Final: Sensory Systems: Ears Slides

Question 1

Other names for sensory cells

Answer 1

Receptor cells and modified neurons

Question 2

Types of receptors (7)

Answer 2

Photoreceptors, mechanoreceptors, chemoreceptors, thermoreceptors, nociceptors, electroreceptors, magnetoreceptors

Question 3

Function of sensory cells

Answer 3

Transduce physical or chemical stimuli into action potentials (convert signals into electrical activities)

Question 4

Which types of receptors do humans have, and which do we lack?

Answer 4

Have: photo, mechano, chemo, thermo, nociceptors
Lack: electro, magneto

Question 5

Photoreceptor function and location

Answer 5

Respond to light, found in eyes

Question 6

Mechanoreceptor function and location

Answer 6

Convert their motion to electrical activity, found on skin and ears

Question 7

Chemoreceptor function and location

Answer 7

Sense chemicals, can be internal (monitor pH/O2/CO2/etc. levels) or external (on tongue, nose, etc.)

Question 8

Thermoreceptor function

Answer 8

Sense temperature

Question 9

Nocicpetor function

Answer 9

Pain receptors

Question 10

Electroreceptor function

Answer 10

Sense electrical fields (sharks have them)

Question 11

Magnetoreceptor function

Answer 11

Sense magnetic fields (birds have them)

Question 12

What is sound and how does it travel?

Answer 12

Vibration of air molecules; waves that dissipate as they travel

Question 13

How can sound waves be characterized?

Answer 13

Amplitude (loudness) and frequency (pitch)

Question 14

What organs does sound pass through as it’s transmitted (external to internal)?

Answer 14

Pinna, auditory canal, tympanic membrane, ossicles (malleus, incus, stapes), oval window, stimulation of hair cells in cochlea, auditory nerve, relay to temporal lobe of brain

Question 15

Pinna (oracle) structure and function

Answer 15

Shaped like funnel; directs sound into ear

Question 16

Parts of outer ear

Answer 16

Pinna and auditory canal

Question 17

Parts of middle ear

Answer 17

Tympanic membrane (eardrum), malleus, incus, stapes

Question 18

Parts of inner ear

Answer 18

Cochlea (where hearing occurs)

Question 19

Function of ossicles

Answer 19

Amplifiers

Question 20

Cochlea basic structure

Answer 20

Bone filled with fluid, hard tissue, connects to auditory nerve

Question 21

Chambers of cochlea

Answer 21

Scala vestibuli, scala media/cochlear duct, scala tympani

Question 22

Which cochlea chambers contain which fluid?

Answer 22

Scala media contains endolymph, scala vestibuli and scala tympani contain perilymph

Question 23

What is the hearing apparatus and where is it located?

Answer 23

Organ of corti; located in scala media

Question 24

Membranes in organ of corti

Answer 24

Tectorial membrane (on top) and basilar membrane (where hair cells sit)

Question 25

Hair cell function

Answer 25

Mechanoreceptors that convert vibrational movement into electrical activity by forming synapses with sensory neurons (mechanical to electrical signal)

Question 26

Kinocilium vs stereocilia

Answer 26

Kinocilium is tallest cilia, stereocilia are all the other cilia

Question 27

Function of kinocilium

Answer 27

Point of direction when vibration occurs: depolarization when cell moves toward kinocilium, hyperpolarization when cell moves away from kinocilium

Question 28

What triggers stretch gated channels to open?

Answer 28

Movement; they open when there's vibration

Question 29

Where are stretch gated channels located?

Answer 29

Between the cilia of hair cells

Question 30

What kind of electrical activity do hair cells have?

Answer 30

Graded potential (or receptor potential)

Question 31

What happens when hair cells are depolarized?

Answer 31

Cell moves towards kinocilium - stretch gated channels open - K+ ions enter - causes depol - activates voltage gated Ca chanels - triggers NT (glutamate) release - eventually cause action potential in afferent/sensory neuron

Question 32

What neurotransmitter is involved in hair cell depolarization?

Answer 32

Glutamate

Question 33

What happens when hair cells are hyperpolarized?

Answer 33

Cell moves away from kinocilium - stretch gated channels close - voltage gated calcium channels do NOT open - no NT release, no signal

Question 34

Why does K+ enter instead of exit hair cells? (this is a SPECIAL CASE)

Answer 34

Endolymph fluid (surrounds hair cells) is rich in K+

Question 35

What is the neural pathway of hearing?

Answer 35

Cochlear nerve fibers synapse on neurons in cochlear nuclei in medulla oblongata, signal sent to thalamus, information travels to auditory cortex of temporal lobe

Question 36

What are some accessory structures in the ear and what do they do?

Answer 36

Oval window, round window, structures of outer and middle ear; they ensure that hair cells can send signals