Question

Threadlike cytoplasmic extensions that extend out from the cell body of _____ send and receive signals. A. neuron B. neuroglial cell C. fibroblast D. melanocyte

Short answer

The cell is a neuron (A).

Step-by-step solution

Understand the Context

The question asks us to identify the type of cell that has threadlike cytoplasmic extensions to send and receive signals. Recognizing that different cells have specialized structures can help us identify the correct answer.

Identify Cell Types and Functions

Each option corresponds to a specific type of cell: - Neurons (A) are known for having extensions called axons and dendrites that send and receive signals in the nervous system. - Neuroglial cells (B) support neurons but do not typically have threadlike extensions for signaling. - Fibroblasts (C) are involved in producing extracellular matrix and do not have threadlike extensions for signaling. - Melanocytes (D) produce melanin, and they do not function to send and receive signals.

Analyze Cytoplasmic Extensions

Neurons are notable for their specialized cytoplasmic extensions, namely axons and dendrites, which facilitate the transmission of nerve signals throughout the body. This specialization is consistent with the requirement of sending and receiving signals.

Confirm the Correct Answer

Given the explanation above, neurons (option A) are the only cell type in the options that prominently feature threadlike cytoplasmic structures (axons and dendrites) crucial for sending and receiving signals.

Key concepts

Cytoplasmic Extensions

Cytoplasmic extensions are vital cell structures that protrude from the main cell body. In neurons, these extensions come in the form of axons and dendrites. They play a crucial role in the functionality of the neuron within the nervous system. These extensions allow the neuron to interact with other cells, facilitating communication and signal transmission.
Unsheathing from the cell body, axons and dendrites reach out to establish connections with other cells. Establishing proper connections is essential for the overall operation of the nervous system. Through these connections, neurons can pass along vital information quickly and efficiently over varying distances, allowing the body to respond aptly to different stimuli.
The process characterized by these extensions entails transmitting electrical signals that move along the axon and then transfer to another cell via the dendrites, ensuring a continuous flow of information inside the body.

Axons and Dendrites

Axons and dendrites are distinct types of cytoplasmic extensions emanating from neurons. Each type has a particular structure and function. Axons are typically long, singular extensions that carry electrical impulses away from the neuron's cell body. This action occurs through voltage changes along the axon's length, which ultimately leads to the release of neurotransmitters at the axon's terminal.
Dendrites, on the other hand, are shorter and branched. They are responsible for receiving signals from the axons of other neurons or from sensory stimuli and transmitting this information to the cell body.

• Axons: Long, singular, carry signals away
• Dendrites: Short, branched, receive signals

Together, axons and dendrites facilitate rapid and complex communication within the nervous system, contributing to the coordinated actions required for sensation, response, and cognition.

Nervous System

The nervous system is a complex network of neurons and supporting cells responsible for transmitting signals throughout an organism's body. Comprised of the central nervous system (CNS) and peripheral nervous system (PNS), this vast network ensures efficient communication between various body parts.
The CNS includes the brain and spinal cord, acting as the control center. It processes and interprets sensory information received from the body and sends out instructions. The PNS, however, includes all other neural elements, such as peripheral nerves, connecting the CNS to limbs and organs.

• Central Nervous System: Brain and spinal cord
• Peripheral Nervous System: Sensory and motor neurons

Through this well-coordinated system, the body can respond to different stimuli, whether internal or external, allowing for sensation, movement, and cognition.

Cell Signaling

Cell signaling is a fundamental process where cells communicate with each other to perform various functions necessary for survival and adaptability. In neurons, signaling occurs both electrically and chemically, enabling rapid transmission of information across the nervous system.
Electrical signals travel along the length of the neuron in the form of action potentials. When these potentials reach the end of an axon, they trigger the release of chemical messengers known as neurotransmitters. These chemicals cross synapses, the small gaps between neurons, reaching the dendrites of the nearby cells to either initiate or inhibit further action potentials.

• Electrical Signaling: Action potentials traveling along neurons
• Chemical Signaling: Neurotransmitters facilitating synaptic communication

This dual method of signaling allows precise control over physiological processes, ensuring that organisms can quickly adapt to changes in their environments.