Do you know about this important vein inside our stomach? (Superior Mesenteric Vein)

Have you ever wondered how, after we absorb the energy from the food we eat, that nutrient-rich blood is purified before it is distributed throughout the body? Today we are going to talk about a very important blood vessel hidden inside our stomach that helps with this task. It is the Superior Mesenteric Vein, also known as SMV for short. This is an essential part of the healthy functioning of our digestive system.

Simply put, what is the function of the Superior Mesenteric Vein?

Imagine that the blood vessel system inside your stomach is like a tree. This SMV is like a big branch on that tree. This big branch receives blood from a bunch of little branches (that is, small blood vessels).

The main function of this vein is to collect nutrient-rich but oxygen-poor blood from the organs in our digestive system and carry it to the liver.

This process occurs through a special system in our body. We call it the hepatic portal system. One of the main veins in this system is the SMV. This means that the nutrients absorbed from our intestines are transported to the liver for purification before being distributed throughout the body.

The SMV collects blood primarily from these organs:

• Small intestine
• Large intestine
• Stomach
• Pancreas
• Appendix

The SMV collects blood from all these places and supplies it to an even larger vein called the portal vein. If we take the example of the tree we mentioned earlier, if the SMV is a large branch, the portal vein is like the trunk of that tree. This trunk is directly connected to our liver.

After this blood reaches the liver, the liver filters it, cleans it, and prepares it for the body's needs. Then, the blood is sent to the heart. From the heart, the blood goes to the lungs to pick up oxygen, and then comes back to the heart to be distributed throughout the body. Do you understand how important this process is?

What are the tributaries that bring blood to the SMV?

We said that the SMV receives blood from a small collection of veins. Let's take a simple look at those veins and the organs they collect blood from.

Where in the stomach is this SMV located?

This SMV vein is located inside our abdominal cavity. Simply put, it's inside the large space in our abdomen that's below the chest and above the pelvis, where the important organs are located.

It starts near our rib cage. From there, this vein travels up and joins with the splenic vein near the first lumbar vertebra (L1) of our spine to form the aforementioned portal vein.

The way this vein travels is very special!

Normally, a vein and an artery in our body run side by side, just like cars going in both directions on a road. The SMV runs on the right side of its corresponding artery, the superior mesenteric artery. While the artery carries oxygen-rich blood to the intestines, the vein carries nutrient-rich blood away from the intestines and towards the liver.

However, sometimes, due to a condition that occurs at birth (malrotation) or something like a tumor in the abdomen, pressing on surrounding organs, this vein can also pass on the left side of the artery.

What are the medical conditions that affect SMV?

Like any other organ, there are conditions that can affect the SMV vein. It is important to be aware of these, as some conditions can be serious and require emergency treatment.

There are two main conditions that affect:

1. SMV thrombosis

This is when a blood clot forms inside the SMV vein. This can be a very serious condition.

• Main symptom: Sudden, severe abdominal pain is the most common symptom.
• Other forms: However, for some people, this pain may come and go for days or weeks. Sometimes, this condition may be present without any symptoms.

Getting treatment for this condition as soon as possible can be life-saving. Therefore, if you experience severe stomach pain, you should go to a hospital's Emergency Department (ETU) immediately.

2. Portal hypertension

This means that the blood pressure in the portal venous system we talked about earlier increases.

• Causes: Cirrhosis of the liver and blood clots are the main causes.
• Severity: This can cause life-threatening complications, such as internal bleeding.

Treatment involves controlling complications and, in some cases, diverting blood flow to lower blood pressure. This is all determined by your doctor.

Learning about such complex things about the body can feel a little overwhelming. That's okay. If your doctor tells you that you have a medical condition related to this, don't be afraid. Ask your doctor again and again about anything you don't understand. He or she will explain everything to you in simple terms. The more we know about our bodies, the easier it will be for us to make the right decisions about our health.