The human nervous system consists of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
- Central Nervous System (CNS): The CNS is made up of the brain and the spinal cord, which are responsible for processing and coordinating incoming sensory information and outgoing motor responses. The brain is the control center of the body, responsible for interpreting sensory input, making decisions, and sending commands to the rest of the body via the spinal cord.
- Peripheral Nervous System (PNS): The PNS is made up of all the nerves that extend from the CNS to the rest of the body. It is further divided into two parts:
- Somatic Nervous System: This system controls voluntary movements and transmits sensory information from the body to the CNS. It includes the nerves that control skeletal muscles, as well as the sensory receptors in the skin, muscles, and joints.
- Autonomic Nervous System: This system controls involuntary functions such as heartbeat, digestion, and breathing. It is divided into two branches:
- Sympathetic Nervous System: This system prepares the body for “fight or flight” responses to stressful or dangerous situations, such as increased heart rate and dilated pupils.
- Parasympathetic Nervous System: This system promotes “rest and digest” responses to conserve energy and promote digestion, such as decreased heart rate and constricted pupils.
Overall, the nervous system plays a crucial role in maintaining homeostasis and allowing us to interact with the environment around us.