They have the same private parts like for males and females but, when it comes to females, dogs have more breasts than human females because when female dogs give birth, they give birth to more than just 2 puppies.
nothing bcause the heart pump model is the representation of the human heart
in case you don't know how:
you can set your tumblr private by going to "settings" below "customize appearance" from your dashboard. scroll down to the bottom and tick the box where it says "password protect this blog"