Hopefully someone else can pop in to go more in depth, but /u/Illegal1234x gave a good write up on the importance of Gettysburg here. This comment is more related to why it overshadowed Vicksburg, but until someone pops into the comments here, it's a good start.

Could the OP please explain what they mean by integral? If so I may be able to help.

Beyond the issues touched upon in the linked post (boon to northern morale, last chance of the south to invade, etc), I'll go into the military details in a little greater depth.

Rather obviously, Gettysburg resulted in huge casualties for Lee's army. Somewhere around 28,000 of his ~75,000 men were killed, wounded, or captured. The First and Third Corps were particularly hard hit, the former losing at least 8,172 out of 20,704 present for duty, the latter at least 7,602 of 20,779 present for duty. This was bad enough in itself, but when combined with the heavy losses suffered at Chancellorsville a month earlier, and those suffered in the fall at Bristoe Station and Mine Run, Lee's army suffered about 43,000 casualties for the year, losses the manpower-poor Confederacy could ill afford.

Beyond the shattering losses inflicted on the rank and file, Gettysburg was particularly devastating for Lee's officer corps. Just under one-third of Confederate general officers present became casualties: five were killed or mortally wounded (and a sixth was killed during the retreat), eight wounded, and three captured. This is to say nothing of the dozens of colonels, lieutenant colonels, and majors who were lost. The lack of qualified field grade and general officers would plague Lee's army for the remainder of the war.

Finally, and this may seem a small point, the Confederate artillery suffered extreme losses of gun teams during the battle. This, combined with shortages of fodder that plagued the Army of Northern Virginia for the duration of the war, crippled Lee's artillery and, consequently, his ability to wage offensive warfare.