Question

What is important about beta 1 adrenergic receptors of the sympathetic nervous system? A) They are primarily found in smooth muscles, regulating involuntary movements. B) They are responsible for increasing heart rate and the force of heart contractions. C) They control pupil dilation and are crucial for vision in low light conditions. D) They are involved in the regulation of blood glucose levels and insulin production.

Answer 1

Beta 1 adrenergic receptors play a key role in the sympathetic nervous system by increasing heart rate and strength of contractions in response to stress (Option B).

Step-by-step explanation:

The important role of beta 1 adrenergic receptors in the sympathetic nervous system is to increase heart rate and the force of heart contractions when stimulated by agonists such as adrenaline or noradrenaline. These receptors are coupled to Gs proteins, which activate a signaling cascade that results in increased intracellular cAMP levels.

The rise in cAMP ultimately enhances cardiac muscle contraction, thus elevating heart rate and strength of the contractions, which is essential in stress responses or fight-or-flight situations. Hence, B is the correct option.