Human body

The human body is a complex biological system involving cells, tissues, organs, and systems all working together to make up a human being.

Main Structures

From the outside, the human body can be divided into several main structures. The head, which houses brain controls the body while neck and trunk house many important systems that keep the body alive and healthy. The limbs help the body to move about and function.

Senses

The human body has five main senses that are used by it to communicate information about the external world to the brain. These senses are: seeing (eyes), hearing (ears), smell (nose), taste (tongue), and touch (skin).

Organ Systems

The human body consists of several organ systems made up of organs and other body structures that work collectively to perform a specific function. Commonly, a body is divided into 11 systems.

Skeletal System - The skeletal system is made up of bones, ligaments, and tendons. This system supports the overall structure of the body as well as protects the organs.

Muscular System - It works closely with the skeletal system and helps the body move and interact externally.

Cardiovascular/ Circulatory System - This system consists of the heart, blood, and blood vessels and helps in delivering nutrients across the body.

Digestive System - It includes the stomach, small intestine, large intestine, liver, & pancreas and helps to convert food into nutrients & energy for the body.

Nervous System - It helps the body to communicate and allows the brain to control various functions of the body. It includes the brain, spinal cord, and a large network of nerves.

Respiratory System - It brings oxygen into the body through the lungs and windpipe and also removes carbon dioxide from the body.

Endocrine System - It produces hormones that help in regulating other systems in the body and includes the pancreas, adrenal glands, thyroid, pituitary, and more.

Urinary System - It uses kidneys to filter blood and eliminate waste and includes kidneys, bladder, and urethra.

Immune/Lymphatic System - Along with immune systems, it work together to protect the body from diseases.

Reproductive System - It includes the sex organs that enable people to have babies. This system is different for male and female body.

Integumentary System - It helps in protecting the body from outside world. It includes the skin, hair, and nails.

Cells, Tissues, and Organs

A human body is made up of cells. There are different types of cells in the human body. When lmany similar cells work together to do a function, they create tissue. There are 4 main types of tissues, including muscle tissue, connective tissue, epithelial tissue, and nervous tissue.

Organs are independent parts of the body that carry out special functions. They are made up of tissues. Examples of organs include the eyes, heart, lungs, liver, and stomach.

Interesting Facts about the Human Body

• The human body is made up of around 37 trillion cells.
• The average human heart beats around 100,000 times every day.
• If you spread out the wrinkles in the brain it would be about the size of a pillow case.
• Fingernails grow much faster than toenails. They are both made of a protein called keratin.
• About 60% of the human body is made up of water.
• The brain itself does not feel pain.
• The largest of the human internal organs is the small intestine.
• Acid in the stomach is powerful enough to dissolve some metals.
• The left lung is typically around 10% smaller than the right lung. This is to make room for the heart.
• Humans are born with 270 bones. Several of these bones fuse together by adulthood making a total of 206 bones in the adult human body.