Norepinephrine is released from sympathetic nerves, causing the heart rate to increase to higher values.
Norepinephrine is a neurotransmitter (i.e., a chemical messenger) which is well known for sending information to the brain in order to increase alertness during some particular situation and also serve to constrict blood vessels.
In conclusion, norepinephrine is released from sympathetic nerves, causing the heart rate to increase to higher values.
Learn more about Norepinephrine here:
https://brainly.com/question/13753173
#SPJ1