Which type of injury is characterized as a blow or jolt to the head that disrupts the brain's normal function?

The type of injury characterized as a blow or jolt to the head that disrupts the brain's normal function is a concussion. A concussion is classified under the broader category of Traumatic Brain Injury (TBI), but it specifically refers to a type of mild TBI where the brain is affected temporarily due to a forceful impact.

While Traumatic Brain Injury encompasses different types of brain injuries, not all TBIs are concussions; thus, it is important to distinguish that a concussion represents the specific disruption caused by such a jolt. It is marked by symptoms such as confusion, headache, dizziness, and sometimes loss of consciousness, all of which indicate a temporary change in the brain's functionality after the trauma.

Cerebral contusions and fractures of the skull are also related to head injuries, but they involve more specific damage (contusions involve bruising of the brain, and fractures involve breakage of the skull). Therefore, the most precise answer identifying the blow or jolt described in the question is a concussion.