Changing levels of certain substances in the blood, such as sodium, can cause confusion. Increased heart rate...heart palpitations, which feel like your heart is racing or throbbing. To make up for the loss in pumping capacity, the heart beats faster.
The pitch plane of a pair of gears is the plane perpendicular to the axial plane and tangent to the pitch surfaces. A pitch plane in an individual gear may be any plane tangent to its pitch surface.
For diametral pitch, the # means how many teeth will fit on a pitch circle of 1 diameter. For metric module, it is the arc distance x Pi along the pitch circle from one tooth to the next. So, a 16DP gear with 32 teeth has a pitch circle of exactly 2 diameter. If you straightened out the gear, the teeth would be 1/16 x Pi apart. A 2mm metric module gear with 32 teeth has a pitch circle of exactly 64mm diameter. If you straightened this gear out, the teeth would be 2mm x Pi apart. There are a gazillion other parameters and formulas for the rest of the gear form.