Touch Response to a mechanical stimulus The skin

Touch • Response to a mechanical stimulus. The skin is the largest sensory organ. Sensory receptors detect pressure, pain, heat, cold.

Smell • Response to a _chemical_____ stimulus. Sensory receptor cells are bathed in mucus and respond to different chemicals

Taste • Response to a _chemical_stimulus. Sensory receptors called _taste buds_ are located on the _tongue. Detect sweet, sour, salty, bitter

Vision • Response to a _light___ stimulus. • Cornea – Light first passes through the _cornea_____, a transparent, protective covering which begins _focusing___ the light. The light then enters a chamber filled with watery fluid called the _aqueous humor. • _Pupil____ - Hole that light passes through. The size of the pupil is controlled by a ring of muscles known as the _iris___. • _Lens____ - Completes focusing of the light ray. There is also a thick jellylike substance to help maintain the shape of the chamber known as the _vitreous humor_. • Retina – Nerve tissue at the back of the eyeball that converts light energy to an _electrical impulse_. Made up of two types of cells: – Rods - Cells that detect _shape & movement; are stimulated even in _dim___ light. – Cones - Cells that detect _color; provide a _sharp image; require _bright light for stimulation. • Optic Nerve - Transmits the impulse to the _brain___. • Additional Structures – Sclera - _”White of the eye”; continuation of the _cornea – Choroid - Layer of blood vessels that _nourish the eye.