At very low concentrations, epinephrine causes an artery to dilate. At higher concentrations epinephrine causes the same artery to constrict. How can these different effects be explained?

A. There are two types of receptors for epinephrine that use the same second-messenger system.
B. There are two types of epinephrine receptors with different affinities for epinephrine that use two different second-messenger systems.
C. There is one type of epinephrine receptor that uses two second-messenger systems.
D. At higher concentrations epinephrine can pass through the plasma membrane and directly stimulate contraction within the cell.


Answer: B

Anatomy & Physiology

You might also like to view...

Which ligament is not associated with the glenohumeral joint?

A. Humeral collateral ligament B. Coracoacromial ligament C. Transverse humeral ligament D. Coracohumeral ligament E. Glenohumeral ligament

Anatomy & Physiology

Which of the following are paired correctly?

A. Nociceptors-stimulated by blood pressure changes B. Thermoreceptors- stimulated by energy from light C. Baroreceptors-stimulated by damage to tissues D. Proprioceptors- stimulated by tension changes in muscles and tendons

Anatomy & Physiology

The descending colon is the first part of the large intestine.

Answer the following statement true (T) or false (F)

Anatomy & Physiology

The blood suplly of the nail bed is called the __________

Fill in the blank(s) with correct word

Anatomy & Physiology