nerve
Definition
A nerve is a bundle of nerve fibres that conducts electrical signals between the central nervous system (CNS) and the peripheral nervous system (PNS). Nerves are made up of long, thin cells called neurons. Neurons are the basic unit of the nervous system. They are responsible for transmitting information throughout the body.
There are two main types of nerves: sensory nerves and motor nerves. Sensory nerves carry information from the body to the CNS. Motor nerves carry information from the CNS to the body.
Sensory nerves have receptors that detect stimuli in the environment. These stimuli can be light, sound, touch, taste, or smell. When a receptor is activated, it sends an electrical signal to the CNS. The CNS interprets the signal and tells us what we are sensing.
Motor nerves carry signals from the CNS to the muscles. When the CNS wants a muscle to contract, it sends an electrical signal to the motor nerve that innervates the muscle. The motor nerve then activates the muscle fibres, which contract and cause the muscle to move.
Nerves are essential for our survival. They allow us to interact with our environment and control our bodies.
How can the word be used?
The word "nerve" was first used in English in the 13th century. It was used to describe the sinews or tendons that connect muscles to bones.
Different forms of the word
Noun: A long, slender, threadlike structure that carries impulses from the brain and spinal cord to the muscles and other parts of the body.
Adjective: Relating to nerves or the nervous system.
Derivative: Nervate, nerveless, nervous.
Etymology
The word "nerve" comes from the Latin word "nervus," which means "sinew, tendon, cord, or bowstring." The Latin word "nervus" is derived from the Proto-Indo-European root *ner-," which means "to twist.".
The word "nerve" was first used in English in the 13th century. It was used to describe the sinews or tendons that connect muscles to bones.
Question
What is a nerve?
AQA Science Exam Question and Answer
Question:
Describe the structure and function of a nerve cell (neuron) in the human body.
Answer:
A nerve cell, or neuron, is a specialised cell that plays a crucial role in transmitting signals within the nervous system. It consists of various components that enable it to carry out its function effectively.
The main parts of a neuron include the cell body (soma), dendrites, an axon, and axon terminals. The cell body contains the nucleus and essential organelles, supporting the neuron's metabolic functions. Dendrites are short, branch-like extensions that receive signals from other neurons or sensory cells. The axon is a long projection that carries the electrical signal (action potential) away from the cell body toward other neurons or target cells. Axon terminals are the endpoints of the axon, connecting with other neurons through synapses.
Neurons transmit information through electrical impulses. When a neuron is stimulated, a change in voltage occurs across its membrane, resulting in an action potential that travels along the axon. This impulse is propagated down the axon and transmitted to other neurons or target cells at synapses.
The neuron's function is essential for communication within the nervous system. Sensory neurons transmit signals from sensory organs to the central nervous system, motor neurons carry signals from the central nervous system to muscles and glands, and interneurons facilitate communication between different neurons.