If you were to describe the human body as political system, how would you describe it?

Functioning.
I would call it funky.

It is difficult for me to see the body of a human or any other lifeform as a political system, since the inner workings are mechanical. There is no decision mechanism. We can say that the brain makes decisions, but its knowledge of what is going on in the body is pretty minimal.

Brexit, with all that shit going on you’re better off out.

Benevolent dictatorship, with the brain being the autocratic leader, but all organs with the autonomy to do their own thing.

All branches of the government do the best they can with the resources available to them. There is very little corruption or competition between branches. There is, however, a strong system of checks and balances and all eventually report to the brain.
A Monarchy perhaps?

A cooperative collective commune, but I wouldn’t call it “communist”, per se.

Cancer would be an anarchist uprising. The body would be a dictatorship.

It is most assuredly a dictatorship:

I recall a story, a biblical parable I assume:

One day, the parts of the body got into an argument over who was in charge.

The brain said that it should be since it did the reasoning and decision making.

The heart said that it should be because without it the blood would not circulate and the body would die.

The stomach said it should be because it provided the basic nutrients that kept the system functioning.

The legs said they should be in charge since they got the body around in a speedy efficient manner.

The eyes said they should run things because they allowed the body to see and avoid trouble.

In turn, each body part gave a sensible, rational reason that they should be in charge.

Finally the rectum spoke up and demanded to be in charge.

All the other body parts laughed at the rectum and insulted him, so in a huff, he shut down tight. Within a few days, the brain had a terrible headache, the stomach was bloated, the legs got wobbly, the eyes got watery, and the blood Was toxic. Inevitably, all finally agreed that the rectum should be in charge.

Which just goes to show that although it takes teamwork to make things work properly it is usually the asshole that is the boss.