Every murderer knows they face life behind bars if they are caught and convicted. But only in a few rare cases does that really mean they will never taste freedom again â there are fewer than 50 people who have been told they will die in jail.
The human body is made up of trillions of cells. Cells of the nervous system, called nerve cells or neurons, are specialized to carry messages through an electrochemical process. The human brain has approximately 100 billion neurons.
While neurons are the building blocks of the bodyâs communication system, it is the networks of neurons that allow signals to move between the brain and body. These organized networks, composed of up to one trillion neurons, make up what is known as the nervous system. The human nervous system is composed of two parts: the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which is composed of nerves and nerve networks throughout the body. The endocrine system is also essential to communication. This system utilizes glands located throughout the body, which secrete hormones that regulate a variety of things such as metabolism, digestion, blood pressure and growth. While the endocrine system is not directly linked to the nervous system, the two interact in a number of ways. The Central Nervous System The central nervous system (CNS) is made up of the brain and spinal cord.