--- title: The human body deeper: the heart and blood in amazing numbers — a lesson of Mova's school · trees and pragmatics description: «The human body deeper: the heart and blood in amazing numbers», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Your heart is a muscle about the size of your own fist, and it never takes a day off: it squeezes blood out --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/) [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/) / The human body deeper: the heart and b… # The human body deeper: the heart and blood in amazing numbers Lesson 261 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/261-human-body-deeper-heart-and-blood/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/0/) — Your heart is a muscle about the size of your own fist, and it never takes a day off: it squeezes blood out with every beat, more than 100,000 times a day. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/1/) — Each squeeze sends a wave along your arteries, and that wave is the pulse you can feel in your wrist after a race in the playground. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/2/) — The blood travels through tubes called blood vessels, so many of them that laid end to end they would go more than twice around the Earth, and a drop sets off round the whole body and is back in about a minute. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/3/) — Blood is never blue: it is bright red when it is full of oxygen and darker red when it has given some away; veins only look blue because of the way skin lets light through. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/4/) — Cartoons like Tom and Jerry show a heart bursting out of Tom's chest when he falls in love, but a real heart stays safely inside the ribs, beating faster when you run, get scared or excited; in a race it speeds up to send more blood to the working muscles. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/5/) — Each heartbeat squeezes blood out and sends a wave along the arteries, which you feel as your pulse. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/6/) — A child's heart beats about 70 to 110 times a minute at rest, which is more than 100,000 times a day. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/7/) — Your heart is about the size of your own fist and has four rooms called chambers; the «lub-dub» sound is its valves snapping shut. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/8/) — An adult's blood vessels laid end to end would stretch roughly 100,000 kilometres, more than twice around the Earth; this is an estimate, and books give different numbers. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/10/) — Blood has red cells that carry oxygen, white cells that fight germs, and platelets that help stop bleeding; one tiny drop holds millions of red cells. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/11/) — When you cut yourself, platelets and stringy fibres make a net that plugs the cut and hardens into a scab. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/12/) — An adult has about 5 litres of blood, and one blood donation is about half a litre, which the body soon makes again. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/14/) — Red blood cells are made in the bone marrow, the soft middle of big bones, about 2 million every second. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/15/) — The stethoscope was invented in 1816 by René Laennec, who first used a rolled-up tube of paper to listen to a heart; before that, doctors put an ear straight onto the patient's chest. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/16/) — A blue whale's heart weighs about 180 kilograms and can beat as slowly as two times a minute on a deep dive; small animals have fast hearts and big animals slow ones. - [17](https://md.mova.elamur.ai/free/en/corpora/school/biology/261-human-body-deeper-heart-and-blood/17/) — When you exercise, blood vessels in your skin widen to let heat out, so your face goes red; regular exercise makes the heart stronger, so it beats more slowly at rest. - ← previous: [The human body deeper: the brain and nerves](https://md.mova.elamur.ai/free/en/corpora/school/biology/260-human-body-deeper-the-brain-and-nerves/) - next →: [The human body deeper: lungs, stomach and guts](https://md.mova.elamur.ai/free/en/corpora/school/biology/262-human-body-deeper-lungs-stomach-and-guts/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)