<p><img alt="" class="" height="475" src="https://data.ulearngo.com/assets/51ad1f7c-4ab2-4d21-a0cf-7bcef80ccd51" width="396"/></p>
<h3><strong>The skeletal system consists of all the bones of the body. How important are your bones?</strong></h3>
<p>Try to imagine what you would look like without them. You would be a soft, wobbly pile of skin, muscles, and internal organs, so you might look something like a very large slug. Not that you would be able to see yourself—folds of <a data-lesson="skin" data-subject="biology" data-tutorial="human-biology" href="https://app.ulearngo.com/biology/human-biology/skin">skin</a> would droop down over your eyes and block your vision because of your lack of skull bones. You could push the skin out of the way, if you could only move your arms, but you need bones for that as well!</p>
<h2>The Skeleton</h2>
<p>The human skeleton is an internal framework that, in adults, consists of 206 <strong>bones</strong>, most of which are shown in the figure below.  </p>
<p>In addition to bones, the skeleton also consists of cartilage and ligaments:</p>
<ul>
<li><strong>Cartilage</strong> is a type of dense connective tissue, made of tough <a data-lesson="tertiary-and-quaternary-protein-structures" data-subject="biology" data-tutorial="biological-macromolecules" href="https://app.ulearngo.com/biology/biological-macromolecules/tertiary-and-quaternary-protein-structures">protein</a> fibers, that provides a smooth surface for the movement of bones at joints.</li>
<li>A <strong>ligament</strong> is a band of fibrous <a data-lesson="connective-tissue" data-subject="biology" data-tutorial="plant-and-animal-tissues" href="https://app.ulearngo.com/biology/plant-and-animal-tissues/connective-tissue">connective tissue</a> that holds bones together and keeps them in place.</li>
</ul>
<div class="wp-caption alignnone" id="attachment_336390" style="width: 530px"><img alt="The human skeleton consists of bones, cartilage, and ligaments." class="wp-image-336390 size-full" height="1024" src="https://data.ulearngo.com/assets/9674116f-54b3-4207-887a-069367bf6437" width="530"/><p class="wp-caption-text">The human skeleton consists of bones, cartilage, and ligaments.</p></div>
<p>The skeleton supports the body and gives it shape. It has several other functions as well, including:</p>
<ol>
<li>protecting internal organs</li>
<li>providing attachment surfaces for muscles</li>
<li>producing <a data-lesson="blood-2" data-subject="biology" data-tutorial="human-biology" href="https://app.ulearngo.com/biology/human-biology/blood-2">blood</a> cells</li>
<li>storing minerals</li>
<li>maintaining mineral homeostasis.</li>
</ol>
<p>Maintaining <strong>mineral homeostasis</strong> is a very important function of the skeleton, because just the right levels of calcium and other <a data-lesson="minerals" data-subject="biology" data-tutorial="chemistry-of-life-intro" href="https://app.ulearngo.com/biology/chemistry-of-life-intro/minerals">minerals</a> are needed in the blood for normal functioning of the body. When mineral levels in the blood are too high, bones absorb some of the minerals and store them as mineral salts, which is why bones are so hard. When blood levels of minerals are too low, bones release some of the minerals back into the blood, thus restoring homeostasis.</p>
<p><iframe allowfullscreen="allowfullscreen" frameborder="0" height="281" src="https://www.youtube.com/embed/RW46rQKWa-g?rel=0&amp;modestbranding=1&amp;cc_lang_pref=en&amp;cc_load_policy=1" width="500"></iframe></p>
<h3>Science Friday: Jump in Jerboas</h3>
<p>Jerboas are adorable creatures that are capable of jumping up to three feet. In this video by , Dr. Kim Cooper reveals how the extremely springy leg bones of jerboas make this possible, and the implications it might have for human bone growth.</p>
<p><iframe allowfullscreen="allowfullscreen" frameborder="0" height="318" src="https://www.youtube.com/embed/nuM8kqayIrY?rel=0&amp;modestbranding=1&amp;cc_lang_pref=en&amp;cc_load_policy=1" width="551"><span class="mce_SELRES_start" data-mce-type="bookmark" style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;">﻿</span></iframe></p>
<h2>Summary</h2>
<ul>
<li>The adult human skeleton includes 206 bones and other tissues.</li>
<li>The skeleton supports the body, protects internal organs, produces blood cells, and maintains mineral homeostasis.</li>
</ul>

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Skeletal System

Biology studies life and living organisms. Biology can be divided into different sections that cover the morphology, physiology, anatomy, behavior, and so on of living organisms.

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Discover the different systems of the human body, including the nervous, circulatory, respiratory, digestive, and immune systems, as well as reproductive organs and common diseases, infections, and conditions related to each.


Skeletal System

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