The brain and nerves Lesson 68 of the biology course of Mova's primary school: 16 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: the lesson at school .
0 Your brain weighs about as much as a big bag of sugar, is soft like tofu, and runs everything you do, think, feel and remember. 1 It talks to the body through nerves, long thin wires of living cells; the thick main cable, the spinal cord, runs down inside the bones of your back. 2 Stub your toe and there is a strange gap: first a bump, then a moment later the ache arrives and you yell, because the signal has to travel all the way up your leg and spine to the brain, and pain signals are not the fastest ones. 4 The brain never switches off: while you sleep it sorts the day's memories and makes dreams, and every time you practise your times tables the paths between its cells grow stronger. 5 The adult brain weighs about 1.3 to 1.4 kg and is soft like tofu; it is protected by the skull and floats in a clear fluid that cushions it. 6 The brain has about 86 billion nerve cells; it is only about 2 percent of the body's weight but uses about a fifth of its energy. 8 Nerves carry signals between the body and the brain; the fastest signals travel at over 100 metres a second, but some pain signals travel only about 1 or 2 metres a second. 9 A reflex is a quick automatic movement: in the knee-jerk test the signal goes to the spinal cord and straight back to the muscle without waiting for the brain. 10 The brain has two halves; the left half mostly controls the right side of the body and the right half controls the left side. 12 During sleep the brain is busy: it sorts and stores the day's memories, clears away waste and helps the body grow and repair. 13 Most vivid dreams happen in REM sleep, when the eyes dart about under the eyelids; everyone dreams several times a night, even if they forget. 14 Each time you practise something, the connections between the nerve cells involved get stronger, so the memory gets easier to find. 15 Brain freeze happens when very cold food chills the roof of the mouth quickly; blood vessels there change size and nerves send a pain signal felt in the forehead; slowing down and warming the roof of the mouth with your tongue makes it pass soon. 16 The spinal cord is a thick bundle of nerves running through a tunnel in the bones of the spine, carrying messages between the brain and the body. 17 An octopus has about 500 million nerve cells, and about two thirds of them are in its eight arms, which can taste and feel and act partly on their own. 18 Pins and needles come when pressing on a nerve stops it sending signals properly; when the pressure is gone the nerve wakes up with lots of tingly signals. ← previous Digestion: the journey of a sandwichnext → Senses: eyes and ears↑ back to Biology This page in Markdown → https://md.mova.elamur.ai/free/en/corpora/school/biology/68-the-brain-and-nerves/