1 1 Anatomy and Physiology Compared In this section we compare anatomy and physiology and present the general subdivisions of these sciences Anatomy is the study of structure and form The word anatomy is derived from the Greek word anatome which means to cut apart or dissect Anatomists are scientists who study the structure and form of organisms Specifically they examine the relationships among parts of the body as well as the structure of individual organs Physiology is the study of function of the body parts Physiologists are scientists who examine how organs and body systems function under normal circumstances as well as how their functioning may be altered via medication or disease Table 1 1 compares how anatomists and physiologists may examine the same organs The sciences of anatomy and physiology are intertwined one cannot study physiologic function without first having some understanding of anatomic form Likewise one cannot adequately describe and understand the anatomic form of an organ without first learning that organ s function Throughout these chapters we have attempted to integrate the study of anatomy and physiology showing how form and function are interrelated 1 1a Anatomy Details of Form LEARNING OBJECTIVES 1 Describe the science of anatomy 2 List the subdivisions in both microscopic and gross anatomy As mentioned in the previous section anatomy examines the structure and form of organisms The discipline is extremely broad and can be divided into several more specific fields Microscopic anatomy examines structures that cannot be observed by the unaided eye For most of these studies scientists prepare individual cells or thin slices of some part of the body and examine these specimens under the microscope Microscopic anatomy has several subdivisions with two main divisions Cytology s tol j cyto cell logos study is the study of body cells and their internal structure Histology his tol j histos web tissue is the study of tissues Gross anatomy also called macroscopic anatomy investigates the structure and relationships of body parts that are visible to the unaided eye such as the intestines stomach brain heart and kidneys In these macroscopic investigations specimens or their parts are often dissected cut open for examination Gross anatomy may be approached in several ways Systemic anatomy studies the anatomy of each functional body system For example studying the urinary system would involve examining the kidneys where urine is formed and the organs of urine transport ureters and urethra and storage urinary bladder Most undergraduate anatomy classes study anatomy using this systemic approach Regional anatomy examines all of the structures in a particular region of the body as a complete unit For example one may study the axillary armpit region of the body and in so doing examine the blood vessels axillary artery and vein nerves branches of the brachial plexus lymph nodes axillary lymph nodes musculature connective tissue and skin Most medical school gross anatomy courses are taught using a regional anatomy approach Page 3 Surface anatomy focuses on both superficial anatomic markings and the internal body structures that relate to the skin covering them Health care providers use surface features to identify and locate important landmarks such as pulse locations or the proper body region on which to perform CPR Most anatomy classes also instruct students on important surface anatomy locations Comparative anatomy examines similarities and the differences in the anatomy of different species For example a comparative anatomy class may examine limb structure in humans chimps dogs and cats Embryology em br ol o j embryon young one is the discipline concerned with developmental changes occurring from conception to birth Several specialized branches of anatomy focus on the diagnosis of medical conditions or the advancement of basic scientific research Pathologic path loj ik pathos disease anatomy examines all anatomic changes resulting from disease Both gross anatomic changes and microscopic structures are examined Radiographic anatomy investigates the relationships among internal structures that may be visualized by specific scanning procedures such as ultrasound magnetic resonance imaging MRI or x ray It may seem as though nothing new can be learned about anatomy after all the body has been much the same for thousands of years Yet in fact new information is being learned from ongoing anatomic studies some of which displace the traditional thinking about the workings of various organs Never forget that anatomy is a dynamic changing science not a static unchanging one WHAT DID YOU LEARN What subdiscipline of anatomy may explore how the lower limb differs between humans and chimpanzees 1 1b Physiology Details of Function LEARNING OBJECTIVES 3 Describe the science of physiology 4 List the subdivisions in physiology Physiologists examine the function of various organ systems and they typically focus on the molecular or cellular level to gain a complete understanding of the system s workings Thus a basic knowledge of chemistry is essential in understanding physiology and that s why we ve included an early chapter about chemistry The discipline of physiology parallels anatomy because it also is very broad and may be subdivided into smaller groups Many specific physiology subdisciplines focus their studies on a particular body system For example cardiovascular physiology examines the functioning of the heart blood vessels and blood Cardiovascular physiologists examine how the heart pumps the blood what are the parameters for healthy blood pressure and details of the cellular exchange mechanisms by which respiratory gases nutrients and wastes move between blood and body structures Other examples include neurophysiology which examines how nerve impulses travel throughout the nervous system and how nervous system organs work respiratory physiology which studies how respiratory gases are transferred by gas exchange between the lungs and the blood vessels supplying the lungs among other things and reproductive physiology which explores how the regulation of reproductive hormones can drive the reproductive cycle and influence sex cell production and maturation Pathophysiology investigates the relationship between the functioning of an organ system and disease or injury to that organ system For example a pathophysiologist would examine how blood pressure contractile force of the heart