Exam 5 Chapter 15 part 1

Question 1

where is the olfactory epithelium located?

Answer 1

in the root of the nasal cavity

Question 2

what is olfaction?

Answer 2

the sense of smell

Question 3

what does olfaction occur in response to?

Answer 3

odors that stimulate sensory receptors

Question 4

what are basal cells in olfaction?

Answer 4

stem cells that replace dead olfactory neurons

Question 5

what does olfactory epithelium contain?

Answer 5

10 million olfactory neurons

Question 6

what projects from a bulb-like olfactory vesicle into the mucus layer?

Answer 6

several cilia (olfactory hairs)

Question 7

what does the cilia do for olfaction?

Answer 7

increases the receptor membrane surface area

Question 8

what are odorants?

Answer 8

air-borne chemicals that dissolve in the mucus and bind to odor receptors in the membrane

Question 9

are all odorants detected with equal sensitivity?

Answer 9

no

Question 10

what do odorant receptors use as a second messenger?

Answer 10

G proteins and cAMP

Question 11

what does odorant binding cause?

Answer 11

sodium and calcium channels to open

Question 12

what happens when sodium and calcium channels open dafter odorant binding?

Answer 12

it creates a depolarization and an action potential in the olfactory neuron

Question 13

what does the olfactory system distinguish?

Answer 13

about 4000 different smells

Question 14

what are the 4000 different smells that the olfactory system distinguishes based on?

Answer 14

which odorant receptors are stimulated

Question 15

what are lost olfactory cells replaced by?

Answer 15

proliferation of basal cells in the olfactory epithelium

Question 16

what do olfactory receptors show?

Answer 16

adaption and central adaption occurs

Question 17

what do olfactory neuron axons (cranial nerve I) pass through?

Answer 17

the cribiform plate

Question 18

where do olfactory neuron axons (cranial nerve I) synapse?

Answer 18

in the olfactory bulb

Question 19

after the olfactory neuron axons (cranial nerve I) pass through the cribiform plate and synapse in the olfactory bulb what occurs?

Answer 19

they pass through the olfactory tract to the olfactory cortex as well as the hypothalamus, limbic system and frontal lobe

Question 20

where do a majority of neurons in the olfactory tracts project to?

Answer 20

central olfactory cortex areas in the temporal and frontal lobes of the cerebrum

Question 21

what areas do the central olfactory cortex include? (3)( PAO)

Answer 21

1) the piriform cortex (in the junction between the temporal and frontal lobes)
2) the amygdala (temporal lobe)
3) oribitofrontal cortex

Question 22

where do olfactory tract neurons project to which are involved with emotional and autonomic responses to olfactory stimuli?

Answer 22

secondary olfactory areas

Question 23

what areas are included in secondary olfactory areas?

Answer 23

1) hypothalamus
2) hippocampus
3) limbic system

Question 24

where do gustatory (taste) receptors occur?

Answer 24

in taste buds on the superior tongue surface

Question 25

what does the superior surface of the tongue have?

Answer 25

projections called papillae

Question 26

what does the filiform papillae do?

Answer 26

make the tongue surface rough

Question 27

what does the fungiform, foliate and vallte papillae have?

Answer 27

recessed taste buds

Question 28

what is the most numerous papillae on the surface of the tongue?

Answer 28

filiform

Question 29

what is unique about filiform?

Answer 29

it has no taste buds

Question 30

what does filiform papillae provide?

Answer 30

a rough surface on the tongue allowing it to manipulate food more easily

Question 31

which are the largest papillae but least numerous?

Answer 31

vallate papillae

Question 32

what does taste (gustatory) cells synapse with?

Answer 32

sensory neurons

Question 33

what extends through a taste (gustatory) pore on the epithelial surface?

Answer 33

taste hairs (microvilli)

Question 34

what replaces dead taste cells?

Answer 34

basal stem cells

Question 35

what is a life span of a taste cell?

Answer 35

about 10 days

Question 36

what is our sense of taste formed in conjunction with?

Answer 36

our sense of smell

Question 37

what do human primary tastes include? (5) (SSSBU)

Answer 37

1) sweet 2) salty 3) sour 4) bitter 5) umami (broth)

Question 38

what binds receptor proteins in the taste hair membrane?

Answer 38

dissolved chemicals (tastants)

Question 39

what do tastants generate?

Answer 39

depolarizations

Question 40

what do some tastants act on?

Answer 40

some on ion channels others on G proteins and second messengers

Question 41

are all chemicals detected with equal sensitivity?

Answer 41

no

Question 42

what is an example of not all chemicals being detected with equal sensitivity?

Answer 42

bitter is detected with more sensitivity than sweet

Question 43

what does taste receptor depolarization generate?

Answer 43

an action potential in the sensory neuron

Question 44

where do taste bud sensory neurons travel?

Answer 44

along 3 cranial nerves

Question 45

where do taste bud sensory neurons synapse?

Answer 45

in the tractus soltarius in the medulla

Question 46

what 3 cranial nurse do taste bud sensory neurons travel along?

Answer 46

facial (VII), glossopharyngreal (IX) and vagus (X)

Question 47

where do secondary neurons cross over and synapse?

Answer 47

in the thalamus

Question 48

what does secondary neurons cross over and synapse in the thalamus with?

Answer 48

tertiary neurons that reach the taste area in the insula lobe

Question 49

does receptor and central adaption for taste occur?

Answer 49

yes

Question 50

what is refraction used for?

Answer 50

to bend light and form an inverted image on the retina

Question 51

how is a clear, sharp image formed?

Answer 51

by changing the thickness of the lens (focusing or accomodation)

Question 52

what is an important characteristic of light rays?

Answer 52

that they can bend

Question 53

what is happening when the lens is thin for far away object?

Answer 53

ciliary muscle is relaxed

Question 54

what is happening when the lens is thick for close objects?

Answer 54

sphincter-like ciliary muscle contracts

Question 55

what does pupil restriction do?

Answer 55

reduce the light entering and increases the depth of field

Question 56

when object come close what must the eyes do?

Answer 56

converge to keep the image on the center of retina (convergence)

Question 57

what does the neural part of the retina have?

Answer 57

several layers

Question 58

what does the outer layer of the retina contain?

Answer 58

photoreceptor cells (rods and cones)

Question 59

what is the middle layer of the retina composed of?

Answer 59

bipolar neurons

Question 60

what does the inner layer of the retina contain?

Answer 60

ganglion cells whose axons extend out the optic nerve

Question 61

what are in between the layers of the retina?

Answer 61

synapses in the plexiform layers

Question 62

what does the pigmented lauyer or pigmented epithelium of the retina consist of?

Answer 62

a single layer of cells filled with the pigment melanin

Question 63

is pigmentation strictly necessary for vision?

Answer 63

no, people with albinism can see but their visual acuity is reduced because of light scattering

Question 64

what are the rods and cones (photoreceptors)

Answer 64

modified neurons

Question 65

what does the inner segment of the eyes photoreceptors synapse with?

Answer 65

a bipolar cell

Question 66

what does the outer segment of the eye's photoreceptors contain?

Answer 66

membranes for photoreception

Question 67

what are rods specialized for?

Answer 67

vision in dim light

Question 68

what does rods produce?

Answer 68

grays

Question 69

what does the membrane of rods contain?

Answer 69

rhodopsin

Question 70

what is rhodopsin?

Answer 70

a protein called opsin + the pigment retinal

Question 71

what is retinal made from?

Answer 71

vitamin A

Question 72

what is rhodopsin associated with?

Answer 72

a G protein (transducin) and a cGMP phosphodiestrerase

Question 73

what does the cGMP phosphodiestrerase do?

Answer 73

converts cGMP into GMP

Question 74

what happens during darkness?

Answer 74

chemically gated sodium channels in the outer segment are open in the presence of cGMP

Question 75

what does the open chemically gated sodium channels in the outer segment during darkness cause

Answer 75

a potential of -30mV

Question 76

as a result of the potential of -30mV what do the photoreceptors release?

Answer 76

the inhibitory neurotransmitter glutamate continually at the synapse

Question 77

what a photon of light strikes the retinal what happens?

Answer 77

it changes from 11-cis retinal to 11-trans retinal

Question 78

what dose the changing from 11-cis retinal to 11-trans retinal do?

Answer 78

activates transducin and the cGMP phosphodiesterase that breaks down cGMP

Question 79

what happens after the transducin and phosphodiesterase that breaks down cGMP is activated? (4) (SMCP)

Answer 79

1) the sodium channels are closed 2) the membrane hyperpolarizes 3) the cell releases glutamate 4) the bipolar cell releases a neurotransmitter

Question 80

what happens once the bipolar cell releases a neurtransmitter?

Answer 80

the 11-trans retinal is then removed from opsin and enzymatically converted to 11-cis retinal to regenerate photopigment

Question 81

what are cones for?

Answer 81

specialized color vision and high visual acuity in bright light

Question 82

what different cones have?

Answer 82

different opsins

Question 83

what do the different opsins of cones form?

Answer 83

photopigments (RGB) (Red, green, blue)

Question 84

what do the different photopigments absorb?

Answer 84

different wavelengths of light for color vision

Question 85

what does the sensitivity of the visual system vary from?

Answer 85

a dark-adapted state (rods) to a light-adapted state (cones)

Question 86

where are cones located?

Answer 86

they are concentrated near the macula

Question 87

where are rods located?

Answer 87

more numerous away from the macula

Question 88

does the retina do any visual processing?

Answer 88

yes, some

Question 89

what do bipolar cells that monitor rods monitor many rods show?

Answer 89

considerable convergence and produce coarse images in dim light

Question 90

what do bipolar cells that monitor cones often monitor a single cone show?

Answer 90

little convergence and produce detailed, sharp images in bright light.

Question 91

where is the optic nerve located?

Answer 91

it leaves the eyes and travels to the optic chiasm

Question 92

how does the field of view work?

Answer 92

the lateral half of the field of vision crosses over at the optic chiasm

Question 93

why does the lateral half of the field of vision cross over at the optic chiasm?

Answer 93

so that each visual cortex gets the opposite side of the field of view from both eyes

Question 94

what does binocular vision allow?

Answer 94

depth perception

Question 95

where does the optic tract go?

Answer 95

to the lateral geniculate nucleus and then onto the visual cortex

Question 96

where do collaterals go?

Answer 96

to other locations such asthe superior colliculus

Question 97

where is the visual cortex located?

Answer 97

in the occipital lobe