reporter: that is powerful stuff, piers. you cannot argue with this guy s dee meaner, too. he was looking to the jury and telling them his explanation. the second thing that was, i thought, very significant was he testified that zimmerman s injuries also fit his account involving being stunned. tell me about this. reporter: oh, this is huge. if it s second-degree murder, they have to determine if these injuries were bad enough, that this defendant can say i feared for my life. they said those injuries were minor. it was a bit of blood but the scalp bleeds a lot. these weren t intention and listen to dr. vincent di maio what it s like when you get your bell rung. you fall and hit your head and you can get a mild
and that has a reserved supply of 10 to 15 seconds. reporter: that is powerful stuff, piers. you cannot argue with this guy s dee meaner, too. he was looking to the jury and telling them his explanation. the second thing that was, i thought, very significant was he testified that zimmerman s injuries also fit his account involving being stunned. tell me about this. reporter: oh, this is huge. if it s second-degree murder, they have to determine if these injuries were bad enough, that this defendant can say i feared for my life. they said those injuries were minor. it was a bit of blood but the scalp bleeds a lot. these weren t intention and listen to dr. vincent di maio what it s like when you get your bell rung.
b sybrina fulton walked out. we can t blame her. who would want to listen to this testimony about your son. we re so clinical talking about the trajectory and the stipling and injuries. it s really painful to remember especially when you sthee that bottle of ice tea. it s a kid. somebody wants justice. jean stand by for one moment because there was another moment that vincent dimaio was able to bring out and that s the argument that the prosecutors have been making that george zimmerman s injuries weren t severe enough to be in fear for his life hence bring up this whole self-defense. listen as he talks about what happens when you get your bell rung. impacts of the head when it s
shocking, jamie. they sent 8,900 students from seventh to 12th grade questionnaires and asked if the past year have you had a blackout from hitting your head? we re talking worse than a concussion where you get your bell rung. literally a brain injury which is related to a concussion but even worse. the centers for disease control says 15% of people that have concussions have prolonged symptoms where you continue to be dizzy, you have trouble concentrating, you re not yourself for several weeks. what was most concerning about this study, though, was that these students reported that they didn t do as well on tests, that they drank more alcohol, that they used more marijuana. dr. samadi pointed out to me before we came out here, we already know that alcohol and marijuana leads to more falls and you get your head injured more easily, but now we re thinking that it may also be the other way around. once you hilt your head, you re more prone to alcohol, marijuana use, and poor scores on te
move. that s what s been happening here. we do look like we re going to open by 60 points but that was about half the gains we saw early this morning. the market got its bell rung this week. have a great friday. enjoy your weekend. we move on. coming up next, the showdown over syria. congressman adam shift will join us live. we ll ask him what s next for american involvement as secretary kerry heads to that region this weekend. first, the politics planner. president obama will announce he s nominated jim comey to serve as the next fbi director. he s also meeting with the privacy and civil liberty group today. we ll be right back with more daily rundown right here on msnbc. asional have constipation,