The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human organism.
The study of the human body involves anatomy, physiology, histology and embryology. The body varies considerably in size and appearance from individual to individual; however, there are certain basic proportions that are maintained within a population. For example, the average height of an adult male is approximately 1.7 m, while the average height of an adult female is approximately 1.6 m. The average weight of an adult male is approximately 75 kg, while the average weight of an adult female is approximately 65 kg.
There are various methods used to investigate the human body. These include medical imaging techniques such as X-rays, computed tomography (CT) scans and magnetic resonance imaging (MRI). Other techniques include gross anatomy (the study of large structures visible to the naked eye), histology (the study of tissues under a microscope) and immunohistochemistry (the use of antibodies to visualise specific proteins within tissue sections).
The human body consists of several organs that work together to perform specific functions. These organs are grouped into systems based on their common function or location within the body. For example, the digestive system includes all organs involved in digestion, such as the mouth, stomach and intestines; whereas, the respiratory system includes all organs involved in respiration, such as the nose, trachea and lungs.