Question

A(n) ________ neuron has one axon and multiple dendrites. a. unipolar b. bipolar c. multipolar d. pseudounipolar

Short answer

Answer: Multipolar

Step-by-step solution

Understanding Neuron Structure

To solve this exercise, first, let's understand the basic structure of a neuron. A neuron is a nerve cell that consists of three main parts: the cell body (soma), an axon, and dendrites. The axon is a single elongated projection that carries electrical messages away from the cell body, while dendrites are branched projections that receive these messages from other neurons.

Identifying the Characteristics of Each Type of Neuron

Now that we understand the basic structure of a neuron, let's go over the characteristics of each type of neuron mentioned in the answer choices: a. Unipolar: These neurons have one process extending from the cell body, which then divides into an axon and dendrite. They are usually found in sensory neurons. b. Bipolar: These neurons have two processes extending from the cell body, one axon, and one dendrite. They are commonly found in sensory systems like the retina of the eye. c. Multipolar: These neurons have one axon and multiple dendrites extending from the cell body. They are the most common type of neuron found in the central nervous system. d. Pseudounipolar: These neurons initially have one process extending from the cell body, which then divides into two separate processes: an axon and a dendrite. They are typically found in sensory neurons, similar to unipolar neurons.

Selecting the Correct Answer

With the information on each type of neuron, we can now identify which one matches the description given in the exercise, which is a neuron with one axon and multiple dendrites. The correct answer is: c. Multipolar Multipolar neurons have one axon and multiple dendrites, which is consistent with the characteristics described in the exercise.

Key concepts

Neuron Structure

Neurons, also known as nerve cells, play a crucial role in the communication within the nervous system, conveying messages through electrical and chemical signals. Their structure is key to their function. The neuron’s structure can be likened to a tree with multiple branches. At the base of this 'tree', you find the cell body, or soma, which contains the neuron's nucleus and is where most of the cell's metabolic processes occur.

Extending from the cell body are the dendrites, which resemble the branches of a tree. Dendrites are responsible for receiving signals from other neurons and conveying these messages toward the cell body. On the other side of the neuron is a contrasting, singular extension known as the axon. The axon is analogous to the trunk of the tree, transmitting the neuron's signals away from the cell body to other neurons, muscles, or glands.

The axon ends with the axon terminals, which connect with the dendrites or cell body of another neuron at a junction known as a synapse. This is where the electrical signal is usually converted into a chemical signal, to be passed on to the next cell. Understanding this neuronal architecture is fundamental to grasp the complex interactions that allow us to think, move, and sense the world.

Multipolar Neuron

Multipolar neurons are the most common type of neuron found in the central nervous system, which includes the brain and spinal cord. Their defining characteristic is having one axon and several dendrites. This multi-branching allows them to receive signals from various neurons, process this information, and communicate with multiple cells at once.

The multiple dendrites provide a large surface area for connecting with other neurons, which is essential for the complex networking required for many brain functions. Multipolar neurons vary in size and shape, but their numerous processes enable them to perform sophisticated tasks such as muscle control, sensory processing, and the integration of information that leads to higher cognitive functions.

The versatility of these neurons makes them vital in the processes of learning and memory, as they can create intricate networks through which information can travel and be stored. As such, understanding multipolar neurons is essential for research into neurological diseases and the development of treatments that might affect these critical pathways.

Nerve Cells Biology

The biology of nerve cells, or neurons, underlies all functions of the nervous system. Nerve cells are specialized to transmit information throughout the body in the form of electrical and chemical signals. The biology of nerve cells encompasses not only their structure but also their physiology and the complex interactions they have with each other.

In terms of physiology, neurons have a resting membrane potential, a balance between positively and negatively charged ions that sits waiting, like a loaded spring, ready to be triggered. When stimulated, changes in this potential lead to an action potential, the electrical impulse that travels down the axon. Neurotransmitters are the chemical messengers released at the synapse to propagate the signal to the next neuron.

The intricate biology of neurons is affected by factors such as genetics, environment, and even daily activities, all of which can influence neuronal function. Diseases such as Alzheimer's, Parkinson’s, and multiple sclerosis occur when there are problems within this complex system. Thus, studying nerve cells biology is crucial for understanding how the nervous system works and for developing medical therapies for neurological disorders.