Hearing and Equilibrium

Question 1

In general, how do all sensory receptors work?

Answer 1

The receptors collect info, stimulating neurons. Then the cerebral cortex integrates the info with that of the other senses. Then a perception is formed.

Question 2

Nociceptors

Answer 2

Pain receptors that detect noxious agents, internally and externally

Question 3

Thermoreceptors

Answer 3

detect changes in temperature.

Question 4

mechanoreceptors

Answer 4

sense physical deformation (hearing and touch)

Question 5

chemoreceptors

Answer 5

detect chemical signals (taste and smell)

Question 6

photoreceptors

Answer 6

detect changes in light (eyes)

Question 7

What effect do the nerve fibers that run through the limbic system have?

Answer 7

This ties the sense of smell and taste to emotion.

Question 8

What type of cells form the receptors of the sense of smell?

Answer 8

nervous tissue with supporting epithelial cells (bipolar neurons)

Question 9

Where are the receptors for the sense of smell located?

Answer 9

bipolar neuron’s axons pass through the cribiform plate and about 1,000 filia synapse with one mitral cell in the olfactory bulb. The dendrites are open in the free space.

Question 10

Describe the olfactory mucosa.

Answer 10

olfactory mucosa contains sensory fibers form the trigeminal nerve.

Question 11

What role does mucus play in the sense of smell?

Answer 11

If the mucus doesn’t dissolve substances fully, the receptors wouldn’t be stimulated.

Question 12

How do we recognize thousands of different odors?

Answer 12

the combinations of 7 primary scents

Question 13

Are olfactory receptors replaced during a person’s lifetime? Why is this unusual? How long do the receptors live?

Answer 13

The receptors are bipolar neurons. usually nervous tissue isn’t regenerated. They last 30-60 days.

Question 14

What happens to our sense of smell as we age?

Answer 14

We lose about 1% of neurons every year.

Question 15

What bony structure do olfactory fibers pass through on their way to the olfactory bulb?

Answer 15

Cribiform plate

Question 16

How quickly does the sense of smell adapt?

Answer 16

50% in the first second. Smell has a very low threshold.

Question 17

What are the three main divisions of the ear?

Answer 17

Outer, Middle, and Inner

Question 18

What structures make up the outer ear? What glands are found here?

Answer 18

Auricle, External auditory canal. Ceruminous glands

Question 19

What is the primary function of the outer ear?

Answer 19

Collection, amplification and localization of sound.

Question 20

What is the structure of the tympanic membrane? What does it do?

Answer 20

Separates the outer and middle ear. It transmits sound from the air to the ossicles inside the middle ear.

Question 21

What structures make up the middle ear?

Answer 21

Tympanic membrane, auditory tube, malleus, incus, stapes, tensor tympani muscle, stapedius muscle, round and oval window.

Question 22

What is the function of the middle ear?

Answer 22

to decrease the acoustic energy moving into the ear.

Question 23

What do we call an infection of the middle ear?

Answer 23

otitis media

Question 24

What does the tensor tympani do?

Answer 24

limits vibration amplitude of eardrum and makes sound transmission less efficient

Question 25

What does the stapedius muscle do?

Answer 25

contraction changes the axis of oscillation of the oscular chain and causes dissipation of movement before it reaches the oval window. `

Question 26

Describe the membranous labyrinth of the ear.

Answer 26

contains receptors for equilibrium, endolymph.

Question 27

Describe the bony labyrinth of the ear.

Answer 27

hollow space carved into bone that contains the vestibule, semicircular canals, and cochlea. Lined by periosteum and contains perilymph.

Question 28

Perilymph

Answer 28

like cerebrospinal fluid, contains Na+ and low in K+

Question 29

Endolymph

Answer 29

Like intracellular fluid, high in K+ and low in Na+

Question 30

What is the cochlea for?

Answer 30

hearing. Sound enters through the oval window. It passes through either the membranous labyrinth or around the helicotrema, and around the round window. The cochlea is hollow, contains the spiral organ of corgi, located in the basilar membrane. Scala vestibuli, scala tympani, scala media (cochlear duct).

Question 31

What is the vestibule for?

Answer 31

static equilibrium.

Question 32

What are the semicircular canals for?

Answer 32

dynamic equilibrium

Question 33

What type of tissue makes up the organ of corgi receptors?

Answer 33

mechanoreceptors made up of epithelial tissue.

Question 34

What is the function of the round window?

Answer 34

it allows fluid in the cochlea to move, which ensures that hair cells of the basilar membrane will be stimulated.

Question 35

How do we hear high sounds differently from low sounds, or soft sounds differently from loud sounds?

Answer 35

Soft vs loud is affected by how many hair cells are activated. Low vs high is how deep through the cochlea the waves pass.

Question 36

What is the range of human hearing?

Answer 36

20-20,000 hertz

Question 37

How do the otoliths help maintain static equilibrium?

Answer 37

They move due to gravity to keep the head oriented . they are located in the saccule.

Question 38

How do the maculae of the utricle and saccule function?

Answer 38

Use small stones and viscous fluid to stimulate hear cells to detect motion.

Question 39

What part of the inner ear helps the sense of dynamic equilibrium?

Answer 39

Crista ampullaris in the semicircular canals