Diffusible Signaling
Diffusible Signaling - Related Videos
03:31
Diffusion and Osmosis - Concepts
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2019
Cell Membranes and Diffusion In order to function, cells are required to move materials in and out of their cytoplasm via their cell membranes. These membranes are semipermeable, meaning that certain molecules are allowed to pass through, but not others. This movement of molecules is mediated by the phospholipid bilayer and its embedded proteins, some of which act as transport channels for molecules that otherwise would not be able to pass through the membrane, such as ions and carbohydrates.
08:18
Diffusion and Osmosis - Student Protocol
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2019
Diffusion in Agar ExpandNOTE: In this exercise, you will be given agar containing an indicator chemical called phenolphthalein. When phenolphthalein is exposed to the normal alkaline conditions in the agar, it will look pink. But when it is exposed to neutral or acidic conditions, it changes from pink to clear. You will make different size and shaped agar cubes as a model for cells to study the impact of cell size and shape on diffusion rate. To make the first set of cells, measure out and cut...
02:55
Diffusion and Osmosis - Instructor Prep
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2019
Preparation of Solutions for the Agar Cube Experiment ExpandIMPORTANT: Wear gloves, goggles, and appropriate personal protective equipment – chemicals can be hazardous at high concentrations. For the diffusion indicator solution, weigh out 1 g of phenolphthalein and add it to a beaker containing 100 mL of 95% ethanol. To make the basic solution for the agar, measure 80 mL of water into a beaker, and then add 0.4 g of NaOH. Stir until the solute is dissolved then bring the total volume of the...
09:28
Assaying the Ability of Diffusible Signaling Molecules to Reorient Embryonic Spinal Commissural Axons
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Cited by 4 •
2010
This assay assesses the ability of a signaling molecule, here Bone Morphogenetic Protein 7 (BMP7), to reorient commissural axons. An explant of embryonic dorsal spinal cord is cultured adjacent to an aggregate of COS cells secreting the candidate growth factors. Reoriented commissural axons growing within the explant are visualized by immunohistochemistry.
01:21
Diffusion
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2023
Diffusion is a type of passive transport. In passive transport, a substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across the space. For example, take the diffusion of substances through the air. When someone opens a perfume bottle in a room filled with people, the perfume is at its highest concentration in the bottle and is at its lowest at the edges of the room. The perfume vapor will diffuse, or spread away, from the...
FAQs
A concentration gradient gives cells positional information by exposing them to different signal levels across a tissue. Cells can therefore respond according to where they are located relative to the signaling source, helping coordinate developmental organization. This spatial patterning allows one diffusible signal to influence multiple neighboring regions while producing different biological effects across the tissue.
Receptors determine which cells can detect a released ligand, while intracellular pathways convert that detection into a cellular response. After receptor binding, signaling can alter gene expression, metabolism, or cell behavior. This two-stage arrangement provides selectivity: a molecule may spread through extracellular fluid, but only cells with the appropriate receptor can respond in a defined way.
Disruption at any stage can interfere with communication between cells. Abnormal signal production may change how much ligand is available, altered transport may affect where it reaches, and defective reception may prevent target cells from responding. Because diffusible signaling coordinates development, immunity, tissue repair, and physiological regulation, such failures can disturb tissue function or contribute to disease.
Major applications include coordinating embryonic and tissue development, directing immune responses, supporting tissue repair, and regulating physiological functions. The relevant ligand may act as a hormone, cytokine, or developmental morphogen, depending on the biological context. Studying these signals helps connect molecular communication with larger outcomes such as organized tissues, environmental responses, and regulated body functions.
Cells can use signals moving through extracellular fluids to coordinate their behavior with nearby or more distant cells. Receptor-mediated responses then influence gene expression, metabolism, or behavior in ways that support tissue-level organization. Concentration-dependent information is especially relevant when cells must adopt coordinated roles according to their position within a developing or repairing tissue.
A useful investigation considers the signal-producing cells, the movement of the ligand through extracellular fluids, the target cells and their receptors, and the intracellular responses that follow. Researchers can then relate these stages to outcomes such as altered gene expression, metabolism, behavior, development, immunity, repair, or physiological regulation, while identifying where communication may become disrupted.