| cortex [`kȯr´teks] ANATOMY The outer portion of an organ or structure, such as of the brain and adrenal glands. BOTANY A primary tissue in roots and stems of vascular plants that extends inward from the epidermis to the phloem. CYTOLOGY A peripheral layer in many cells that includes the plasma membrane and associated cytoskeletal and extracellular components. INVERTEBRATE ZOOLOGY The peripheral layer of certain protozoans. |