GCSE Biology: Memory Trick | Human Defence

Added: 2026-05-06

[00:00:00]Here's a memory trick on how to memorize all the human defenses against disease.

[00:00:04]You just need to remember the word snazzy. The S stands for skin, which acts as a barrier that stops pathogens from entering the body. The skin also produces these antimicrobial substances that can kill any pathogens if they do land on the skin. The N is for the nose, which contains hairs and mucus, which trap particles that have pathogens in them and stop them from going further into the body. Next, we have the A, which stands for air passages. And this includes the trachea and the bronchi.

[00:00:34]These also produce mucus, which trap pathogens. The surface of these air passages are lined with cilia, which are hair-like structures, which waft the mucus and pathogens back up to the back of the throat, where it's swallowed into the stomach. The second S is for the stomach, and here we've got hydrochloric acid that gets produced, which kills any pathogens that enter it. And finally, the I is for the immune system, which kicks in if all of these defenses fail and the person becomes infected with a disease. They help to kill the pathogens by phagocytosis, producing antibodies, and producing antitoxins.

[00:01:09]If you've got any other good biology memory tricks, then let us know in the comments, and we might just make a video out of it.