🌌 The Simple Guide to Astrocytes: Your Brain's Star-Shaped cells

neuronest1
Nov 11, 2023
7 min read

By: Adolina Kiflay | Published On Nov,11, 2023

Introduction: Ever wondered about the unsung heroes in your brain? Meet astrocytes, the star-shaped guardians keeping things in check. Let's break down their starry structure, superhero functions, where they live, how big they are, and their link to certain brain cancers.

🌟 Shape:

The shape of astrocyte cells can be defined as a star shaped figure. Astrocytes have a distinct star-shaped appearance, which is why they are named after the Greek word "astron," meaning star. The shape of astrocytes are crucial to the role of the astrocyte cell. The shape of the astrocytes are formed by tendrils that are an extension from the cell and they can come in various sizes such as short, long, crooked, and straight. It's a common belief among many scientists that the cells ``star-shape” is used to support the neurons and to assist it numerous ways such as, providing mechanical support, assisting with neuronal cell development, providing assistance with the release of energy and nutrition such as glucose and lactate, neurotransmission which in simple terms is the transfer of information between neurons , vasomodulation which is the process of expanding or broadening blood vessels to ensure the blood flow in the body is going to all areas of the body, especially the places in the body that are lacking oxygen and nutrients. The shape of the astrocyte cell is crucial in supporting its structure, the neurons, and making sure that the cell is working properly and able to complete its main role/function.

The shape of the astrocyte also has main components in its shape that contribute significantly towards the cell and how it works. The foot of the cell assists in the tasks that the cell takes towards the blood brain barrier. The branches of the cell also play a major part in how the cell is able to perform its tasks, the branches make sure that the astrocyte is able to communicate with the numerous parts of the atrocytes’s neuronal soma. The ‘soma” in neuronal soma is latin for “a body” and it is the cell body of a neuron that contains organelles such as the nucleus and also has various other components that contribute to its structure. The structure of the cell body of the neuron contributes to the chemical processing of the cell which further then contributes to the function of the cell. The shape of the astrocyte is related to the function of the cell, and directly impacts the purpose of the cell. The student graduate, Yi-Ting Cheng, of the renowned scientist Dr. Benjamin Deneens, says, “The ends of the branched-out astrocyte structure interact with neurons and regulate activity”. The PhD researcher also mentions that without the shape and structure of the cell, the function of the cell will not be performed in a proper manner.

🧠Function:

Astrocytes perform various crucial functions that contribute significantly to the blood circulation of the brain and the general flow of blood throughout the nervous system. One of the main functions of astrocytes is to maintain and amplify blood flow throughout the brain, which is caused by neuronal activity. This response can be often described as functional hyperemia, which in more detail is the increased level of blood movement through the activity of tissues. This is where astrocytes come in because their job is to get this response, functional hyperemia. Astrocytes are able to do this by transporting mitochondria to neurons that are experiencing slow movement of blood. Astrocytes transform the mitochondria because it provides energy (atp) which is what the neurons need to increase blood movement, thus getting a functional hyperemia response. Another crucial function of astrocytes is its contribution to brain homeostasis. In further detail, the astrocyte maintains homeostasis in extracellular fluids through various ways such as, creating the blood brain barrier, moderating the outlet of neurotransmitters, and moderating the brain immune system. Astrocytes have made a big impact on the blood brain barrier, which is a type of membrane for the brain that is selectively permeable, and is used to build a barrier between the blood and the brain so that the brain is protected from potential diseases and has a layer of protection. Astrocytes work to support the blood brain barrier by providing it with energy for the neuronal function. Astrocytes moderate the outlet of neurotransmitters by controlling the concentration level (or pH level) of ions found in the blood vessels and the neurotransmitters. Neurotransmitters are chemical compounds, precisely molecules that work as messengers in the human brain; they are able to do this by signaling other nerves in the brain. Additionally, astrocytes moderate the brain immune system by aiding in tissue repair , which is to basically restore the function and structure of the tissue. Tissue can be damaged by the release of harmful chemicals .

Astrocytes, are also often described as the "caretaker" cells in the brain, play a crucial role in supporting and protecting nerve cells (neurons). They provide essential nutrients to neurons, ensuring they have the energy needed for their functions. Astrocytes also help clean up waste generated by neurons, maintaining a clean and efficient brain environment.

Another important function of astrocytes is their involvement in regulating the chemical signals in the brain. They help control the balance of these signals, which is essential for accurate communication between neurons and overall brain health. In simple terms, astrocytes are like the brain's caregivers, making sure neurons have what they need to work properly and that brain messages are transmitted accurately.

🔬Organs cell found In:

Astrocytes are a type of cell primarily found in the central nervous system (CNS), which consists of the brain and spinal cord. They serve as essential support cells in the CNS, playing a critical role in maintaining its health and proper functioning. The central nervous system, or CNS, is the control center for the body. It's made up of two main parts: the brain and the spinal cord. The brain is responsible for our thoughts, emotions, and actions, while the spinal cord acts as a communication pathway between the brain and the rest of the body. Astrocytes have several key functions in the CNS such as nourishment: Astrocytes provide essential nutrients to neurons, which are the primary cells responsible for transmitting information in the CNS. This nourishment ensures that neurons have the energy and materials they need to function correctly. Waste Removal: Astrocytes play a crucial role in maintaining a clean environment in the CNS. They help clear away waste products produced by neurons. This cleanup is essential to prevent the accumulation of harmful substances. Communication Regulation: Astrocytes help regulate the communication between neurons. They ensure that signals are transmitted accurately and at the right times, which is vital for the proper functioning of the CNS. Astrocytes are fundamental to the overall well-being of the CNS. Their support and maintenance functions contribute to the CNS's ability to process information, control bodily functions, and respond to various stimuli.

🧬Cell Size

Astrocytes found in the central nervous system (CNS), are important for maintaining the health and proper functioning of the brain and spinal cord. While their functions are well-known, understanding their size and structure is equally important. Astrocytes are a particular type of glial cell, which are the non-neuronal cells in the CNS. When we talk about the size of astrocytes, it's important to note that they are relatively small compared to neurons. In terms of size, astrocytes are typically quite tiny, with diameters ranging from about 10 to 25 micrometers. To put that into perspective, a typical human hair is about 50 to 100 micrometers in diameter, so astrocytes are about half the width of a human hair. This small size allows them to be numerous and densely packed within the CNS (central nervous system), ensuring that they can efficiently support and interact with nearby neurons. Astrocytes are not the same in size and shape; they can vary depending on their location and specific functions. Some astrocytes have more extensive and complex processes, while others have simpler structures. The diversity in size and shape is related to the specific roles that astrocytes play in different regions of the brain and spinal cord. While astrocytes are relatively small compared to some other cells in the CNS, their size is well-suited for their roles in supporting neurons. They are not the only cell type in the nervous system, and each type of cell has its specific size and function, and they work together to maintain the health and proper functioning of the CNS. Their small size, along with their star-shaped structure, allows them to efficiently interact with and support nearby neurons and maintain the health and proper function of the brain and spinal cord.

🦠Cancers connected:

While astrocytes themselves do not directly cause cancer, there are specific brain tumors associated with these cells. These tumors are known as astrocytomas, and they can vary in their characteristics and potential for harm. Low-Grade Astrocytomas: These tumors grow slowly and are considered less harmful. They are often found in younger individuals and can sometimes exist for many years without causing significant issues. Low-grade astrocytomas are usually categorized into Grade I or Grade II, with Grade I being the least harmful.

Anaplastic Astrocytomas: Anaplastic astrocytomas are more harmful than low-grade tumors. They are classified as Grade III and have a higher chance of spreading into nearby brain tissue. These tumors grow faster and are linked with more severe symptoms.

Glioblastoma Multiforme (GBM): GBM is the most harmful type of astrocytoma and is classified as Grade IV. These tumors grow quickly and are highly invasive. GBMs are hard to treat and have a poor outlook. They can rapidly spread into the nearby brain tissue, making complete surgical removal challenging. It's essential to understand that not all brain tumors are astrocytomas. Other types of brain tumors have different origins and characteristics. The exact cause of astrocytomas is not entirely known, and they can occur in people of all ages. Some genetic factors and exposure to radiation may increase the risk of developing these tumors, but the exact mechanisms are still being studied. The treatment for astrocytomas typically involves a combination of surgery, radiation therapy, and chemotherapy, depending on the tumor's grade and location. The goal of treatment is to remove as much of the tumor as possible while preserving healthy brain tissue. Astrocytoma brain tumors are connected to astrocyte cells. They can range from low-grade, slow-growing tumors to highly harmful and invasive cancerous tumors. While astrocytomas are the most well-known tumors associated with astrocytes, it's important to understand that not all brain tumors come from astrocyte cells.

🔍Check your understanding -

What is the shape of astrocyte cells, and why is it significant for their function?
What does "astron" mean and what language is it from?
How do astrocytes contribute to the brain's response known as functional hyperemia?
What crucial function do astrocytes perform in maintaining brain homeostasis?
What is the main role of astrocytes in supporting neurons in the central nervous system?
Are astrocytes the only type of cell in the nervous system, and why is their size important?
What are the three main types of astrocytomas, and how do they differ in terms of aggressiveness?