Nervous System Subsystems

Main

The nervous system is divided into two main subsystems based on their location and function: the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which includes all the nerves and ganglia that branch out from the brain and spinal cord to the rest of the body.

Differences between the CNS and PNS:

• Location: CNS is located in the brain and spinal cord, while PNS is located throughout the body.

• Function: CNS processes and integrates information, while PNS transmits information to and from the CNS.

• Protection: CNS is protected by the skull and vertebrae, while PNS is more exposed and vulnerable to injury.

• Regeneration: CNS has limited ability to regenerate damaged cells, while PNS has a greater capacity for regeneration.

Terms

• Nervous System: A complex network of cells and tissues that transmits messages and controls actions throughout the body.

• Brain: The central organ of the nervous system, responsible for processing and integrating information from the entire body.

• Spinal Cord: A long, thin, and tubular bundle of nervous tissue that extends from the brain and serves as a conduit for signals between the brain and the rest of the body.

• Nerves: Bundles of fibers that transmit signals between the CNS and the rest of the body.

• Ganglia: Clusters of nerve cell bodies located outside the CNS that relay signals between nerves.

• Neuron: The basic structural and functional unit of the nervous system. It is a specialized cell that transmits messages through electrical and chemical signals.

Analogy

The nervous system can be compared to a city's transportation system. The CNS (brain and spinal cord) is like the central hub, where all the information is processed and decisions are made. The PNS (nerves and ganglia) is like the network of roads and highways that connect the central hub to different parts of the city, allowing information and commands to travel between the CNS and the rest of the body.

Misconception

Some people believe that the nervous system consists of three main subsystems: the central nervous system, the peripheral nervous system, and the enteric nervous system (which controls the gastrointestinal system). However, the enteric nervous system is actually a part of the peripheral nervous system, not a separate subsystem. While the enteric nervous system can function independently to some extent, it still communicates with and is influenced by the CNS and other parts of the PNS.

History

5. 1950s-1960s: The structure of the neuron and the mechanisms of synaptic transmission were elucidated.

6. 1970s-1980s: Advancements in molecular biology and genetics allowed for the study of the genetic basis of nervous system development and function.

7. 1990s: The decade of the brain, which saw increased funding and public awareness of neuroscience research.

8. 2010s-present: Optogenetics, a technique that uses light to control neural activity, has revolutionized the study of neural circuits and behavior. Brain-machine interfaces and neural prosthetics have also made significant progress.

How to use it

1. Understanding the role of the autonomic nervous system in stress can help you develop coping strategies, such as deep breathing and meditation, to reduce the negative effects of chronic stress on your health.

2. Knowing the differences between the CNS and PNS can help you better understand the effects of injuries or diseases on different parts of the nervous system. For example, a spinal cord injury may affect the PNS's ability to transmit signals to and from the CNS, leading to paralysis or sensory loss.

3. Recognizing that the PNS has a greater capacity for regeneration than the CNS can inform your expectations and treatment options for nerve injuries. For instance, peripheral nerve damage may be more likely to heal with proper care and therapy compared to damage to the brain or spinal cord.

Facts

• The human brain weighs about 1.4 kg (3 pounds) and consumes about 20% of the body's total energy.

• There are over 100 billion neurons in the human brain, and each neuron can form thousands of connections with other neurons.

• The longest nerve in the human body is the sciatic nerve, which runs from the lower back to the feet and can be over 1 meter (3 feet) long.

• The blood-brain barrier is a specialized structure that protects the brain from harmful substances in the bloodstream while allowing essential nutrients to pass through.

• Some animals, such as sea stars and planarians, have the ability to regenerate their entire nervous system after injury.