It all comes down to the inner part of our adrenal glands—the adrenal medulla—which releases adrenaline into the body, says Peter ... the neural networks that connect the brain and the muscles.

Keeping everything safely wrapped up is your skin. Most of us have the same kind of body parts in the same places. You have a head and a neck. You have arms, elbows, hands and fingers. You have a ...

The brain connects to the spine and is part of the central nervous system ... The brain sends chemical and electrical signals throughout the body to regulate different biological functions ...

The shaft is the longest part of it. The head or glans is at the end of the ... Nerves relay messages to and from other parts of your body. An erection occurs when your penis fills with blood ...