like in the nervous system? if that then they are called neurotransmitters
nerve is the answer
the nerve system conducts messages trough the human body
Hormones send messages throughout the body using chemical signals. For example, adrenaline, or ephinephrine, is sent to the brain when something stressful is present, and causes a height in energy, higher pulse, perhaps sweaty hands, etc.
biology
the artery(oxygenated blood) and vein(de-oxygenated blood)
Nerves
nerve is the answer
the nerve system conducts messages trough the human body
Hrmones
I think the answer you're looking for here is nervous tissue which carries action potentials, or nervous impulses, between the tissues and are central nervous system. However, from another point of view you could also consider the cardiovascular system as carrying hormonal messages throughout the body.
Hormones send messages throughout the body using chemical signals. For example, adrenaline, or ephinephrine, is sent to the brain when something stressful is present, and causes a height in energy, higher pulse, perhaps sweaty hands, etc.
nevous tissue
biology
Biology
Biology
the artery(oxygenated blood) and vein(de-oxygenated blood)
Iron is a part of all cells and does many things in our bodies. For example, iron (as part of the protein hemoglobin) carries oxygen from our lungs throughout our bodies. Iron also helps muscles store and use oxygen.