Botox and Wrinkle Reduction

How Wrinkles Formed?

There are three types of wrinkles: dynamic wrinkles, static wrinkles, and wrinkle folds with each formed by different factors. The articles will be explaining more on dynamic wrinkles as botox works well in it.

Figure 1: Release of Acetylcholine into synaptic cleft
(Image adopted from Rugged Elegance)

The dynamic wrinkles are formed by repeated contraction of muscle through facial expression. When impulse arrives at axon terminal, neurotransmitter acetylcholine is exocytosised into the synaptic cleft to attach to the receptors on the postsynaptic membrane. This generate muscle action potential and trigger muscle contraction.(Tortora G.J, Derrickson.B. 2010.) The shortening of sarcomeres and fiber during muscle contraction will then causes the skin to becomes bunch together, forming lines between the muscles. 

 

Click on the video to show how muscle contract(Adopted from youtube.com)

 

Besides, frequent muscle contraction causes the skin elastic tissue network deteriorates by deformation of the dermis and the hypodermis layers. The skin will becomes looser, loses the ability to snap back to its original state after being deformed and thus wrinkles are formed. Furthermore, as skin cells regenerate themselves at slower rate and tend to favor a specific orientation with age, frequent facial expression with muscle contraction causes wrinkles to become permanent and more pronounced.In addition, the height of the bulging of the wrinkles depends on the amplitude of the muscle contraction.(Dr. Jonathan Hoenig. 2002-2004.)

The second type static wrinkles occur from the loss of elasticity of the skin due to lifestyle and age while wrinkle folds, is caused by the loss of subcutaneous facial fat and sagging of the underlying facial structures.Folds appear when skin is deformed but disappear after removal of the deformation. Repetition of skin folding on the same site would progressively give rise to permanent wrinkles.(Nadia M.T, Prem.K,Jean L. n.d.)