Ls2 Ch 45-Sensory Systems

Front 1

What is the term for transforming stimuli into neuronal signals?

Back 1

Sensory Transduction

Front 2

How does sensory transduction begin?

Back 2

Receptor protein detects a specific stimulus

Front 3

What are the classes of receptor proteins? (2)

Back 3

IONOTROPIC: ion channels or directly affect ion channels

METABOTORPIC: affect ion channels through G proteins and second messengers

Front 4

Ionotropic Examples:

Back 4

Mechanoreceptors
Thermoreceptors
Electrosensors

Front 5

Metabotropic Examples

Back 5

Chemoreceptors
Photoreceptors

Front 6

What do SENSORY RECEPTOR CELLS do?

Back 6

transduce energy of stimulus into change in MEMBRANE POTENTIAL

Front 7

What is an action potential of a sensory receptor cell called?

Back 7

RECEPTOR POTENTIAL-

Front 8

How do cells code for the INTENSITY of sensation?

Back 8

frequency of action potentials

Front 9

What happens when a cell is repeatedly stimulated?

Back 9

ADAPTATION: the response diminishes (enables organism to ignore background conditions)

Front 10

What sensory cells do not adapt?

Back 10

Mechanoreceptors for balance, others.

Front 11

How do insects attract mates? (1 example)

Back 11

PHEROMONES: chemical signals released in air (ie BOMBYKOL)

Front 12

What is the sense of smell called?

Back 12

OLFACTION

Front 13

Where are olfactory sensors located?

Back 13

in epithelial tissue at top of nasal cavity. Axons extend to olfactory bulb in brain

Front 14

What is the name for a chemical that binds to olfactory sensors?

Back 14

ODORANT

Front 15

What happens when an odorant binds to a receptor protein?

Back 15

Activates a G protein, which activates cAMP, binds to cation channels, causes action potential

Front 16

What happens in the olfactory bulb?

Back 16

Axons from neurons with same receptors converge on GLOMERULI, allows us to discriminate complex odors.

each odorant triggers multiple glomeruli

Front 17

What is the name for the sense of taste?

Back 17

GUSTATION

Front 18

What are taste buds?

Back 18

Clusters of CHEMORECEPTORS

Front 19

Where are taste buds located?

Back 19

on PAPILAE in tongue EPITHELIUM

Front 20

What is the life of a taste bud?

Back 20

cells last only 10 days, neurons form new synapses with taste bud cells as they are formed

Front 21

What are the five taste senses?

Back 21

Salty
Sour
Sweet
Bitter
UMAMI

Front 22

What kind of receptors sense saltiness?

Back 22

ionotropic

Front 23

What kind of receptors sense sweetness and bitterness?

Back 23

metabotropic

Front 24

What kinds of cells respond to physical force? How do they work?

Back 24

MECHANORECEPTORS

physical distortion of plasma membrane causes ion channels to open, leads to action potential

Front 25

Kinds of mechanoreceptors in the skin (5)

Back 25

RUFFINI ENDINGS: deeper, adapt slowly. react to low vibrations

PACINIAN CORPUSCLES: deep, adapt rapidly, react to high frequency vibrations

MERKEL'S DISCS: adapt slowly, continuous info (very sensitive)

MEISSNER's CORPUSCLES: adapt quickly, info about change

FREE NERVE ENDINGS: pain, itch, temp

Front 26

Why are some parts of the body more sensitive than others?

Back 26

density of touch receptors (ie lips vs back)

Front 27

How do muscles detect stretching?

Back 27

MUSCLE SPINDLES with STRETCH RECEPTORS (mechanoreceptors)

Front 28

What is the name for the outer ear?

Back 28

PINNAE

Front 29

Where does the pinnae direct sound?

Back 29

into the AUDITORY CANAL

Front 30

What is the eardrum, what does it do?

Back 30

TYMPANIC MEMBRANE: covers end of auditory canal, vibrates in response to pressure

Front 31

What is the middle ear, what is in it?

Back 31

Air filled cavity.

has OSSICLES

Front 32

What is the opening to the inner ear?

Back 32

EUSTACHIAN TUBE: connects to the throat, equilibrates air pressure between middle ear and outside

Front 33

What are the ossicles, name them

Back 33

tiny bones transmit vibrations of tympanic membrane to OVAL WINDOW

malleus, incus, stapes

Front 34

What is the purpose of the ossicles?

Back 34

Amplifies the force to the smaller oval window

Front 35

What does the oval window do?

Back 35

Translates the vibrations into pressure change in the fluid of the inner ear

Front 36

What is the main part of the inner ear?

Back 36

the COCHLEA-coiled chamber of three panels

Front 37

What are the parts of the cochlea?

Back 37

REISSNER's MEMBRANE
BASILAR MEMBRANE

ORGAN OF CORTI-transduces pressure into action potentials

ROUND WINDOW-end

Front 38

How does the cochlea work?

Back 38

Pressure waves travel around cochela, take "shortcuts" at their specific frequencies where they trigger hair cells on organ of corti corresponding with frequency (INSERT PICTURE)

Front 39

Which frequencies travel the furthest in the cochlea?

Back 39

LOW FREQUENCIES-go all the way around.

Front 40

What are two ways to go deaf?

Back 40

CONDUCTION DEAFNESS: tympanic membrane stops working

NERVE DEAFNESS: inner ear/nerve pathways damaged

Front 41

What are the key cells in the organ of corti?

Back 41

HAIR CELLS:

Front 42

How do hair cells work?

Back 42

They have STEROCILIA-connected by filaments. When stereocilia bend it opens/closes ion channels (INSERT PHOTO)

Front 43

How does the ear help us sense position/orientation?

Back 43

SEMICIRCULAR CANALS=three of them at angles to each other

Front 44

How does the ear sense position/acceleration?

Back 44

VESTIBULAR APPARATUS

Front 45

What kind of pigments help in sensation of light?

Back 45

RHODOPSINS

Front 46

What is rhodopsin made of, how does it work?

Back 46

OPSIN protein
11-CIS-RETINAL: absorbs light, changes to ALL-TRANS-RETINAL, changes conformation of opsin

Front 47

Where is rhodopsin located?

Back 47

Plasma membrane of a photoreceptor cell

Front 48

What are the two kinds of photoreceptors? What is the main difference?

Back 48

CONES-sense color
RODS-better at sensing light

Front 49

What is the structure of rod cells?

Back 49

Outer segment is a stack of plasma membrane discs filled with rhodopsin,

Front 50

How do rod cells function?

Back 50

when rhodopsin absorbs light, activates G protein (transducin), activates PDE, converts cGMP to GMP, CLOSING NA+ channels, membrane becomes HYPERPOLARIZED,
STOPS action potentials

Front 51

What is a special area of density in the eye?

Back 51

FOVEA-high density of cone cells

Front 52

How do cones differ from rods?

Back 52

Cones have low sensitivity to light but sense color better. rods are responsible for night vision

Front 53

How many types of cone cells do humans have

Back 53

3

Front 54

How many cell layers are in the retina?

Back 54

5

Front 55

How does light move in the retina?

Back 55

must pass through all layers to back where it is captured by rhodopsin

Front 56

What is at the back of the retina?

Back 56

PIGMENTED EPITHELIAL CELLS:
absorb light not captured by rhodopsin, phagocytose shed discs from photoreceptors

Front 57

What is the front layer of the retina cells?

Back 57

GANGLION CELLS-axons form optic nerve

Front 58

What connects the photoreceptor cells to ganglion cells?

Back 58

BIPOLAR CELLS

Front 59

What are two other kinds of cells in the retina?

Back 59

HORIZONTAL CELLS-form synapses between photoreceptors. sharpens contrast between light and dark

AMACRINE CELLS: interconnect bipolar and ganglion cells, sensitive to changing illumination/motion

Front 60

Describe how light stimulates the eye?

Back 60

When there is no light, photoreceptors constantly excite the bipolar, which inhibit the ganglion cells.

When there is light, photoreceptors don't fire. bipolar don't inhibit ganglion, ganglion fire action potentials.

(INSERT PICTURE)