Some neurons have a fatty layer covering called around their axons. this layer isn’t continuous, and the gaps are called . the action potential jumps through these gaps to the transmission. nextreset

Some neurons have a fatty layer covering called MYELIN SHEATH around their axon. This layer is not continuous and the gaps are called NODES OF RANVIER. 
Because the myelin sheath is made up of insulating fatty substances, the nodes of ranvier allow the fast transmission of electrical impulses along the axon.

Since a female is both xx chromosome and the male passes down the x chromosome, than the offspring would be female since a female is xx.