Some systems require that you need a five-card suit to open 1♥ or 1♠. Standard American, Precision and the standard system in many countries in continental Europe use five-card majors.
Responder can happily give a single raise from 1♥ to 2♥ or 1♠ to 2♠ with three-card support. Opinions vary about the wisdom of making a jump raise with the necessary values and three-card support for partner’s major.
When playing five-card majors, you often have to open 1♣ or 1♦ with fewer than four cards in the suit. Responder generally strains to show a four-card major in response to 1♣ or 1♦ as otherwise the partnership might miss a 4-4 major-suit fit.