The hearing part called THE COCHLEA and the balance part called the VESTIBULE and THE SEMI-CIRCULAR CANALS. The inner ear consists of the: The COCHLEA – the hearing part The VESTIBULAR LABYRINTH – the balance part Details The floor of the middle ear is formed by the bulge of two big blood vessels usually covered by a plate of bone – these are the carotid artery and the jugular vein. The middle ear is normally filled with air. The incus bone attaches between the malleus bone and the stapes bone and the base of the stapes bone fills the opening into the inner ear.Īny movement of the ear drum is transmitted into the inner ear. The malleus bone attaches to the ear drum and the incus bone. In the middle ear space there are three hearing bones: The roof of the box separates the middle ear space from the brain. This nerve controls the muscles of the face. One opening is covered with the stapes bone and is called the oval window the other opening is covered with a thin membrane and is called the round window.Ī very important nerve called the facial nerve runs across the inner wall from front to back then turns downwards and runs down the back wall. On the inside wall of the box are two openings into the inner ear. The mastoid bone is the bone behind the ear which is hollow. On the back wall of the box is another opening which leads into the mastoid bone. On the front wall of the box is an opening that leads to a tube which runs down to the back of the nose. On the outside wall of the box has a large hole in it which is covered by the ear drum. The middle ear can be thought of like a box. The middle ear consists of the: The EAR DRUM, The AIR FILLED SPACE behind the ear drum = THE MIDDLE EAR The HEARING BONES (OSSICLES) Details If you put an ink dot on the ear drum and take regular photographs you will see the ink dot move from the ear drum onto the ear canal and out towards the opening of the ear canal where it sheds off and becomes mixed with the wax.
#Auditory canal function skin
There is a continual movement of the top layer of the skin cells from the centre of the ear drum to the edge of the ear drum and then out along the ear canal. It does this by a process called ‘migration’. There is no friction in the ear canal so the continually growing skin has to clear itself in a different way. The new skin cells start growing in the deepest layer of the skin and move up to the surface layer where they are rubbed off by friction.
The skin over your body is continually growing and replacing itself. You should never put anything into your ear canal. The skin over the deep part of the ear canal is very thin and easily damaged by cotton buds, hairgrips, matchsticks or any of the other things people sometimes stick into their ears. These secretions keep the ear canal acidic and protect the ear from infections. The skin over the outer part of the ear canal is thick and has hairs and glands which produce secretions that mix to form wax. The ear canal and the ear drum are covered with skin just like the skin on the outside of the body. The ear drum is fixed to part of the first hearing bone which is called the malleus. The ear drum is a thin membrane which separates the ear canal from the middle ear.
The inner two thirds of the ear canal is a bony tube facing downwards and forwards.Īt the end of the ear canal is the ear drum. The outer third is a tube of cartilage continuous with the pinna and extend upwards and backwards. The ear canal is about 2.5 cm long and is not straight but curved. This function of the pinna is less developed in humans. In many animals the pinna is important in funnelling the sound into the ear canal and can be moved towards the direction of the sound. It is made of cartilage covered with skin. The pinna is the part of the ear that everyone can see. The outer ear consists of the: The PINNA (the part you can see on the side of the head) The EAR CANAL Details