In the last four decades, the number of nurse practitioners has risen to more than 140,000. And more and more are working on their own, especially in poor inner-city neighborhoods and rural areas, where there are few doctors in private practice. The scope of what nurses can do medically has also been growing for the past decade, at a time when the pool of primary care, or family doctors, has been shrinking. And now the need for professionals to do basic family medicine has never been greater. In 2014, when key provisions of the federal health care reform law kick in, it's estimated 32 million Americans who currently have no health insurance will be able to buy coverage. And the experts tell us that's going to make the shortage of primary care physicians worse.