The Beta-2 receptor is a type of protein found on the surface of certain cells in the body. It belongs to a group of proteins called adrenergic receptors, which respond to hormones like epinephrine and norepinephrine. When these hormones bind to the Beta-2 receptor, it triggers various physiological responses, such as relaxation of smooth muscles in the airways, making it important for respiratory function. These receptors play a crucial role in the body's fight-or-flight response, helping to regulate processes like heart rate and blood flow. They are also targeted by certain medications, such as bronchodilators, which are used to treat conditions like asthma by opening up the airways and improving breathing.