Deep down inside, we all know it: It’s inevitable, this living, breathing, beautiful, multipart machine, the human body, is — at some point, somewhere — going to break down.

We’ve all heard the warnings, the doctors’ admonitions to get brave and submit to any one of an array of screenings, but too many of us brush them off — thinking, “Not me. I’m immune.” Or maybe we’re scared silly.

Well, here are just a few medical realities to ponder, to make you think twice about putting off those routine screenings. The goal is happier endings.

HEART DISEASE

What you should know: Of the more than 400,000 Americans who died of a heart attack in 2008, a full 50 percent had no prior symptoms of heart disease, says Dr. John Gordon Harold, vice president of the American College of Cardiology, clinical professor of medicine at UCLA’s David Geffen School of Medicine, and a practicing cardiologist at Cedars-Sinai Heart Institute in Los Angeles.

What you can do: Harold says that one of the most vexing issues in the field of cardiology over the last decade has been the subject of screening for patients with no signs of heart disease.

CERVICAL CANCER

What you should know: Globally, cervical cancer is a major health problem, with a yearly incidence of 371,000 cases and an annual death rate of 190,000 women, according to the American Congress of Obstetricians and Gynecologists (ACOG). It’s estimated by the National Institutes of Health that 50 percent of the women diagnosed with cervical cancer each year have never had a Pap smear, and another 10 percent had not been screened within five years of the diagnosis, says Dr. Jessica Shepherd, a member of ACOG’s Committee for Gynecologic Practice.

What you can do: When a woman turns 21, she should have Pap smears every two years during her 20s, according to the latest ACOG recommendations. When a woman turns 30, she can be screened every three years as long as she’s had three consecutive negative (or clear) Pap tests, and no history of abnormal Pap tests or findings of human papillomavirus (HPV) in the past. However, women with certain risk factors and health issues might need more frequent screenings.

COLON CANCER

What you should know: The survival rate for colon cancer diagnosed at Stage 1 is 74 percent, according to the American Cancer Society. The survival rate for Stage 4 colon cancer is 6 percent. It can take anywhere from eight to 10 years for symptoms to arise, and for polyps to grow cancerous, so early detection is your best bet, when the cancer is considered highly curable.

What you can do: If you have no family history of colon cancer, and no symptoms, celebrate your 50th birthday with a colonoscopy. If it’s clean, with no signs of suspicious polyps – and no onset of symptoms down the road – you can wait another 10 years before the next scope.