This video describes the structure and function of astrocytes. Astrocytes, often called star cells, are the workhorses of the central nervous system. They provide structural support, form a protective glial scar after injury, maintain homeostasis, contribute to the blood-brain barrier, and clear out synapses. These versatile cells play a crucial role in keeping our nervous system functioning optimally. By Matt Jensen.
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- at 2;08 he says a word about the astrocytes "pro....". something...whats that word?
i got the meaning as he explained pretty well later...but i require the words(8 votes)
- At2:08he says, "Processes". According to my own Anatomy and Physiology textbook, these are arm like structures that extend from the cell body of all neurons. There are two types.
1. Dendrites are short, tapering, and diffusely branching extensions. They convey incoming messages toward the cell body.
2. Axons arise from the axon hillock, then narrow to form the slender process. They are the conducting region of a neuron.
Hope that helps!(17 votes)
- at4:30, how does neuron process lactate into ATP, is this process similar to how liver cells process lactate back to pyruvate for later oxidative phosphorylation (since lactate is a product of fermentation)?(5 votes)
- I found an explanation concerning your question about neuron lactate process into ATP in an article entitled "Brain Energy Metabolism: Focus on Astrocyte-Neuron Metabolic Cooperation." Here is what the authors wrote. "Glucose is the energy substrate of the adult brain. Nevertheless, under particular circumstances the brain has the capacity to use other blood-derived energy substrates, such as ketone bodies during development and starvation (Nehlig, 2004, Magistretti, 2008) or lactate during periods of intense physical activity (van Hall et al., 2009). Glucose enters cells trough specific glucose transporters (GLUTs) and is phosphorylated by hexokinase (HK) to produce glucose-6-phosphate. As in other organs, glucose 6-phosphate can be processed via different metabolic pathways (Figure 1A ), the main ones being (1) glycolysis (leading to lactate production or mitochondrial metabolism), (2) the pentose phosphate pathway (PPP), and (3) glycogenesis (in astrocytes only, see below). Overall, glucose is almost entirely oxidized to CO2 and water in the brain (Clarke and Sokoloff, 1999). Nevertheless, as evidenced by the different metabolic routes that glucose can follow, each individual brain cell does not necessarily metabolize glucose to CO2 and water. Indeed, a wide range of metabolic intermediates formed from glucose in the brain can subsequently be oxidized for energy production (e.g., lactate, pyruvate, glutamate, or acetate) (Zielke et al., 2009)."(4 votes)
- I was told that the MCAT doesn't require much knowledge of these (astrocytes, microglia, etc), and to just know their main function. Is this still true or is my source outdated?(4 votes)
- I would just know the basic information to be sure that you don't miss anything. But in general, I don't think the MCAT would be too worried about the in-depth detail about the glial cells.(3 votes)
- Could you explain a little more about the blood brain barrier? I have heard Matt talk about it in other videos. Is it just like it sounds, the astocytes using their end feet to prevent blood from entering the CNS? Am I missing anything important? Thanks.(3 votes)
- The BBB is anatomically composed of the tight junctions of the capillary endothelial cells which provides a very efficient barrier to large molecules and/or molecules that are not coupled to a carrier. This presents a challenge to pharma aimed at the CNS by requiring carriers and other mechanisms to allow the drugs into the protected CNS.
The astrocytic endfeet insulate synapses and cerebral vasculature. They form a ring around the perivascular pericytes (I will explain if you have not heard of them yet) which themselves form a ring around the endothelial cells of the BBB.
It's an amazing system. If you have any more questions, please, ask away!(3 votes)
- If Astrocytes exists only in CNS, therefore for PNS, there will be only 3 ways to remove the neurotransmitters:
is this right?(3 votes)
- I would say this is also true in the CNS, only that the three methods you listed are facilitated by the astrocytes.(2 votes)
- Glial scar function is function of microglial cells? isn't it?(1 vote)
- yes but there are significantly less microglia relative to astrocytes. That is why when hearing the term "glial scar," it is pertaining to an astrocyte. Hence the synonymous terms of astrogliosis. hope this helps! =](3 votes)
- are all the glial cells are derived from neural stem cell?(2 votes)
- No, not all of them. Glial cells of the peripheral nervous system are derived from neural CREST cells (e.g. Schwann cells)(1 vote)
- What exactly do you mean about the synapses needing to turn on and off for the neurotransmitters to work? If it's off, how exactly does it convert the information and send it to the target cells?(1 vote)
- I believe the point he was trying to make is that synapses would be non-functional if neurotransmitters "lingered" between the neuron and target cell. In this way, the presynaptic neuron must have the ability to "turn on" the synapse through release of neurotransmitters and "turn off" by removing them. The astrocyte helps to remove these neurotransmitters thus effectively resetting the synapse for further use.(2 votes)
- I've heard reference to 'glial cell plaque' with regard to Alzheimers. Is the the same as or related to a glial scar?(1 vote)
- you might be getting glia scar mixed up with "amyloid plaques" that are present in alzheimers disease. While it is believed that neurotrophic factor from glial cells may play a role in the presence of amyloid plaque, the terms glial scar and amyloid plaque are different.(2 votes)
- What things should I know before studying the potential stuffs of the neurons?
By this I mean any pre-knowledge in chemistry or any membrane stuff?(1 vote)
- Take a look at Crash Course Biology 'Nervous System' and see if you understand the material. It is very fast paced, but fun. If it makes sense, then come back to this. If it doesn't make sense, look at more basic biology and chemistry videos either in Crash Course or in the college or AP level courses.. My best to you. https://www.khanacademy.org/science/biology/crash-course-bio-ecology/modal/v/crash-course-biology-125(2 votes)