Search results
Results from the WOW.Com Content Network
A tiny person inside a sperm cell as drawn by Nicolaas Hartsoeker in 1695. Preformationism is the formerly popular theory that animals developed from miniature versions of themselves. Sperm cells were believed to contain complete preformed individuals called "animalcules". Development was therefore a matter of enlarging this into a fully formed ...
In mammals, the auditory hair cells are located within the spiral organ of Corti on the thin basilar membrane in the cochlea of the inner ear. They derive their name from the tufts of stereocilia called hair bundles that protrude from the apical surface of the cell into the fluid-filled cochlear duct.
Cross-section through the spiral organ of Corti at greater magnification, showing position of the hair cells on the basement membrane. The organ of Corti is located in the scala media of the cochlea of the inner ear between the vestibular duct and the tympanic duct and is composed of mechanosensory cells, known as hair cells. [2]
The name 'cochlea' is derived from the Latin word for snail shell, which in turn is from the Ancient Greek κοχλίας kokhlias ("snail, screw"), and from κόχλος kokhlos ("spiral shell") [4] in reference to its coiled shape; the cochlea is coiled in mammals with the exception of monotremes.
There are two types of hair cells specific to the auditory system; inner and outer hair cells. Inner hair cells are the mechanoreceptors for hearing: they transduce the vibration of sound into electrical activity in nerve fibers, which is transmitted to the brain. Outer hair cells are a motor structure.
The cranial region includes the upper part of the head while the; facial region includes the lower half of the head beginning below the ears. The forehead is referred to as the frontal region. The eyes are referred to as the orbital or ocular region. The cheeks are referred to as the buccal region. The ears are referred to as the auricle or ...
The human head consists of a fleshy outer portion, which surrounds the bony skull. The brain is enclosed within the skull. There are 22 bones in the human head. The head rests on the neck, and the seven cervical vertebrae support it. The human head typically weighs between 2.3 and 5 kilograms (5.1 and 11.0 lb) Over 98% of humans fit into this ...
In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp.The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows.