Struggling with Shylock...and all that talk about blood

I cannot seem to keep up with all these characters in Merchant of Venice. I still struggle with Shylock as a villain and try to give him a sympathetic ear as well (this proves difficult for me despite his poor treatment). He certainly plays on the fact that he is just as human as everyone else in his famed speech in Act III Scene 1 ("Hath not a Jew eyes?") but also justifies his thirst for revenge by claiming that it is human and any Christian would do the same. Surely Shakespeare meant for readers to think twice about the Jew question but at the same time he certainly plays up the negativity towards Judaism as was popular during his time.

Throughout the play blood acts as a common recurring theme. This is very interesting to me. It appears that blood is an idea that connects people in this play. Shylock and Jessica are linked (this may be unfortunate in Jessica's mind) because, being his daughter she is Shylock's "own flesh and blood" (Act III Scene 1). In the same act, Shylock links himself to Christians by finding the common ground with the question "if you prick us do we not bleed?" The Moroccan prince claims to be as good a suitor as anyone else by offering to "prove whose blood is reddest" (Act II Scene 1). In Act I Scene 3, Shylock demands "a pound of fair flesh" from Antonio, but when time comes for Antonio to pay, Shylock is duped by Portia (dressed as a lawyer, Balthasar) who says that the "bond doth give thee here no jot of blood. The words expressly are 'a pound of flesh'." (Act IV Scene 1) Thus Antonio is saved by a technicality and his "Christian blood." All these blood ties and mentions seem to be the core life of the story. Blood runs throughout the plot forging ties between characters and situations and ultimately leads to the resolution of the play. How fascinating!