Anatomy - we have 1 heart, 2 lungs!
Beta 1 receptors are found in the heart and if bound will cause positive ionotropic and chronotropic effects (hence, selective beta 1 receptor blockers metoprolol and atenolol)
Beta 2 receptors are found in the bronchi, when bound, will cause bronchodilation (hence, beta 2 agonists such as salbutamol)
(Beta 2 receptors are also found in the heart but 1:3 ratio compared to Beta 1 receptors. They are also found in blood vessels and when bound, cause vasodilation)
Beta 1 receptors are found in the heart and if bound will cause positive ionotropic and chronotropic effects (hence, selective beta 1 receptor blockers metoprolol and atenolol)
Beta 2 receptors are found in the bronchi, when bound, will cause bronchodilation (hence, beta 2 agonists such as salbutamol)
(Beta 2 receptors are also found in the heart but 1:3 ratio compared to Beta 1 receptors. They are also found in blood vessels and when bound, cause vasodilation)