Question

A bundle of fibres found outside the central nervous system is known as a
A. Meninx
B. Nerve
C. Dendrite
D. Tract

Answer 1

Hint: Bundles of fibres or axons, in the central nervous system relay information to each other through a complex electrochemical process. It is because of these electrical signals, we are able to sense, see, smell, feel, etc.

Complete answer:
A bundle of fibres found outside the central nervous system is known as nerves, and bundles of afferent fibres are known as sensory nerves. A nerve is a bundle of fibres that receives and sends messages between the body and the brain. The messages are sent by chemicals and electrical changes in the cells, technically called neurons, that make up the nerves. An efferent nerve fibre conducts signals from a motor neuron in the central nervous system to muscles. The basic workings of the nervous system depend a lot on tiny cells called neurons. The brain has billions of them. Sensory neurons send information from eyes, ears, nose, tongue and skin to the brain. Motor neurons carry messages away from the brain to the rest of the body.
i. Meninx: It is a singular form of meninges. These are three membranes that envelope the brain and spinal cord. The function of the meninges is to protect the brain and spinal cord from trauma, to support the blood vessels.
ii. Dendrite: Dendrites are extensions from the cell body. They receive signals from other neurons. The number of dendrites on a neuron can vary.
iii. Tract: Axon bundles are called “tracts” in the CNS. A nerve tract is a bundle of nerve fibres (axons) connecting nuclei of the central nervous system. A tract may also be referred to as a commissar, fasciculus or decussation.
Hence, the correct answer is option B.

Note: A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. Our brain alone contains approximately 100 billion neurons. Nerves are made up of bundles of axons that work together to facilitate communication between the CNS and PNS.