Скачать или смотреть The special senses | Ross and Wilson Anatomy and Physiology | Audio book

The special senses are a group of five senses that have specialized organs and tissues dedicated to them, and they are located in the head. This distinguishes them from the general senses, like touch and pain, which are felt throughout the body.
Here is a description of each of the five special senses:
1. Sight (Vision)
Organ: The eye.
Description: Vision is the ability to perceive light and interpret it as images. The eye works like a camera. Light enters the eye through the cornea and passes through the pupil. The lens then focuses the light onto the retina at the back of the eye. The retina contains specialized photoreceptor cells: rods, which are highly sensitive to low light and are essential for night vision and peripheral vision; and cones, which are responsible for color vision and high-acuity detail. The signals from these cells are transmitted to the brain via the optic nerve for processing into the images we see.
2. Hearing (Audition)
Organ: The ear.
Description: Hearing is the sense of sound perception. Sound waves enter the outer ear and travel down the ear canal, causing the eardrum to vibrate. These vibrations are amplified by three tiny bones in the middle ear (malleus, incus, and stapes) and then transferred to the fluid-filled cochlea in the inner ear. Inside the cochlea, a structure called the organ of Corti contains hair cells that convert the mechanical vibrations into electrical signals. These signals are then sent to the brain via the auditory nerve to be interpreted as sound.
3. Balance (Equilibrium)
Organ: The inner ear.
Description: The sense of balance, or equilibrium, is closely linked to hearing and is managed by the vestibular system in the inner ear. This system is composed of the semicircular canals, which detect rotational movements of the head, and the otolith organs (the utricle and saccule), which sense linear acceleration and gravity. These structures are filled with fluid and hair cells that are stimulated by movement. The information is sent to the brain through the vestibulocochlear nerve, allowing the body to maintain its posture and spatial orientation.
4. Smell (Olfaction)
Organ: The nose and nasal cavity.
Description: Smell is the sense of detecting and identifying odors. The primary organ for smell is the olfactory epithelium, a patch of tissue located high in the nasal cavity. When you inhale, odorant molecules dissolve in the mucus of this tissue and bind to olfactory receptor cells. This binding action triggers an electrical signal that travels along the olfactory nerve to the brain's olfactory bulb, where the sensation of smell is processed.
5. Taste (Gustation)
Organ: The tongue.
Description: Taste is the sense of perceiving flavors. The specialized organs for taste are the taste buds, which are primarily located on the tongue, as well as on the soft palate and epiglottis. Each taste bud contains gustatory receptor cells. When food molecules dissolve in saliva, they stimulate these cells, creating a nerve impulse. The five basic tastes are sweet, sour, salty, bitter, and umami (savory). These signals are transmitted to the brain via several cranial nerves for interpretation.