An access system, comprising: an access device configured for positioning in an opening in tissue, the access device including a first body defining a first passageway therethrough, a first annular proximally-oriented surface towards a proximal end thereof, and a first annular distally-oriented surface towards a distal end thereof; and a removable seal assembly configured for releasable engagement within the first passageway of the access device, the removable seal assembly including: a second body including a proximal portion, a distal portion, and a second passageway extending longitudinally therethrough, wherein the proximal portion defines a second annular distally-oriented surface and wherein the distal portion defines a second annular proximally-oriented surface, wherein the second body is configured for positioning within the first passageway of the first body such that the second annular distally-oriented surface is engaged with the first annular proximally-oriented surface and such that the second annular proximally-oriented surface is engaged with the first annular distally-oriented surface; characterized in that: the access device is a tissue retractor comprising a proximal flange extending radially-outwardly from the proximal end of the first body, wherein the proximal flange defines the first annular proximally-oriented surface; and the removable seal assembly further comprises an O-ring disposed about the second body between the second annular distally-oriented surface and the second annular proximally-oriented surface, the O-ring configured to establish a fluid tight-seal between the first and second bodies. an access device configured for positioning in an opening in tissue, the access device including a first body defining a first passageway therethrough, a first annular proximally-oriented surface towards a proximal end thereof, and a first annular distally-oriented surface towards a distal end thereof; and a removable seal assembly configured for releasable engagement within the first passageway of the access device, the removable seal assembly including: a second body including a proximal portion, a distal portion, and a second passageway extending longitudinally therethrough, wherein the proximal portion defines a second annular distally-oriented surface and wherein the distal portion defines a second annular proximally-oriented surface, wherein the second body is configured for positioning within the first passageway of the first body such that the second annular distally-oriented surface is engaged with the first annular proximally-oriented surface and such that the second annular proximally-oriented surface is engaged with the first annular distally-oriented surface; characterized in that: the access device is a tissue retractor comprising a proximal flange extending radially-outwardly from the proximal end of the first body, wherein the proximal flange defines the first annular proximally-oriented surface; and the removable seal assembly further comprises an O-ring disposed about the second body between the second annular distally-oriented surface and the second annular proximally-oriented surface, the O-ring configured to establish a fluid tight-seal between the first and second bodies. the access device is a tissue retractor comprising a proximal flange extending radially-outwardly from the proximal end of the first body, wherein the proximal flange defines the first annular proximally-oriented surface; and the removable seal assembly further comprises an O-ring disposed about the second body between the second annular distally-oriented surface and the second annular proximally-oriented surface, the O-ring configured to establish a fluid tight-seal between the first and second bodies.