Human Ear

30 flashcards · Biology · by lakesare

1. Name 3 portions of the ear.

   Outer ear Middle ear Inner ear

2. Name 2 parts of the outer ear.

   pinna auditory canal

3. Where is pinna?

   [1] The visible part is called the auricle, also known as the pinna, especially in other animals. It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue.

4. Where is auditory canal?

   [2] A 3cm long tube

5. What is the primary purpose of pinna/auricle?

   Deduce the direction of sound. Amplifies sounds in the frequency range of human speech The auricle's functions are to collect sound and transform it into directional and other information. The auricle collects sound and, like a funnel, amplifies the sound and directs it to the auditory canal. The filtering effect of the human pinna preferentially selects sounds in the frequency range of human speech. The fennec fox uses its distinctive oversized pinnae to radiate excess heat and to amplify the…

6. What frequencies does pinna preferentially amplify?

   Frequencies around 3kHz. One consequence of the configuration of the outer ear is selectively to boost the sound pressure 30- to 100-fold for frequencies around 3 kHz. This amplification makes humans most sensitive to frequencies in this range — and also explains why they are particularly prone to acoustical injury and hearing loss near this frequency. Most human speech sounds are also distributed in the bandwidth around 3 kHz.

7. What's at the end of auditory canal?

   Eardrum (Tympanic membrane)

8. What is the purpose of earwax (cerumen)?

   protects the skin of the human ear canal, assists in cleaning and lubrication, and provides protection against bacteria, fungi, insects, and water. Earwax consists of dead skin cells, hair, and the secretions of cerumen by the ceruminous and sebaceous glands of the outer ear canal.

9. What's the function of the eardrum?

   To transmit sound from the air to the ossicles inside the middle ear.

10. What is this?

    Eardrum perforation. The oval perforation in this left tympanic membrane was the result of a slap on the ear. Flying with a severe cold can also cause perforation due to changes in air pressure and blocked eustachian tubes resulting from the cold. This is especially true on landing. Perforated eardrums rarely require medical intervention, as between 80 and 95 percent of ruptures recover completely within two to four weeks :-)

11. Name 3 parts of the middle ear.

    Ossicles - 3 small bones, known as the malleus or hammer, incus or anvil and stapes or stirrup. Eustachian tube (or auditory tube) - connects tympanic cavity with the nasal cavity Tympanic cavity

12. What is the function of the middle ear?

    Transfer acoustic energy from compression waves in air to fluid–membrane waves within the cochlea.

13. What is archaic for drum?

    Tympanum :-) That's why eardrum is also called the tympanic membrane. Early 17th century via Latin from Greek tumpanon ‘drum’, based on tuptein ‘to strike’.

14. What is [13], [12], and [11]?

    Ossicles.

15. What is [4]?

    Tympanic cavity

16. What is [3], and what's [11]?

    [3] Eardrum (tympanic membrane) [11] Oval window

17. What are relative sizes of tympanic membrane VS oval window?

    The oval window has only approximately 1/18 the area of the tympanic membrane and thus produces a higher pressure.

18. What is middle-ear-muscles (MEM) reflex?

    The acoustic reflex (also known as middle-ear-muscles (MEM) reflex) is an involuntary muscle contraction that occurs in the middle ear in response to high-intensity sound stimuli or when the person starts to vocalize.

19. Name 2 parts of the inner ear.

    cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. vestibular system, dedicated to balance Mid 16th century (used to denote spiral objects): from Latin, ‘snail shell or screw’, from Greek kokhlias. The current sense dates from the late 17th century.

20. Where is cochlea?

    [7]

21. What's [11] and [5]?

    [11] - oval window [5] - round window The cochlea is filled with perilymph fluid which is essentially incompressible; the action of the stapes on the oval window causes the fluid to move round the cochlea all the way to the circular window, which can move to compensate for the oval window’s movement.

22. What portions of cochlea respond to what frequencies?

23. What is this?

    It's the back of our nose, and to the left is the eustachian tube :-)

24. Difference in pressure in what and what causes the clogged ear?

    Between tympanic cavity and the outside.

25. What does yawning do to the clogged ear?

    When we yawn, eustachian tube opens, equalizing the pressure between the tympanic cavity and the outside. Tympanic cavity acts as a balloon. If air pressure outside is smaller than air pressure inside the tympanic cavity, - tympanic membrane bulges.

26. Name 2 ways the middle ear helps to transmit pressure waves from air to much denser fluid. We can appreciate the effect of the ossicles by noting that in patients whose ossicles have been damaged beyond surgical repair, it is necessary to increase the sound by a factor of 10 to 50 to achieve the same hearing as when the ossicles were functioning. Environments inside the outer, middle, and inner ears. The fact that liquid fills the inner ear poses a problem for the transmission of sound vibratio…

    Tympanic membrane VS 20 times smaller oval window - middle ear concentrates the vibration of the large tympanic membrane onto the much smaller stapes, which increases the pressure by a factor of about 20. Ossicles function as lever - ossicles are hinged to create a lever action that creates an effect similar to what happens when a fulcrum is placed under a board, so pushing down on the long end of the board makes it possible to lift a heavy weight on the short end. (a) A diagrammatic representa…

27. What's organ of corti?

    The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. Transduction occurs through vibrations of structures in the inner ear causing displacement of cochlear fluid and movement of hair cells at the organ of Corti to produce electrochemical signals.The organ of Corti is located in the scala media of the cochlea of…

28. When do hair cilia in the organ of corti generate the action potential?

    Movement of hair cilia in one direction opens ion channels in the hair cell, which results in the release of neurotransmitter onto an auditory nerve fiber. (b) Movement in the opposite direction closes the ion channels, so there is no ion flow and no transmitter release. If our hearing were much more sensitive than it is now, we would hear the background hiss of colliding air molecules!

29. Where is basilar membrane?

    Organ of corti is located on the basilar membrane.

30. Name 2 parts of the inner ear, and describe the function they play.

    Cochlea - hearing, converts sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain. Vestibular labyrinth - dedicated to balance.