Question

What is the function of the nervous system? What are neurons? What are their functions? These main questions require that you know the basics of electrical and chemical aspects of neural information processing (action potential generation and transmission, synaptic transmission, reuptake mechanisms etc.)

Answer 1

Nervous system- It is the network of neurons in the body to receives and sends information throughout the body.

Neurons- It is a fundamental functional and structural unit of the nervous system. It receives information from sense organs and this information to the brain and then again the brain sends information to motor muscles.

Functions of neurons-

When neurons are at rest or there is no signal and the potential of neurons at resting potential is -70mv and Na⁺ and Cl⁺ ions present outside the neuron; whereas K⁺ is present inside the neuron. when a neuron receives signals it turns into an action potential. Action potential starts with depolarization, it is the process of reversibility of charge. The threshold value for depolarization is -55mv. At resting potential, the internal side of the neuron is negatively charged and the external side is positively charged, in response to signal Na⁺ and K⁺ ions channel open and close when it receives threshold potential. Na⁺ channels open at the beginning of the action potential, and Na⁺ moves into the axon, causing depolarization. When depolarization occurs polarity of neuron change and reached the action potential. And repolarization occurs when the K⁺ channels open and K⁺ moves out of the axon, again polarity of neuron change. This signal travels down the axon only in one direction from dendrites to terminal buttons where it signals the next neurons.

When the signal from presynaptic neurons transmits signals to the postsynaptic neurons, this process is known as synaptic transmission. In this process, neurotransmitters are secreted by the presynaptic neurons terminal button and bind to the receptors of membrane of the postsynaptic neurons. After the binding with the membrane of the receptor and react with receptor site. Once the post-synaptic membrane has responded the neurotransmitter in the synaptic cleft is either inactivated or removed by some processes such as breakdown, re-uptake, and diffusion.

Re-uptake is the process of taken back into the pre-synaptic neuron by the membrane. These neurotransmitters are recycled into vesicles by proteins.