A port is a harbor viewed esp. with reference to its commercial activities and facilities: a thriving port. haven is a literary word meaning refuge, although occasionally referring to a natural harbor that can be utilized by ships as a place of safety: to seek a haven in a storm. See also cherish.
The reason why bleeding gums is a big deal is because the bad bugs now have access to the whole body via the bloodstream. Yes, unfortunately, these disease causing microorganisms can and do swim into the bloodstream to access the rest of the body.
There are also other reasons for gum discoloration that cause a higher concern. First is acute necrotizing periodontal disease, also referred to as black gum disease. This black discoloration of the gums is due to dead tissue, or necrosis. This is a serious health issue, with symptoms that can also include bleeding gums, strong pain, and a foul smelling mouth. Along with improper oral care, the causes of this disease can include stress, smoking, viral infections, and HIV.