Here’s hoping you use your muscles a lot since they become smaller if you don’t challenge them. Plus, you’ll also lose muscle strength if you adopt a sedentary lifestyle. Fortunately, we know that exercise, including strength training, is necessary for healthy muscles. However, you might not know these things about the tissue that contracts and causes you to move.
There Are Three Types of Muscles
Not all muscles are the same. In fact, they come in three varieties in the human body: skeletal, smooth, and cardiac. Skeletal muscles are ones that attach to tendons and move a joint when they contract and are the most abundant type of muscle in the human body. You can distinguish skeletal muscle from smooth muscle, under a microscope, by looking for striations or banding. The repetitive striations that characterize skeletal muscles are made up of actin and myosin, the proteins that interact with each other and allow a muscle to contract.
In contrast, smooth muscle looks smooth under a microscope because of the lack of striations, hence its name. These muscles line the surfaces of organs such as the digestive tract and aren’t under your control. Thank goodness! You wouldn’t want to have to voluntarily contract your digestive muscles to digest a meal. It would be inconvenient to have to consciously focus on digesting your food!
Cardiac muscle looks similar to skeletal muscles since it has striations. However, the organization is less regular, and the fibers connect at points called intercalated discs. Like smooth muscle, cardiac muscle is under involuntary control. So, you don’t have to think about it to keep your heart beating.
The Largest Muscle in Your Body Is?
The largest muscle in your body is the one you’re sitting on, the gluteus maximus. This large glute muscle has to be substantial since it serves as the center of gravity and stabilizes your body when you rise from a chair or stand. Despite its size, the gluteus maximus isn’t the strongest muscle in your body, that distinction goes to the muscles that make up your jaw.
What are the smallest muscles in the human body? The ones in your inner ear such as the stapedius, a tiny muscle that helps stymy the small bones in the ear that vibrate in response to sound. If you didn’t have this muscle, your inner ear would be damaged from unrestrained vibrations of the bones in your inner ear. If you hear well, thank you stapedius muscles!
Your Fingers Don’t Have Muscles
Fingers move quite skillfully. Watch as someone types at a rapid speed or plays The Minute Waltz and you’ll see how agile fingers can be! However, fingers don’t have muscles. Instead, your fingers move when the muscles in your palm and forearm contract with the help of long tendons that connect them to your fingers. So, the next time someone tells you need to strengthen your fingers, tell them they’re wrong! You need to strengthen the muscles in your forearm instead.
Muscles Become Fatter with Age
Muscles become fatter with age, but it’s not because muscles turn to fat, as some people think. If you compare the muscles of a 20-year-old to the muscles of someone in their 80s via MRI imaging, you’ll see the older muscle contains more fat and less contractile muscle tissue. No wonder we lose muscle strength with age! The fat that we accumulate in our muscles because of aging also increases the risk of developing insulin resistance and type 2 diabetes.
Muscles Can Only Grow So Big
What if your muscles could grow without limits? You would quickly outgrow your clothes! Even if you lift as heavy as you can and eat massive amounts of protein your muscles will only get so large, thanks to a hormone-like protein called myostatin. That goes for men too.
What reigns in muscle growth? Muscle cells release myostatin to limit muscle growth. However, there are people with a mutation in the gene that produces myostatin. These rare individuals can have extreme muscle hypertrophy and strength gains. Since we have two copies of each gene, mutations in each gene copy produces the greatest gains in muscle size and strength. People with a mutation in only one copy can develop big muscles but not to the same extreme as those who have a double mutation and produce little or no myostatin. Mice and cattle can also have this mutation and develop grossly enlarged muscles.
Most of the Heat You Generate Comes from Your Muscles
Muscle contraction generates a lot of heat! In fact, research shows that over 80% of the heat your body makes comes from the force of your muscles contracting. That comes in handy when it’s cold outside and your muscles jump into action and shiver to help you warm up. No wonder you feel so overheated after a high-intensity workout! Your muscles use a lot of energy when they contract and that generates some heat. The more muscle you have, the more heat you’ll generate.
The Bottom Line
By now, it’s possible that you have more respect for your muscles. Keep them healthy. The best way to keep the skeletal ones strong and in ship shape is to weight train. If you don’t use your muscles, they’ll atrophy and become smaller and weaker. It happens in people who are ill and older individuals who don’t stay active. Don’t let it happen to you!
References:
- com. “Can You Turn Fat into Muscle?
- International Journal of Endocrinology. Volume 2014 |Article ID 309570 | 11 pages | https://doi.org/10.1155/2014/309570.
- Mosher DS, Quignon P, Bustamante CD, et al. A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs. PLoS Genet. 2007;3(5):e79. doi:10.1371/journal.pgen.0030079.
- com. “Fun Facts About the Muscular System You Didn’t Know”
- National Institute of Health: National Cancer Institute. “Introduction to the Muscular System”
- Hamrick MW, McGee-Lawrence ME, Frechette DM. Fatty Infiltration of Skeletal Muscle: Mechanisms and Comparisons with Bone Marrow Adiposity. Front Endocrinol (Lausanne). 2016;7:69. Published 2016 Jun 20. doi:10.3389/fendo.2016.00069.
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