Often, familiar and seemingly obvious things require explanation if you think about them. How many have wondered why the ears are located on the sides of the head, and not on the crown, for example? Perhaps it would be fun to turn them in the direction of the sound source, and it would look pretty. However, nature is wise, it is such a location of a person’s ears that is provided for it not at all to make it more convenient for us to wear hats or symmetrically arrange jewelry. So why are the ears on the sides of the head?
Briefly about the head and its structure
The head is the part of the human body attached to the body by the neck, with the help of which it is fixed in a certain position. In the head is the brain and the main senses, and its front part is called the face.
Depending on the angle from which the head is examined, the following zones are distinguished in it:
- from above: fronto-parietal, temech, parieto-occipital;
- side: temporal, ear, cheek;
- back: nape;
- front: forehead, eyebrows, with eyebrows located on them, nose, mouth, chin.
The design of the human head is such that all its lateral parts are paired, and such important components as the eyes and eyebrows are duplicated on the front area.
What are ears, what are they for?
Ears - a paired organ that performs two important functions - it is both the auditory and vestibular apparatus.
In addition to the fact that they perceive sound signals, it is this function that explains why the ears are located on the sides of the head. This body is the apparatus responsible for the ability to maintain balance and position in space.
If we give a generalized description of the zones of the head, then it should highlight the brain and facial parts. They are distinguished by a line that can be conditionally drawn along the upper edge of the orbits and zygomatic bones, zygomatic arches to the external auditory meatus.
The ears are located opposite the temporal lobes of the brain of the head.
How are human ears
What is commonly called the ear consists of three sections - internal, secondary and external. Each of them is called the ear and is characterized by the corresponding adjective depending on its location.
The outer ear includes the cartilaginous auricle (its lobe differs from the rest in that it contains adipose tissue under the skin), leading to the auditory tube, which ends with the eardrum, a thin and very sensitive membrane.
The middle is deeper and is located in the temporal bone. It consists of a cavity in which air is contained and a complex device of small bones - a malleus, anvil and a stirrup. The middle ear is connected to the nasopharynx by the ear canal, known as the Eustachian tube.
The inner ear is closer than the rest to the brain. This department is a complex combination of cavities and channels connecting into a maze. It includes sensitive formations characteristic only for this organ: tubules, called semicircular tubules, responsible for the work of the vestibular apparatus, and the cochlea - filled with a fluid that performs an auditory function in the inner ear.
Parts of the labyrinth are composed of bone tissue and are duplicated by the same membranous tissues located inside them.
Also, a feature of the structure of the inner ear is the presence of two sacs of the vestibule entering the vestibular apparatus.
Ear coordination function
The vestibular apparatus is responsible for coordination in space. Violations in his work also lead to the disappearance of the sensitivity of human skin.
With every change in the position of the head, an impact on the receptors of the vestibular apparatus. They are irritated and the brain, by a signal unconscious by a person, makes the muscles of the body react, adapting to the situation.
The main components of the vestibular apparatus are sensitive cilia and otolith crystals. The semicircular canals of the middle ear are filled with endolymph - a fluid that acts on the otoliths immersed in it, causing their displacement. Such changes irritate the ciliated cells, and they transmit signals about this to the brain.
Ear as an organ of hearing
It is this function that explains why the ears are located on the sides of a person’s head. Auditory function is distributed between all three parts of the ear:
- the auricle, which is the outer part, picks up and collects sound vibrations in space;
- sound vibrations through the ear canal reach the eardrum, causing it to vibrate;
- the membrane transfers sound to the next - middle section;
- along the auditory ossicles located in it - a hammer, anvil and stapes, the sound enters the oval window of the inner ear;
- through the oval window, the vibrations reach the ciliated cells that transmit signals for processing to the brain.
Binar effect and its importance
The name of this phenomenon is derived from two Latin words - bini - "couple", and auris - "ear". He explains the ability of people and animals to recognize which side of the sound source is from them.
This happens due to the distance between the ears - it determines the difference in time with which the sound signal reaches each of them. It is this feature that explains why the ears are located on the sides of the head.
Sources of low frequencies are determined by a person more accurately and simply. For a correct perception of high sounds, the difference in the strength of their impact on the left and right hearing organs is more important.
Finding and understanding the height of the sound source is more difficult. For this purpose, most animals have to change the position of the ears, and people - the head as a whole.
The complexity and versatility of the human brain explains the immobility of the ears and this arrangement - why they are not on the top of the head, like many animals, but on the sides. It is the presence of the ability to perceive such complex information that provides this difference.
Animals, which also use sound information for orientation in space, are basically unable to process signals entering their brain in this way. Therefore, nature has endowed them with the ability to unfold the external part of their hearing organ in relation to the source of sounds.