Human Body Systems and Organs: Structure and Function

Organs, Systems, and Apparatuses

Organs are structures composed of various tissues associated with performing a specific function. Organs are part of the apparatuses and systems that, in turn, constitute the human body.

Understanding Organs and Organography

Organography is the science that studies the structure and morphology of organs, while physiology is the science that studies their functions.

Major Systems of the Human Body

Systems consist of organs of the same type that perform similar functions.

• Muscular System

  This is the active part of the locomotor system. It consists of skeletal muscles composed of striated muscle tissue. It is responsible for locomotion, facial expressions, and the maintenance of posture.

• Skeletal System

  This is the passive part of the locomotor system. It consists of bones, which can take many forms and shapes. The bone matrix is mineralized to provide resistance and stiffness. It is responsible for locomotion, together with the muscular system, and the protection of organs and structures.

• Nervous System

  Composed of nerve tissue, its organs include the brain, spinal cord, and nerves. Through the nervous system, information is captured from the external and internal environments, nerve impulses are conducted, and orders are prepared to provide responses.

• Endocrine System

  It consists of glandular epithelial tissue. Its organs are endocrine glands that produce hormones. Hormones are chemicals that travel through the blood and act on cellular reactions, development, and other vital processes.

Essential Human Apparatuses

Apparatuses are made of different organs that act in concert to perform one or more higher functions.

• Digestive System

  It consists of the gastrointestinal tract and adjoining glands (salivary glands, liver, and pancreas). It obtains nutrients (organic and inorganic) from food.

• Respiratory System

  It consists of the airways and lungs. It facilitates gas exchange with the blood, which provides oxygen to the body and removes carbon dioxide produced by cells.

• Urinary System

  It consists of the kidneys, urinary tract (ureters, bladder, and urethra), and other organs such as the sweat glands. Thanks to this apparatus, waste substances from chemical reactions in the cells are eliminated by the body in a process known as excretion.

• Reproductive System

  It consists of various external and internal organs and can be male or female. These systems produce reproductive cells or gametes, which, after fertilization, give rise to a new individual within the mother.

• Circulatory System

  It consists of the heart, blood vessels (arteries, veins, and capillaries), and blood. It distributes blood throughout the body to deliver nutrients and oxygen to all cells. In turn, it collects excretory products and carbon dioxide from the cells.

• Locomotor System

  It consists of the muscular system (muscles) and the skeletal system (bones). It is responsible for locomotion and the voluntary movements of the body.