Ch.15 Flashcards

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1
Q

Olfaction

A

sense of smell
in response to odors that stimulate sensory receptors in the olfactory region

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2
Q

Where is the olfactory region and what is it lined with?

A

Olfactory region is located in the extreme superior area of nasal cavity and lined with specialized epithelium called the olfactory epithelium

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3
Q

The olfactory epithelium contains approx ________ olfactory neurons, which are ________ _________ cells

A

10 million
Olfactory receptor cells

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4
Q

Olfactory vesicles

A

Bulbous enlargements of dendrites of olfactory neurons that extend into the epithelial surface of the nasal cavity

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5
Q

Olfactory hairs

A

Cilia on the olfactory vesicles which lie in thin mucous film on epithelial surface

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6
Q

Olfactory neurons are considered what type of receptor?

A

Chemoreceptor

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7
Q

Odorants

A

Airborne molecules that enter the nasal cavity and are dissolved into the fluid covering the olfactory epihelium

Bind to odorant receptor molecules

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8
Q

What is the process for a binding of an odorant to activating a olfactory neuron?

A
  1. Odorant binds to receptor molecule
  2. Receptor molecule activates G protien, which activates adenylate cyclase.
  3. Adenylate cyclase catalyzes the formation of cAMP from ATP
  4. cAMP in these cells causes Na+ and Ca2+ channels to open
  5. The influx of ions causes depolarization and an action potential
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9
Q

What are the 7 primary smells?

A

Camphoraceous (mothballs)
Musky
Floral
Pepperminty
Ethereal (fresh pears)
Pungent
Putird

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10
Q

Can a olfactory receptor react to more than one odorant?

A

yes

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11
Q

What is the neuronal pathway for olfaction?

A

Axons from the olfactory neuron which forms olfactory nerve, project through small foramina in the bony cribiform plate to the olfactory bulb where olfactory neurons synapse with 2ndry neurons which relay olfactory info to the brain via olfactory tracts

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12
Q

Olfactory stimuli cause not only perception of odors but also a emotional and autonomic responses. What parts of the brain do the olfactory neurons lead to?

A

Central olfactory cortex areas in temporal and frontal lobes

Also to the hypothalamus, hippocampus, and structures of limbic system

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13
Q

What are the structures that dectect taste or gustatory stimuli?

A

Taste buds

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14
Q

Papillae on tounge

A

bumps on tounge / not taste buds

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15
Q

What are the 4 major types of papille and where are they located?

A
  • *Filiform** - most numerous but no tastebuds/rough surface helping with food
  • *Vallae** - Surrounded by a wall/largest and least numerous, V shape separeting anterior and posterior tounge
  • *Foliate** - leaf shaped / sides of tounge and most sensative taste buds
  • *Fungiform** - mushroom shaped / scattered irregulary

Taste buds are associated with vallate, foliate, and fungiform papillae

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16
Q

What is the life span of a taste cell?

A

10 days

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17
Q

Each of the 10,000 taste buds found in the oral cavitiy consists of what 3 types of specialized epithelial cells?

A

Taste cells - sensory
Basal cells - non sensory
Supporting cells - non sensory

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18
Q

Each taste cell has several microvilli, called?

A
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19
Q

Tastants

A

Substances dissolved in saliva which enter taste pores and stimulate the taste cells

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20
Q

What are the 5 classes of tastants?

A

Salt
Sour
Sweet
Bitter
Umami

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21
Q

How does the taste of Salt occur?

A

When Na+ diffuses through Na+ channels resulting in depolarization of taste cells

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22
Q

How do we taste sweet ?

A

bind to receptor molecules and cause depolarization through G protien mechanisms

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23
Q

How do we taste Sour ?

A

Results when H+ of acids cause depolarization 1 of 3 ways

  1. enter through H+ channels
  2. Bind to ligand gated K+ channels and block the exit of K+
  3. open ligand gated channels for other positive ions and allow them to diffuse into the cell
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24
Q

How do we taste Bitter ?

A

Simular to how we taste sweet, through G protiens

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25
Q

How do we taste Umami ?

A

results when amino acids bind to receptors and causes depolarization through g protien mechanisms

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26
Q

What other factors can affect the perception of taste?

A

Texture
hot or cold temp

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27
Q

What are the neuronal pathways for taste?

A

Facial nerve VII - Chorda tympani transmits taste sensations from anterior 2/3s of tounge, except from vallae papillae

Glossopharyngeal nerve IX - carries taste sensations from posterior 1/3 of tounge, the vallate papillae and superior pharynx

Vagus nerve X - carries fibers from epiglottis

*The fibers then go to Medulla oblongata then decussate then go to thalamus. then go to cerebrum

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28
Q

The visual system includes

A

Eyes
Accessory structures
Optic nerves, tracts and pathways

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29
Q

What are the accessory structures of the visual system?

A

Eyebrows
Eyelids
Eyelashes
conjuntiva
Lacrimal apparatus
Extrinsic eye muscles

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30
Q

What is the function of eyebrows?

A

Prevent perspiration from running down forehead and shade eyes from sunlight

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31
Q

What is the function of the eyelids?

Palpebrae

A

their eyelashes protect eyes from foriegn objects

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32
Q

What are the 5 layers of tissue that make up eyelids

A
  1. thin layer of skin on external surface
  2. thin layer of aerolar connective tissue
  3. layer of skeletal muscle containing orbicularis oculi and levator palpebrae superior muscles
  4. cresent shaped layer of Dense connective tissue which helps maintain shape of eyelid
  5. Palpebral conjunctiva which lines inner surface of eyelid and anterior surface of eyeball
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33
Q

Ciliary glands

A

modified sweat glands that open into the follicles of the eyelashes to keep them lubricated

*A sty forms when one of these glands becomes inflamed

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34
Q

Meibomian glands

aka Tarsal glands

A

are sebaceous glands near inner margins of eyelids, produce sebum which lubricates the lods and restrains tears from flowing over the margins of eyelids

Chalazion - infection or blockage of a meibomian gland

35
Q

Conjunctiva

A

thin transparent mucous membrane associated with the eyelids and exposed areas of the eye

36
Q

Palpebral conjunctiva

A
  • covers inner surface of eyelid
37
Q

Bulbar conjunctiva

A
  • covers anterior white surface of eye
38
Q

Conjunctival fornices

A
  • where palpebral and bulbar conjunctiva meet
39
Q

Conjunctivitis

A

inflammation of conjunctiva caused by infection or other irritation

Acute contagious conjunctivitis (pink eye) - caused by a bacterium

40
Q

Lacrimal apparatus

A

consists of a lacrimal gland situated in the superolateral corner of the orbit and a nasolacrimal duct

41
Q

Lacrimal gland

A

innervated by parasympathetic fibers from facial nerve VII

Produces tears which leave the gland through lacrimal ducts

Produces tears at a rate of about 1mL/day

42
Q

What are the 6 extrinsic muscles attached to the eye?

A

Superior rectus muscle
Inferior rectus
Medial rectus
Lateral rectus
Superior oblique
Inferior oblique

43
Q

Clincal test for noraml eye movement is called

A

H test

*a persons inability to move their eye to one part of the H may indicate dysfunction of a muscle or cranial nerve

44
Q

They eyeball is a hollow fluid filled sphere. The wall of the eyeball consists of what 3 layers?

A

Fibrous tunic
Vascular tunic
nervous tunic

45
Q

Fibrous tunic

A

Outer layer of eyeball
Consists of sclera and cornea

46
Q

Vascular tunic

A

middle layer of eyeball
consists of choroid, ciliary body and iris

47
Q

Nervous tunic

A

inner layer of eyeball

consists of retina

48
Q
A
49
Q

Sclera

A

white outer layer

Firm opaque tissue layer that consists of dense collaganeous connective tissue with elastic fibers

Helps maintain shape of eye, protects internal structures, provides attachement point for muscles

50
Q

Cornea

A

avascular, transparent structure that permits light to enter the eye

As light passes through it bends or refracts

*Part of eyes focusing system

*most common eye injury are cuts or tears of cornea

51
Q

What makes cornea easy to transplant

A

Easily accessable and easily removed

Avascular

less immunologically active

52
Q

Vascular tunic

A

Consists of choroid, ciliary body, iris

Has short ciliary arteries which pierce sclera in the circle around optic nerve,

Contains a large number of melanin containing pigment cells and appears black in color

53
Q

The smooth muscle of the iris is organized into what 2 groups?

A

Sphincter pupillae - when contracts pupil decreases
dilator pupillae - when contracts the pupil increases

54
Q

Nervous tunic

A

Retina and consists of pigmented layer and inner neural layer

55
Q

What 2 features can be observed when the retina is examined with an ophhalmoscope?

A

Macula & optic disc

56
Q

The interior of the eye is divided into what 3 chambers?

A

Anterior chamber
Posterior chamber
Vitreous chamber

57
Q

Refraction

A

Bending of light

58
Q

As light rays converge, they reach a point in which they cross called

A

Focal point

59
Q

Causing light to converge is called

A

Focusing

60
Q

reflection

A

When a ray of light bounces off a surface that is not transparent

61
Q

When an object is brought closer than 20 feet to the eye what 3 events bring the image into focus?

A

Accomodation by the lens -(changing shape of lens)
constriction of the pupil
convergence of the eyes

62
Q

Near point vision

A

the point at which blurring occurs when an object is too close to see

63
Q

Presbyopia

A

increase in near point of vision that develops with age

64
Q

Depth of focus

A

the greatest distance through which an object can be moved and still remain in focus on the retina

Main factor affecting depth of focus is pupil size

65
Q

Convergence

A

medial rotation of the eyes

66
Q

Myopia

A

nearsightedness

Can see close objects clearly and far objects are blurry

Focal point is too near the lens and the image is focused in front of the retina

Corrected by concave lens aka minus lens

radial keratotomy and LASIK

67
Q

Radial keratotomy

A

a series of 4-8 radiaing cuts are made in cornea, so it becomes flattened and eliminates myopia

68
Q

Hyperopia

A

farsightedness

can see distant objects clearly but close objects are blurry

Cornea or lens system is too weak or eyeball too short

Image is focused behind the retina

can be correct by convex lenses (plus lenses)

69
Q

Presbyopia

A

normal unavoidable degeneration of accommodation power of eye associated with aging

*Lens becomes less flexible

When near point of vision increases beyond 9 inches

Avg age is mid 40’s

70
Q

Astigmatism

A

type of refractive error that affects quality of focus

Can be corrected with glasses if normal astigmatism

71
Q

The retina consists of a neural layer and a pigmented layer. The neural layer has what 3 sublayers?

A

Photoreceptor cells
bipolar cells
and ganglionic cells

and 2 plexiform layers where neurons of adjacent layer synapse with eachother

72
Q

Pigmented layer

A

consists of a single layer of cells filled with melanin

73
Q

Rods

A

bipolar photoreceptor cells involved in non-color vision, responsible for vision under conditions of reduced light

74
Q

Rhodopsin

A

purple pigment that consists of the protien opsin

75
Q

Cone

A

color vision; visual activity

76
Q
A
77
Q

Cones

A

bipolar phooreceptor cells

color vision and visual acuity are the functions of cone cells

Cones require relatively bright light to function

Contain visual pigment, iodopsin (red,blue,green)

78
Q

Where is color interpreted?

A

In the visual cortex of occipital lobe

79
Q

What does colorblindness result from?

A

dysfunction of 1 or more of the 3 photo pigments (red, blue,green)

80
Q

What are the organs of hearing and balance?

A

External ear
Middle ear
Inner ear

*The external ear and middle ear are involved in hearing only, while the inner ear functions both in hearing and balance

81
Q

What are the 3 layers of the tympanic membrane?

A
  1. simple cubodial epithelium
  2. middle layer of connective tissue
  3. thin stratified squamous epithelium
82
Q

The semicircular canals do what?

A

involved in balance

83
Q

Cochela does what?

A

involved in hearing

84
Q

What are the 2 major features of sound?

A

Volumne and pitch

Volume is a function of sound wave amplitude or height measured in decibels

Pitch is the sound wave frequency measured in hertz