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Pressure to Rupture an Eardrum The Physics Factbook Edited by Glenn Elert -- Written by his students An educational, Fair Use website topic index | author index | special index The eardrum is a thin, oval layer located deep in the ear canal. It is also known as the tympanic membrane. It helps protect the middle and the inner ear. The eardrum receives vibrations from the outer ear and transmits them to the middle ear. Because it is so thin, the eardrum can be ruptured or punctured. Pressure is one factor that can damage the eardrum. If the air pressure in the ear canal from the outside and the air pressure in the middle air are unequal, the eardrum can be damaged. Pressure is the force per unit area applied on a surface in the perpendicular direction. The equation for determining pressure is P = F/A Where: P is pressure F is force and A is area Pressure is measured in pascals. A pascal is equal to a newton per square meter. The eustachian tube connects the middle air and the nose. It helps to maintain equal pressure on the both sides of the eardrum. When the pressure outside changes suddenly, air moves through the tube to equalize the pressure in the middle ear. If the Eustachian tube is blocked or partially blocked because of an infection, cold, allergy or scarring, air can no longer enter or leave the ear. The pressure difference may cause the eardrum to rupture and bleed. If the difference is great, the entrance to the middle ear will rupture. The tympanic membrane can only withstand a limited amount of pressure. The eardrum may rupture at pressures above 35,000 pascals or 35 kPa. Shemika White -- 2007 A ruptured or perforated eardrum is an opening in the tympanic membrane (eardrum). The ear is a sense organ that is used to detect sounds. The ear is used to receive sound and to establish a sense of balance. Like any other organ, the ear is susceptible to injury and is vital to the owner’s survival. The ear is separated into three main parts; the outer ear, middle ear, and the inner ear. The outer ear consists of the pinna, ear canal, and the surface of the ear drum. The pinna (auricle) is very easy to damage because of the lack of blood supply to the area due to it being mostly cartilage. Meanwhile, the middle ear has three ear bones: malleus (hammer), incus (anvil), and stapes (stirrup). In addition, the inner ear contains two parts: the cochlea which is an organ used for hearing and an organ that senses gravity and motion which is called the vestibular apparatus. The general frequency range in which humans can hear is 20 Hz to 20 kHz. There are many causes for rupturing an eardrum and they include but are not limited to: blasts, constant loud noises, and pressure from swimming deep. A typical overpressure required to guarantee a rupture to an eardrum would be about 100,000 pascals or 100 kPa. Since eardrum rupture tests cannot be performed on humans, the numbers for blast induced eardrum rupture have been almost theoretical and are more available for animals. The numbers used to predict injury were discovered by clinical experiences, rather than from experiments. William Wong -- 2007
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Autor: Dr. Oz Uho je vrlo osjetljiv organ za ronioca (apneist). Primarni problem u dišnim kanalima ili u samom uhu znači nemogućnost ronjenja na dah. Stoga je vrlo važno prema ovim dijelovima tijela odnositi se s velikim oprezom. To znači da morate razumjeti kako određeni organ funkcionira i najvažnije, kako ih učiniti otpornima kako bi uvijek bili u dobrom stanju. Uho je podijeljeno u tri dijela: vanjsko, srednje i unutarnje uho. Vanjsko uho čine uška i zvukovod. Oni dovode zvuk do srednjeg uha. U zvukovodu se nalaze sićušne dlačice koje štite uho od vanjskih utjecaja. Vanjski zvukovod dugačak je 3 centimetra. Uška hvata i skuplja zvukove iz okoliša i usmjerava zvučne valove prema zvukovodu. Srednje uho - na početku srednjeg uha nalazi se bubnjić koji služi kao opna, zatim 3 sićušne koščice (čekić, nakovanj i stremen) i eustahijeva cijev koja izjednačava tlak u srednjem uhu (pri ronjenju). Pločica stremena zatvara ovalni prozorčić što je i granica između srednjeg i unutarnjeg uha. Srednje uho se opisuje oblikom kao tijelo sa šest stranica, tj. dio organa koji je omeđen sa šest stijenki (lateralna, medijalna, gornja, donja, prednja i stražnja). Unutarnje uho se sastoji od koštanog i membranskog dijela. Koštani labirint čine tri dijela: pužnica, predvorje i polukružni kanalići. Pužnica ima oblik puževe kućice i savijena je dva i pol puta. Uzduž pužnice ide spiralna pločica koja njezin koštani kanal nepotpuno dijeli na dva kanala. Donji kanal na donjem kraju, kroz okrugli prozorčić, u dodiru je s bubnjištem. Kanali su međusobno spojeni na gornjem kraju, na vrhu pužnice otvorom helikotrema. Membranski labirint nalazi se unutar koštanoga. U polukružnom kanalima nalaze se tri polukružne membranske cijevi, a uzduž pužnice nalazi se (lat.) ducutus cochlearis. Svi dijelovi membranskog labirinta međusobno su spojeni, a ispunjava ih endolimfa. Vrlo je važno da je srednje uho uvijek čisto. Prema anatomskom izgledu uho je najizloženije i najosjetljivije na efekt pritiska (tlak) za vrijeme urona. Kada je uho direktno izloženo razlikama u temperaturi i tlaku, za vrijeme podvodne aktivnosti možete naučiti lekciju, da osim oštre boli uho možete i trajno oštetiti. Naravno zato jeste ovdje da u jednom od članaka naučite to preventirati.