--- title: Skin: layers, sweat, goosebumps, freckles and sunburn — a lesson of Mova's school · trees and pragmatics description: «Skin: layers, sweat, goosebumps, freckles and sunburn», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Your skin is an organ, like your heart or lungs, and it is the biggest one you have: a waterproof, germ-proof, self- --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Skin: layers, sweat, goosebumps, freck… # Skin: layers, sweat, goosebumps, freckles and sunburn Lesson 353 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](https://md.mova.elamur.ai/free/en/school-run/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/0/) — Your skin is an organ, like your heart or lungs, and it is the biggest one you have: a waterproof, germ-proof, self-repairing coat that also helps keep your temperature right. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/1/) — It has three main layers: the thin outer epidermis that protects, the dermis below with blood vessels, nerves, sweat glands and hair roots, and a fat layer underneath that cushions and keeps you warm. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/2/) — Look at a sunbeam in your bedroom: those floating specks of dust are partly your own dead skin, because the outer layer is always flaking off and being replaced from below. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/3/) — Skin also reacts to the world: it sweats to cool you, makes goosebumps when you are cold, makes extra brown melanin in the sun, and burns if the sun's ultraviolet light is too strong. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/4/) — Skin is the body's largest organ; an adult's skin would cover roughly two square metres if laid out flat. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/5/) — Skin keeps water in and germs out and helps keep your temperature right; it is thinnest on the eyelids and thickest on the soles of the feet. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/6/) — Skin has three main layers: the outer epidermis, the dermis with blood vessels and nerves, and a fat layer underneath; the outer layer has no blood vessels, so a very light scrape does not bleed. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/7/) — People shed tens of thousands of tiny dead skin flakes every minute, which become part of house dust, and tiny dust mites eat them. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/8/) — The outer layer of skin replaces itself about every four weeks, bit by bit, while a snake sheds its whole skin in one go. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/9/) — Skin has two to four million sweat glands; sweat cools you as it dries, because drying takes heat from the skin, and on a humid day it dries slowly and cools less. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/10/) — Dogs sweat only a little, through their paws, and cool down mainly by panting; pigs barely sweat at all, so they roll in mud to keep cool. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/11/) — Each hair has a tiny muscle that pulls it upright, making a goosebump; in furry animals raised fur traps warm air or makes them look bigger, like a scared cat. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/12/) — Some people get goosebumps from music they love, and scientists are still studying why. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/14/) — Freckles are spots of extra melanin; sun makes them darker, they often fade in winter, and people with red hair and fair skin often have more. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/15/) — Ultraviolet light from the sun damages skin cells and causes sunburn; you can burn on a cloudy day, snow and water reflect sunlight onto you, and sunburn in childhood raises the risk of skin cancer later. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/353-skin-layers-sweat-goosebumps-freckles-and-sunburn/16/) — Skin makes vitamin D in sunlight, which helps bones use calcium; in Britain the winter sun is too weak for this, so many people take vitamin D in autumn and winter. - ← previous: [Teeth: enamel, sugar, holes, brushing and the dentist](https://md.mova.elamur.ai/free/en/corpora/school/biology/352-teeth-enamel-sugar-holes-brushing-and-the-dentist/) - next →: [Skin: fingerprints, scabs, scars, bruises and blisters](https://md.mova.elamur.ai/free/en/corpora/school/biology/354-skin-fingerprints-scabs-scars-bruises-and-blisters/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)