The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. It is essentially the body’s electrical wiring.
Structurally, the nervous system has two components: the central nervous system and the peripheral nervous system. According to the National Institutes of Health, the central nervous system is made up of the brain, spinal cord and nerves. The peripheral nervous system consists of sensory neurons, ganglia (clusters of neurons) and nerves that connect to one another and to the central nervous system.
Central nervous system
The central nervous system consists of the brain and spinal cord. It is referred to as “central” because it combines information from the entire body and coordinates activity across the whole organism.
The brain is protected by the skull (the cranial cavity) and the spinal cord travels from the back of the brain, down the center of the spine, stopping in the lumbar region of the lower back.
The brain and spinal cord are both housed within a protective triple-layered membrane called the meninges.
The central nervous system has been thoroughly studied by anatomists and physiologists, but it still holds many secrets; it controls our thoughts, movements, emotions, and desires. It also controls our breathing, heart rate, the release of some HORMONES, body temperature, and much more.
The brain is the most complex organ in the human body; the cerebral cortex (the outermost part of the brain and the largest part by volume) contains an estimated 15–33 billion neurons, each of which is connected to thousands of other neurons.
total, around 100 billion neurons and 1,000 billion glial (support) cells make up the human brain. Our brain uses around 20 percent of our body’s total energy. The brain is the central control module of the body and coordinates activity. From physical motion to the secretion of hormones, the creation of memories, and the sensation of emotion.
To carry out these functions, some sections of the brain have dedicated roles. However, many higher functions — reasoning, problem-solving, creativity — involve different areas working together in networks.
The brain is roughly split into four lobes:
Temporal lobe (green): important for processing sensory input and assigning it emotional meaning. It is also involved in laying down long-term memories. Some aspects of language perception are also housed here.
Occipital lobe (purple): visual processing region of the brain, housing the visual cortex.
Parietal lobe (yellow): the parietal lobe integrates sensory information including touch, spatial awareness, and navigation.
Frontal lobe (pink): positioned at the front of the brain, the frontal lobe contains the majority of dopamine-sensitive neurons and is involved in attention, reward, short-term memory, motivation, and planning.
Spinal cord
The spinal cord, running almost the full length of the back, carries information between the brain and body, but also carries out other tasks. From the brainstem, where the spinal cord meets the brain, 31 spinal nerves enter the cord. Along its length, it connects with the nerves of the peripheral nervous system (PNS) that run in from the skin, muscles, and joints.
Motor commands from the brain travel from the spine to the muscles and sensory information travels from the sensory Tissues — such as the skin — toward the spinal cord and finally up to the brain. The spinal cord contains circuits that control certain reflexive responses, such as the involuntary movement your arm might make if your finger was to touch a flame.
The circuits within the spine can also generate more complex movements such as walking. Even without input from the brain, the spinal nerves can coordinate all of the muscles necessary to walk. For instance, if the brain of a cat is separated from its spine so that its brain has no contact with its body, it will start spontaneously walking when placed on a treadmill. The brain is only required to stop and start the process, or make changes if, for instance, an object appears in your path.
Peripheral nervous system
The peripheral nervous system (PNS) consists of all neurons that exist outside the brain and spinal cord. This includes long nerve fibers containing bundles of axons as well as ganglia made of neural cell bodies. The peripheral nervous system connects the central nervous system (CNS) made of the brain and spinal cord to various parts of the body and receives input from the external Environment as well.
Functionally, the PNS is divided into sensory (afferent) and motor (efferent) nerves, depending on whether they bring information to the CNS from sensory receptors or carry instructions towards muscles, organs or other effectors. Motor nerves can be further classified as somatic or autonomic nerves, depending on whether the motor activity is under voluntary conscious control.
Anatomically, the PNS can be divided into spinal and cranial nerves, depending on whether they emerge from the spinal cord or the brain and brainstem. Both cranial and spinal nerves can have sensory, motor or mixed functions. The enteric nervous system, surrounding the gastrointestinal tract is another important part of the peripheral nervous system. While it receives signals from the autonomic nervous system, it can function independently as well and contains nearly five times as many neurons as the spinal cord.
The primary function of the peripheral nervous system is to connect the brain and spinal cord to the rest of the body and the external environment. This is accomplished through nerves that carry information from sensory receptors in the eyes, ears, skin, nose and tongue, as well as stretch receptors and nociceptors in muscles, glands and other internal organs. When the CNS integrates these varied signals, and formulates a response, motor nerves of the PNS innervate effector organs and mediate the contraction or relaxation of skeletal, smooth or cardiac muscle.
Thus, the PNS regulates internal homeostasis through the autonomic nervous system, modulating Respiration, heart rate, blood pressure, digestion Reproduction and immune responses. It can increase or decrease the strength of muscle contractility across the body, whether it is sphincters in the digestive and excretory systems, cardiac muscles in the heart or skeletal muscles for movement. It is necessary for all voluntary action, balance and maintenance of posture and for the release of secretions from most exocrine glands. The PNS innervates the muscles surrounding sense organs, so it is involved in chewing, swallowing, biting and speaking. At the same time, it mediates the response of the body to noxious stimuli, quickly removing the body from the injurious stimulus, whether it is extremes in temperature, pH, or pressure, as well as stretching and compressing forces.,
The nervous system is a complex Network of cells that controls all of the body’s functions. It is made up of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS is made up of the brain and spinal cord. The brain is the control center of the body. It receives information from the senses and sends signals to the muscles and glands to control movement and other body functions. The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. It carries messages between the brain and the rest of the body.
The PNS is made up of all the nerves that connect the CNS to the rest of the body. It is divided into two parts: the somatic nervous system and the autonomic nervous system.
The somatic nervous system controls voluntary movement. It sends signals from the brain to the muscles, telling them to move.
The autonomic nervous system controls involuntary movement. It controls functions such as heart rate, breathing, and digestion. It is divided into two parts: the sympathetic nervous system and the parasympathetic nervous system.
The sympathetic nervous system is activated when the body is under Stress. It causes the heart to beat faster, the blood vessels to constrict, and the pupils to dilate.
The parasympathetic nervous system is activated when the body is at rest. It causes the heart to beat slower, the blood vessels to dilate, and the pupils to constrict.
Neurons are the basic units of the nervous system. They are specialized cells that transmit information in the form of electrical and chemical signals.
Neurons have three main parts: the cell body, the dendrites, and the axon.
The cell body contains the nucleus and other organelles that are necessary for cell function.
The dendrites are short, branching projections that receive signals from other neurons.
The axon is a long, slender projection that carries signals away from the cell body.
The axon is covered by a myelin sheath, which insulates it and helps to speed up the transmission of signals.
The end of the axon is called the synaptic knob. It contains neurotransmitters, which are chemicals that transmit signals to other neurons.
Synaptic transmission is the process by which neurons communicate with each other. When a signal reaches the synaptic knob, it causes the release of neurotransmitters into the synaptic cleft, which is the space between the axon of one neuron and the dendrite of another neuron.
The neurotransmitters bind to receptors on the dendrite of the other neuron, and this causes a change in the electrical potential of the neuron. If the change is large enough, it will trigger an action potential, which is a wave of electrical activity that travels down the axon of the neuron.
The action potential eventually reaches the cell body, where it causes the release of neurotransmitters into the synaptic cleft. This process repeats itself, and the signal is transmitted from neuron to neuron.
Nervous system disorders are a group of conditions that affect the brain, spinal cord, or nerves. They can cause a variety of symptoms, including problems with movement, sensation, thinking, and behavior.
Some common nervous system disorders include Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, epilepsy, stroke, head injury, spinal cord injury, Guillain-Barré syndrome, myasthenia gravis, amyotrophic lateral sclerosis (ALS), Huntington’s disease, Creutzfeldt-Jakob disease, neurofibromatosis, tuberous sclerosis, spina bifida, hydrocephalus, and cerebral palsy.
The etiology of nervous system disorders is complex and varies depending on the specific disorder. Some nervous system disorders are caused by genetic mutations, while others are caused by environmental factors such as infections, trauma, autoimmune disorders, or cancer.
The treatment of nervous system disorders also varies depending on the specific disorder. Some nervous system disorders can be treated with medications, while others require surgery or other interventions such as physical therapy, occupational therapy, speech therapy, rehabilitation, or palliative care.
The prognosis of nervous system disorders also varies depending on the specific disorder. Some nervous system disorders, such as Alzheimer’s disease and Parkinson’s disease, are progressive and have no cure. Other nervous system disorders, such as multiple sclerosis and epilepsy, can be managed with medication and other treatments.
The prognosis for individuals with nervous system disorders is often better if they receive early diagnosis and treatment. Individuals with nervous system disorders may need to make lifestyle changes, such as adjusting their diet and exercise routine, to manage their condition. They may also need to learn how to use assistive devices and adapt their homes and workplaces to accommodate their disability. With support and treatment, many individuals with nervous system disorders can live full and productive lives.
What is the nervous system?
The nervous system is the part of an animal’s body that coordinates the voluntary and involuntary actions of the animal and transmits signals between different parts of its body. In most types of animals it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory or afferent. Spinal nerves serve both functions and are called mixed nerves. The PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems. Somatic nerves mediate voluntary movement. The autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems. The sympathetic system uses noradrenalin as its postganglionic neurotransmitter, and is activated to a large degree during the “fight-or-flight response”. The parasympathetic system uses acetylcholine as its postganglionic neurotransmitter, and is activated when organisms are in a relaxed state. The enteric nervous system functions to control the gastrointestinal system.
What are the functions of the nervous system?
The nervous system is responsible for controlling and coordinating the body’s functions. It does this by sending and receiving signals throughout the body. The nervous system is made up of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists of nerves that connect the CNS to the rest of the body.
The nervous system has many different functions, including:
- Controlling voluntary and involuntary movements
- Regulating body functions such as heart rate, breathing, and digestion
- Processing information from the senses
- Thinking and feeling
What are the different types of neurons?
Neurons are the basic units of the nervous system. They are specialized cells that transmit information throughout the body. There are three main types of neurons: sensory neurons, motor neurons, and interneurons.
- Sensory neurons transmit information from the senses to the CNS.
- Motor neurons transmit information from the CNS to the muscles.
- Interneurons transmit information between neurons within the CNS.
How does the nervous system work?
The nervous system works by sending and receiving signals. These signals are electrical and chemical in nature. When a neuron is stimulated, it sends an electrical signal down its axon. This signal then causes the release of chemicals called neurotransmitters. The neurotransmitters bind to receptors on other neurons, which can either excite or inhibit the activity of those neurons.
This process of sending and receiving signals is how the nervous system controls and coordinates the body’s functions.
What are some common disorders of the nervous system?
There are many different disorders that can affect the nervous system. Some of the most common include:
- Alzheimer’s disease: A progressive brain disorder that causes memory loss, confusion, and eventually death.
- Parkinson’s disease: A disorder that affects the nervous system and causes tremors, stiffness, and difficulty with balance and coordination.
- Multiple sclerosis: A disease that affects the central nervous system and causes a variety of symptoms, including numbness, tingling, weakness, and vision problems.
- Epilepsy: A neurological disorder that causes seizures.
- Stroke: A condition that occurs when a blood clot blocks an artery in the brain, depriving the brain of Oxygen and nutrients.
- Brain tumor: A Growth of abnormal cells in the brain.
What are some treatments for disorders of the nervous system?
There is no cure for most disorders of the nervous system. However, there are many treatments that can help to manage the symptoms and improve the Quality Of Life for people with these disorders. Some of the most common treatments include:
- Medications: There are many different medications that can be used to treat disorders of the nervous system. These medications can help to reduce symptoms such as pain, seizures, and tremors.
- Surgery: In some cases, surgery may be necessary to treat a disorder of the nervous system. For example, surgery may be used to remove a brain tumor or to repair a damaged nerve.
- Rehabilitation: Rehabilitation can help people with disorders of the nervous system to regain lost function and improve their quality of life. Rehabilitation may include physical therapy, occupational therapy, and speech therapy.
- Support groups: Support groups can provide emotional and practical support to people with disorders of the nervous system and their families.
- The nervous system is responsible for controlling all of the body’s functions. True or False?
- The nervous system is made up of two main parts: the central nervous system and the peripheral nervous system. True or False?
- The central nervous system is made up of the brain and spinal cord. True or False?
- The peripheral nervous system is made up of the nerves that connect the central nervous system to the rest of the body. True or False?
- The nervous system uses electrical signals to communicate with the rest of the body. True or False?
- The brain is the control center of the body. True or False?
- The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. True or False?
- The spinal cord is responsible for sending messages from the brain to the rest of the body and for receiving messages from the rest of the body to the brain. True or False?
- The nerves are responsible for carrying messages from the brain and spinal cord to the rest of the body and for carrying messages from the rest of the body to the brain. True or False?
- The nervous system is divided into two main parts: the somatic nervous system and the autonomic nervous system. True or False?
- The somatic nervous system is responsible for voluntary actions, such as walking and talking. True or False?
- The autonomic nervous system is responsible for involuntary actions, such as breathing and heart rate. True or False?
- The autonomic nervous system is further divided into the sympathetic nervous system and the parasympathetic nervous system. True or False?
- The sympathetic nervous system is responsible for the “fight or flight” response. True or False?
- The parasympathetic nervous system is responsible for the “rest and digest” response. True or False?
Answers:
1. True
2. True
3. True
4. True
5. True
6. True
7. True
8. True
9. True
10. True
11. True
12. True
13. True
14. True
15. True