The nervous system has two main parts:
- The central nervous system is made up of the brain and spinal cord.
- The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
The nervous system transmits signals between the brain and the rest of the body, including internal organs. In this way, the nervous system’s activity controls the ability to move, breathe, see, think, and more.1
The basic unit of the nervous system is a nerve cell, orneuron. The human brain contains about 100 billion neurons. A neuron has a cell body, which includes the cell nucleus, and special extensions calledaxons(pronouncedAK-sonz) anddendrites(pronouncedDEN-drahytz). Bundles of axons, called nerves, are found throughout the body. Axons and dendrites allow neurons to communicate, even across long distances.
Different types of neurons control or perform different activities. For instance, motor neurons transmit messages from the brain to the muscles to generate movement. Sensory neurons detect light, sound, odor, taste, pressure, and heat and send messages about those things to the brain. Other parts of the nervous system control involuntary processes. These include keeping a regular heartbeat, releasing hormones like adrenaline, opening the pupil in response to light, and regulating the digestive system.
When a neuron sends a message to another neuron, it sends an electrical signal down the length of its axon. At the end of the axon, the electrical signal changes to a chemical signal. The axon then releases the chemical signal with chemical messengers calledneurotransmitters(pronouncednoor-oh-TRANS-mit-erz) into the synapse(pronouncedSIN-aps)—the space between the end of an axon and the tip of a dendrite from another neuron. The neurotransmitters move the signal through the synapse to the neighboring dendrite, which converts the chemical signal back into an electrical signal. The electrical signal then travels through the neuron and goes through the same conversion processes as it moves to neighboring neurons.
The nervous system also includes non-neuron cells, called glia (pronounced GLEE-uh). Glia perform many important functions that keep the nervous system working properly. For example, glia:
- Help support and hold neurons in place
- Protect neurons
- Create insulation called myelin, which helps move nerve impulses
- Repair neurons and help restore neuron function
- Trim out dead neurons
- Regulate neurotransmitters
The brain is made up of many networks of communicating neurons and glia. These networks allow different parts of the brain to “talk” to each other and work together to control body functions, emotions, thinking, behavior, and other activities.1,2,3
FAQs
What Are the Parts of the Nervous System? The nervous system is made up of the central nervous system and the peripheral nervous system: The central nervous system includes the brain and spinal cord. The peripheral nervous system includes the nerves that run throughout the whole body.
What are the parts of the nervous system answer? ›
What Are the Parts of the Nervous System? The nervous system is made up of the central nervous system and the peripheral nervous system: The central nervous system includes the brain and spinal cord. The peripheral nervous system includes the nerves that run throughout the whole body.
What is part of the nervous system quizlet? ›
The nervous system is divided into two main portions: the central nervous system (CNS) and the peripheral nervous system. Brain: control organ; responsible for all the voluntary body activities.
What are the 4 main things in the nervous system? ›
It is an organ system that is composed of the brain, spinal cord, nerves, ganglia, and receptors.
What are 3 main things the nervous system does? ›
4 major functions of the nervous system
- Reception of general sensory information (touch, pressure, temperature, pain, vibration)
- Receiving and perceiving special sensations (taste, smell, vision, sounds)
- Integration of sensory information from different parts of the body and processing them.
- Response generation.
The nervous system includes the brain, nerves and spinal cord.
What is your nervous system? ›
The nervous system is made up of the brain, spinal cord and nerves. It controls many aspects of what you think, how you feel and what your body does. It allows you to do things such as walk, speak, swallow, breathe and learn. It also controls how the body reacts in stressful situations.
What are the 4 nervous system responses? ›
Fight, flight, freeze, and fawn are a broader collection of natural bodily reactions to stressful, frightening, or dangerous events. This sympathetic nervous system response dates back to our ancestors coming face-to-face with dangerous animals.
What are the 3 main divisions of the nervous system? ›
The nervous system can be divided into three main divisions:
- Central nervous system (CNS)
- Peripheral nervous system(PNS)
- Autonomic nervous system (ANS).
Nerve fibers of the PNS are classified according to their involvement in motor or sensory, somatic or visceral pathways. Mixed nerves contain both motor and sensory fibers. Sensory nerves contain mostly sensory fibers; they are less common and include the optic and olfactory nerves. Motor nerves contain motor fibers.
The central nervous system (defined as the brain and spinal cord) is usually considered to have seven basic parts: the spinal cord, the medulla, the pons, the cerebellum, the midbrain, the diencephalon, and the cerebral hemispheres (Figure 1.10; see also Figure 1.8).
How to heal the nervous system? ›
Rebalancing your nervous system means getting back to a state where you feel calm and centered. You can try practicing deep breathing exercises, spending time in nature, or taking short breaks during the day. Regular sleep, a balanced diet, and talking to someone you trust can also help.
What are the main divisions of the nervous system? ›
The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
What is the nervous system for kids? ›
The nervous system controls everything you do, including breathing, walking, thinking, and feeling. This system is made up of your brain, spinal cord, and all the nerves of your body. The brain is the control center and the spinal cord is the major highway to and from the brain.
What are the parts of the neurons and their functions? ›
They have three distinct parts, including a cell body, axon, and dendrites. These parts help them to send and receive chemical and electrical signals. While there are billions of neurons and thousands of varieties of neurons, they can be classified into three basic groups based on function.
