The medulla oblongata is the lower portion of the brainstem. It deals with autonomic functions. The cardiac center is the part of the medulla oblongata responsible for controlling the heart rate.
HazMat Endorsement Requirements. Below is what you can expect when applying for a Class H endorsement: You must have a valid commercial drivers license (CDL) for the state in which youâre applying. It must be valid (not currently suspended or revoked) and not checkered with serious road violations.
You May Need a CDL. You will find it necessary to have a Texas commercial driver's license, if you want to operate a Class A, B, or C commercial vehicle. Endorsements will also be needed for double/triple trailers, tanker vehicles, passenger vehicles, and vehicles placarded for hazardous materials.