Quadruplets pursue medical careers to honor late mom Toni Murphy died at 36 when her quadruplets were just 2 years old.

 -- Toni Murphy was just 36 when she died in 2001, leaving behind five children, including 2-year-old quadruplet daughters.

Now, Toni Murphy’s quadruplet daughters, Erin, Kelly, Rachel and Casey Murphy, are 18-year-old college freshman fulfilling their mom’s legacy.

Three of the sisters are studying nursing at Rutgers University in Camden, New Jersey. Erin Murphy is studying veterinary medicine at Oklahoma State University.

Toni Murphy worked as a nurse for more than a decade before she died of complications from an infection.

“I wanted to follow in my mom’s footsteps,” Casey Murphy told ABC News. “My dad tells us stories a lot and [it was] just something that I wanted to do.”

The sisters’ father, Michael Murphy, raised the four girls and their older sister, Lyn, 31, on his own after his wife died.

“I’ve got pictures of her up around the house and would always say, ‘Your mother used to do this,’” he said of keeping Toni Murphy’s memory alive. “I kept those stories going to make sure that they knew that she was part of their lives even though they don’t remember too much of it.”

Toni Murphy worked in obstetrics and was also an elementary school nurse and a prison nurse, according to her family.

“Ever since I knew about nurses, I always just wanted to be one,” said Rachel Murphy. “Since I was little, I’ve always wanted to help people.”

Toni Murphy’s daughters each have their own dreams of what they want to do in the medical field. Kelly Murphy is considering becoming a doctor, Casey Murphy wants to work in pediatrics and find a cure for cancer, Rachel Murphy wants to be a flight trauma nurse and Erin Murphy wants to become a veterinarian.

Their older sister, Lyn Murphy, also works in the medical field as an X-ray technician in New Jersey.

"I wanted to follow in the footsteps of both of them," Kelly Murphy said of her mom and older sister. "I just had this passion for helping people and I’m really interested in the human body and how it works."

Michael Murphy said he watched his daughters fall in love with the medical field after shadowing nurses and doctors while in high school.

“It’s nice that they’ve embraced the fact that [their mom] was a nurse and wanted to honor her in that way,” Michael Murphy said. “I never forced them … they fell in love with it.”

Rachel, Casey and Kelly Murphy commute to Rutgers from their family's home in Swedesboro, New Jersey. The three sisters take the same schedule of classes and rely on the same built-in study group that helped them thrive in high school.

“I don’t think we mean to be competitive but we push each other to do the best we can and we’re always anxious to see who did the best,” Rachel Murphy said. “We don’t think of it as competitive but it just kind of happens to be that way.”