Sensory receptors are responsible for perceiving infortion, which they convert into a nerve impulse. The nerve impulse travels to the brain and produces a feeling.
Photoreceptors: they detect light stimuli and are located in the eye. Some of them respond to dim light conditions and produce black and white vision; others respond to bright light and produce colour images.
Mechanoreceptors: they are stimulated by mechanical changes such as pressure, contact or sound waves. They are several receptors in the skin, muscles and joints. Auditory receptors are included in this group.
Chemoreceptors: they respond to chemical changes. Taste and smell receptors belong to this group.
Thermoreceptors: they detect temperature changes. Some skin receptors are included in this group.
External receptors: they are located on the surface of the body and are responsible for collectiong about the external enviroment.
Internal receptors: they are located in the internal organs where they collect information about them.
-They eye is the organ where the sense of sight is located. It´s a complex structure that receives light and carries it to the areawhere the photoreceptors are located.
-They eye is formed by the ocular globe and a series of accesory organs.
Globe: spherical, hollow structure located in a cavity of the cranium known as orbit:
Regulating of light intensity: if it is too bright, it can cause injuries in photoreceptors cells, and if it is too dark, the process of sight won´t take place.
Focusing on images: in order not to see blurred images when light is reflected by a an object needs to be focused properly in the retina.
-The ears are the sensory organs located inside the cavities of the temporal bones, which are fond in areas on both sides of the head called the temple. These organs percieve 2 types of stimuli in 2 differents areas: sounds, and changes of body posture (balance):
The outer ear: this is formed by the pinna and auditory canal, which penetrates the bone and has an elastic membrane at the end called the eardrum. In this duct there are glands that secrete protective wax.
The middle ear: this is a cavity in the temporal bone that starts at the eardrum and reaches certain membranes called the oval window and the round window. It contains 3 small bones: hammer, anvil, stirrup.