Chapter 17: Lecture Midterm II Flashcards

1
Q

On each side of the nose, there are 40 or so bundles of axons of

A

olfactory sensory neurons from the right and left olfactory (I) nerves

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2
Q

the olfactory nerves pass through the

A

cribriform foramina of the cribriform plate of the ethmoid bone

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3
Q

where do olfactory nerves extend to?

A

parts of the brain known as olfactory bulbs, which contain glomeruli

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4
Q

where do the second order neurons synapse with the olfactory nerves

A

at the glomerulus (second order neurons called; mitral cells)

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5
Q

Each glomerulus of the olfactory pathway recieves input from

A

only one type of olfactory sensory neuron

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6
Q

the axons of mitral cells form

A

the olfactory tract

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7
Q

where does conscious awareness of smell occur

A

olfactory cortex in the temporal lobe of the cerebrum

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8
Q

olfactory sensations are the only sensations that

A

reach the cerebral cortex without synapsing in the thalamus

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9
Q

where does out emotional responses to odours occur

A

some axons of the olfactory tract project to the limbic system

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10
Q

what type of sense is smell

A

chemical

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11
Q

the olfactory epithelium covers the…

A

inferior surface of the cribriform plate and extends along the superior nasal concha

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12
Q

extending from the dendrite of an olfactory sensory neuron are several nonmotile

A

olfactory cilia,

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13
Q

olfactory cilia are the site of

A

olfactory transduction

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14
Q

within the plasma membranes of the olfactory cilia are

A

olfactory receptor proteins that detect inhaled chemicals

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15
Q

Odorants:

A

chemicals that bind to and stimulate olfactory sensory neurons in the olfactory cilia

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16
Q

Supporting epithelial cells:

A

columnar epithelial cells of the mucous membrane lining the nose
- they provide physical support, nourishment and electrical insulation for the olfactory sensory neurons and help detoxify chemicals that they come in contact with

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17
Q

Basal epithelial cells

A
  • stem cells located between the bases of the supporting epithelial cells
  • they continue to undergo cell division to product new olfactory sensory neurons, which live for only about 2 months before being replaced
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18
Q

Olfactory glands (Bowman’s glands)

A
  • within the connective tissue that supports the olfactory epithelium
  • produce mucus that is carried to the surface of the epithelium by ducts
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19
Q

Olfactory transduction

A

binding of an odorant molecule to an olfactory receptor protein

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20
Q

Chemical reactions involving cyclic AMP (cAMP) cause

A

depolariztion

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21
Q

Neural pathway for olfaction

A
  • action potential travels to the primary olfactory area
  • impulses travel to the frontal lobe (orbitofrontal area) for odor identification
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22
Q

taste is a

A

chemical sense

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23
Q

taste buds contain

A

receptors for the sensation of taste

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24
Q

where are taste buds found

A

tongue, soft palate, pharynx, epitlottis

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25
Q

What kind of epithelial cells do tastebuds contain

A
  • supporting cells
  • gustatory receptor cells
  • basal stem cells
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26
Q

Where on the tongue are taste buds located

A

on elevations called papillae

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27
Q

What are the three types of papillae on the tongue

A
  • vallate papillae
  • fungiform papillae
  • foliate papillae
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28
Q

Vallate papillae

A

about 12 that contain 100-300 taste buds

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29
Q

Fungiform papillae:

A

Scattered over the tongue with about 5 taste buds each

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30
Q

Filiform papillae:

A
  • cover the entire surface of the tongue
  • increased friction to make it easier for the tongue to move food within the mouth
  • contain tactile receptors but no taste buds
    MOST ABUNDANT ON TONGUE
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31
Q

What are the 5 primary tastes

A
  • sour
  • sweet
  • bitter
  • salt
  • umami (meaty)
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32
Q

Chemicals that stimulate gustatory epithelial cells are known as

A

tastants

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33
Q

Once a tastant is dissolved in saliva…

A

it can make contact with the plasma membranes of gustatory microvilli

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34
Q

gustatory microvilli are the sites of

A

Taste transduction

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35
Q

After there is contact with gustatory microvilli,

A

it results in depolarizing receptor potential which stimulates exocytosis of synaptic vesicles

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36
Q

After there is depolarization in the gustatory pathways…

A

neutrotransmitter molecyles trigger a graded potential which produces nerve impulses in the first order sensory neurons

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37
Q

an individual gustatory epithelial cell responds to only

A

one type of tastant because each cell has either ion channels or receptors for only on of the primary tastes

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38
Q

each taste bud contains

A

gustatory epithelial cells for each tupe of tastant to allow dfferent tastes to be detected in different parts of the tongue

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39
Q

A bitter cell cannot respond to

A

a sour or sweet cell and vice versa

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40
Q

what three cranial nerves contain axons of the first-order gustatory neurons that innervate taste buds

A
  • facial nerve (VII)
  • glossopharyngeal (IX)
  • vagus (X)
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41
Q

The facial nerves serves taste buds on

A

anterior 2/3rds of the tongue

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42
Q

the glossopharyngeal nerves serve taste buds on

A

posterior 1/3rd of tongue

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43
Q

the vagus nerve serves taste buds in the

A

throat and epiglottis

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44
Q

from the gustatory epithelial cells in taste buds, nerve impulses propagate along cranial nerves to…

A

the gustatory nucleus in the medulla

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45
Q

from the medulla, some axons carrying taste signals project to…

A

the limbic system and hypothalamus, others project to the thalamus

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46
Q

Taste signals that go to the thalamus then go to..

A

gustatory cortex in the insula of the cerebrum

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47
Q

the gustatory cortex in the insula of the cerebrum gives rise to

A

conscious perception of taste and discrimination of taste sensations

48
Q

Light passes through which structures of the eye

A
  • cornea
  • anterior chamber
  • pupil
  • posterior chamber
  • lens
  • vitreous humor
  • retina
49
Q

more than half the sensory receptors in the human body are located in the…

A

eyes

50
Q

the eyes are responsible for visible light on the electromagnetic spectrum with wavelengths ranging from

A

400-700 nm

51
Q

wavelength 400 would be the color —- whereas 700 is —-

A

violet, red

52
Q

what are the accessory structures of the eye

A
  • eyelids
  • eyelashes/eyebrows
  • lacrimal apparatus
  • extraocular muscles
53
Q

the levetator palpabrae superioris muscle controls

A

the upper eyelid

54
Q

the tarsal plate is what

A

gives form and support to the eyelids

55
Q

the tarsal glands secrete

A

fluid that prevents the eyelids from sticking to eachother

56
Q

conjunctiva:

A

thin, protective mucus membrane that lines the eyelids and covers the sclera

57
Q

eyelashes protect the eyeballs from

A
  • foreign objects
  • perspiration
  • direct rays of sun
58
Q

lacrimal apparatus

A
  • group of structures that produces and drain lacrimal fluid or tears in a process called lacrimation
59
Q

Lacrimal glands:

A

each about the size and shape of an almond, secrete lacrimal fluid which drains into 6-12 exretory lacrimal ducts that empty tears onto the surface of the conjunctiva of upper eyelid

60
Q

tears pass into 2 ducts…

A

the superior and inferior lacrimal canaliculli which leads to the lacrimal sac

61
Q

lacrimal sac

A

within the lacrimal fossa of the lacrimal bone

62
Q

extraocular muscles extend from

A

the walls of the bony orbit to the sclera (white) of the eye and are surrounded by a significant quantity of periorbital fat

63
Q

what are the 6 extraocular muscles

A
  • superior rectus
  • inferior rectus
  • lateral rectus
  • medial rectus
  • superior oblique
  • inferior oblique
64
Q

what are the extraocular muscles supplied by

A
  • oculomotor nerves (III)
  • trochlear (IV)
  • abducens (VI) nerves
65
Q

What are the three layers of the eyeball:

A
  1. fibrous layer
  2. vascular layer
  3. inner layer (retina)
66
Q

Fibrous layer of the eyeball:

A
  • most superficial layer
  • consists of anterior cornea and posterior sclera
67
Q

Cornea:

A

transparent coat that covers the coloured iris; because it is curved it helps focus light onto the retina

68
Q

Since the centra part of the cornea receives oxygen from outside area

A

contact lenses that are worn for long periods of time must be permeable to oxygen

69
Q

Sclera

A
  • the white of the eye
  • dense layer of connective tissue made up of collagen fibers and fibroblasts
  • gives shape to the eyeball, makes it more rigid and protects inner parts
70
Q

the sclera covers the entire eyeball except for the

A

cornea

71
Q

Vascular layer (uvula) of the eyeball:

A
  • middle layer of the eye ball
  • composed of three parts: choroid, ciliary body and iris
  • numerous blood vessels provide nutrients to the posterior surface of the retina
72
Q

Choroid:

A
  • posterior portion of vascular layer; lines most of the internal surface of sclera
  • contains melanocytes that produce pigment (melanin) which causes this later to appear black or dark brown in color
73
Q

Melanin in the choroid absorbs

A

stray light rays, which prevents reflection and scattering of light within the eyeball; as a result the image cast on the retina remains sharp

74
Q

In the anterior portion of the vascular layer, the choroid becomes the

A

ciliary body

75
Q

Ciliary body:

A
  • extends from the ora serrata; the jagged anterior margin of the retina, to a point just posterior to the junction of the sclera and cornea
  • contains ciliary processes and ciliary muscle
76
Q

like the choroid, the ciliary body appears

A

dark brown in color because it contains melanocytes

77
Q

Ciliary processes:

A
  • protrusions or folds on the internal surface of the ciliary body; contain blood capillaries that secrete aqueous humor
78
Q

extending from ciliary processes are…

A

zonular fibers that attach to the lens

79
Q

Ciliary muscle:

A
  • circular band of smooth muscle
80
Q

contraction and relaxation of the ciliary muscle changes the tightness of the zonular fibers which…

A

alters the shape of the lens, adapting it for near or far vision

81
Q

Iris

A

coloured portion of the eyeball which is suspended between the cornea and the lens and is attached to ciliary processes

82
Q

What helps determine eye color

A

melanocytes

83
Q

What is a principle function of the iris

A

regulate the amount of light entering the eyeball through the pupil

84
Q

Pupil:

A

hole in the center of the iris; appears black because as you look through the lens, you can see the heavily pigmented choroid and retina

85
Q

What else controls the dilation and constriction of the pupil

A

oculomotor nerve (III)
- the pupil constricts as pupillae muscles contract
- the pupil dilates as dilator pupillae muscles of the iris contract

86
Q

Inner layer of the eyeball:

A
  • the third inner layer of the eyeball, the retina, lines the posterior three quarters of the eyeball and is the beginning of the visual pathway
87
Q

the surface of the retina is the only place in the body where blood vessels

A

can be viewed directly ad examined for pathological changes such as those that occur with htn, DM, cataracts, and macular disease

88
Q

Where do the optic nerves exit the eyeball

A

optic disc

89
Q

bundled together with the optic nerves are the

A

central retinal artery and central retinal vein

90
Q

The point where the optic nerve exits at the optic disc is the

A

blind spot

91
Q

What is the exact center of the retina clled

A

macula lutea

92
Q

In the center of the macula lutea is the

A

fovea centralis, area of highest visual acuity (sharpest vision)

93
Q

The retina contains photoreceptors known as

A

rods and cones

94
Q

Lens

A
  • behind the pupil and the iris
  • contains proteins called crystallins, arranged like layers of onions -makes up refractive media
95
Q

the lens helps to focus

A

images to the retina to faciliate clear vision

96
Q

The lens divides the interior of the eyeball into 2 segments

A
  • anterior and posterior segment
97
Q

The anterior segment of the eyeball

A

space between the cornea and the lens - consists of two chambers: anterior and posterior chamber

98
Q

Anterior chamber of the anterior segment

A

lies between the cornea and the iris

99
Q

Posterior chamber of the anterior segment

A

lies behind the iris and in front of the zonular fibers and lens

100
Q

Both chambers of the anterior segment are filled with

A

aqueous humor, a transparent watery fluid that nourishes the lens and cornea

101
Q

Aqueous humor continually filters out of blood capillaries in the

A

ciliary processes of the ciliary body and enters the posterior chamber

102
Q

Flow of aqueous humor

A

Goes from anterior chamber - filters through the ciliary processes -enters posterior chamber - flows forward between iris and lens and throguh the pupil

103
Q

the aqueous humor is replaced

A

every 90 minutes

104
Q

The larger posterior portion of the eyeball, the posterior segment lies between

A

the lens and the retina

105
Q

The posterior segment contains a jelly like substance;

A

the vitreous humor

106
Q

The vitreous humor functions to

A

hold the retina flush against the choroid, giving the retina an even surface for the reception of clear images
- it also contains phagocytic cells that remove cell debris which keeps this part of the eye cllear for unobstructed vision

107
Q

The vitreous humor occupies about

A

4/5ths of the eyeball

108
Q

images that are focused on the retina are

A

inverted (upside down)

109
Q

refraction is accomplished through a process called

A

accommodation

110
Q

Convex

A

something that curves outward like a ball

111
Q

what muscles contract during accommodation

A

ciliary muscles

112
Q

the increase in curvature of the lens is called

A

accommodation

113
Q

convergence

A

both eyes moving at the same time for example: when our eyes are focussed on a pencil that is moving closer to our eyes

114
Q

the single type of photopigment in rods is

A

rhodopsin

115
Q

light causes rod photoreceptors to

A

decrease their release of the inhibitory neurotransmitter glutamate

116
Q

in darkness, the rod photoreceptors

A

increase the release of inhibitory neurotransmitter glutamate