How your muscular system works – Emma Bryce


Each time you take a step, 200 muscles work in unison
to lift your foot, propel it forward, and set it down. It’s just one of the many thousands
of tasks performed by the muscular system. This network of over 650 muscles
covers the body and is the reason we can blink, smile, run, jump, and stand upright. It’s even responsible for
the heart’s dependable thump. First, what exactly
is the muscular system? It’s made up of three main muscle types: skeletal muscle, which attaches
via tendons to our bones, cardiac muscle, which is only
found in the heart, and smooth muscle, which lines
the blood vessels and certain organs, like the intestine and uterus. All three types are
made up of muscle cells, also known as fibers,
bundled tightly together. These bundles receive signals from
the nervous system that contract the fibers, which in turn
generates force and motion. This produces almost all
the movements we make. Some of the only parts of the body whose motions aren’t governed
by the muscular system are sperm cells, the hair-like cilia in our airways, and certain white blood cells. Muscle contraction can be split
into three main types. The first two, shortening muscle fibers
and lengthening them, generate opposing forces. So the biceps will shorten
while the triceps will lengthen or relax, pulling up the arm and making it
bend at the elbow. This allows us to, say, pick up a book, or if the muscle relationship
is reversed, put it down. This complementary partnership
exists throughout the muscular system. The third type of contraction
creates a stabilizing force. In these cases, the muscle fibers
don’t change in length, but instead keep the muscles rigid. This allows us to grip a mug of coffee
or lean against a wall. It also maintains our posture
by holding us upright. Skeletal muscles form the bulk
of the muscular system, make up about 30-40% of the body’s weight, and generate most of its motion. Some muscles are familiar to us,
like the pectorals and the biceps. Others may be less so,
like the buccinator, a muscle that attaches your cheek
to your teeth, or the body’s tiniest skeletal muscle, a one-millimeter-long tissue fragment
called the stapedius that’s nestled deep inside the ear. Wherever they occur, skeletal muscles are
connected to the somatic nervous system, which gives us almost complete control
over their movements. This muscle group also contains
two types of muscle fibers to refine our motions even further,
slow-twitch and fast-twitch. Fast-twitch fibers react instantly
when triggered but quickly use up their energy
and tire out. Slow-twitch fibers, on the other hand,
are endurance cells. They react and use energy slowly
so they can work for longer periods. A sprinter will accumulate more
fast-twitch muscles in her legs through continuous practice, enabling her to quickly, if briefly,
pick up the pace, whereas back muscles contain
more slow-twitch muscles to maintain your posture all day. Unlike the skeletal muscles, the body’s
cardiac and smooth muscles are managed by
the autonomic nervous system beyond our direct control. That makes your heart thump
roughly 3 billion times over the course of your life, which supplies the body
with blood and oxygen. Autonomic control also contracts
and relaxes smooth muscle in a rhythmic cycle. That pumps blood through the smooth
internal walls of blood vessels, enables the intestine to constrict and
push food through the digestive system, and allows the uterus to contract
when a person is giving birth. As muscles work, they also use energy
and produce an important byproduct, heat. In fact, muscle provides
about 85% of your warmth, which the heart and blood vessels
then spread evenly across the body via the blood. Without that, we couldn’t maintain
the temperature necessary for our survival. The muscular system
may be largely invisible to us, but it leaves its mark on almost
everything we do, whether it’s the blink of an eye
or a race to the finish line.

100 Replies to “How your muscular system works – Emma Bryce

  1. The muscles used to make a smile actually send a biochemical message to our Nervous System that it is safe to relax the flight of freeze response.

  2. Here is a video that discusses how muscles contract at the molecular level. Very interesting stuff.
    https://youtu.be/zopoN2i7ALQ

  3. A muscle cell needs a signal to relax. No signal and it contracts or stiffens. That why bodies stiffen up shortly after death.

  4. HUMANS ARE JUST ONE OF GOD'S INFINITE CREATIONS. GOD MEANS INTELLIGENCE OF THE HIGHEST LEVEL. ACCORDING TO SANATAN DHARMA GOD IS FORMLESS SHAPELESS BEYOND SPACE AND TIME. GOD IS SUPREME CONSCIOUSNESS. GOD IS CREATOR, PRESERVER AND DESTROYER. GOOD IS GREAT.

  5. Wish me luck, I have a test tomorrow (April 20, 2018) based on the muscles and it’s worth the most of my grade for science class.

  6. Im really interested in this video but whenever i think of the muscular system, i always think of the Colossal titan from Attack on titan.

  7. What i learned is that there are three{3} types of muscles
    1.Skeletal Muscle attach to each bone
    2.Cardiac Muscle which can only be seen by the heart
    3.smooth Muscle Examples:Uterus and Large intenstince and small
    What i also learned is that There are two twicthes
    1.fast twicth {it's hard to explain}
    2.slow twicth Ummm a muscle that moves slow so that you can move longer {maybe}
    Others Well… it's hard to explain but this video is helpful!

  8. سبحان الله وبحمده سبحان الله العظيم (قل هو الله أحد الله الصمد لم يلد ولم يولد ولم يكن له كفوا أحد) 3مرات تساوي القرآن كاملا وصلوا على النبي صلى الله عليه وسلم

  9. 🌻السہ‿لًٱ۾ عَلْيّہ‿كَ۾ وٍرٍحَمُہ‿ةٌ اللَّہ‿ہ🌻 ممكن حد يرخص لي هاد الفيديو بليييز

  10. بد حّـْــْSOMEONEـَـْـَـْد يفهمني يااه بالعربي عِنـ.̷̷ـديّ صعوبه بالانجلش

  11. “And allows the uterus to contract when a PERSON is giving birth” sure, my uterus contracted last time when I was giving birth to my son.

  12. Hello
    Giougnaeu
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