The Effects of the Autonomic Nervous System on Organ Systems

Sympathetic Parasympathetic Organ Target Actiona Receptorb Actiona Receptorb Eye Iris Radial muscle Contracts α1 — — Circular muscle — — Contracts M3 Ciliary muscle [Relaxes] β Contracts M3 Heart Sinoatrial node Accelerates β1, β2 Decelerates M2 Ectopic pacemakers Accelerates β1, β2 — — Contractility Increases β1, β2 Decreases (atria) [M2] Blood vessels Skin, splanchnic vessels […]