Why getting kicked in the balls causes abdominal pain?
Testes originally forn in the abdomen near the stomach and kidneys. Nerves and blood vessels are attached to that region. When the balls are squished, the pain travels up into the abdominal cavity, then to the spine. So it kind of tricks the brain to think the pain is originating from the abdomen. Sometimes men will also experience nausea, when you see them fall on the floor of pain... It's caused by a huge rush of sympathetic nervous system discharge. Vomiting is sometimes another symptom...
Why is it nearly impossible to tickle yourself?
Simply because of the anticipation. Your brain does that unconsciously to speed up response time. Basically your brain pays a lot more attention to unexpected sensation. While doing this it discards sensation it deems unimportant. In short you can't tickle yourself because there is no element of surprise and your brain doesn't pay attention to it.
What causes muscle soreness after exercising?
Most think that the soreness you experience the next day is causes by lactic acid build up, it''s not true. Your body actually uses lactic acid right after the activity to recover from lack of oxygen. Recently research showed that the soreness is caused by microfractures in the muscle cells. Your muscles aren't used to doing certain activities and can't handle it anymore. They quickly adapt though, to prevent further damage in the future. As a general rule, if you increase your exercise by less than 10% every time, you won't experience any soreness.
About 85% of people breath out of one nostril at a time...
Even more interesting is that we switch from one nostril to another every 4 hours or so, although this can vary from one person to another bases on body position or nasal congestion. This is a result of erectile tissue similar to the one in a penis or a clitoris. Erectile tissue will swell up in one nostril blocking it and leaving the other open. More interesting is that depending on which nostril you are breathing out of at a given moment, it affects your body and brain. Breathing through the right nostril significantly increases blood glucose level, have more oxygen and your right hemisphere of your brain will be more active than your left and vice-verse. It might be handy to know that the right hemisphere of your brain is responsible for your creativity and imagination, while your left is your logical side.
Why your nose gets runny when you are cold?
An average person will produce just under one liter of mucus fluid a day. Mostly passed back to the throat and swallowed without even realizing. When we are breathing cold air our body responds to it by increasing the blood flow to our noses to warm the nose and the air before it gets to our lungs. As a result, mucus glands get a much bigger supply of blood than it usually does and produce a lot more mucus. When you get back to warm air you get back to your normal 4 cups of snot per day.
Humans have a lot more than 5 senses.
As it turns out we have at least 9. Most researchers even think we have close to 21 or so. Just for reference the commonly held definition of a "sense" is, any system that consists of a group of sensory cell types that respond to a specific physical phenomenon and that corresponds to a particular group of region within the brain where signals are received and interpreted. Human senses are, sight, taste, sound, smell, touch, pressure, itch, thermoception (ability to sense heat and cold), proprioception (ability to tell where your body parts are) tension sensor (ability to monitor muscle tensions), equilibrioception (ability to balance), stretch receptors (senses dilation of blood vessels, often involved in headaches), chemoreceptors (ability to detect blood born hormones and drugs, thirst, hunger, magentoception (ability to detect magnetic fields), and time.
Why mosquito bites itch?
When a female mosquito pokes us to suck our blood, it also inject us with some of her saliva. This helps them drink our blood quickly. As a response to that your immune system kicks in and produces various antibiotics which in turn bind to the antigens in the mosquito's saliva. This triggers the release histamine which among other things, it triggers an inflammatory response. Bottom line histamine ends up making the blood vessels near the bite swell up and produce an itchy pink bump. Scratching makes it worse because it causes more irritation to the area making your immune system think it needs more histamine.
What causes pain in your side when running?
With a little bit of physics we can explain this very simply. When you are running, swimming or doing other active movement you feel this pain basically because of stress to the diaphragm ligaments as well as spasms or cramps in the diaphragm itself. When you inhale, your diaphragm goes down, when exhaling the diaphragm rises. When you are running, every time your foot hits the floor your organs go down. Most people naturally and unconsciously time their exhales when their foot hit the ground which pulls the diaphragm up and pulls the organs down. Knowing that the diaphragm is connected to the organs through ligaments, this puts a lot of stress on those ligaments and that's why the pain in your side occures.
What causes ice cream headaches?
When you put anything extremely colder than your body in your mouth and you swallow it, you get a headache because your palate is cooled down. This is caused by a nerve center located just above the back of your mouth. Nerve clusters send signals to your brain about a dramatic change in temperature. When over stimulated by the loss of heat, the brain vessels rapidly contract in your head which results in headaches. It's how your brain kind of "freaks out". Shortly after everything goes to normal after your palate goes back to normal temperature. This shows you how fast our bodies respond to any changes that deviate from the norm.
Why poop is brown?
Due to the bile in your gall bladder being metabolized by the bacteria in your intestines. This results in a byproduct called stercobilin, which, in turn, makes poop look brown-ish. Without this your poop would look grey-ish. If you ever notice that your poop is grey-ish, it is probably because of problems with bile production, such as blocked bile duct by gall stone or something more serious like pancreatic cancer. I'm going to take a second to let you know that if you also notice that your poop is very dark, it would be wise to mention this to a doctor because it is sign of blood in the stool. So if you notice that your poop is brown, it is a good sign, it means your digestive system is healthy and well functioning.