english: It has a central space of spongy erectile tissue that fills with fluid -- in this case blood -- surrounded by a wall of tissue that's rich in a stiff structural protein called collagen.
non_english: Ima centralni prostor od erektilnog, sunđerastog tkiva koji je ispunjen tečnošću -- u ovom slučaju krvlju -- a okružen je zidom tkiva bogatim čvrstim strukturnim proteinom koji zovemo kolagen.