1. Plica Semilunaris

Yes, you have a third eyelid and it is called the plica semilunaris. It is a small fold of bulbar conjunctiva located on the inner corner of the eye. An accessory organ of the eye, plica semilunaris is a left over from what’s known as a “nictitating membrane.” For most mammals, it is a vestigal organ, which is still present in chickens, lizards and sharks. But for humans, plica semilunaris serves an important purpose: it produces a fatty substance (rheum) that collects foreign bodies such as dirt and dust from entering the eye and damaging the cornea. These foreign bodies are then deposited near the tear duct as eye gunk, ready to be brushed away in the morning.  😉

2. Body Hair

Three million years ago, “humans” were much hairier. Earth temperature at that time was much colder than today so our body hair was a  good insulator for the colder climate. But by the time Homo erectus arrived, the ability to sweat & the warmer climate meant we could shed our woolly ways. Today, having body hair is considered aesthetically unpleasing and many people having this predicament seek the help of dermatologists to permanently remove their excessive fuzz.

An interesting fact: Humans have the SAME amount of hair follicles as our closest (and hairier) relative the Chimpanzee – its just that the hair on our bodies is much finer.  It is referred to as “peach fuzz” –  even on your cheek there are hair follicles!  Instead of coarse hair the follicles produce fine, almost invisible fuzz.

3. Sinuses

Humans have four pairs of sinuses that are found in the bones of the head and face. These air-filled spaces are lined with a moist, thin layer of tissue called a mucous membrane. The mucous membrane secretes mucus that traps dust and germs that are in the air we breathe. Doctors don’t really know much about sinuses but some researchers think they keep the head from being too heavy. Sinuses also give you the pitch and tone of our voice.  Many Doctors endorse the irrigation of the sinus cavities with a “Neti Pot”  here are two videos – the first video is about the medical research behind it, the second shows an actual demonstration.

4. Adenoids

The adenoids are lumpy mass of lymphoid tissue that help protect kids from getting sick. They situated at the very back of the nose and the roof of the mouth. Most people’s adenoids are not even in use after a person’s third year of life. In fact, adenoids usually shrink after about age 5, and by the teenage years they often almost disappear. Adenoids do important work as infection fighters for babies and little kids.  They become less important once a kid gets older and the body develops other ways to fight germs. Also, they are prone to swelling and infection – and speaking of swelling & infection…. 😯

5. Tonsils

Tonsils are clusters of lymphoid tissue on either side of the throat. They act as part of the immune system to help protect against infection. But are they really important. Researches lead us to believe that adenoids and Tonsils are developed to deal with certain types of infections, such as worms or other parasites. It is clear that in many cases, the Tonsils become “dysfunctional” and are more of a liability than an asset since they are prone to swelling and infection. Also prone to swelling and infection — If you have them by your 30s, it’s almost an accomplishment  😉

6. Coccyx

The coccyx or the tailbone, is the final segment of the human vertebral column.

It is made up of three to five separate or fused vertebrae held in place by joints and ligaments. In humans and other tailless primates since Nakalipithecus (a Miocene hominoid), the coccyx is the left over of a vestigial tail, but still not entirely useless. It is part of a weight-bearing support structure which act as a support for sitting. Also, it serve as a place for the insertion of some of the muscles of the pelvic floor.

7. Arrector Pili

Arrector pili are tiny microscopic muscle tissues that connect hair follicles to the dermis. When stimulated, the arrector pili will contract and cause the hair to stand on end when we needed to appear bigger and scarier, causing goose bumps. They exist in most mammals including humans but in some animals arrector pili serve an important function; acting as insulation to keep their body warm. Other animals, such as porcupines use them as a defensive mechanism when threatened by enemies.

8. Wisdom Teeth

Third Molar teeth also known as wisdom teeth are the last teeth to appear in your mouth. This generally occurs between the ages of 17 and 25. Back in the day, when man ate a rough diet but didn‘t bother to floss afterwards, there resulted in an excessive wear of their teeth. Therefore, when those “wisdom teeth,” came in, they were welcomed. Nowadays, modern diet, which is much softer, and the popularity of fluoride and orthodontic tooth straightening procedures have helped to make wisdom teeth a huge pain when they enter the mouth.

9. Appendix

The appendix is a blind ended tube connected to the cecum that averages 10 cm in length. It is located near the connection of the small intestine and the large intestine. Evolutionists claimed that the appendix is a part of a large digestive system during man’s early plant-eating years and has no function in modern human. However, present day researches and studies suggest that it may harbor beneficial bacteria & immune cells that are helpful in the function of the human colon.

Most people will have no complications with their appendix – BUT a  burst appendix can be fatal if it is not attended to quickly. Although the exact causes of a burst appendix are not completely understood it seems that the appendix can become blocked and eventually become inflamed and rupture.

When the appendix bursts it leaks bacteria from the intestines into the abdominal cavity. This can cause the formation of an abscess or a condition known as peritonitis, which is a serious infection of the abdominal cavity. Before the advent of modern antibiotics this condition often resulted in death. Now the majority of people that have their appendix survive with proper treatment.

A problem appendix will be preceded by extreme abdominal pain that often starts near the belly button and then migrates to the lower right quadrant of the abdomen. You will experience nausea and possibly vomit.   If you were to get up and attempt to walk with these symptoms the pain would begin to get even worse.


If the appendix does burst the pain will lessen but you will then get a high fever, your abdominal region will swell up and your heart rate will get faster.

But again – don’t worry – this RARELY happens!

10. Male Nipples

Humans have 23 pairs of chromosomes.  One pair of chromosomes determines sex: XX chromosomes for female and XY means male. The other 22 pairs (autosomes) supply the standard equipment that all humans get.

All embryos are actually “pre-female” until the TDF (testes determining factor) gene on the Y chromosome  turns on and signals the embryo to develop into a male rather than a female.   If this does not turn on at the right time hermaphrodia can occur.  Human nipples appear in the third or fourth week of development, well before sex determination. (The sex hormones start to assert themselves at seven weeks.)

As many as seven pairs of nipples are arranged along either side of a “milk line,” a ridge of skin that runs from the upper chest to the navel.   Normally only one pair amounts to anything, but on about one baby in a hundred you can detect some vestige of the other ones, usually on the order of a freckle as seen below…

Supernumerary nipples. (Third and fourth nipple of male Scandinavian). A - regular birthmark. B - regular nipple. C - Supernumerary nipple

Supernumerary (aka: extra) nipples. A - regular birthmark. B - regular nipple. C - Supernumerary nipple

Both male and female babies are born with the main milk ducts intact–the mammary gland that produces milk is present in males, but it remains dormant unless stimulated by the female hormone  estrogen. Occasionally, a male baby is born with enough of his mother’s estrogen in his body to produce a bizarre phenomenon known colloquially as “witches’ milk,” with the male glands (stimulated by estrogen) lactating at the moment of birth – it is only a temporary condition!

In the adult male, the dormant glands can still be revived by a sufficient dose of estrogen. Actual lactation is rare–only a couple cases have been recorded.