The Human Body

The spinal cord acts as the information highway, shuttling messages from the brain to the periphery at speeds of up to 270 miles per hour. The body also possesses a "second brain"—the enteric nervous system, a mesh of 500 million neurons lining the gastrointestinal tract, which governs digestion independently of the central brain.

: You have 206 bones that act as your internal frame. Interestingly, you were born with about 300, but some fused together as you grew. The Muscles

5. The Future of the Human Body: Biological Adaptation and Technology The Human Body

The only organ system not required for the immediate survival of an individual, its sole biological purpose is the survival of the species. It produces gametes (sperm and egg cells) and hormones necessary for the creation and development of offspring. Homeostasis: The Balance of Life

Over 600 muscles drive human movement. They are categorized into three distinct types: The spinal cord acts as the information highway,

includes ovaries (eggs and estrogen/progesterone), fallopian tubes, uterus, cervix, and vagina. Females are born with about 1–2 million immature eggs (oocytes); by puberty, only about 300,000 remain, and roughly 400 will ovulate over a lifetime.

Our bodies were originally designed for a very different world. For millions of years, humans evolved to be bipedal endurance runners who spent their days hunting and gathering. The Adaptation Paradox: Interestingly, you were born with about 300, but

Without functioning kidneys, toxic waste accumulates rapidly – which is why dialysis or transplantation is necessary in kidney failure.

Cells are the fundamental building blocks of the human body. The average adult body contains roughly 30 to 37 trillion cells, working in perfect unison. Specialized Functions