Cell Signaling

by Thad Wilson, PhD

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    00:01 Extracellular and intracellular signaling.

    00:05 We’ll discuss how cells speak with each other and deliver communique.

    00:10 This could be in close proximity or those that are far away in the body.

    00:15 Also, cells need to communicate vital information within the cell.

    00:20 And how do they do that? These will be covered within.

    00:28 There are many modes of communication.

    00:31 You can come up with a lot of these on your own.

    00:33 Some of them are personal in nature such as a handshake, other ones involve things like a delivered package or envelope, or even on the internet you can communicate very easily with a number of friends at the same time.

    00:48 How do these communique work? Well, one of the things to think about with the body is what modes of communication does it have.

    00:56 One of the more vital ones are endocrine control.

    01:00 Here, you release a signaling molecule or a hormone.

    01:04 It travels around in the bloodstream and is delivered to certain target cells.

    01:09 How do you know which cells will get the communique? The ones with the right receptors.

    01:15 If you don’t have the right receptor, you won’t receive that information or that signal.

    01:22 Neural signals are also very important.

    01:24 Here, a neuron can signal via long projections of axons going to an axon terminal and then releasing a packet of information to the cell it’s trying to signal.

    01:39 These neural signals are very powerful in that they are direct communications rather than just releasing the substance into the blood, letting it travel around throughout the body.

    01:50 Here, it’s more targeted in nature.

    01:54 Now, if we move to some more local control, these are signaling molecules that will signal varying cells right around a cell.

    02:05 This involves passive diffusion in which a molecule is released from the signaling cell and will only be able to diffuse in the distance around it.

    02:16 Which particular cells will receive the communique? It’s all based upon the receptor.

    02:22 You need to have a receptor to catch that signaling molecule.

    02:28 Interestingly, there are also times in which a cell will want to receive the information that it is releasing.

    02:35 A good example for this, if you’re releasing signals, you would want to make sure you knew how many signals were released.

    02:43 You could have a receptor on the own cell that is sending these out to get feedback about that information.

    02:53 Now, besides sending a signaling molecule, you could also have direct contact with the cell next to you.

    03:02 Some of the direct contacts involve things called gap junctions.

    03:07 Gap junctions are these specialized tubes that allow communication between two cells like it’s not even leaving that cell.

    03:17 So these tubes will communicate electrical information, sometimes its ionic information, and this will allow a propagated and coordinated response between a number of cells.

    03:33 Some direct signaling can happen via paracrine mechanisms.

    03:37 For these paracrine mechanisms, you have to have one cell that can move around and be able to recognize another.

    03:45 So the immune system is a very good example, where you might have immune cells that can travel around and recognize other cells based upon what projections they have sticking out.

    03:57 Here, it’s like a handshake, where one cell will get up to a close proximity to another and if they can recognize each other’s projections, they might be able to bind and signal each other.

    About the Lecture

    The lecture Cell Signaling by Thad Wilson, PhD is from the course Membrane Physiology.

    Included Quiz Questions

    1. A receptor to which the signal can attach
    2. A specific distance
    3. Availability within the same organ
    4. A cell to which the signal attaches
    5. A blood vessel
    1. ...a gap junction.
    2. ...a neural-mediated channel.
    3. ...a hormonally-mediated communication.
    4. ...a paracrine connexon.
    5. endocrine connexon.
    1. Neural
    2. Endocrine
    3. Paracrine
    4. Hormonal
    5. By blood
    1. Simple diffusion and uptake by neighboring cells
    2. Transmission of signals directly from cell to cell
    3. Release of the signal into the blood
    4. Release of the signal from a nerve ending
    5. Release of the signal and re-uptake by the same cell
    1. By autocrine signaling
    2. By endocrine signaling
    3. By paracrine signaling
    4. By neural signaling
    5. By simple diffusion and uptake by neighboring cells
    1. A direct connection between the cytosol of two different cells.
    2. Connections between cells that allow communication via osmosis
    3. Connections between cells that allow communication via the release of a mediator into the interstitial space
    4. Connections between cells that allow communication via the release of a mediator into the blood
    5. Connections between cells that allow communication via a nerve ending
    1. Via a membrane-bound signaling compound
    2. By releasing the information and letting it flow in the blood
    3. By reaching a nerve ending
    4. By connecting directly with another cell and injecting the information via a gap junction
    5. By releasing the information in the extracellular space

    Author of lecture Cell Signaling

     Thad Wilson, PhD

    Thad Wilson, PhD

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    By Rufaydah A. on 20. December 2018 for Cell Signaling

    Some points are not stated clearly enough. Overall, good presentation.

    Simply Stated
    By Joe U. on 21. April 2017 for Cell Signaling

    This video was easy to understand. I appreciated how everything was stated in a simple manner. This allowed me to grasp the concept without confusing me. Keep up the good work.