7 most useless private parts

Is every part of the human body indispensable? That’s not necessarily the case. Some parts may exist for "decoration", such as male nipples. The United States reported the latest discovery that there are 7 parts of the human body that seem to be of no use.

1. Male nipples

Dr. Weinhaus said one theory is that human embryos are initially programmed as females and then differentiate into males and females, but males still retain many of the same anatomical features as females. Men's and women's nipples are the same, but without enough estrogen, men's nipples are just chest ornaments.

2. Armpit Hair

Daniel Lieberman, professor of human evolutionary biology at Harvard University, said that the human body has two types of sweat glands: one is the apocrine gland, which is mainly distributed in the armpits and opens near the hair roots; the other is the eccrine gland, which is distributed throughout the body and opens in the epidermis. People send out sexual signals through apocrine sweat glands, and armpit hair simply preserves the smell of apocrine sweat gland secretions, helping to attract opposite-sex partners.

3. Eyebrows

There are different opinions on the evolutionary purpose of eyebrows. One theory is that eyebrows served to shield the eyes from sweat and rain, which was useful for primitive hunting and navigation. Professor Lieberman supports the hypothesis that eyebrows express both emotions and identity. Behavioral neuroscientists at MIT found that people have a harder time recognizing photos of celebrities when they don't look at their eyebrows than when they look at their eyes. Researchers believe that eyebrows exist to help recognize faces and navigate social environments.

4. Appendix

The appendix is ​​a large vestigial organ in the human body. Professor Lieberman said one theory is that the appendix was once the body's "intestinal fermentation chamber". As humans evolved, people no longer ate raw and low-quality food, so the function of the appendix gradually degenerated. However, recent studies suggest that the appendix may be an important stronghold for beneficial bacteria in the body. The beneficial bacteria in the appendix can help with intestinal inflammation and digestive issues.

5. Tonsils

Professor Lieberman said that tonsils are located in the throat and are part of the lymphatic system (human immune system). Since the throat is the only way for food to enter the body, tonsils have a strong function of preventing bacteria from invading, but removing them will not affect survival. Some people have their tonsils removed because of recurring infections and inflammation.

6. Wisdom Teeth

Like monkeys, humans also have third molars (wisdom teeth), which grow gradually during people's biting process. Like other organs in the human body, teeth require support and proper use to develop normally. Nowadays, humans have been eating soft cooked food since childhood, and the pressure on the jawbone (the bones that make up the mouth) has become less and less, the teeth cannot fully develop, and wisdom teeth have gradually degenerated.

7. Male foreskin

It takes many years for the male foreskin to become independent of the glans penis. One view is that the foreskin's function is to help protect against infection, especially during infancy. Dr. Weinhaus says the foreskin helps protect the urethra opening from contaminants or bacteria, while also protecting the reproductive organs. If there is no foreskin, the skin of the glans will become thicker due to friction with clothing, which will reduce its sensitivity and affect male pleasure. It is this function of the foreskin that encouraged human ancestors to reproduce more offspring.