If the epidermis is such a good barrier, how can cortisone easily travel through it?

cortisone is a lipid-soluble molecule hence can pass through the epidermis

Explanation:

Our adrenaline glands secrete various hormones including cortisol (also known as hydrocortisone) and corticosterone.

They belong to a group of steroid hormone bodies known as glucocorticoids and are used in a wide range of physiological processes such as inflammation regulation.

Pharmaceutical derivatives of these natural glucocorticoids include dexamethasone, fludrocortisone, prednisone, prednisolone, triamcinolone, which differ in strength. As all glucocorticoids have a similar effect, they all fall under the common name "cortisone".

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

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