It’s time to talk about mucus and slime – lovely stuff! JV Chamary explains all you need to know – but were afraid to ask… <\/p>
Goo, gunge, gunk… while there are many names for the stuff that makes things slippery or sticky, slime isn\u2019t a single material but a label for a variety of substances with similar physical properties. <\/strong><\/p> Those qualities are desirable to many living things, which is why slime is made by such a wide range of organisms.<\/p> There\u2019s no exact definition: the word reflects characteristics. So you could say (perhaps unhelpfully!) slime is any substance that feels slimy \u2013 it\u2019s something that will slip or ooze from your hand when you hold or squeeze it, for instance. <\/p> The best-known slime is mucus, a material that covers many external and internal body surfaces. Mucus keeps an amphibian<\/a>\u2019s skin moist, for example, and prevents the lining of a mammal\u2019s lungs from drying out. Technically a viscous (thick) liquid, mucus doesn\u2019t flow in its steady state and behaves like a solid \u2013 it\u2019s a gel.<\/p> The gel\u2019s main function is to serve as a barrier that lines a surface to protect an animal\u2019s outermost cells from infection or damage. In the human body, snot (nasal mucus) captures invaders such as viruses, while the mucus within the digestive system stops your stomach digesting itself.<\/p> All complex creatures secrete mucus and, importantly, the gel is a selective filter: it traps disease-causing microbes (pathogens) while housing a body\u2019s inner ecosystem of friendly bacteria. So a mucosal surface extends an animal\u2019s innate immune system and supports its microbiome.<\/p> It can be a dedicated lubricant. Bony fish are covered in a thin layer of slick mucus or \u2018slime coat\u2019 that helps to smooth the rougher texture of scales (which improves hydrodynamics for swimming), while gastropods (such as slugs and snails<\/a>) exploit mucus to reduce friction during locomotion, which leaves a slime trail.<\/p> Mucus can serve as a glue, too, enabling molluscs to climb walls or travel upside-down. In fact, garden snails make three distinct secretions: lubricating, adhesive and protective mucus. The qualities are different due to the molecules they contain.<\/p> The key ingredients are molecules called mucins. Each mucin is a \u2018glycoprotein\u2019 with a long protein backbone and sugars (glycans) that radiate outward from its core, resembling a bottlebrush structure. Mucins cross-link with one another or other molecules. <\/p> These molecular interactions give mucus its properties of a gel. More specifically, mucus is a \u2018hydrogel\u2019 \u2013 once released from special \u2018goblet cells\u2019 in the epidermis, mucin molecules combine with water (hydration) and suddenly expand to several hundred times their original volume through an almost explosive process.<\/p>What is slime?<\/strong><\/h2>
What is mucus?<\/h2>
How does mucus protect animals?<\/strong><\/h2>
How else is mucus used?<\/strong><\/h2>
What is mucus actually made of?<\/strong><\/h2>
Do plants make slime?<\/strong><\/h2>