Without muscles, our heart wouldn’t beat, our bones couldn’t move, and food couldn’t be digested.
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Skeletal Muscles
Humans have over 600 skeletal muscles. These muscles, working together with the skeleton, allow us to move. When we are cold and shivering and our muscles are shaking, our brain is telling our muscles to move. When in use, skeletal muscles generate heat, so that we can warm up.
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Head and Neck Muscles
The head and neck muscles are responsible for rotating our head, chewing, blinking, moving the eyes, and making facial expressions. The muscles in our eyes are the fastest responding muscles in the human body.
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Shoulder and Arm Muscles
This muscle group is responsible for controlling our shoulders and arms. The biceps brachii is the muscle that produces the bulge when you bend or flex your arm.
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The chest and back muscles
Chest and back muscles are essential for other muscles to complete their tasks, especially the arm and neck muscles. Breathing cannot occur without the muscles on the ribs and upper back.
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The Abdomen Muscles
The abdomen muscles hold our organs in place by controlling internal abdominal pressure. They also protect our spine and help us keep our balance. Together with the back muscles, they make up our core muscles.
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Leg Muscles
These powerful groups of muscles located in the legs not only enable us to move but are almost always making tiny adjustments to keep us upright, whether we are sitting down or standing up.
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Hip and Glutes
There are 4 muscle groups located in the hip and glutes area. They control the movements of our hip, one of the most flexible joints in our body, as well as sitting, climbing, walking, and running.
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Cardiac Muscles
Cardiac muscles are a specialized type of muscle that is located only in the heart. Also known as myocardium, these muscles only have one job: pump blood through the heart in order to then circulate the blood throughout the entire body.
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Cardiac Muscles Close-up
Like skeletal muscles, cardiac muscles are striated. Striations look like lines throughout the muscle. These special filaments are designed to allow the muscle to contract and relax repeatedly.
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Cardiac Muscles
Cardiac muscles have one role in the body — to pump blood. Cardiac muscles also must move continuously which means these muscles have evolved to be quite different from other muscles found in the body.
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Rhythmic Contraction
Cardiac muscles move without conscious thought. The muscles work together to pump all of the blood in the body through the heart in less than a minute. Cardiac muscles are the only muscles to contract to a rhythm.
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Intercalated Disks
Each cardiac muscle cell is branched so that it is within contact of at least 3 other cardiac muscle cells. Intercalated disks at the end of each cell hold the muscles together while the muscles contract and help pass on electrical signals.
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Smooth muscles
Smooth muscles are thousands of times smaller than skeletal muscles. They are called smooth because they lack the striation that occurs in skeletal and cardiac muscles. These muscles operate without conscious thought and are located throughout the body.
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Smooth Muscle in The Eye
The eyes contain smooth muscles which change the size of the pupils to control how much light enters the eye. Muscles also change the shape of the lens in the eye when we focus.
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Smooth Muscle in the Skin
The Arrector pili muscle is a smooth muscle attached to hair follicles on the skin. Controlled by the nervous system, these muscles contract when humans are cold or frightened, producing goosebumps.
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Smooth Muscle in the Digestive System
Many smooth muscles are located in the digestive system. They push food down our esophagus, and then smooth muscles in the stomach contract to mix food around. Lastly, smooth muscles push the digested food through the intestines.
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Smooth Muscle in the Reproductive System
Smooth muscles play a vital role in birth. When the hormone oxytocin is released, this gives the signal to the smooth muscles in the uterus to begin labor. These muscles contract to push the baby out.
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Muscles in Detail
Each type of muscle in the human body has its own set of unique characteristics. It is because of those special characteristics that muscles are able to complete all of the different tasks that are necessary to keep the body functioning.
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Muscle Fiber
Skeletal muscles are attached to the skeleton by stretchy tissues called tendons, although some skeletal muscles are attached directly to rough patches of bone. Skeletal muscles are striated; full of thin fibers giving the muscles a stripy look.
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Cardiac Muscles
Cardiac muscles are branched in appearance. Like skeletal muscles, they are also striated. At the end of each cardiac muscle intercalated disks can be found. Cardiac muscles surround the heart completely.
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Smooth muscles
As the name suggests, smooth muscles lack the striation that appears on skeletal and cardiac muscles. Smooth muscles are often found in single layers around major organs.
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Muscles in Action
The 3 different types of muscles located in the human body are designed to move the body in some way. Skeletal muscles work to move the skeleton, cardiac muscles move the heart, and smooth muscles move various organs like the stomach and eyes.
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Tendons
Skeletal muscles attach to the skeleton via stretchy fibers called tendons. In order to move, muscles need to contract and relax. For example, when the biceps brachii muscle contracts, the muscle pulls on the tendons attached to the arm bones, which moves the forearm.
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Flexors and Extensors
There are 2 types of skeletal muscles, called flexors and extensors. Once a muscle pulls a limb into position via contraction, it needs assistance returning the limb to its original position. This assistance comes from extensors. Flexors bend the limb, extensors straighten the limb.
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Cardiac Muscles
The heart has its own electrical system that controls the cardiac muscles. Electrical impulses travel via the intercalated disks, causing one side of the heart to contract and forcing blood out of the heart. Cardiac muscles need to contract and relax without rest throughout our lifetime.
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Neck Muscles
In addition to movement, the skeletal muscles play an essential role in helping us stay still. Keeping our head upright requires many minute contractions from neck muscles, for example.
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Smooth Muscles
There are 2 types of smooth muscles. Phasic smooth muscles spend most of the time in a relaxed, non-contracted state, like the bladder, which only needs to contract a few times a day. Tonically active smooth muscle is mostly found in a contracted state, rarely relaxing.
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Looking After Muscles
Exercise along with a varied, well-balanced diet are essential for looking after our muscular system. Although we have several different types of muscles in our bodies, all muscles have the same basic requirements to keep them both healthy and strong.
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Diet and Nutrition
Diet plays a crucial role in muscular health. Muscles need a variety of nutrients to function correctly so a diet rich in vegetables, fruits, whole grains, and dairy products is necessary to maintain muscle health as well as the health of tendons and joints.
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Iron-rich Food
A diet rich in iron is important as iron helps muscles produce oxygen-storing myoglobin. Lack of iron causes the whole body to feel tired due to lack of oxygen in muscles. Iron is found in red meats, beans, and dark green leafy vegetables.
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Exercise
Exercise is vital in looking after muscles, especially core abdominal muscles that provide a strong base for both upper and lower body. They also help maintain good balance and reduce the chance of back pain. An easy way to strengthen these muscles is to maintain good posture.
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Aerobic Exercise
Aerobic exercise strengthens and tones both skeletal and cardiac muscles. Aerobic means to require oxygen, so any exercise that stimulates the lungs does the job. This includes jogging, swimming, cycling, jumping on the trampoline, anything that gets the heart beating faster.
