The human body is made up of trillions of cells organized into tissues, organs, and systems that work together to keep us alive every second of every day.
The human body contains an estimated 37 trillion cells, each performing specialized functions. Groups of similar cells form tissues, such as muscle tissue, nerve tissue, and connective tissue, which then combine to form organs like the heart, lungs, and liver.
The heart pumps roughly 2,000 gallons of blood through the body every day, traveling through a network of blood vessels that would stretch about 60,000 miles if laid end to end.
The brain contains approximately 86 billion neurons that communicate through electrical and chemical signals, controlling everything from voluntary movements to involuntary functions like breathing and heartbeat.
Adults have 206 bones that provide structure, protect internal organs, and allow movement in coordination with over 600 muscles.