Progesterone & Estrogen
It causes narrowing of the small blood vessels in tissues, resulting in an increase in blood pressure
vasoconstrictor
Histamine causes the dilation of the small blood vessels while constrict the large blood vessels.
When the heart beats it causes blood to flow through the blood vessels which causes them to expand. This expansion can be felt by touching the vessels that are close to the skin.
The organism not only damages the blood vessels by causing them to leak, but also causes clotting inside the vessels.
its possible.
pressure.
Suddenly angry and hypertension.
Long term alcohol use causes the blood vessels to become more fragile and prone to rupture. Alcoholics have a much higher risk of stroke, aneurysms esophageal varicies and bleeding disorders.
Blood vessels will expand to keep the bite from bleeding. This expansion of blood vessels can irritate nerves that are nearby which causes the insect bites to sting and/or itch.
the blood vessels
How about cocaine. It causes vaso-constriction of blood vessels in your body including vessels in your heart, which can result in a heart attack.