nor epinephrine stimulate B1 adrenergic receptor and alpha adrenergic receptor.. increase contractility and heart rate .vasoconstriction and increase blood pressure

nor epinephrine stimulate B1 adrenergic receptor and alpha adrenergic receptor?

• A- increase contractility and heart rate
• B- vasoconstriction and increase blood pressure
• C- a+b***
• D- non.

The answer is (C).

Norepinephrine stimulates both alpha and beta adrenergic receptors. Alpha adrenergic receptors are found in blood vessels and smooth muscle, while beta adrenergic receptors are found in the heart, lungs, and other tissues. When norepinephrine binds to alpha adrenergic receptors, it causes vasoconstriction, which is the narrowing of blood vessels. This increases blood pressure. When norepinephrine binds to beta adrenergic receptors, it increases the heart rate and contractility, which is the force of the heart's contraction. It also dilates the bronchioles, making it easier to breathe.

Therefore, norepinephrine stimulation of both alpha and beta adrenergic receptors results in increase contractility and heart rate, vasoconstriction and increase blood pressure.

The other options are incorrect:

• Option (A) is only partially correct, as norepinephrine also stimulates alpha adrenergic receptors.
• Option (B) is also only partially correct, as norepinephrine also stimulates beta adrenergic receptors.
• Option (D) is incorrect, as norepinephrine does stimulate both alpha and beta adrenergic receptors.