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{{stub}}Physiology is the study of how organs function in an[[organism]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia

{{stub}}Physiology is the study of how organs function in an [[organism]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia

Educational Ministries, Inc. 1998</ref>

Educational Ministries, Inc. 1998</ref>

==Human physiology: Eleven systems==

==Organ systems==

Human physiology and anatomy classifies organs into eleven systems. They are Circulatory, Immune/Lymphatic, Skeletal, Muscular, Digestive/Excretory, Endocrine, Respiratory, Reproductive, Nervous/Sensory, Integumentary, and Urinary. Some physicians consider the nervous and sensory to be two distinct systems, and consider the skeletal and muscular as one (the Skeletomuscular), thus retaining the number of eleven systems total.

In physiology the various organs are grouped into systems based on their function. This makes it easier to understand how an organism works. More and more, however, we learn that the organs interface with one another in ways outside of the classic definitions of the systems. For example, the kidneys, generally thought of as being in the urinary system, are involved in producing hormones (endocrine system) that regulate blood pressure (circulatory system). The systems are: Circulatory, Immune/Lymphatic, Skeletal, Muscular, Digestive/Excretory, Endocrine, Respiratory, Reproductive, Nervous/Sensory, Integumentary, and Urinary. Not every physician or scientist uses the same groupings. For example, skeletal and muscular may be together, as the musculoskeletal system, and the reproductive and urinary system may be together, as the genitourinary system.

==Circulatory==

==Circulatory==