Test:Neuron - NEET MCQ

Bipolar neurons have one axon and one dendrite. These neurons are found in specialized areas like the retina of the eye, where they transmit visual signals from photoreceptor cells to other parts of the visual system.

Topic in NCERT: NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM

Line in NCERT: "bipolar (with one axon and one dendrite, found in the retina of eye)"

Axons are long fibers while dendrites are short fibers. Axons carry or transmit nerve impulses away from the cell body towards synapses. Their terminal ends are branched and end with synaptic knobs.

Topic in NCERT: NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM

Line in NCERT: "The axon is a long fibre, the distal end of which is branched."

Neurilemma (also known as neurolemma, sheath of Schwann, or Schwann's sheath) is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurilemmocytes) that surrounds the axon of the neuron. It forms the outermost layer of the nerve fiber in the peripheral nervous system.

Topic in NCERT: Myelination of Nerve Fibres

Line in NCERT: The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon. The gaps between two adjacent myelin sheaths are called nodes of Ranvier. Myelinated nerve fibres are found in spinal and cranial nerves. Unmyelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath around the axon, and is commonly found in autonomous and the somatic neural systems

Unmyelinated nerve fibers are enclosed by Schwann cells but do not have a myelin sheath around the axon. They are typically found in the autonomous and somatic neural systems, where slower transmission is sufficient for their function.

Topic in NCERT: NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM

Line in NCERT: "Unmyelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath around the axon, and is commonly found in autonomous and the somatic neural systems."

Neurons or nerve cells are classified into three types based on the number of axon and dendrites. The three types of neurons are namely, multipolar neurons, unipolar neurons and bipolar neurons.

Topic in NCERT: NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM

Line in NCERT: "Based on the number of axon and dendrites, the neurons are divided into three types, i.e., multipolar (with one axon and two or more dendrites; found in the cerebral cortex), bipolar (with one axon and one dendrite, found in the retina of eye) and unipolar (cell body with one axon only; found usually in the embryonic stage)."

Transmission of Nerve Impulse to the Cyton

• Axon: Axons transmit nerve impulses away from the cell body (cyton) towards other neurons or effector cells.


• Dendrite: Dendrites generally transmit nerve impulses from other neurons towards the cell body (cyton).


• Node of Ranvier: Nodes of Ranvier are small gaps in the myelin sheath of axons where action potentials are regenerated. They do not transmit nerve impulses to the cyton.


• Synaptic knob: Synaptic knobs are located at the end of axons and are responsible for transmitting signals to the next neuron at the synapse. They do not transmit nerve impulses to the cyton.


 

Explanation

In the context of transmitting nerve impulses to the cyton, dendrites are the structures that play a crucial role. Dendrites are specialized extensions of the neuron that receive signals from other neurons and transmit these signals towards the cell body (cyton). This process is essential for integrating incoming signals and determining whether the neuron will generate an action potential.

While axons, nodes of Ranvier, and synaptic knobs are important components of the nervous system and play key roles in transmitting nerve impulses, they do not primarily transmit signals to the cyton. Axons carry impulses away from the cyton, nodes of Ranvier regenerate action potentials along the axon, and synaptic knobs transmit signals to the next neuron at the synapse.

An axon is also known as a nerve fiber. It is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body. The function of the axon is to transmit information to different neurons, muscles and glands.

Topic in NCERT: Generation and Conduction of Nerve Impulse

Line in NCERT: "The sequence is repeated along the length of the axon and consequently the impulse is conducted."

The nodes of Ranvier are gaps between two adjacent myelin sheaths in myelinated nerve fibers. These nodes enable saltatory conduction, where nerve impulses jump from one node to the next, greatly increasing the speed of transmission.

Topic in NCERT: Myelination and Nodes of Ranvier

Line in NCERT: "myelin sheaths are called nodes of Ranvier."

The axon is responsible for transmitting nerve impulses away from the cell body. It ends in the synaptic knob, where neurotransmitters are released to communicate with other cells.

Topic in NCERT: Neuron Structure and Function

Line in NCERT: "The axons transmit nerve impulses away from the cell body to a synapse or to a neuro-muscular junction."