Question

Assertion: Neurons are said to possess the property of excitability. Reason: Neurons can get excited by a given stimulus.

Short answer

Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

Step-by-step solution

Identify the Concept

The concept here is 'excitability', which in context of neurons, means the capacity of neurons to react or respond to stimuli.

Understanding Assertion and Reason

Now, let's analyze the assertion and reason. The assertion states 'Neurons are said to possess the property of excitability' which is accurate as neurons have this ability as a fundamental function. The reason is 'Neurons can get excited by a given stimulus.' which describes the concept of 'excitability' in a simplified manner.

Comparing Assertion and Reason

Finally, comparing the assertion with the reason, it's clear that the reason accurately explains what excitability in neurons means. So, the assertion and reason hold true individually, and the reason is a correct explanation for the assertion.

Key concepts

Neurons

Neurons, often referred to as the building blocks of the nervous system, are specialized cells designed to transmit information throughout the body.

Their unique structure, consisting of a cell body, dendrites, and axon, enables them to carry out their key function: communication. Neurons manage this communication by using electrical impulses and chemical signals to transmit information between different areas of the brain, as well as between the brain and the rest of the nervous system.

A neuron's ability to propagate an electrical signal, known as an action potential, is critical to its communicative function. When neurons function correctly, they enable us to do everything from moving and sensing our environment, to thinking and expressing emotion.

Stimulus Response

Stimulus response is a fundamental aspect of neuronal excitability. A stimulus could be any change in the environment that's strong enough to elicit a reaction from a neuron. This can range from physical stimuli, like touch or temperature changes, to chemical ones, like neurotransmitters or hormones.

When a neuron reacts to a stimulus, it does so by changing its electrical state, creating an action potential. This all-or-nothing electrical impulse travels along the axon and communicates with other neurons, muscles, or glands to produce a response.

However, not every stimulus leads to an action potential. Neurons have a certain threshold level that must be reached for them to 'fire'. Sub-threshold stimuli won't result in an action potential, which prevents the nervous system from being overwhelmed by weak signals.

Neural Function

Neural function encompasses all the tasks that neurons perform, which range from receiving sensory information from the external world to executing complex cognitive processes.

At the core of this functionality is the ability of neurons to respond to stimuli and communicate rapidly and precisely. This is facilitated by synapses, specialized junctions where neurons can transmit signals to each other. Synaptic plasticity – the ability of synapses to strengthen or weaken over time, based on the frequency of their activity – is essential for learning and memory, illustrating the adaptable nature of neural function.

Moreover, proper neural function is essential not just for voluntary actions, like speaking or moving, but also for involuntary processes like breathing, digestion, and heart rate regulation. A disruption in neural function can lead to a wide range of neurological disorders, making the study of neurons and their pathways critical for understanding and treating these conditions.