Cone of light Cone of light The cone of light, or light reflex, is a visible phenomenon which occurs upon examination of the tympanic membrane with an otoscope. Shining light on the tympanic membrane causes a cone-shaped reflection of light to appear in the anterior inferior quadrant. This corresponds to the 4 o'clock to 5 o'clock position in the right eardrum and the 7 o'clock to 8 o'clock position in the left eardrum. The apex of the cone is at the most depressed part of the tympanic membrane, known as the umbo. The absence of a cone of light does not necessarily signify
Plasma membrane H+-ATPase Plasma membrane H+-ATPase This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides to catalyse transmembrane movement of substances. To be specific, the protein is a part of the P-type ATPase family. The systematic name of this enzyme class is ATP phosphohydrolase (-exporting). -exporting ATPase is also known as proton ATPase or more simply proton pump. Other names in common use include proton-translocating ATPase, yeast plasma membrane -ATPase, plant plasma membrane -ATPase, yeast plasma membrane ATPase, plant plasma membrane ATPase, and ATP phosphohydrolase. The yeast (Saccharomyces cerevisiae) enzyme is encoded by the gene Pma1 and hence