Sense Organs: Types of Sensory Receptors

Eye Anatomy and Functions

• The sclera provides protection and structure to the eyeball.
• Aqueous humor is located in the anterior and posterior chambers of the eye.
• The ciliary body produces aqueous humor and helps to focus the lens.
• The conjunctiva is a thin membrane that covers the white part of the eye and the inside of the eyelids, protecting them from infection and inflammation.
• The iris controls the amount of light that enters the eye by adjusting the size of the pupil.
• The anterior chamber is located between the cornea and the iris, containing aqueous humor that nourishes the cornea.
• The choroid layer contains blood vessels that supply oxygen and nutrients to the retina.
• The main function of the cornea is to refract light and help focus it on the retina.
• The sclera does not have a function in detecting light or transmitting visual signals.

Sensory Receptors

• Mechanoreceptors are involved in detecting pressure, stretch, and specialized movement and balance.
• Thermoreceptors respond to changes in both internal and external temperature.
• Nocireceptors are stimulated by lack of oxygen, chemicals released from damaged cells, and inflammatory cells.
• Chemoreceptors detect changes in oxygen, carbon dioxide, and pH levels in the blood.
• The skin contains widely distributed general (somesthetic, somatosensory) receptors.
• Cranial nerves II, III, VII, VIII, IX, and X innervate the relatively complex sense organs responsible for vision, hearing, equilibrium, taste, and smell.
• Somatic or visceral receptors are associated with general somesthetic receptors.
• Proprioceptors are primarily associated with joints and muscles, helping to detect movement and position.
• The olfactory system is primarily associated with the sense of smell.
• Skin receptors that detect hot, cold, pressure, and pain are categorized as somesthetic receptors.