What are the functions performed by histamine in the body?

(N/A) Histamine is a potent vasodilator. It performs various functions in the body:
$(i)$ It contracts muscles in the gut and bronchi.
$(ii)$ It relaxes other muscles,such as those in the walls of blood vessels.
$(iii)$ It is responsible for congestion in the nose associated with common cold and allergies.
$(iv)$ It stimulates the release of pepsin and $HCl$ in the stomach.