The Muscular System

The Muscular System: Common Questions Answered

Introduction to the Muscular System:

Muscles are some of the most important features our body has. They work as the engine that makes things move (literally) in our body. The muscular system consists of tiny fibers, or cells, that contract to help you move your body. Muscles can be attached to bones and to internal organs.They are so important that almost nearly all movement in the body is done by them. 30-40% of our body weight is made up of muscular tissue, and we each have approximately 640 muscles in our bodies. Speaking of muscle tissue, there are three type: Skeletal, cardiac , and smooth. In this blog post, we will focus on the the different types of tissue, previously mentioned, and talk about what makes up an individual muscle.

Here are just SOME of the 640 muscles in the human body

What Makes Up a Muscle?

What are the Different Types of Muscle? (There are different types of muscle???)

Skeletal: 

Skeletal muscle is the only type of muscle that is voluntary, meaning we can control it. These muscles are primarily connected to the Central Nervous System (CNS). In fact, the peripheral section of the CNS is all connected to skeletal muscle. They are also striated. Meaning their fibers run transversely. The fibers also each have multiple nuclei compared to smooth and cardiac cells which each have one central nucleus.

Cardiac:

Cardiac muscle, found in the walls of the heart, is also under control of the autonomic nervous system. The cardiac muscle cell has one central nucleus, as previously stated, like smooth muscle. Cardiac muscle is also striated, just like skeletal muscles. The contraction of cardiac muscle is involuntary, strong, and rhythmical. Imagine having to control your heart beat. 
Fun Fact: An Average Human Heart beats 1-3 times per second... thank goodness that its involuntary! I cant even remember to take my vitamins every morning.

Smooth:

Smooth muscle, found in the walls of the hollow internal organs such as blood vessels, the gastrointestinal tract, bladder, and uterus, is under control of the autonomic nervous system,as well as cardiac muscle. Smooth muscle is involuntary meaning it cannot be controlled by our minds. The non-striated (smooth) muscle cell is spindle-shaped and has one central nucleus.

How Does a Muscle Work? ( Don't you mean "contract"?)

Each muscle fiber, it turns out, are made up of sarcomeres. Sacromeres are tiny little compartments of the fiber that contain thick and thin filaments. All of these compartments and their contents work together to contract a muscle and produce enough movement to complete the task at hand. The thick and thin filaments do the actual work of a muscle, and the way they do this is incredibly interesting. Thick filaments are made of a protein called myosin & the thin filaments are made of a protein called actin. During contraction, the myosin thick filaments grab on to the actin thin filaments by forming crossbridges. The thick filaments pull the thin filaments past them, making the sarcomere shorter and pull themselves toward the M-Line or the "Mid- Line". In a muscle fiber, the signal for contraction is synchronized over the entire fiber so that all of the myofibrils that make up the sarcomere shorten simultaneously. This whole process is driven by something called Adenine Triphosphate A.K.A. ATP. When the crossbridges are formed, the ATP is turned into ADP because a phosphate bond is released or broken.
Heres a video that explains things more clearly: 

How Does this all Relate to the Circulatory System, You Ask? 

THE CIRCULATORY SYSTEM IS ALL MADE OF MUSCLE!!!! 

Yes, that's what i said. CARDIAC muscle and SMOOTH muscle are all part of the circulatory system! Smooth muscle is what veins and arteries are made out of. Who would have known? Oh, and isn't it obvious that CARDIAC muscle is for the HEART? Yes! Even as obvious as it is, the whole heart is made up of cardiac muscle. 
However, sometimes the cardiac muscles fail, which results in heart failure. In Cardiomyophathy, the heart muscles fail to pump blood throughout the body because they become hard, thick, and rigid.

The main types of cardiomyopathy are:

• Dilated cardiomyopathy
• Hypertrophic (hi-per-TROF-ik) cardiomyopathy
• Restrictive cardiomyopathy
• Arrhythmogenic (ah-rith-mo-JEN-ik) right ventricular dysplasia
  (dis-PLA-ze-ah)

Each individual can either inherit or aquire the disease. Inherit meaning, your parents could have passed it on to you. Most of the time however, the cause is unknown with out a pre-existsing condition.Some people who have cardiomyopathy have no signs or symptoms and need no treatment. For other people, the disease develops quickly, symptoms are severe, and serious complications occur. Treatments for cardiomyopathy include lifestyle changes, medicines, surgery, implanted devices to correct arrhythmias, and a nonsurgical procedure. These treatments can control symptoms, reduce complications, and stop the disease from getting worse.

Fun Fact: You can take a sample of cardiac muscle cells and grow them on a Petri dish and they will still "beat" simultaneously!

Citations:

"SEER Training Modules." SEER Training:Muscle Groups. N.p., n.d. Web. 10 Feb. 2015. <http://training.seer.cancer.gov/anatomy/muscular/groups/>.

Mauk, Ben. "How Many Muscles Does a Human Have?" LiveScience. TechMedia Network, 01 Dec. 2012. Web. 10 Feb. 2015. <http://www.livescience.com/32312-how-many-muscles-does-a-human-have.html>.

Taylor, Tim. "Muscular System." InnerBody. N.p., n.d. Web. 04 Feb. 2015. <http://www.innerbody.com/image/musfov.html>.

"What Is Cardiomyopathy?" - NHLBI, NIH. N.p., 1 Jan. 2011. Web. 10 Feb. 2015. <http://www.nhlbi.nih.gov/health/health-topics/topics/cm>.