The apical or upper side, is exposed to either the outside of your body, or whatever internal cavity it's lining.

顶或，露在你身体外或它任何内腔中。

These organisms navigate their environments not through locomotion, but apical extension -- growing through the tips of their bodies.

这些生物体不是通运动而是通顶延伸来导航它们环境——通它们身体生长。

Blood vessels and nerves come from the jaw bones, and enter the center of the root through a narrow passage, called the apical foramen.

血管和神经从颌骨通一个叫做牙根孔狭窄通道进入牙根中央。

Clusters of stem cells, called apical meristems, at the tip of every stem and root continually produce the materials needed to build new body parts.

在每个茎和根，被称为根分生组织干细胞群不断地产生构建新身体位所需材料。

We also talked about how epithelial cells are polar, having both apical and basal sides, and are selectively permeable, and lastly we took a brief look at how our glandular epithelial tissue forms both out endocrine and exocrine glands.

我们还讨论了皮细胞是如何极性，具有顶和基底两侧，并且具有选择性渗透性，最后我们简要了解了我们腺皮组织如何形成内分泌腺和外分泌腺。