Blood is supplied to the brain by the:

Failure to obtain blood because the needle was not inserted deeply enough can be remedied by ________

a. advancing the needle slightly forward b. withdrawing the needle and trying again with a thinner gauge needle c. withdrawing the needle and trying again with a thicker gauge needle d. withdrawing the needle and reinserting it

The AV node has an intrinsic rate of self excitation, which is ______ beats per minute

A) 20 to 40 B) 40 to 60 C) 60 to 100 D) 80 to 100