It’s pretty easy to figure out the source of your bleeding when you’ve received a flesh wound, but it's harder to figure out what’s going on when blood leaks out somewhere unexpected. That sort of bleeding can be harmless or potentially life-threatening.

Penis

Your urine may be red with blood if you have kidney stones, and there may also be some pain at the tip of the penis. Because kidney stones are compacted minerals and salts that have traveled from the kidneys and down the urinary tract to the bladder, the Urology Care Foundation says people may also feel sharp pain in their back, side and groin, a feeling of urgency to pee and frequent urination, burning while peeing and nausea.

When the blood is in the semen rather than the urine, that’s a different story. The British Association of Urological Surgeons notes that condition, called hematospermia, can be the result of an infection or other inflammation and usually in the prostate gland, which produces semen and helps force it out during ejaculation. In rare cases, it could also be a sign of cancer in the testicles or the prostate or severely high blood pressure. The U.K.’s National Health Service describes this as looking as though the semen “may be blood-stained, brownish-red in colour or have a pink tinge.”

Stool and rectum

Often rectal bleeding is related to a tear in the skin of the anus, hemorrhoids, constipation or hard stools, according to the Mayo Clinic. But less commonly it can also be a sign of anal or colon cancer; an inflammation in the gallbladder or the colon; a sore on the rectum’s wall; sores in the digestive tract; or a condition called diverticulosis, in which small pouches form along the digestive tract, usually in the colon, which is the large intestine. One clue about the source of the bleed is how dark the blood is — if the blood is bright red, the bleeding is lower down, perhaps in the colon or the rectum. But darker blood has been exposed longer, meaning it came from earlier in the route to the anus.

Vagina

Like men, women can get kidney stones that can cause blood to appear in the urine, along with other kidney stone symptoms, or can have some bleeding with a urinary tract infection. But that blood is coming from the urethra, not the vagina. Blood from the vagina can be breakthrough bleeding, a common condition in which blood from the uterus comes out between menstrual periods. It often occurs in women who are using oral contraceptives.

Pregnant women may also bleed. The Huffington Post says that blood may not be cause for alarm, as about 10 percent of women have some bleeding while pregnant “and for the vast majority, it signifies nothing serious,” merely a sign that the body is still adjusting to its new condition. But when the blood flow is heavy and comes with painful cramps, it could be a miscarriage. Later in pregnancy, dark blood, clots and abdominal plain could be a sign of a placental abruption, in which the placenta comes away from the uterus ahead of delivery — in that case, the baby may have to be delivered early.

Nose

Nosebleeds happen from time to time, but frequent bleeding from the nose and “an unusual-looking blood spot” on the face, lips or hands could be a sign of a rare blood vessel disorder, according to the Cleveland Clinic. Hereditary hemorrhagic telangiectasia is most often marked by “a bloody nose that gets worse over time. This bloody nose reoccurs without any known warning or trauma to the nose.” In some people, abnormal blood vessels in the brain and the lungs enlarge, which could eventually lead to bleeding with a stroke in the brain or a lung bleed.

Nosebleeds can also be a sign of leukemia, a blood cancer.

Mouth

Leukemia reduces the body’s number of platelets, which makes clotting more difficult. That means people with the cancer could bleed from their gums or noses, in addition to finding blood in their pee or poop.

Then there’s scurvy, the dreaded pirate disease. It’s actually a deficiency of vitamin C — the National Institutes of Health measure that deficiency as less than 10 milligrams a day for about a month. Those people will have bleeding within the body as well as on the inside. Swollen, bleeding gums are one symptom, as is bleeding from the hair follicles and underneath the skin.

Eye

If trauma has not occurred, bleeding in the eye could be an infection or extreme dryness that caused a sore on the cornea, which is the protective layer in front of the pupil, according to the American Academy of Ophthalmology. If the bleeding is visible, but on the inside, that could be a hyphema or a hemorrhage. With the former, “blood collects inside the front of the eye,” the organization describes, between the cornea and the iris. Vision may be blocked and the condition is painful. A subconjunctival hemorrhage, however, is painless and is the result of a broken blood vessel in the eye, with the blood appearing in the white part of the eye. That hemorrhage can come from a strain as simple as coughing, sneezing, rubbing the eye, “or any similar action that temporarily raises blood pressure in the veins, leading to a small rupture.” In some cases, it can also be related to diabetes or high blood pressure.

Ear

Cover your ears if you hear an insect hanging around the side of your head — if it gets inside it could cause a serious problem, including bleeding. According to the New York Times, an insect could have much of the same symptoms as other types of ear trauma, like pain and hearing loss, and could “irritate the sensitive skin of the ear canal.” If there is an insect inside your ear, do not stick a finger in there after it, because it could sting to protect itself. The Times recommends, in addition to getting medical help, turning the affected ear upward to see if the insect vacates the premises.