The human body is a complex biological system involving cells, tissues, organs, and systems all working together to make up a human being. The study of the structure of the human body is called anatomy. Herophilus (335-280 BC) is called the ‘Father of Anatomy’.
Different aspects of human anatomy are:
The cell is the smallest unit of the human body. It is the basic functional and structural unit of the body.
A group of cells of similarity in structure, function, and origin is called ‘tissue’.
A group of different kinds of tissues for performing specific functions is called an ‘organ’.
A collection of different organs of the body that work collectively to perform some kind of function are called a ‘system’. For example, the respiratory system, digestive system, etc.
The human body consists of several organ systems. Each system is made up of organs that work together to perform a specific function. The human body is divided into 11 systems:
1. Skeletal system – The skeletal system is made up of bones, ligaments, and tendons. It supports the overall structure of the body and protects the organs.
2. Circulatory/Cardiovascular system - The circulatory system consists of the heart, the blood vessels, and the blood. It performs three functions:
3. Digestive system – The digestive system helps to convert food into nutrients and energy for the body. Some of the organs included in the digestive system are the stomach, small intestine, large intestine, liver, and pancreas.
4. Respiratory system – The respiratory system consists of the upper respiratory tract which is made up of the nose, nasal cavity, sinuses, larynx and trachea, and the lower respiratory tract which is made up of the lungs, bronchi, and bronchioles, and alveoli (air sacs). Its purpose is to breathe in the oxygen we need to live and get rid of the carbon dioxide produced by the body.
5. Muscular system – The muscular system works closely with the skeletal system. Muscles help the body to move and interact with the world. This is the body’s largest system and normally comprises about 40 percent of body weight.
6. Nervous system – The nervous system or the neural system is a complex network of neurons specialized to carry messages. It is one of the most complex organ systems to ever evolve. The nervous system consists of two parts, namely: The central nervous system (CNS) consists of the brain and the spinal cord, and the Peripheral nervous system (PNS) consists of nerves that connect the CNS to every part of the body.
7. Endocrine system – The endocrine system produces hormones that help regulate the other systems in the body. It includes the pancreas, adrenal glands, thyroid, pituitary and more.
8. Excretory/Urinary system – The excretory system is our waste disposal system and consists of the kidneys, urinary bladder, and urethra. It uses the kidneys to filter the blood, and eliminate excess water and waste.
9. Immune system – The immune system is the body's defense against infectious organisms and germs. The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. One of the important cells involved are white blood cells, also called leukocytes.
10. Reproductive system – Human reproduction is when an egg cell from a woman and a sperm cell from a man unite and develop in the womb to form a baby. A number of organs and structures in both the woman and the man are needed in order for this process to occur. These are called the reproductive organs and genitals.
11. Integumentary system – The integumentary system is the body’s first line of defense against bacteria, viruses and other pathogens. It consists of the largest organ in the body: the skin. It protects the internal structures of the body from damage, prevents dehydration, stores fat and produces vitamins and hormones.
