write long note on nerve cell of brain ????
Answers
A neuron (also called neurone or nerve cell) is a cell that carries electrical impulses.[1] Neurons are the basic units of the nervous system and its most important part is the brain.
Every neuron is made of a cell body (also called a soma), dendrites and an axon.[1] Dendrites and axons are nerve fibres. There are about 86 billion neurons in the human brain, which comprises roughly 10% of all brain cells. The neurons are supported by glial cells and astrocytes.
Neurons are connected to one another and tissues. They do not touch and instead form tiny gaps called synapses. These gaps can be chemical synapses or electrical synapses and pass the signal from one neuron to the next.
- By connection
There are three classes of neurons: afferent neurons, efferent neurons, and interneurons.
Afferent neurons carry information from tissues and organs into the central nervous system.
Efferent neurons transport signals from the central nervous system to the effector cells.
Interneurons connect neurons within the central nervous system.
- By function
Sensory neurons carry signals from sense organs to the spinal cord and brain.
Relay neurons carry messages between sensory or motor neurons and the central nervous system (CNS).
Motor neurons carry signals from the CNS to muscles, motor neurons are connected to the relay neurons. The signal passes between the neurons via synapses. Synapses are microscopic voids between cells where chemicals are released from the axon terminal of one cell to specialized chemical receptors on the dendrite of the receiving cell.
Answer:
Neurons (also called neurones or nerve cells) are the fundamental units of the brain and nervous system, the cells responsible for receiving sensory input from the external world, for sending motor commands to our muscles, and for transforming and relaying the electrical signals at every step in between. More than that, their interactions define who we are as people. Having said that, our roughly 100 billion neurons do interact closely with other cell types, broadly classified as glia (these may actually outnumber neurons, although it’s not really known)
Function of neurons
Neurons send signals using action potentials. An action potential is a shift in the neuron’s electric potential caused by the flow of ions in and out of the neural membrane.
Action potentials can trigger both chemical and electrical synapses.
Types of neurons
Neurons vary in structure, function, and genetic makeup. Given the sheer number of neurons, there are thousands of different types, much like there are thousands of species of living organisms on Earth.
In terms of function, scientists classify neurons into three broad types: sensory, motor, and interneurons.