Do you know about the muscles that we work unconsciously inside our bodies? (Smooth Muscle)

Think about the muscles in your arms and legs. You can move them, bend them, and stretch them at will. That means you have control over those muscles. But have you ever wondered how food moves through your intestines, how blood moves through your veins, and how air is controlled when you breathe? You probably don't think about these things. Similarly, there is a special type of muscle in our bodies that we can't control, but that does a lot of work that is essential for the survival of our bodies. Today, we are going to talk about that silent worker, that is, smooth muscle.

What is this smooth muscle?

Simply put, smooth muscle is a type of muscle that we cannot consciously control (operate automatically) and is found in the walls of our body's internal organs and vascular systems.

This is called "smooth" because of how it looks under a microscope. The muscles we control in our arms and legs (skeletal muscles) look striated when viewed under a microscope. But these muscles don't have those striations, they have a smooth appearance. That's why it's called that.

There are three main types of muscles in our body. Understanding the differences between these three makes the uniqueness of smooth muscles even clearer.

You see, except for skeletal muscle, both types work without our control. But cardiac muscle is only found in the heart. Smooth muscle is the one that works silently in the many internal organs throughout the body.

Where are these smooth muscles located in the body?

It wouldn't be wrong to say that these are found almost everywhere on the body. Here are some of the main places where they can be seen:

• Blood vessels: These are the muscles in the walls of the arteries and veins that carry blood throughout your body. They contract and relax to control blood pressure and pump blood to different parts of the body.
• Digestive system: These are the organs that run from your esophagus to your large intestine (the last part of your large intestine). After we eat, the food moves through your intestines because of these muscle waves called peristalsis. This process is called peristalsis.
• Airway: These are also found in the walls of the tiny air passages that carry air to the lungs. They help to widen and narrow these passages to make breathing easier.
• Urinary system: These smooth muscles are found in the walls of the bladder. They are responsible for expanding the bladder when it fills with urine and contracting when urine is expelled.
• Reproductive system: The wall of the uterus in women is mainly made up of smooth muscle. It is these muscles that cause contractions (dilation) during childbirth. They also contribute to various functions in the male reproductive system.
• Eyes: Smooth muscles in the iris control the size of your pupil, which controls the amount of light entering your eye. They also help change the focal length of your eyes when looking up and down.
• Skin: When you feel cold or scared, your hair "stands up," right? That's because the tiny smooth muscles at the roots of the hairs in your skin contract, causing the hairs to stand up straight.

What are the main things that happen with smooth muscles?

Looking at the above, you might have some idea of ​​the function of these. Let's talk about it a little more clearly.

1. Controlling the width of the ducts

Think of a water pipe. We can control the speed and pressure of the water by changing the width of the pipe. Similarly, the width (diameter) of things like our blood vessels and respiratory tract is controlled by these smooth muscles.

2. Transporting materials

These muscles help move things from one place to another inside the tube-like organs of our body. The best example is the digestive system. After we eat, the food travels down the esophagus to the stomach, and from there through the intestines to the anus due to the rhythmic contractions (peristalsis) of these smooth muscles. If this process stops, digestion stops completely.

3. Acting as gatekeepers (Gatekeeping)

Smooth muscles in some parts of the body are normally tightly closed (contracted) and only open (relax) when needed. We call these sphincters.

• Bladder sphincter: This is a muscle that closes the passageway for urine to exit the bladder. When the bladder is full, the brain is notified that we need to urinate, and when we are ready, this muscle relaxes and urine is released.
• Anal sphincter (anus): This same muscle controls the passage of stool.

These work like gates, allowing things to come out only at the right time.

What diseases affect smooth muscles?

Like all other organs, these smooth muscles can be affected by various diseases and conditions. Some of these are:

• Anti-smooth muscle autoantibodies: This is when our own immune system mistakenly attacks our own smooth muscles. It's like our house security guard mistaking us for an enemy and attacking us. This condition is common in people with autoimmune diseases like autoimmune hepatitis.
• Muscular dystrophies: These are a group of inherited diseases that cause muscles to gradually weaken and become unable to function over time.
• Muscle spasms: Smooth muscles can suddenly contract (contract) violently without control.
• Vasospasm: This can interfere with blood flow.
• Respiratory tract infections: Asthma is a good example of this. Asthma patients experience difficulty breathing because the smooth muscles in the airways suddenly tighten.
• Visceral myopathies: These are a group of diseases that affect the smooth muscles of internal organs (visceral). They are often caused by genetic factors and can be life-threatening if they affect areas such as the bladder and large intestine.

What are the symptoms?

Since smooth muscles are found throughout the body, the symptoms that occur if there is a problem with them will vary depending on the location of the problem and the function performed by those muscles.

• Blood pressure abnormalities: If the smooth muscles in the blood vessels do not function properly, high blood pressure can occur, or blood pressure can suddenly drop and cause fainting (low blood pressure) .
• Poor digestion: If the smooth muscles in the intestines don't work properly, food can get stuck moving forward. This can cause symptoms like stomach pain, bloating, and constipation .
• Difficulty urinating: If the bladder muscles become weak, you may not be able to urinate properly or empty your bladder completely.

These smooth muscles are a part of our body that silently, unseen, and yet play a vital role. As long as they are working properly, we don't even remember they are there. But if there is a slight change in their function, it can affect our entire body system. Therefore, it is very important to be aware of these silent workers.

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