Angle that is smaller than a right angle (less than 90Â°). Angle formed by two lines or two perpendicular planes that measures 90Â°. Symbol denoting that a straight line meets another at a right angle. Symbol denoting that two straight lines do not remain at a constant distance from one other. Symbol denoting that two straight lines remain at a constant distance from one another.
Constriction vs. Dilation. Constriction and dilation are opposite, but related, processes in the body. Whereas dilation is an opening or widening of a structure or passageway to increase material flow, constriction leads to a decrease in material flow by closing the passage.
Vasoconstriction can occur due to medical condition or due to psychological disorder. This condition happens when the small muscles of the walls constrict causing narrowing of blood vessels. Actually this process is exactly opposite condition of vaso-dilation in which the blood vessels enlarge or open widely.