Severely injured jockey Michael Martinez continues to show improvement after the Sunday spill at Golden Gate Fields that severed his spinal cord. On Tuesday, his lung function improved enough for him to be removed from a breathing machine and a chest tube was removed from his right side. Doctors at Highland Hospital in Oakland hope to remove the chest tube from his left side Wednesday, according to Golden Gate Fields’ track physician, Dr. David Seftel. The 24-year-old Martinez, who is paralyzed from the waist down, spoke Tuesday for the first time since the accident, answering “Michael” when asked his name after doctors lightened his sedation, said Seftel. He also asked his wife, Charlotte, if he could be released from the hospital. Get-well cards or contributions toward Martinez’s medical expenses can be sent to Michael Martinez in care of Golden Gate Fields, 1100 Eastshore Highway, Berkeley, Calif., 94710.