There are three main types of volcano-composite or strato, shield and dome. Composite Volcanoes. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows. The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.
A vagal episode or vasovagal response or vasovagal attack (also called neurocardiogenic syncope) is a malaise mediated by the vagus nerve. When it leads to fainting, also known as a syncope, it is called a vasovagal syncope, which is the most common type of fainting.
Electrical stimulation of the vagus nerve, called vagus nerve stimulation (VNS), is sometimes used to treat people with epilepsy or depression. The vagus nerve is involved in one of the most common causes of fainting, called vasovagal syncope. This is an overreaction of the body to certain stimuli, like the sight of blood, which involves the stimulation of the vagus nerve. This stimulation causes a drop in blood pressure and heart rate. Less blood flows to brain, resulting in loss of consciousness.