Problem 52 - Objective Biology for NEET

Question

Which of the following are excitable cells? (a) Muscle cells (b) Neural cells (c) Both (a) and (b) (d) None of these

Step-by-Step Solution

Answer

The correct answer is (c) Both (a) and (b). Both muscle cells and neural cells are classified as excitable cells.

Step 1: Identify the Characteristics of Muscle Cells

Muscle cells, also referred to as myocytes, are specialized to contract. They are triggered to do so by electrical impulses, this means that they are excitable cells.

Step 2: Identify the Characteristics of Neural Cells

Neural cells, or neurons, are the fundamental units of the brain and nervous system, converting incoming electrical signals into outgoing signals. These cells indeed are excitable.

Step 3: Determine the Answer

From the above information, it can be concluded that muscle cells and neural cells are both excitable. So, the correct answer is choice (c): Both (a) and (b)

Key Concepts

Muscle Cells

Muscle cells, also known as myocytes, play a pivotal role in the body's movement and stability. Different types of muscle tissue, such as skeletal, cardiac, and smooth muscles, each have distinct functions but share the characteristic ability to contract.

Skeletal muscles attach to bones and are under voluntary control, allowing us to perform activities like walking or lifting objects. Cardiac muscle cells are found exclusively in the heart, contracting rhythmically to pump blood throughout the body without conscious effort. Lastly, smooth muscles are found in various internal organs like the stomach and bladder, where they help regulate involuntary actions like digestion and urination.

What makes muscle cells 'excitable' is their ability to respond to stimuli, usually in the form of neurotransmitters or electrical impulses, by changing their membrane potential. This leads to muscle contraction, and the process is facilitated by specialized proteins within the muscle cells, such as actin and myosin.

For students striving to understand how muscle cells function, it is crucial to explore the mechanism of muscle contraction, the process of excitation-contraction coupling, and the role of calcium ions in these activities.

Neural Cells

Neural cells, or neurons, serve as the building blocks of the nervous system. The nervous system can be likened to a complex communication network, and neurons are the messengers that transmit signals throughout the body. These cells are unique for their long extensions, known as axons and dendrites, which allow them to establish networks through which they communicate with other neurons, muscle cells, and glands.

The neural cells are outfitted with an array of ion channels, receptors, and pumps that maintain a resting membrane potential and enable the cells to become excited in response to various stimuli. When a neuron gets activated, it generates an action potential, an electrical impulse that travels along its axon, ultimately leading to the release of neurotransmitters at synaptic junctions.

Key aspects to grasp about neural cells for educational comprehension include the roles of the different types of neurons, such as sensory neurons, motor neurons, and interneurons, as well as understanding synaptic transmission and how neurotransmitters influence the activity of target cells.

Neuron Functions

Neuron functions can be broadly categorized based on the role they play in processing and transmitting information. Sensory neurons, for instance, convert external stimuli from the environment into internal electrical impulses. Motor neurons, conversely, receive signals from the brain and spinal cord to control muscle contractions.

Interneurons serve as intermediaries, processing information within the central nervous system by creating neural circuits. These circuits enable complex functions such as learning, memory, and decision-making. Another critical aspect of neuron function is the generation and propagation of the action potential, which allows rapid communication over long distances within the body.

Understanding neuron functions involves delving into neurotransmitters and their effects, synaptic plasticity, and how neurons integrate signals through excitatory and inhibitory synapses. These concepts are fundamental for students aiming to comprehend how the nervous system orchestrates a vast array of bodily functions and behaviors.