Muscles – Skeletal, Cardiac, and Smooth Muscle

Apart from bones, what do you think gives structure to your body? Fatty tissues? yes, they are a part of it too. What else could it be?

Can you wiggle your fingers and toes? Jump high or sit down? That is your muscles helping your body move and function.

FUN FACT: A human body has approximately 600 muscles and each one has a specific function!!

Muscles cover up your bones, giving them a nice protective layer, like mittens/gloves helping you keep your hands safe from hot food. The muscles that cover your abdomen, chest and back, they help protect internal organs like a shield. Did you know that your muscles also play a part in keeping you hot when it’s cold outside and the other way around too?

Now, there are a set of other muscles that you can control like, the muscles in your arms and leg. For example, when you dance, you move according to how your brain decides to control those muscles and bring about a movement. Such muscles are called voluntary muscles, and as explained above, they move on command.

Some other muscles help you eat and digest food. Some other muscles, like your heart, pump blood throughout the day; but do these muscles work on our command? These muscles are called involuntary muscles, and they are powerful and work on their own. Can you name another such activity which we do not control? (Hint: it’s related to the respiratory system)

Other such examples of involuntary muscle movements are the contraction and relaxation of diaphragm, breathing, digesting muscles etc.

Muscles are made of elastic tissues and are flexible and they work like a rubber band. Some muscles attach to your bones by tendons helping the skeleton to move by relaxing and contracting them. When the muscle contracts, the muscles bulge like biceps, and when they relax, they return back to their original state. 

Some muscles are not attached to your bones, and these are responsible for the movement of blood and food through your body. This even includes getting goosebumps !!

There are three main types of muscles:

(a) Cardiac muscles: these are involuntary muscles like your heart muscles. When these contract and relax, they pump blood throughout your body, through heart and blood vessels.

 (b) Smooth muscles: theses are also involuntary muscles, existing in layers. These are present in your bladder, stomach and intestines. When smooth muscles contract, they control the flow of the vessels and also other organs, like leading to movement of the food through the digestion process.

(c) Skeletal muscles: these work by moving bones and are voluntary. Each movement you make is due to these muscles working together. These are controlled by the nervous system. Your face has 43 muscles.

FUN FACT: It takes 17 muscles to smile, and all 43 muscles to frown !! a scientific proof that it is easier to smile.. say cheese !!

The tongue is also a muscle. Which category does it fall into? It helps you form words when you communicate, except sign language, which requires the use of hand muscles.

FUN FACT: Did you know that when you shiver, it is because of the skeletal muscles, which burn energy and create heat to keep you warm from the cold !!

Since your muscles don’t eat, they need nutrients through food. There are some food products which provide good amounts of protein to keep your muscles healthy like chicken, eggs, nuts, spinach( a classic example of Popeye cartoon), milk and other dairy products. Exercise regularly too.

Let’s have a quick check for understanding.


Q1. Muscles are a part of which body system?

a) Digestive

b) Respiratory

c) Circulatory

d) All of the above

Q2. What do you mean by cardiac?

a) Heart related

b) Stomach related

c) Brain related

c) Liver related

Q3. Smooth muscles are voluntary muscles.

a) True

b) False

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