4Tissue Structure and Organization Introduction Although the cell is a basic unit of life, complex functions in multicellular animals require interaction and cooperation between cells. With increased development, specialized functions…

13Cardiovascular System The cardiovascular system (cardio = heart; vascular = blood vessels) includes three components: blood, the heart, and blood vessels. Blood is essential for transporting nutrients and wastes, thermoregulation,…

14Respiratory System Introduction As animals evolved from single‐celled organisms to multilayered organisms, it became impossible for oxygen to diffuse effectively to all cells. Consequently, systems evolved to deliver oxygen and…

17Digestive System Digestive System Overview All animals need a supply of nutrients and oxygen that are obtained via the digestive system and respiratory system, respectively. The digestive system consists of…

12Endocrine System Introduction and Overview The nervous system, with its sensors and capacity for rapid response, combined with often longer‐term impacts of the endocrine system is critical for the maintenance…

6Bones and Skeletal System Bones Introduction Osteology is the study of bones. The skeleton provides the basic scaffolding for the body. The skeletal system includes the bones, cartilage, ligaments, and…

2The Cell: The Common Physiological Denominator Cells: A Common Denominator All physiological systems, for example, digestive, respiratory, or cardiovascular, depend on the actions and activities of cells. Groups of cells…

7Muscular Tissue Muscle Tissue Overview Introduction Muscle tissue is specialized for contraction and is responsible for body movements and changes in size and shape of internal organs. Muscle cells are…