Human Anatomy - H. I. Koliadenko 2009

Structure of the Human Body
Organs, Organ Systems, and Apparatuses

An organ (from the Greek organon, meaning instrument or tool) has a specific shape and Structure designed to perform a particular function. Humans possess various Organs located both externally and internally. External organs include the Skin, ears, and eyes, whereas Internal Organs comprise The Heart, Lungs, Liver, and Blood Vessels, among others.

Every organ is constructed from distinct types of Tissues, but one of them serves as the primary, "working" tissue responsible for its main function. For instance, a Skeletal Muscle contains Striated Muscle tissue, Connective Tissue (such as BLOOD AND Lymph), Epithelial Tissue (the mesothelium of blood vessels), and nerve fibers; however, striated muscle tissue is predominant, driving its primary action—contraction.

Morphologically and physiologically, organs are integrated into systems. An organ system is a group of organs sharing a common developmental origin, structural similarities, and a unified function.

The Human Body comprises the following Anatomical and physiological systems: 1) The Musculoskeletal System, formed by bones, their joints, and Muscles; 2) the Respiratory system, consisting of organs that facilitate oxygen uptake and the elimination of carbon dioxide and other Metabolic waste products; 3) the Digestive System, uniting organs responsible for food Digestion and nutrient assimilation; 4) the Urogenital System, formed by organs that clear metabolic waste and ensure species reproduction; 5) The Cardiovascular system, which maintains the constancy of the internal environment and transports nutrients and physiologically active substances; 6) the Endocrine System, whose glands secrete highly active substances directly into the blood; 7) The Nervous system, which integrates all PARTS OF THE body into a single whole and mediates its interaction with the external environment; 8) Sensory systems (analyzers), which ensure the perception of information from both the external and internal environments.

These systems are also referred to as apparatuses: the musculoskeletal, digestive, respiratory, and urogenital apparatuses.

All of these individual anatomical and physiological systems are integrated into a single, cohesive entity that continuously interacts with the external environment and maintains a state of dynamic equilibrium. This complex, historically evolved system is known as the Organism.

The human body is structurally divided into the soma (from the Greek soma, meaning body) and the viscera (Greek splanchna), located within the Body Cavities (the heart, lungs, and Esophagus in the thoracic cavity; The Stomach, intestines, liver, and Spleen in the Abdominal cavity). Both the soma and the internal organs are supplied with blood vessels, lymphatic vessels, and nerves. The soma and viscera function in a coordinated, holistic manner, driven by the integrative activity of the Central Nervous System and humoral regulation.

The fundamental principles of human body Organization include: polarity (differences in Structure and function between poles), segmentation (which in humans is largely preserved in the trunk), bilateral Symmetry (similarity in structure between the left and right sides of the body, though not absolute), and correlation (a specific Functional and Structural relationship among individual body parts).

In anatomy, as in physiology, The concepts of norm and anomaly exist. Anatomically, a condition of an organ, system, or apparatus is considered normal when its Functions remain unimpaired, whereas an anomaly represents a deviation from the general pattern that is accompanied by a disruption in the function of the organ or the entire organ system.