Alpha vs Beta Receptors
Are you familiar with the fight-or-flight syndrome? Everyone experiences it. It is our physiological reaction towards a stressful or terrifying experience. Doesn’t it make you wonder how we are able to respond in stressful situations? This fight-or-flight syndrome is regulated by our body’s adrenergic receptors. Adrenergic receptors are a type of protein which are sensitive to our body’s neurotransmitters: norepinephrine and epinephrine. Adrenergic receptors help regulate our responses in certain stimulators. These receptors have two main types: alpha receptors and beta receptors.
We can locate the alpha receptors at the postsynaptic area of our organs’ sympathetic neuroeffector junctions. Alpha receptors have two main types: alpha 1 and alpha 2. These alpha receptors play very important roles. Generally, the alpha receptors contribute large effects on our body’s systems. With regards to our vascular, smooth muscles, alpha receptors can constrict the vessels of our skin and skeletal muscles. Aside from that, alpha receptors are also responsible in the splanchnic vessel constriction. Since it mediates vessel constriction, it can help regulate our blood pressure.
Alpha receptors also control the myenteric plexus inhibition of our gastrointestinal system. As for our genitourinary system, it regulates the uterine contractions of pregnant women. It is also one of the factors that regulates the penis and seminal vesicle ejaculations of men. As for our skin, alpha receptors regulate our pilomotor smooth muscle contractions and apocrine gland contractions. With regards to our metabolic processes, alpha receptors are responsible for gluconeogenesis and glycogenolysis. In other words, alpha receptors serve as the body’s mediators in the stimulation of several effector cells.
Like the alpha receptors, beta receptors are located postsynaptically at our organs’ sympathetic neuroeffector junctions. Specifically, beta receptors are found under the smooth, involuntary muscles which include our heart, airways, blood vessels, uterus, and even fatty tissues. If the alpha receptors are for the stimulation of effector cells, the beta receptors are for the relaxation of effector cells. There are three main types of beta receptors: beta 1, beta 2, and beta 3. When beta receptors are activated, there will be muscle relaxation. However, when it comes to our heart, beta receptors stimulate it to beat faster. If alpha receptors make the uterus of pregnant women contract, beta receptors make the uterus’ surrounding blood vessels dilate, and they widen the airways; hence relaxing the uterine wall.
To top it off, beta receptors act the opposite way of what alpha receptors do. Alpha receptors can cause stimulation and constriction; whereas beta receptors can cause relaxation and dilatation. These body processes become our local responses to particular stressors when we are faced with the fight-and-flight phenomenon.
Summary:
-
Adrenergic receptors have two main types, namely, alpha and beta receptors. Both of these receptors help regulate our fight-and-flight response when we are exposed to certain stressors.
-
Alpha receptors and beta receptors are both located postsynaptically at the sympathetic junctions of several organs. You can find these receptors in the heart, blood vessels, airways, uterus, fatty tissues, and many other areas.
-
There are two main types of alpha receptors: alpha 1 and alpha 2. There are three main types of beta receptors: beta 1, beta 2, and beta 3.
-
Alpha receptors are mostly involved in the stimulation of effector cells and constriction of blood vessels. On the other hand, beta receptors are mostly involved in the relaxation of effector cells and dilatation of blood vessels.
-
Though beta receptors regulate our body’s relaxation functions, when the heart organ is involved, they make our heart beat faster and more forcefully.