Kristyn Ulanday / for NBC News

Jennifer Anstead, a runner, had three friends injured in the marathon attack, including one who lost a leg.

BOSTON -- Scores of marathon runners, doctors, nurses and others descended on Boston on Thursday to join a memorial service to pay respect to the victims of the bombings that struck the iconic road race as the city continued to reel from the twin blasts.

Some nurses attended in their blue scrubs, while others in the crowd wore their blue-and-yellow Boston Marathon jackets. There were many large contingents of staff from the various city hospitals that responded to the trauma.

Jennifer Anstead, a runner who was about 20 feet away from the second blast, choked up as she talked about three of her friends who had come to cheer her on and were injured in the explosions, including one who lost her leg.

"I still feel a lot of guilt. It's a lot to process. It's a lot to take in," she said.

"I'm trying to be strong for her," Anstead, a 37-year-old operating room nurse, said through sobs. Her friend has a "long road ahead," she added. "She's incredibly strong, she's an amazing person."

Another runner, Brian Ladley, said he found himself between the two bomb blasts but emerged unscathed. He appeared solemn and paused between words as he spoke with a reporter.

"I'm here for the runners who can't be here today," said Ladley, 39, who just moved to Boston. "It's still surreal, but (I'm) coping, managing. It's good to be here with people ... people are coming together."

Rodney Bensley, a resident at Beth Israel Deaconess Medical Center who worked in the trauma unit as patients were incoming, said the last few days have been emotionally challenging, especially since a number of the victims were young.

"We personally cared for a lot of these patients and want to pay our respects to the ones that lost their lives and the ones that are injured as well as their families," said Bensley, 34, who waited with a long line of colleagues to attend the service.

"I kind of think about what happened and how to move forward and ... heal as a city," he added.

Registered nurses Linda Denekamp and Kim Cross, who work with Bensley, said the service offered a period of reflection for the staff.

"It's partly to decompress, partly to offer support to them and their families," said Denekamp.

"It's just nice to come here to take ... a step back and reflect," Cross, 26, added.

Kristyn Ulanday / for NBC News

Jennifer Dunphy, outside the memorial service: "I guess I'm just looking for ... maybe some peace, some understanding, something, a little bit of hope."

Another runner, Jennifer Dunphy, 29, stood in line with a friend who offered her a ticket to the service to help her cope with her feelings from that day. She said she was nearing the finish line as the blasts went off, and ultimately ended up crossing it as she searched for safety.

She later learned that some of her friends were hurt in the attack.

"You were numb at first, and then you're in shock and then you're angry,” said Dunphy, a political consultant and Charlestown resident. “Now I guess I'm just looking for ... maybe some peace, some understanding, something, a little bit of hope."

Related:

• Bombing victims try to track down heroes who saved them
• Who is the FBI’s agent in charge of Boston marathon case?

Earl Gibson III/Getty Images

At a candlelight vigil for singer Jenni Rivera on Dec. 10 in Long Beach, Calif.

The family of Jenni Rivera announced that a public memorial service will be held for the singer, who died Dec. 9 in a plane crash, Wednesday at the Gibson Amphitheatre in Los Angeles.

The memorial - called a "Celestial Graduation" by her family - will be held from 10 a.m. to noon PT and be led by the Rev. Pedro Rivera Jr., the singer's older brother.

"We will celebrate the graduation into heaven, with honors, of our beloved mother, daughter and sister Jenni Rivera," the statement read. "We appreciate the privacy and discretion given to the family on the day she is laid to rest. The burial services will be privately held."

Rivera died when the private plane she was traveling in crashed in a mountainous region of Mexico.

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Born in Long Beach, Calif., to Mexican immigrant parents, Rivera sold more than 15 million albums worldwide throughout her career and was a household name in Mexico and to Spanish-speaking communities throughout the United States.

The 43-year-old mother of five was one of the biggest stars of banda, a brass-based, percussive form of Spanish-language pop music invented in northern Mexico but played heavily throughout the American Southwest. Banda traditionally was the domain of men, and Rivera's emergence and eventual dominance in the genre was groundbreaking.

Rivera's fame was expanding prior to the crash, thanks to a stint on television as the star of her own reality series, "I Love Jenni," on Telemundo's mun2 cable channel, and the recent announcement that she had signed to take the lead role in a sitcom for ABC.

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The company that owns the luxury jet on which she was traveling is under investigation by the U.S. Drug Enforcement Administration, and the agency seized two of its planes earlier this year as part of the probe.

The Rivera family requested that in lieu of flowers at the memorial, donations be made to the Jenni Rivera Love Foundation - the charity founded by the singer, which offers support services to single mothers and victims of both domestic and sexual abuse.