1. Pons
   Pituitary gland
2. Pineal gland
   Thymus

Have you ever let your sleep schedule slide so that you were staying up late and sleeping in half the day? Once your sleep schedule is off, it can be hard to get back on track because your pineal gland starts producing melatonin at inappropriate times.

1. Appendix
   Liver
2. Pancreas
   Thyroid gland

Getting an appendectomy is one of the most common emergency surgeries. It's was long thought that the appendix served no function in modern humans, but some scientists now believe it may play a role in protecting healthy bacteria after a stomach illness.

1. Mammary glands
   Pancreas
2. Thymus
   Thyroid

Both men and women have mammary glands for milk production. In women, the glands become developed after estrogen levels increase. In cases of extreme hormonal imbalances, men can also produce milk.

1. Retina
   Skin
2. Scrotum
   Iris

You might not think of your skin as an organ, but it's the largest organ in your body based on the surface area. Like any other organ, it can become damaged if you don't take care of it properly. So wear your sunscreen!

1. Ciliary body
   Olfactory bulb
2. Cochlea
   Pons

Your olfactory bulb is located on the base of your brain and extends in a series of 'roots' into your nasal cavity. If this organ became damaged, not only would your sense of smell be destroyed, but you might not enjoy your meals as much either. Don't believe us? Try eating your next meal with your nose plugged.

1. Olfactory bulb
   Cerebrum
2. Thymus
   Cochlea

Your snail-shaped cochlea converts sound waves into neural signals that your brain can interpret. Damage to this organ can lead to hearing loss. Unfortunately, it isn't able to heal itself, so damage is usually permanent.

1. Pituitary gland
   Cochlea
2. Pons
   Thyroid gland

The pons is a critical part of your brainstem that regulates sleep, swallowing, bladder function, facial expressions, taste and other functions. You wouldn't be able to survive without your pons since your body wouldn't have a way to transmit information from your spine to your brain.

1. Capillaries
   Arteries
2. Veins
   Vena cava

Your capillaries are the smallest type of blood vessels. Your arteries carry blood away from your heart and become smaller arterioles. These arterioles eventually become capillaries, which allow for the exchange of oxygen and nutrients.

1. Urethra
   Thyroid gland
2. Pineal gland
   Pancreas

Your urethra creates a passageway from your bladder to your ... well, toilet. Both men and women have this organ. However, women have a shorter urethra, which makes them more susceptible to bladder infections.

1. Esophagus
   Trachea
2. Parathyroid
   Adrenal gland

Your esophagus connects your mouth to your stomach. Can you guess how long it is? From your throat to your stomach, it runs about 8 inches long. Obviously, in a bigger person, it's going to be slightly longer.

1. Large intestines
   Small intestines
2. Appendix
   Liver

Your large intestines serve as the final stage of your food's journey. Despite their name as 'large,' your large intestines are only about a quarter of the length of your small intestines. In the average person, the long intestines measure about 5 feet long.

1. Thymus gland
   Pineal gland
2. Salivary gland
   Thyroid gland

If you've ever noticed your mouth start watering in anticipation before you walked into a restaurant, you can thank your salivary glands. You have six glands in total. Can you guess how much saliva they produce in a day? More than two liters (67oz.)!

1. Small intestines
   Esophagus
2. Trachea
   Large intestines

Your small intestines measure roughly 20 feet. Whereas your stomach is responsible for breaking down food and your large intestines are responsible for absorbing water, the main job of your small intestines is to absorb nutrients.

1. Appendix
   Stomach
2. Gallbladder
   Liver

Besides breaking food, your stomach also releases a hormone called ghrelin. When your stomach is empty, it produces this 'hunger hormone' that signals to your brain that it's time to eat. If you're trying to lose weight, you can reduce ghrelin by eating filling, low-calorie foods.

1. Bladder
   Thyroid gland
2. Gallbladder
   Liver

Your gallbladder stores bile produced by your liver to help break down fatty foods. You can survive without your gallbladder, but your doctor will probably prescribe a low-fat diet. Without a gallbladder, bile flows directly from the liver to the small intestines.

1. Liver
   Pancreas
2. Thymus
   Heart

Most of your organs only have one or two functions, but your liver has dozens. Some of its many jobs include storing sugar to keep your blood sugar balanced, creating hormones, making proteins and filtering blood.

1. Tonsils
   Larnyx
2. Tongue
   Molars

Did you get your tonsils removed as a kid? Many people do if they become infected repeatedly, and it's thought that people have been performing tonsillectomies for thousands of years! Your tonsils are a lymph organ, which means they play a role in boosting your immune system.

1. Larynx
   Pharynx
2. Tonsils
   Adrenal gland

Your larynx is more commonly known as your voice box. You can see it on the front of your throat if you tilt your head up. Your larynx produces sound, but unless you want to speak in Morse code, you still need your mouth to differentiate between different consonant and vowel sounds.

1. Lungs
   Adrenal glands
2. Veins
   Retina

Take a deep breath and feel your lungs expand in your chest. Did you know that your right lung has more lobes than your left? Your left lung only has two lobes instead of three to make room for your heart.

1. Retina
   Adrenal glands
2. Stomach
   Diaphragm

If you take a deep breath that engages your whole stomach region, you're breathing with your diaphragm. If you're a teacher or somebody who speaks loudly regularly, you're probably already familiar with the power of the diaphragm.

1. Esophagus
   Trachea
2. Heart
   Lungs

Don't let your trachea get clogged or you won't be able to breathe. For most people, their 'windpipe' is only about an inch in diameter, and in children, it's even smaller. No wonder they put those chocking hazard signs on toys.

1. Large intestines
   Small intestines
2. Gallbladder
   Urinary bladder

Do you know what your bladder is connected to? Two tubes called ureters connect your kidneys to your bladder. It's your kidneys' job to create urine, and your bladder's duty to hold it. For most people, the bladder holds between one and two cups of liquid.

1. Ovary
   Uterus
2. Cervix
   Vulva

The ovaries serve several functions. They contain the eggs used for fertilization, but they're also the leading site of estrogen production. Ovaries also produce a small amount of testosterone (much less than men produce).

1. Prostate
   Testes
2. Vas deferens
   Seminal vesicle

The walnut-sized prostate creates seminal fluid, which mixes with sperm to make semen. Prostate cancer is one of the most common causes of death in older men. Almost 4% of men die of prostate cancer.

1. Liver
   Seminal vesicle
2. Gallbladder
   Pancreas

Your pancreas produces insulin, which regulates your blood sugar. Cancer of the pancreas is usually fatal because it's hard to detect in the early stages. Right now, the survival rate of pancreatic cancer is about 20%.

1. Pancreas
   Bladder
2. Kidney
   Cecum

Your kidneys act like Brita filters for your blood. Anything that needs to be removed is sent to your bladder for excretion. Your kidneys are also responsible for regulating your mineral balance.

1. Adrenal gland
   Ovaries
2. Thyroid gland
   Thymus

Your adrenal glands produce several other essential hormones besides adrenaline. These include your stress hormone cortisol and your sodium-saving hormone aldosterone. They also produce a small amount of testosterone.

1. Pineal gland
   Olfactory bulb
2. Adrenal gland
   Parathyroid gland

Your parathyroid glands are located behind your thyroid glands in the front of your throat. Do you know what their function is? They release parathyroid hormone, which plays a role in your body's calcium balance.

1. Thyroid gland
   Adrenal gland
2. Thymus
   Pituitary gland

Your thyroid gland is responsible for regulating your metabolism. If your thyroid hormone levels drop, you'll usually notice a decline in your energy levels and weight gain. The opposite is true for when your thyroid is overactive.

1. Pineal gland
   Adrenal gland
2. Thymus
   Pituitary gland

Your pituitary gland produces human growth hormone, which is essential for the production of new muscle, bone and connective tissue. Have you ever heard of athletes taking HGH for performance benefits? It's the same hormone that your body produces naturally.

1. Kidney
   Lung
2. Heart
   Vena cava

It may not look like the kind of heart you see on Valentine's Day, but your heart (along with your brain) is the most important organ in your body. Amazingly enough, surgeons are now able to perform complete heart transplants.

1. Thymus
   Thyroid gland
2. Cecum
   Olfactory bulb

Your thymus gland store T-cells that help your body adapt to foreign invaders. Once you become an adult, your thymus gland is replaced by fat. It's essential for small children with developing immune systems.

1. Bone marrow
   Skin
2. Brain
   Liver

Your bone marrow is the site of hematopoiesis or the production of new blood cells. A large portion of your bodyweight is bone marrow. In the average person, the bone marrow makes up about 4% of the total mass.

1. Blood vessels
   Veins
2. Lymph nodes
   Arteries

Your lymph nodes are connected by a serious of tubes called lymphatic vessels. When you have an infection, your lymph nodes can become swollen as your body tries to fight it off. Unfortunately, cancer can spread through your lymph system.

1. Spleen
   Heart
2. Lungs
   Thymus

As your blood flows throw your spleen, the organ checks your blood cells for damage. If the red blood cells are old or damaged, it breaks them down. Your body also uses your spleen to store extra blood.

1. Pons
   Pituitary gland
2. Olfactory bulb
   Medulla oblongata

Your medulla oblongata is the part of your brain stem responsible for several essential processes including digestion, controlling your heart and swallowing. It's the lowest part of your brain before it transitions into your spinal cord.

1. Thyroid gland
   Cerebellum
2. Hypothalamus
   Corpus callosum

Your hypothalamus may only be a small part of your brain, but it plays a critical role in regulating the hormones in your body to make sure their concentration doesn't get too high or too low. It also regulates your body temperature.

1. Olfactory bulb
   Taste buds
2. Thalamus
   Thyroid gland

You may have learned that there are four types of taste buds: sweet, sour, salt and bitter. However, there's a fifth type of flavor called umami. It's the savory taste of meats and some fermented products.

1. Olfactory bulb
   Retina
2. Tear duct
   Salivary gland

Your retina is the part of your eye that senses light and sends information to your optic nerve. It's located along the back of your eyeball so that light hits it after passing through your pupil.

1. Thymus
   Thalamus
2. Organ of Corti
   Pons

Your organ of Corti is located inside of your cochlea and helps with the transduction of sound vibrations into neural impulses. It was first discovered in 1851 by an Italian scientist.