The Human Body

The Amazing Human Body

The human body is made up of over 100 trillion cells. Cells are the smallest building units of our organism. Although they form structural and functional units, they cannot survive on their own, but only as part of our organism. Our cells form tissues, which in turn form organs and organ systems, whose coordinated functioning sustains life and preserves the species.

Heart

The network of blood vessels in our body form the cardiovascular system. The blood is pumped through the blood vessels by the contractions of the heart.

The nervous system, together with the hormonal system, is responsible for the coordinated, regulated functioning of the body.

Kidneys

Unnecessary and harmful materials are removed from the body by the kidneys. They produce about 1.5 litres of urine per day. Urine is stored in the urinary bladder and is then released from the body through the urethra.

Muscles

Skeletal muscles are the major organs of locomotion. The three types of muscle tissue in the human body are the smooth, the skeletal (or striated), and the cardiac muscle tissue.

Skin

The skin is the largest organ in the human body: the skin of an average adult has a surface area of about 1.5 square metres and a mass of about 12 kg, including the hypodermal fat layer. It protects the body against mechanical damage, UV radiation, and pathogens;
its keratin layer prevents it from drying out. It also plays
an important role in temperature regulation.

Skeleton

The skeleton of an adult human consists of more
than 200 bones. Bones are rigid and flexible at the same time in order to carry a large amount of weight.
Bone metabolism is slow, so bones heal slowly.
A broken bone takes at least 6 weeks to heal.