Question

Neurons contain ________, which can receive signals from other neurons. a. axons b. mitochondria c. dendrites d. Golgi bodies

Short answer

Answer: (c) Dendrites

Step-by-step solution

Identify the function of each option

Let's discuss the function of each part of a neuron listed in the options: a. Axons: Responsible for transmitting signals to other neurons, muscles, or glands. b. Mitochondria: Organelles in cells that provide energy for cellular functions. c. Dendrites: Structures in neurons that receive signals from other neurons. d. Golgi bodies: A cellular organelle involved in processing and packaging proteins and lipids.

Select the correct answer

From the above descriptions, we can conclude that the correct answer is (c) dendrites, as these structures in neurons receive signals from other neurons.

Key concepts

Dendrites

Dendrites are specialized structures within neurons designed to receive signals from other neurons. These are usually branched, tree-like projections that extend from the neuron's cell body. Their branched nature increases the surface area available for receiving messages from other nerve cells. This allows for efficient communication within the nervous system.

When signals, or neurotransmitters, are released from a neighboring neuron, they travel across synapses and bind to receptors on dendrites. This is where the process of transmitting information within the neural network begins. Dendrites essentially act as the entry point for information, which is then sent toward the cell body for processing.

Key points to remember about dendrites:

• They receive and integrate incoming signals.
• They are covered with thousands of synapses where communication with other neurons occurs.
• The structural design allows for a massive surface area to interact with surrounding neurons.

Axons

While dendrites receive information, axons are responsible for sending that information away from the neuron's cell body. A single neuron typically has a single axon, which can extend quite far, even up to a meter in humans, to reach muscles or different parts of the nervous system.

The primary role of an axon is to transmit electrical signals called action potentials to other neurons or target tissues. This is achieved through a process where the axon membrane undergoes rapid changes in electrical voltage, which pulsates as a wave down the length of the axon. At the end, the axon branches out to form terminal ends that communicate with target cells.

Characteristics of axons:

• They can vary in length, depending on their function and location in the body.
• The axon's surface is often covered with a myelin sheath, a fatty layer that helps insulate the axon and speed up signal transmission.
• At their tips, axons form synaptic terminals to transmit signals, converting electrical impulses into chemical signals for cellular communication.

Cellular organelles

Cellular organelles are crucial components found within neurons, as well as all living cells, that perform dedicated functions necessary for the cell's life and activity. In neurons, these organelles play vital roles in maintaining cellular health, supporting signal transmission, and producing energy.

Some important organelles in neurons include:

• Mitochondria: These powerhouses of the cell generate ATP, the energy currency needed for various neuronal processes, particularly the energy-intensive task of signal transmission.
• Golgi bodies: These organelles are involved in modifying, sorting, and shipping proteins and lipids, many of which are critical for the formation of synaptic connections.
• Endoplasmic reticulum: Divided into rough and smooth sections, it's essential for protein synthesis and lipid metabolism, which are crucial for cell membrane repair and regeneration aspects of neurons.

These organelles ensure that neurons have the structure and energy required for effective communication and function.

Signal transmission in neurons

Signal transmission in neurons is a fundamental process of the nervous system involving the transfer of electrical impulses from one part of the neuron to another, and chemical signals forwarded to adjacent cells. This complex process primarily relies on action potentials and synaptic transmission.

The journey begins at the dendrites with the reception of neurotransmitters from a preceding neuron. These chemical signals trigger an electrical response, leading to an action potential traveling along the axon. This electrical charge reversal propagates rapidly due to ionic exchanges and is influenced by the myelin sheath, which aids efficient transmission.

When the action potential reaches the synaptic terminal, the neuron converts this electrical signal into a chemical one. Neurotransmitters are released into the synaptic gap and bind to receptors on the next neuron, thus perpetuating the communication cycle.

Key aspects of signal transmission:

• Action potentials: Rapid, brief electrical changes that move signals quickly along axons.
• Synapses: The junctions where communication between neurons occurs, crucial for maintaining seamless communication pathways throughout the nervous system.
• Neurotransmitters: Chemical molecules that permit neurons to transfer information across synapses, ensuring that information is relayed efficiently across neural networks.