Where is nerves in your body

It controls the muscle in the eye that enables it to point downward and inward. The trigeminal nerve is the largest cranial nerve in the human body, and it has both motor and sensory functions. The trigeminal nerve assists you with chewing and clenching your teeth, and it provides sensation to muscles in your eardrum. The abducens nerve also helps with eye movements, in particular, movements that involve your gaze moving outward. Like the trigeminal nerve, the facial nerve also has motor and sensory functions.

It controls:. The vestibulocochlear nerve actually consists of two nerves in one, the vestibular nerve and cochlear nerve. As with other cranial nerves, the glossopharyngeal nerve has both sensory and motor functions. Its sensory function receives incoming information from the back of your mouth, including the tongue, tonsils, and throat. It is also involved with taste sensation for the back of your tongue. Doctors often use vagus nerve stimulation therapy to treat conditions such as epilepsy, depression, and anxiety.

The vagus nerve is also the longest of all the cranial nerves because it begins in the medulla in the brain and extends all the way to the abdominal area. This cranial nerve, the accessory nerve , provides motor function to some of the muscles in the neck. The last of the cranial nerves is the hypoglossal nerve. It provides necessary motor functions to the tongue muscles. The spinal cord is part of your central nervous system. It begins at the bottom of the brain stem and continues down to your lower back.

There are 31 pairs of spinal nerves, and they control sensory, motor, and other functions of your body. They transmit messages between your spinal cord and the rest of the body, including skin, muscles, and internal organs. Each spinal nerve is responsible for providing sensation to a different area of your body.

Source: neuroxcel. Each group of spinal nerves is involved with movements in certain parts of your body, including your hands, fingers, arms, upper back, hips, and abdominal muscles. Some spinal nerves are even responsible for ensuring you can walk and run properly. Some nerves in the spinal cord are responsible for controlling automatic body functions, such as your heart rate, breathing, and other things your body does automatically.

For example, spinal nerves T1-L5, which are your thoracic and lumbar nerves, are partially responsible for controlling the functions of your:. In the inner part of the forebrain sits the thalamus, hypothalamus, and pituitary gland :. The midbrain, underneath the middle of the forebrain, acts as a master coordinator for all the messages going in and out of the brain to the spinal cord. The hindbrain sits underneath the back end of the cerebrum.

It consists of the cerebellum, pons, and medulla. The cerebellum — also called the "little brain" because it looks like a small version of the cerebrum — is responsible for balance, movement, and coordination. The pons and the medulla, along with the midbrain, are often called the brainstem. The brainstem takes in, sends out, and coordinates the brain's messages. It also controls many of the body's automatic functions, like breathing, heart rate, blood pressure, swallowing, digestion, and blinking.

The basic workings of the nervous system depend a lot on tiny cells called neurons. The brain has billions of them, and they have many specialized jobs. For example, sensory neurons send information from the eyes, ears, nose, tongue, and skin to the brain.

Motor neurons carry messages away from the brain to the rest of the body. All neurons relay information to each other through a complex electrochemical process, making connections that affect the way you think, learn, move, and behave. Intelligence, learning, and memory.

As you grow and learn, messages travel from one neuron to another over and over, creating connections, or pathways, in the brain. It's why driving takes so much concentration when someone first learns it, but later is second nature: The pathway became established.

In young children, the brain is highly adaptable. In fact, when one part of a young child's brain is injured, another part often can learn to take over some of the lost function. But as you age, the brain has to work harder to make new neural pathways, making it harder to master new tasks or change set behavior patterns.

That's why many scientists believe it's important to keep challenging the brain to learn new things and make new connections — it helps keeps the brain active over the course of a lifetime. Memory is another complex function of the brain. The things you've done, learned, and seen are first processed in the cortex. Then, if you sense that this information is important enough to remember permanently, it's passed inward to other regions of the brain such as the hippocampus and amygdala for long-term storage and retrieval.

As these messages travel through the brain, they too create pathways that serve as the basis of memory. The dendrites receive signals from body tissues or other neurons and pass them into the cell body. If an outgoing signal is produced, it zips down the axon to the axon terminal and passes to the next neuron or target cell. This conductive capability sends information up and down nerve pathways and through the central nervous system at incredible speed. Some billion neurons give the brain its awesome processing power.

Nervous system messages travel through neurons as electrical signals. When these signals reach the end of a neuron, they stimulate the release of chemicals called neurotransmitters. Neurotransmitters travel across synapses , spaces between neurons or between neurons and other body tissues and cells. Neurotransmitters can be classified as two types: excitatory or inhibitory. Excitatory neurotransmitters stimulate electrical signals in other neurons and encourage responses from body cells.

Inhibitory transmitters discourage signals and cellular responses. Through these chemicals, the nervous system regulates the activity of muscles, glands, and its own nerve pathways. The spinal cord is an elongated cylinder of neuron cell bodies, bundles of axons and other cells, protected by connective tissue and bone. Synapses may form between 2 neurons or between a neuron and an effector cell. There are two types of synapses found in the body: chemical synapses and electrical synapses.

The axons of many neurons are covered by a coating of insulation known as myelin to increase the speed of nerve conduction throughout the body. In both cases, the glial cells wrap their plasma membrane around the axon many times to form a thick covering of lipids.

The development of these myelin sheaths is known as myelination. Myelination speeds up the movement of APs in the axon by reducing the number of APs that must form for a signal to reach the end of an axon.

The myelination process begins speeding up nerve conduction in fetal development and continues into early adulthood. Myelinated axons appear white due to the presence of lipids and form the white matter of the inner brain and outer spinal cord. White matter is specialized for carrying information quickly through the brain and spinal cord. The gray matter of the brain and spinal cord are the unmyelinated integration centers where information is processed. Reflexes are fast, involuntary responses to stimuli.

Reflexes are integrated in the gray matter of the spinal cord or in the brain stem. Reflexes allow the body to respond to stimuli very quickly by sending responses to effectors before the nerve signals reach the conscious parts of the brain. This explains why people will often pull their hands away from a hot object before they realize they are in pain.

All sensory receptors can be classified by their structure and by the type of stimulus that they detect. Structurally, there are 3 classes of sensory receptors: free nerve endings, encapsulated nerve endings, and specialized cells. Free nerve endings are simply free dendrites at the end of a neuron that extend into a tissue. Pain, heat, and cold are all sensed through free nerve endings.

An encapsulated nerve ending is a free nerve ending wrapped in a round capsule of connective tissue.