The human body is a wonderful machine. It is made up of millions of cells. Cells are the building blocks of our body. A cell is defined as the smallest structural and functional unit of life. There are different kinds of cells in our body. Cells of the same kind join to form tissues. Different tissues join to form an organ. Different organs work together to perform many functions at the same time in an organ system. There are several organ systems in our body that help us to do various things. Some organs are inside the body such as the heart, the brain, the lungs, the kidneys, and the like. These are called internal organs. Some organs are on the surface of the body such as eyes, ears, nose, mouth and the like. These are called external organs. Let us read about some of the important organ systems of our body.
The Skeletal System
The human body has 206 bones. These bones make up the skeletal system. A baby’s bones are soft, and they become hard as he or she grows up. Bones help keep the body strong and provide a structure or a framework for the internal organs to remain safe. Their main job is to keep the internal organs safe. For instance, the rib cage protects the heart and the skull protects the brain.
The Muscular System
Muscles are those organs of the human body which cover the skeletal system. They pull the bones and make them move. All the muscles together form the muscular system. Muscles are made up of soft tissues. They help us many actions such as to walk, run, to dance, to jump, to lift heavy objects, and so on.
The Digestive System
We eat food every day. The food is first changed into simple form for our body to use it. This is done by the digestive system. The organs that help the body to digest food form the digestive system. Digestion is the process of changing food into a simpler form so that it can be used by our body as energy. Our digestive system is made up of the mouth, food pipe, stomach, small intestine, large intestine, and anus.
The Respiratory System
What do we do with our nose? We breathe. Our nose, windpipe, and lungs form the respiratory system. The respiratory system helps us to breathe. We breathe in oxygen and breathe out carbon di oxide. Breathing in oxygen is called inhalation and breathing out carbon dioxide is called exhalation.
The Circulatory System
Our Blood, blood vessels, and heart, together form the circulatory system. These help our heart to beat, pump blood, and to transport this blood to all parts of the body. The blood flows through thin tubes called blood vessels. The blood vessels carry blood rich in oxygen from the heart to all the parts of the body. They also bring back carbon dioxide from the different parts of the body to the heart.
The Excretory System
Our body produces a lot of waste. To keep the body healthy, the waste produced by it must be removed. The process of flushing out the excess waste from our body is done by the excretory system. For instance, our kidneys remove waste from the body in the form of urine, our skin removes extra water and salt from the body in the form of sweat and our lungs help to remove carbon dioxide from the body during respiration.
The Nervous System
Our nervous system is the control centre of the entire body. Organs such as our brain, spinal cord, and nerves together form the nervous system. It controls all our actions and reactions. The Brain is located inside our head. It tells each organ what to do by sending instructions through nerves. Nerves are like wires that carry instructions from the brain to different parts of the body. They also collect information from all the parts of the body and bring them back to the brain. The spinal cord connects all the nerves of the body to the brain.
The Reproductive System
All living organism produce babies or young ones of their own kind. Reproduction is the process of producing more of one’s own kind. This process is carried out in the body with the help of some organs that form the reproductive system. Men and women have different reproductive systems. Women or female animals give birth to babies, and provide them with the care and nutrition that they need.