7 Body Parts That Do More Than You Might Realize

Eyelashes Trigger Your Blink Reflexes

In addition to looking pretty, eyelashes help stop debris from getting in our eyes — but they don’t just shield them. Eyelashes are sensory and function much like whiskers do on a cat. Ever wonder how you’re able to blink just in the nick of time when something comes flying at your eye? When an object gets close to our eyes, like a bug or a speck of dust, eyelashes trigger a blink reflex that protects our fragile peepers. They may also help manipulate airflow around our eyes to keep our lubricating tears from drying up.

Your Ears Keep You Upright

Ears are best known for helping us hear things, but they’re also critical to helping us balance. The inner ear, behind the eardrum, contains our vestibular system, which helps us orient our bodies. Three loops full of fluid, or canals, are connected to two organs full of small crystals inside the inner ear. The canals sense when the head is moving up or down, left or right, and turning sideways. The crystals measure acceleration.

The vestibular system sends the information it processes to other parts of our body, so we can balance and know where we are in space. When the brain gets information that conflicts with what the vestibular system is processing, we get dizzy. This is why an inner ear infection can be so disorienting!

Fingernails Can Indicate Blood Flow

Have you ever been told to remove your nail polish in a medical setting? Some think that nail polish can get in the way of a pulse oximeter, a medical device that clips onto your finger and measures blood oxygen levels — but this isn’t true, even if the polish is glittery. However, painted nails can get in the way of a quick test called the capillary refill test, which checks your circulation in the event of an emergency.

Here’s how it works: A medical professional applies pressure to the nail bed on your finger or your toe so that it turns white, then releases to see how long it takes for the pink color to come back. It’s an indicator of how well oxygen is traveling to your extremities, and is used to check patients for shock.

The capillary refill test is done in a critical care setting, but your nails can tell you about your health at home, too. If they’re not pink under your polish, you might want to get that checked out.

Tonsils Are a Barrier to Germs

Like the appendix, tonsils are perhaps best known as a site of surgical removal — but they do have a purpose. The tonsils are a set of lymph nodes that form a ring at the back of your throat behind your mouth and nose. They provide a barrier to prevent germs from making their way further into your body, and they’re rich in white blood cells, which fight infections.

Technically, there are four types of tonsils. But when people say “tonsils,” they’re often talking about the palatine tonsils, which are located on either side of the back of your mouth. Because they’re the first line of defense against germs, they’re particularly vulnerable to infection, and often become inflamed. When they start interfering with breathing, they sometimes have to come out. The adenoids, the tonsils in the upper airway, are also frequently removed, and the lingual tonsil at the back of the tongue sometimes comes out as a treatment for sleep apnea. The tubal tonsils are located near the entrance to each Eustachian tube and generally receive less attention.

Tonsillectomies are one of the most-performed surgical procedures in the United States, so it’s pretty normal to go through life without tonsils — although recent research has suggested that tonsillectomies are associated with higher risk of some infections.

Uteruses Can Stretch From Pear to Watermelon… and Back Again

It may seem secondary to growing a whole new human being, but the little things a uterus can accomplish during pregnancy are extraordinary, too. When it’s not occupied, an average uterus is pear-shaped and only about 3 inches long, 2 inches across, and 1.5 inches thick. But a full-term baby and everything that comes with it, like amniotic fluid and a placenta, take up a lot of room. The uterus usually outgrows the pelvis during the second trimester of pregnancy, and over the course of 40 weeks, it balloons to the size of a watermelon. The uterus alone can weigh 2 pounds when at full term.

Perhaps just as miraculous is how quickly it shrinks back down. This is called involution, and it takes around six weeks for most people.

The Diaphragm Helps With More Than Breathing

The main function of a diaphragm is to help you breathe in and out, which you probably know if you’ve ever practiced belly breathing. The diaphragm rests between your chest and your abdomen, and contracts and expands on each inhale and exhale; when it tightens, it moves downward to make more room for your lungs. When you breathe out, it relaxes and helps push air out of your body. But it has another important (and related) job, and that’s keeping your guts together.

When something else is going on with your belly or chest — like going to the bathroom or sneezing — the diaphragm helps maintain the appropriate level of pressure in your abdomen so that everything goes where it needs to.

The Appendix Might Not Be So Useless

The appendix, a small pouch attached to the large intestine, has a pretty bad reputation — it gets infected a lot and its actual role in the body is unclear. But it might not be useless after all!

Your gut is full of beneficial bacteria that contribute to your overall health. When you get really sick (or you’re on a long round of antibiotics), your inner ecosystem can start to suffer and good bacteria can be flushed out of your system. According to some theories, the appendix provides a kind of “safe house” so that microorganisms can survive to repopulate the rest of your gut.

It’s still not a top-priority organ, though — and if it gets severely infected, you still need to get it taken out.