Final answer:
The beta receptors are located in various tissues throughout the body and their function depends on the subtype. B₁ receptors increase heart rate and contractility, B₂ receptors dilate airways and blood vessels, and B₃ receptors regulate metabolism.
Step-by-step explanation:
The beta (B)-adrenergic receptors are a type of receptor to which epinephrine and norepinephrine bind. There are three subtypes of beta receptors: B₁, B₂, and B₃. Beta receptors are located in various tissues throughout the body, including the heart, lungs, blood vessels, and smooth muscle.
The function of beta receptors varies depending on the subtype:
- B₁ receptors are primarily found in the heart and play a role in increasing heart rate and contractility.
- B₂ receptors are mainly located in the lungs and blood vessels, and their activation leads to dilation of airways and blood vessels.
- B₃ receptors are found in fat cells and are involved in the regulation of metabolism.