Your mother was wrong – what you don’t know can kill you, or at the very least can make you really sick.

Take these three examples:

* Abdominal aortic aneurysm. This one can literally be a killer. If your aorta ruptures, there’s a very good chance you won’t live through it. Of those who suffer abdominal aortic ruptures, 85 percent don’t survive.

* Peripheral arterial disease, or PAD for short. Often found in your legs, the disease – which is essentially a buildup of plaque that causes arteries to narrow and harden – can also be a sign of worse things to come. People with PAD are also at risk for heart attack, or stroke.

* Carotid artery disease. This too is caused by a buildup of plaque in arteries, in this case the two carotid blood vessels that feed blood to your brain. One consequence: the very real possibility of a stroke.

Of the three, the least is known about the exact causes of abdominal aortic aneurysm. But medical science does know what risk factors are involved that can lead to it, and scientists also know that the larger the aneurysm the more likely it is to rupture.

If the worst happens, and the vessel ruptures, you can bleed internally. If the aorta ruptures, you’ll know pretty quickly. Among the symptoms if that happens:

* Severe, sudden pain in your abdomen or back, groin, buttocks or legs

* Nausea, along with clammy skin

* Increased heart rate

* Shock

Fortunately, there are screening methods that could give you time to be diagnosed and treated before disaster strikes.

The Society for Vascular Surgery says the most common steps are:

* An ultrasound test of your abdomen

* A CT exam (CT stands for Computed Tomography)

* An MRI, more technically called a Magnetic Resonance Imaging exam.

The ultrasound test is the simplest and is safe, without any radiation exposure. It also only takes a few minutes.

Another serious medical issue often not screened for is PAD, the disease that shows up in your legs when blood vessels get constricted by fat and cholesterol. It can cause pain and numbness in your legs, and if you get an infection in that part of your body, you’ll have a tougher time fighting it off. It is also a marker for coronary artery disease, heart attack and stroke. Unfortunately, you may not have any symptoms at all. PAD can be silent.

Doctors often look to lifestyle changes to treat PAD. Quitting smoking is first on the list, followed by lowering blood pressure and cholesterol, lowering blood sugar levels and being physically active. Sign up for the free health e-newsletter by Life Line Screening that can help get you on the right track for healthy living today.

The most common screening test for PAD is called the ankle-brachial index (ABI). The ABI compares the blood pressure in your arm to the blood pressure in your ankle. The test determines if the pressure in your ankles is the same or greater than that in your arms. If it is less, you may have a problem.

Another key problem area involves plaque buildup in the two main blood vessels that feed your brain, your carotid arteries. In this case, the results can also be devastating: a stroke. More than half the strokes in the United States are caused by carotid artery issues. Watch an overview video about stroke risk courtesy of Life Line Screening.

Alas, you might not know you’re in danger until the worst happens, either when the arteries are severely blocked, or a stroke actually occurs. To protect yourself, doctors advise living a healthier lifestyle by keep your weight in check, quitting smoking and getting regular exercise.

Medically speaking, the treatments range from surgery on your artery to remove the plaque in an attempt to improve the blood flow to your brain, to the less invasive angioplasty in which a stent in placed in the artery to achieve the same result.

As with the other arterial diseases, there are several screenings to help you head off a major crisis by learning what is happening inside your carotid arteries before a major stroke occurs.

Included is a test called a carotid ultrasound, which helps doctors use sound waves to create a picture of your arteries. There are also diagnostic tests such as a carotid angiography, which is a type of X-ray in which doctors inject a dye into a vein to track it through your system. And there is an MRA (Magnetic Resonance Angiography) to help doctors diagnose whether you have a problem. It uses a magnet and radio waves to provide your doctors with images.

You should know that typically your health insurance won’t pay for vascular screening tests if you have no symptoms, although they can be life-saving screenings. The best course for you in that case is to talk to your doctor about what is available to you and seek screenings from a community-based organization which usually provides screenings at a reasonable cost. Join Life Line Screening on Facebook to follow what people are saying about their experiences with community-based screening events.