the special sensesare the senses that have specialized organs devoted to them:

• vision (the eye)
• hearing and balance (the ear, which includes the auditory system and vestibular system)
• smell (the nose)
• taste (the tongue)

The distinction between special and general senses is used to classify nerve fibers running to and from the central nervous system – information from special senses is carried in special somatic afferents and special visceral afferents.The classic five senses are sight, smell, hearing, taste, and touch. The organs that do these things are the eyes, nose, ears, tongue, and skin. The eyes allow us to see what is nearby, judge depth, interpret information, and see color. Noses allow us to smell particles in the air and identify dangerous chemicals.The principle function of the special sensory receptors is to detect environmental stimuli and transduce their energy into electrical impulses. These are then conveyed along sensory neurons to the central nervous system, where they are integrated and processed, and a response is produced.

Vision. Sight or vision is the capability of the eye(s) to focus and detect images of visible light on photoreceptors in the retina of each eye that generates electrical nerve impulses for varying colors, hues, and brightness.

Hearing is the process by which the ear transforms sound vibrations in the external environment into nerve impulses that are conveyed to the brain, where they are interpreted as sounds. ... Loudness is the perception of the intensity of sound—i.e., the pressure exerted by sound waves on the tympanic membrane.The human ear has three main sections, which consist of the outer ear, the middle ear, and the inner ear. Sound waves enter your outer ear and travel through your ear canal to the middle ear.The ears are organs that provide two main functions — hearing and balance — that depend on specialized receptors called hair cells.

The number of taste buds within papillae varies, with each bud containing several specialized taste cells (gustatory receptor cells) for the transduction of taste stimuli. These receptor cells release neurotransmitters when certain chemicals in ingested substances (such as food) are carried to their surface in saliva.The sense of taste is mediated by taste receptor cells which are bundled in clusters called taste buds. ... The taste receptor cells within a bud are arranged such that their tips form a small taste pore, and through this pore extend microvilli from the taste cells. The microvilli of the taste cells bear taste receptors.Scientists describe seven basic tastes: bitter, salty, sour, astringent, sweet, pungent (eg chili), and umami. There are however five basic tastes that the tongue is sensitive to: salt, sweet, bitter, sour, and umami.

Smell (Olfaction) The other special sense responsive to chemical stimuli is the sense of the smell, or olfaction. The olfactory receptor neurons are incorporated into a limited region of the nasal epithelium in the superior nasal cavity.

By the end of this course, the students should be able to know

1. Optics of vision
2. receptors and neural functions of retina
3. neurophysiology of vision
4. the sense of hearing
5. the chemical senses-taste and smell

The following books are recommended for this course; 

• Textbook of Medical Physiology, Guyton and Hall
• Review of Medical Physiology, Ganong,W.F
• Physiology Board Review Series, Costanzo, Linda S
• Medical Physiology by Jaypee

At the end of this course, written(MCQs and SEQS) and viva test shall be held which would add up to the internal assessment of the students. Before annual prof, a sendup exam will be taken.