The organ of hearing performs a function that is of great importance for the full functioning of a person. Therefore, it makes sense to study its structure in more detail.
Anatomy of the ears
The anatomical structure of the ears, as well as their components, has a significant impact on the quality of hearing. Human speech directly depends on the full-fledged work of this function. Therefore, the he althier the ear, the easier it is for a person to carry out the process of life. It is these features that determine the fact that the correct anatomy of the ear is of great importance.
Initially, consider the structure of the organ of hearing should start with the auricle, which is the first to catch the eye of those who are not experienced in the subject of human anatomy. It is located between the mastoid process on the back side and the temporal mandibular joint in front. It is thanks to the auricle that the perception of sounds by a person is optimal. In addition, it is this part of the ear that has an important cosmetic value.
As the basis of the auricle, you can define a plate of cartilage, the thickness of which does not exceed 1 mm. On both sides it is covered with skin and perichondrium. The anatomy of the ear also points to the fact that the only part of the shell devoid of a cartilaginous framework islobe. It consists of adipose tissue covered by the skin. The auricle has a convex inner part and a concave outer part, the skin of which is tightly fused with the perichondrium. Speaking about the inside of the shell, it is worth noting that in this area the connective tissue is much more developed.
The auricle is attached to the zygomatic, mastoid process and scales of the temporal bone through muscles and ligaments.
Anatomy of the outer ear
The external auditory canal can be defined as a natural extension of the shell cavity. Its length in an adult is approximately 2.5 cm. At the same time, the diameter can vary from 0.7 to 0.9 cm. This part of the ear has the shape of an epileptic or rounded lumen. The outer part of the ear canal can be divided into two main sections: the outer membranous-cartilaginous and the inner bony. The latter goes all the way to the tympanic membrane, which, in turn, delimits the middle and outer ear.
It is worth noting the fact that two-thirds of the length of the external auditory canal is occupied by the membranous-cartilaginous region. As for the bone department, he gets only a third of it. The basis of the membranous-cartilaginous section is the continuation of the cartilage of the auricle, which has the appearance of a groove open at the back. Its cartilaginous framework is interrupted by vertical Santorini fissures. They are covered with fibrous tissue. The border of the auditory canal and the parotid salivary gland is located exactly in the place where these slots are located. This fact explains the possibility of the development of the disease,appeared in the outer ear, in the region of the parotid gland. It should be understood that this disease can also spread in the reverse order.
Those who are interested in information within the framework of the topic "ear anatomy" should pay attention to the fact that the membranous-cartilaginous section is connected to the bone part of the external auditory canal through fibrous tissue. The narrowest part can be found in the middle of this department. It is called the isthmus.
Within the membranous-cartilaginous section, the skin contains sulfur and sebaceous glands, as well as hair. It is from the secretion of these glands, as well as the scales of the epidermis that has been torn away, that earwax is formed.
The walls of the external auditory canal
Anatomy of the ears includes information about the various walls that are located in the external passage:
- Upper bone wall. If a fracture occurs in this part of the skull, then its consequence may be liquorrhea and bleeding from the ear canal.
- Front wall. It is located on the border with the temporomandibular joint. The transmission of movements of the jaw itself goes to the membranous-cartilaginous part of the external passage. Sharp painful sensations may accompany the chewing process if there are inflammatory processes in the anterior wall area.
- Anatomy of the human ear concerns the study of the posterior wall of the external auditory canal, which separates the latter from the mastoid cells. At the base of this wall is the facial nerve.
- Lower wall. Thispart of the external passage delimits it from the salivary parotid gland. Compared to the top, it is 4-5 mm longer.
Innervation and blood supply to the hearing organs
These functions must be paid attention without fail to those who study the structure of the human ear. The anatomy of the organ of hearing includes detailed information about its innervation, which is carried out through the trigeminal nerve, the ear branch of the vagus nerve, and the cervical plexus. At the same time, it is the posterior auricular nerve that provides nerve supply to the rudimentary muscles of the auricle, although their functional role can be defined as rather low.
On the topic of blood supply, it is worth noting that the blood supply is provided from the external carotid artery system.
The blood supply directly to the auricle itself is carried out using the superficial temporal and posterior auricular arteries. It is this group of vessels, together with a branch of the maxillary and posterior auricular arteries, that provide blood flow in the deep sections of the ear and the tympanic membrane in particular.
The cartilage receives its nourishment from the vessels located in the perichondrium.
Within the framework of such a topic as "Anatomy and Physiology of the Ear", it is worth considering the process of venous outflow in this part of the body and the movement of lymph. Venous blood leaves the ear through the posterior auricular and posterior-mandibular vein.
As for the lymph, its outflow from the outer ear is carried out through nodes that are in the mastoid process in front of the tragus, as well as under the lower wall of the auditoryouter passage.
Eardrum
This part of the hearing organ performs the function of separating the outer and middle ear. In fact, we are talking about a translucent fibrous plate, which is strong enough and resembles an oval shape.
Without this plate, the ear will not be able to fully function. Anatomy reveals the structure of the tympanic membrane in sufficient detail: its size is approximately 10 mm, while its width is 8-9 mm. An interesting fact is that in children this part of the hearing organ is almost the same as in adults. The only difference comes down to its shape - at an early age it is rounded and noticeably thicker. If we take the axis of the external auditory canal as a guideline, then the tympanic membrane is located obliquely with respect to it, at an acute angle (approximately 30 °).
It is worth noting that this plate is located in the groove of the fibrocartilaginous tympanic ring. Under the influence of sound waves, the eardrum begins to tremble and transmit vibrations to the middle ear.
Tympanic cavity
Clinical anatomy of the middle ear includes information about its structure and functions. This part of the organ of hearing includes the tympanic cavity, as well as the auditory tube with a system of air cells. The cavity itself is a slit-like space in which 6 walls can be distinguished.
Moreover, there are three ear bones in the middle ear - anvil, hammer and stirrup. They are connected with small joints. Whereinthe malleus is located in close proximity to the tympanic membrane. It is he who is responsible for the perception of sound waves transmitted by the membrane, under the influence of which the hammer begins to tremble. Subsequently, the vibration is transmitted to the anvil and stirrup, and then the inner ear reacts to it. This is the anatomy of the human ears in their middle part.
How the inner ear works
This part of the organ of hearing is located in the temporal bone and looks like a labyrinth. In this part, the received sound vibrations are converted into electrical impulses that are sent to the brain. Only after the complete completion of this process is a person able to respond to sound.
It is important to pay attention to the fact that the human inner ear contains semicircular canals. This is relevant information for those who study the structure of the human ear. The anatomy of this part of the organ of hearing has the form of three tubes that are curved in the form of an arc. They are located in three planes. Due to the pathology of this part of the ear, disturbances in the functioning of the vestibular apparatus are possible.
Anatomy of sound production
When sound energy enters the inner ear, it is converted into impulses. At the same time, due to the structural features of the ear, the sound wave propagates very quickly. The consequence of this process is the occurrence of hydrostatic pressure, which contributes to the shift of the cover plate. As a result, the stereocilia of the hair cells are deformed, which, having come into a state of excitation, with the help of sensoryneurons transmit information.
Conclusion
It is easy to see that the structure of the human ear is quite complex. For this reason, it is important to ensure that the hearing organ remains he althy and to prevent the development of diseases found in this area. Otherwise, you may encounter such a problem as a violation of sound perception. To do this, at the first symptoms, even if they are minor, it is recommended to visit a highly qualified doctor.
