Question

The fingerlike projections on neurons that receive input from other neurons are called a. dendrites. b. nuclei c. axons. d. terminal buttons.

Short answer

a. Dendrites.

Step-by-step solution

Understanding Neuron Structure

Neurons are specialized cells in the nervous system responsible for transmitting information throughout the body. They have distinct parts, each with different functions.

Identifying Parts of the Neuron

Neurons consist of several key components: the cell body, axons, dendrites, and axon terminals (or terminal buttons). Understanding each component's role is crucial for identifying the correct answer.

Dendrites Explained

Dendrites are the branched, fingerlike projections from the neuron’s cell body. They are primarily responsible for receiving electrical and chemical signals from other neurons, making them integral to neuronal communication.

Examining the Options

- a. Dendrites: Correct, as they receive input. - b. Nuclei: Incorrect, as the term 'nuclei' typically refers to cell bodies or groups of neuron cell bodies in the brain. - c. Axons: Incorrect, as axons transmit information away from the neuron cell body. - d. Terminal buttons: Incorrect, as they are the endings of axons that release neurotransmitters.

Confirming the Correct Answer

Given the definition of each option, the fingerlike projections on neurons that receive input are clearly dendrites.

Key concepts

Dendrites

Dendrites are quite fascinating components of the neuron. They are the branched, tree-like structures that extend from the cell body, which acts as the command center of the neuron.
Dendrites play a key role in how neurons communicate with each other. They are specialized in receiving electrical and chemical signals from other neurons.
Think of dendrites as tiny antennas tuned in to pick up messages from neighboring neurons. These messages are conveyed in the form of electrical impulses called action potentials. Once dendrites receive a signal, they pass it along to the neuron's cell body for processing.

• Dendrites can have thousands of synapses, or contact points, with other neurons, allowing for complex communication.
• The more dendrites a neuron has, the more information it can handle, which is especially important in intricate neural networks like the brain.

Axons

Axons are another critical part of the neuron structure. While dendrites focus on receiving information, axons are tasked with transmitting that information to other cells.
Imagine axons as long, slender tubes that can stretch quite a distance from the neuron's cell body. Their primary job is to carry electrical impulses away from the cell body towards other neurons, muscles, or glands.

• Axons can be incredibly long, even stretching several feet, as seen in the neurons connecting your spinal cord to your toes.
• They are often insulated by a fatty layer called the myelin sheath, which speeds up the transmission of electrical signals.

Different neurons can have varying axon lengths, and the fastest signals travel along the longest axons. It's a remarkable adaptation for efficient communication over larger distances.

Terminal Buttons

The terminal buttons, or axon terminals, are located at the end of axons. Their primary function is to release neurotransmitters, which are chemicals that transmit signals from one neuron to another across the synapse, the tiny gap between neurons.
The process works a bit like a relay race. The axon carries the impulse to the terminal buttons, which then "hand off" the signal in chemical form to the next neuron.

• When an impulse arrives at the terminal buttons, it triggers the release of neurotransmitters stored in small sacs called vesicles.
• These chemicals cross the synapse and bind to receptors on the next neuron, allowing the signal to continue its journey.

This intricate process ensures that neuronal communication is precise and can adapt to the ever-changing needs of the brain and body.