Final answer:
Epithelial tissues exhibit apical-basal polarity, with different structures and functions at the apical and basal surfaces, linked by the basal lamina to the underlying connective tissue.
Step-by-step explanation:
Yes, epithelial tissues always exhibit apical-basal polarity; meaning that cell regions near the apical surface differ from those near the basal surface.
The apical surface of epithelial cells may exhibit structures like cilia, which are not found on the basal surface. In contrast, the basal side has certain organelles segregated to it and attaches to the basal lamina, which in turn attaches to a reticular lamina forming a basement membrane that separates the epithelium from underlying connective tissue.
Furthermore, the polarity of epithelial tissues is critical as it leads to different functional regions: the apical surface often participates in protection, secretion, or the absorption of substances, whereas the basal surface typically interacts with the underlying bodily structures. Additionally, epithelial cells show characteristics like being highly cellular with minimal extracellular material and having a capacity for rapid regeneration, which is important for maintaining barriers such as those found in the airways and digestive tracts.