The hormone epinephrine binds to ß adrenergic receptors on smooth muscle cells of the bronchioles, causing them to dilate (incre
ase in diameter). Thyroid hormone is essential for the synthesis of ß adrenergic receptors; therefore, in the absence of thyroid hormone, epinephrine cannot trigger bronchodilation. This concept if known as __________.
In biology, a permissive effect is defined as the effect that one hormone has enabling that a second hormone to exert its biological activity. Thyroid hormone has a permissive effect on the hormone epinephrine, by synthesizing ß adrenergic receptors, it enables the hormone epinephrine binds to them and cause the cells of the bronchioles to dilate.
Only some of the equator gets to experience day and night. When Uranus revolves around the Sun, one part gets light and day while the other gets night and darkness. So it changes because one time you can be looking and its day. Then you will look again and it will be night since Uranus moved around the Sun.
