Cilia are slender, microscopic, hair-like structures or organelles that extend from the surface of nearly all mammalian cells (multiple or single).ource: Amelia Shoemark. ' Motile ' (or moving) cilia are found in the lungs, respiratory tract and middle ear. These cilia have a rhythmic waving or beating motion (see right). They work, for instance, to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation.
Share. The visible light spectrum is the section of the electromagnetic radiation spectrum that is visible to the human eye. It ranges in wavelength from approximately 400 nm (4 x 10 -7 m) to 700 nm (7 x 10 -7 m). It is also known as the optical spectrum of light. By Andrew Zimmerman Jones.
Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum. Normally when we use the term light, we are referring to a type of electromagnetic wave that stimulates the retina of our eyes. In this sense, we are referring to visible light, a small spectrum from the enormous range of frequencies of electromagnetic radiation. This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm.