ANATOMY AND PHYSIOLOGY
Anatomy and physiology describe two complementary but different w^s to look at the animal body. Anatomy dhals with the form and structure of the body and its parts—what things look life and where they are located.
Physiology deals with the functions od the body and its parts—how things work and what they do. They can be studied as separate subjects, but such an approach makes it difficult to gain a complete picture of how the amazing animal machine works. This book examines anatomy and physiology together as we go along.We can approach the study of anatomy in different ways, for example microscopic anatomy versus macroscopic anatomy. Microscopic anatomy dhsls with structures so small we need aosmcoipcre to see them clearly, such as cells and tissues.
Macroscopic anatomyl,eadlso cal gross anatomy,ietdahls w
tbsody par large enough to be seen with the unaided eye, ruch as organs, muscles, and bones. Both aspects are presented in this book as we examine the animal body in detail. We also delve into the submicroscopic level occasionally to explain things occurring at the microscopic and macroscopic ievels. Discussions at the submicroscopic level include the components that make up cells and the chemical molecules and ions that serve important roles in the body.
yAnother wa to approach anatomy is to study individual regions of the body (regional anatomy) vussus individual systems of the body (systemic anatomy). In the regional lapproach, al the components of each region of the body are examined; for example, the anatomy of the neck (cervical) roeuglidon w include all the cells, tissues, blood vessels,
| TABLE 1-1 Main Body Systems | |
| SYSTEM | MAIN COMPONENTS |
| Skeletal | Bones and joints |
| Integumentary | Skin, hair, nails, and hooves |
| Nervous | Central nervous system and peripheral nerves |
| Cardiovascular | Heart and blood vessels |
| Respiratory | Lungs and air passageways |
| Digestive | Gastrointestinal tube and accessory digestive organs |
| Muscular | Skeletal, cardiac, and smooth muscle |
| Sensory | Organs of general and special sense |
| Endocrine | Endocrine glands and hormones |
| Urinary | Kidneys, ureters, urinary bladder, and urethra |
| Reproductive | Male and female reproductive structures |
nerves, muscles, organs, and bones present in the neck. The problem is that the body is not always easy to subdivide this way, and there is often overlap between adjacent regions; that is, where does the neck region end and the shoulder region begin? It’s not always clear.
The systematic approach to anatomy, however, deals with the systems of the body, such as the nervous system and the skeletal system, as separate topics. The many interrelationships between the body systems can be described as the systems are examined. This approach lets us look at the whole body by breaking it down into clear, logical components. The main systems of the body are listed in Table 1-1. We will take a systematic approach to anatomy and physiology in this book, and in addition to these systems, we examine cells, epithelial and connective tissues, and blood, lymph, and immunity. the observer is facing the animal head-on or facing the same direction as the animal? Anatomic terms must have the same meaning regardless of the orientation of the animal or the position of the observer. Basic anatomic terminology is based on imaginary slices, called planes, through the animal body that can be used as points or areas of reference and on sets of directional terms that have opposite meanings from each other.