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.
Sinus arrhythmia is a normal physiological phenomenon, most commnonly seen in young, healthy people. The heart rate varies due to reflex changes in vagal tone during the different stages of the respiratory cycle. Inspiration increases the heart rate by decreasing vagal tone. With the onset of expiration, vagal tone is restored, leading to a subsequent decrease in heart rate. The incidence of sinus arrhythmia decreases with age, presumably due to age-related decreases in carotid distensibility and baroreceptor reflex sensitivity.