Question

Which of the following is secreted at ends of nerve fibres?
A. Ascorbic acid
B. Acetic acid
C. Acetyl CoA
D. Acetylcholine

Answer 1

Hint: The nervous system is the component of an animal's body that controls and sends information between different parts of the body. The central nervous system (CNS) and the peripheral nervous system (PNS) are the two primary components of the nervous system in vertebrates (PNS). The brain and spinal cord are housed in the CNS.

Complete answer:
The nerve cell is the fundamental unit of communication in the neurological system (neuron). The nucleus, a main branching fiber (axon), and several smaller branching fibers make up the cell body of each nerve cell (dendrites).
In vertebrates, an axon, also known as a nerve fiber (or nerve fiber), is a long, slender projection of a nerve cell, or neuron, that carries electrical impulses known as action potentials out from the nerve cell body. The axon's job is to communicate information between neurons, muscles, and glands. The axons of certain sensory neurons (pseudounipolar neurons), such as those for touch and temperature, are called afferent nerve fibers, and the electrical impulse travels down them from the periphery to the cell body, and then along another branch of the same axon to the spinal cord.
Neurotransmitters are substances that allow messages to go across synapses from one neuron to the next. They're also present in motor neuron axon ends, where they activate muscle fibers. The first neurotransmitter identified was acetylcholine. Choline acetyltransferase is the enzyme that produces it. It attaches to its receptor at the postsynaptic terminal after being released. The enzyme acetylcholinesterase quickly hydrolyzes it. Many hereditary and acquired neurological diseases have been linked to axon malfunction, which can impact both peripheral and central neurons.
So, Acetylcholine is secreted at the ends of nerve fibres.

Thus, the answer is Option D: Acetylcholine.

Note:
Nervous systems may be found in most multicellular creatures, although their complexity varies significantly. Sponge, placozoans, and mesozoans, which have relatively basic body designs, are the only multicellular creatures without a nervous system. A diffuse nerve net makes up the neural systems of radially symmetric animals such as ctenophores (comb jellies) and cnidarians (which include anemones, hydras, corals, and jellyfish).