I am not one who candy-coats reality. You need to honestly assess why you have been unable to earn 'A' or 'B' grades in your anatomy coursework.
If your performance in these courses was the result of life's distractions (e.g., grieving the death of a loved one, working too many hours, abusive situation), go ahead and retake them. Strive for better grades.
If your performance was due partly to poor study skills, buckle down and adopt better study skills before retaking. Figure out what type of learner you are. Conjure up a study plan that meshes with your personal learning style.
Meanwhile, if your performance was due to difficulty understanding the material, I do not see the point of retaking these courses. Some Pollyannish respondents will say, "Never give up!"
However, some people have the academic horsepower to pull it off and others simply do not. Being passionate alone will not cut it in a course that expects students to know the structure of a nephron and/or describe the phases of the cardiac cycle from start to end.
Only you know which category you fall into. Good luck to you!