Human senses are extremely powerful. They effect perception of events, people, and situations that can impact state of mind and who they are. The sensations receive through one sense, combined with the other senses, have the greatest influences over perception. Sight, hearing, and smell are the strongest senses.
One of the most ranked important sense for humans is vision. The way vision work is very complicated. First light enters the eye through the pupil after that the light passes through the color part of the eye called the iris. If the light is very bright the light in the iris contract to make the pupil smaller to protect the eye from damage. The contraction of the muscle helps to see better in light. In dim light the muscle must relax to open the pupil wider to let in as much light as possible. In the pupil the light moves through the lens which focus light to focus on objects that are closer or farther away for the to focus on an object that is very close to the eye. The tiny muscles around the lens contract and make the lens rounder, and for far away objects the muscles work two flatten the lens.
Back regions of the retina there is a small spots called the fovea where images that pass through the lines are in a sharpest focus. The retina contains the receptor cell the is responsible for vision. Retina cells are sensitive for only a faction of spectrum of electromagnetic energy which includes light, along with other energies.
The transportation from the eye to the brain starts with the rods and cones. The rods and cones are connected to bipolar cell. They connect inter-neurons which they link up to receptor cells that is responsible for vison.
The eyes have some defecation though. Stroke victims sometimes suffer form a disorder called prosopagnia. The person who has prosopagia can not recognize faces but otherwise can see as well as a normal person. All but the most severely brain damaged are able to tell whether face in photographs are happy, sad, surprised, disgusted fearful or angry. They can also estimate age as accurately as anyone else can.
Another defect the eye has is glaucoma, that is when fluid pressure inside the eye builds up and can cause permanent damage to the optic nerve and consequent less of vision. In recent research indicates that people in the early stages of glaucoma tends their dim light vision before any permanent damage is done to the optic nerve.
Another important sense is hearing. To hear, a sound has to send sound waves. Sound waves are changes in pressure caused by molecules of air and fluid. The collide with one another and them move a part again transmitting energy at the collisions. The frequency of waves is measured in cycled per pitch of the sound. A human responds to about 20hz to 20,000hz. The sound waves hit the ear drum and causing it to vibrate. The vibrating eardrum vibrates to three bones called the hammer the anvil and the sirup. They all carry the vibrations to the inner ear. The tree bones are attached to pre-membrane called the oval window. Vibrations are transmitted to a fluid inside called cochlea. The cochlea transmits to basilar membrane. Then the sound goes to the organ of certstructure that contains the receptor cells for hearing.
Hearing is a very delicate. You can damage it by loud music, job related, or with age you can loose your hearing. It caused by the stiffening of the connective between the bones of the inner ear. If people get to that point surgery is recommend. To correct the hearing lost surgeon generally break or loosen or replace the bones ambling better transmission across the middle ear.
The last sense is smell. The sense of smell is extremely sensitive. A few molecules of a substance to reach the smell receptors are necessary to cause humans to smell an odor. Humans and mammals have two different sensory systems devoted to the sense of smell. Humans can defect among common odors. A branch called olfactory system helps us to tell the difference between the citrous scents of lemons and orange and the sour smell of spoiled milk. Mammals sense of smell used in communicating sexual, aggressive or territorial scent signals. This system that animals have are not important to humans.
The sense smell works by a complex protein produced in a nasal gland. The noise breathes in fine must of protein called odor ant bringing protein that is sprayed through a duct in the tip of the nose. The protein combined with air binds molecules that then activate the receptors for this senses located high in each nasal carry in a patten of tissue called olfactory epithelium. It is about half the size of a post-age stamp but packet with millions of receptor cells. In humans women have a better sense of smell than men.
impacts us on our perception of people events and situations.