conditions maintained by living things. The study of physiology certainly includes observation, both with the naked eye and with microscopes, as well as manipulations and measurements. 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.

Specialized Areas of Physiology

Like anatomists, physiologists typically specialize in a particular branch of physiology. For example, neurophysiology is the study of the brain, spinal cord, and nerves and how these work together to perform functions as complex and diverse as vision, movement, and thinking. Physiologists may work from the organ level (exploring, for example, what different parts of the brain do) to the molecular level (such as exploring how an electrochemical signal travels along nerves).

Relationship of Form and Function

Form is closely related to function in all living things. For example, the thin flap of your eyelid can snap down to clear away dust particles and almost instantaneously slide back up to allow you to see again.

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. Even the three-dimensional structure of certain molecules is essential to their function.

Your study of anatomy and physiology will make more sense if you continually relate the form of the structures you are studying to their function. In fact, it can be somewhat frustrating to attempt to study anatomy without an understanding of the physiology that a body structure supports.

For example, the human hand, as you know, can easily manipulate pens, hammers, cell phones and other types of tools.

The unique shape of the thumb carpometacarpal joint increases the flexibility of the thumb and makes this hand function possible.

Thumb carpometacarpal joint

To manipulate many tools,  the thumb must move forward from the palm and sideways toward the tips of the other fingers.  This motion is called is opposition

Thumb oppostion

Chapter Review

Human anatomy is the scientific study of the body’s structures. In the past, anatomy has primarily been studied via observing injuries, and later by the dissection of anatomical structures of cadavers. In the past century, however, computer-assisted imaging techniques have allowed clinicians to look inside the living body.

Human physiology is the scientific study of the chemistry and physics of the structures of the body. Physiology explains how the structures of the body work together to maintain life.

It is difficult to study structure (anatomy) without knowledge of function (physiology). The two disciplines are typically studied together because form and function are closely related in all living things.

Lesson Glossary

  • Anatomy – is the science that studies the form and composition of the body’s structures.
  • Gross anatomy (or macroscopic anatomy) – is the study of the larger structures of the body, which is typically done with the unaided eye.
  • Homeostasis – is the steady state of body systems that living organisms maintain.
  • Microscopic anatomy – is the study of very small structures of the body using magnification.
  • Physiology – is the science that studies the chemistry, biochemistry, and physics of the body’s functions.
  • Regional anatomy – is the study of the structures that contribute to specific body regions.
  • Systemic anatomy – is the study of the structures that contribute to specific body systems.

Review Questions

Multiple Choice

Question 1

Which of following types of scientists would specialize in the study of the bones and muscles of the foot?

  1. Microscopic anatomist.
  2. Sectional anatomist.
  3. Regional anatomist.
  4. Systemic anatomist.
Show Answer
c.
Question 2

Which of the following types of scientists most likely studies how the body uses foods and fluids during a marathon run?

  1. Exercise physiologist.
  2. Microscopic anatomist.
  3. Regional physiologist.
  4. Systemic anatomist.
Show Answer
a.

Critical Thinking

Question 3

Name at least three reasons to study anatomy and physiology.

Show Answer

  • An understanding of anatomy and physiology is essential for any career in the health professions.
  • It can also help you make choices that promote your health, respond appropriately to signs of illness, make sense of health-related news.
  • It can help you in your roles as a parent, spouse, partner, friend, colleague, and caregiver.
Question 4

A single motor neuron (nerve cell) typically carries electrochemical impulses from nervous system (CNS) to several skeletal muscle cells. Based on its function, describe the likely general form (shape) of a motor neuron.

Show Answer

  • The CNS portion of the neuron is likely branched, so it can receive excitatory and inhibitory input from other, nearby CNS neurons.
  • The conducting portion of the neuron is likely long and narrow, so impulses can quickly travel an extended distance directly to the muscle cells.
  • The terminal portion of the neuron is most likely branched, so multiple muscles cells can be stimulated.