SANFORD, Fla. -

The jury on Tuesday heard testimony from a state medical examiner expert who called George Zimmerman's injuries minor.

[Chat recap: Tony Pipitone inside courtroom]

Zimmerman, 29, is charged with shooting and killing 17-year-old Trayvon Martin in Sanford.

Dr. Valerie Rao examined Zimmerman's reenactment video, 36 photos, medical history/record, police video, autopsy reports and police reports. Rao did not do the autopsy on Martin.

Prosecutor John Guy asked Rao about Zimmerman's injuries, which she called "not life-threatening" and "very insignificant." She said Zimmerman's head injuries are consistent with hitting concrete but only one strike. Rao said the injuries were not consistent with being repeatedly "slammed" against the concrete since the injuries aren't great-force injuries.

"They were so minor that the individual who treated and examined Mr. Zimmerman decided stitches weren't required," Rao said.

Defense attorney and former Local 6 legal analyst Mark O'Mara questioned Rao in cross-examination about how Special Prosecutor Angela Corey appointed Rao to the medical examiner position.

O'Mara asked Rao if she was suggested Martin only hit Zimmerman once. Rao said she's not suggesting it was only one hit to the nose, but could be one. She then says it could be two, three or four depending on the force/impact.

O'Mara asked if Rao found any injuries in Martin's autopsy reports, to which she said she didn't see any noted, although she didn't do the autopsy herself. Rao also added the facial injury could also be consistent with overhead blow, similar to what witness John Good described.

Rao did not identify bruising on Zimmerman's head, despite O'Mara's efforts, but then found one on the right side. O'Mara then described various scenarios and asked Rao what the injuries would be.

O'Mara then got Rao to expand her "3 impacts" of Zimmerman's head on cement to many more. He asked Rao "what about the next injury?" in hopes to drive home point injuries could have become life-threatening.

The defense objected to the state's next witness, Professor Carter, who would testify about the course Zimmerman took 1-2 years before shooting that included self-defense law instruction. Zimmerman had denied previous knowledge about self-defense law.

The state also wants to show Zimmerman had such interest in law enforcement that was his state of mind at the time of the incident. State prosecutor Richard Mantei said Zimmerman's behavior was an ongoing pattern, including applying and being rejected as law enforcement officer in Virginia and an application to ride around with Sanford police officers.

The state said Carter will expound on written materials to say "stand your ground" was taught in class Zimmerman took.

O'Mara said Zimmerman's schooling is unrelated to the case. Judge Debra S. Nelson said the state wants to show Zimmerman's knowledge of law, investigations and interviews. O'Mara said the "state can't create evidence" to have the professor impeach Zimmerman on it.

"That's their theory of the case," Nelson said, that Zimmerman "understood (the law enforcement) process." The defense sought proffer from state and Nelson gave defense a 30-minute recess to find case law to support their objection.

Nelson wanted to move on to the new witness and deal with the college course/records at 8:30 a.m. on Wednesday.

The state called one last quick witness on Tuesday, Kristen Benson, a Seminole County Sheriff fingerprint examiner. The jury was then dismissed as the court discussed outstanding issues.

The jury also heard on Tuesday Zimmerman's TV interview with Sean Hannity as Zimmerman said he has no regrets about shooting and killing Martin and felt as "it was all God's plan."

In the July 2012 interview with Fox News' "The Sean Hannity Show," Zimmerman said he had never heard of "stand your ground" before the shooting, to which the state claims it has evidence that statement is false.

In his first public interview since the shooting, Zimmerman also discussed how Martin was "trying to intimidate" him by implying he had a weapon and that Martin wasn't running out of fear but "skipping."

Zimmerman said Martin confronted him 30 seconds after he was heading back toward his truck and told Hannity about Martin's attack.

"I thought I'd lose consciousness. I didn't know what would happen at that point," Zimmerman said, describing when his head was hitting the concrete. "After he couldn't hit my head on concrete anymore, he tried to suffocate me, I kept pushing his hands off my mouth, nose."

He then tells Hannity the screams were definitely his.

The first testimony on Tuesday morning came from the lead police detective who investigated Martin's fatal shooting last year. Chris Serino returned to the witness stand, minutes after the judge ruled one of his statements from Monday's testimony be stricken from court record.