How is it that norepinephrine (NE) can inhibit smooth muscle action in airways, yet stimulate contractions in smooth muscles everywhere else in the body?
What will be an ideal response?
Airway passages have smooth muscle cells that are unique in that they have two receptor sites on their outer membrane. One receptor site accepts ACh as the neurotransmitter. When excited it causes the smooth muscle to contract. The second site accepts NE and the inhibitory effect is that the ACh dilates the airway.
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Which of the statements below is an incorrect or false statement?
A) Blood typing for the Kell, Lewis, and Duffy factors is always done before a blood transfusion. B) When a transfusion reaction occurs, the oxygen-carrying capacity of the transfused blood cells is disrupted and the clumping of RBCs in small vessels hinders blood flow to tissues beyond those points. C) Transfusion of incompatible blood can be fatal. D) Unique to the ABO blood group is the presence in the plasma of preformed antibodies.
The neocortex contains which of the following cells?
A) Purkinje and stellate cells B) Pyramidal and Purkinje cells C) Pyramidal and stellate cells D) Pyramidal, stellate, and Purkinje cells
Which of the following belong to the pulmonary circuit?
A. Pulmonary arteries and venae cavae B. Venae cavae and pulmonary veins C. Pulmonary arteries and pulmonary veins D. Aorta and venae cavae E. Aorta and pulmonary veins
The heartbeat is initiated by the cardiac muscle fibers of the ________ node.
Fill in the blank(s) with the appropriate word(s).