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A-BIOL1191 LAB > LAB 3 > Flashcards

LAB 3 Flashcards

1
Q

what are sensory receptors?

A

specialized cells or dendrites of sensory neurons that provide CNS w/ info abt body’s internal/external conditions

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2
Q

why are photoreceptors in retina stimulated by light rays but not smells or sounds?

A

most receptors are sensitive to one particular stimulus but relatively insensitive to others

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3
Q

what are the general senses?

A
  • pain, warmth, cold, tactile, proprioception
  • stretch, chemical, pressure
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4
Q

what are the special senses?

A
  • vision
  • olfaction
  • gustation
  • hearing
  • equilibrium
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5
Q

what must happen for a sensation to be consciously perceived?

A

nerve impulse initiated by sensory receptor must be conducted to CNS and must reach region of brain where stimulus perceived and interpreted

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6
Q

what happens to nerve impulses that reach cerebral cortex?

A

they are consciously perceived as sensations

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7
Q

what happens to nerve impulses that are interpreted at the level of the spinal cord or brainstem

A

they do not reach cerebral cortex, so they cause a reflex response but conscious perception does not occur

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8
Q

what are the somatic senses?

A
  • tactile
  • warmth
  • cold
  • pain
  • proprioception
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9
Q

where are somatic sense receptors located?

A

in the skin, or embedded in muscles, tendons, and joints

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10
Q

what are cutaneous sensations?

A

sensations perceived by somatic sense receptors located in the skin

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11
Q

where are receptors for visceral senses located?

A

in the internal organs

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12
Q

what are the visceral senses?

A
  • stretch
  • chemical
  • pressure
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13
Q

where are stretch receptors found?

A

walls of hollow organs

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14
Q

where are chemical receptors found?

A

in epithelium of hollow organs

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15
Q

what are the two structural types of somatic sensory receptors?

A
  • free nerve endings
  • encapsulated nerve endings
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16
Q

what is special about encapsulated dendrites’ capsule?

A

type of connective tissue capsule around encapsulated nerve endings enhances its sensitivity or specificity to a stimulus

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17
Q

what structural type of neurons are the free and encapsulated nerve endings?

A

pseudounipolar neurons

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18
Q

what are tactile corpuscles?

A
  • encapsulated nerve endings
  • **detect onset of touch
  • detect low frequency vibration**
  • found in dermal papillae of highly sensitive areas of hairless skin
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19
Q

what are hair root plexuses?

A

free nerve endings wrapped around hair follicles

  • detect movement that disturb hairs
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20
Q

what are nonencapsulated sensory corpuscles?

A
  • Merkel discs/tactile discs
  • free nerve endings
  • associate w/ tactile epithelial cells in stratum basale of highly sensitive areas of hairless skin
  • detect pressure and continuous touch
  • numerous in fingertips, hands, lips
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21
Q

what are bulbous corpuscles?

A
  • ruffini corpuscles
  • encapsulated receptors deep in dermis, in ligaments and in tendons
  • detect stretching and steady pressure
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22
Q

what are lamellar corpuscles?

A
  • encapsulated dendrites
  • in dermis and subcutaneous regions
  • detect high frequency vibrations
  • detect steady pressure
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23
Q

what are free nerve endings?

A
  • stimulated by certain chemicals
  • tickling is result of stimulation of a free nerve ending
  • found in skin
  • senses pain, itch, cold, warmth
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24
Q

Describe how to detect touch/test the hair root plexus

A
  1. observe fine hairs on arm or back of hand
  2. gently move one hair in multiple directions w/ pencil tip
  3. flick hair rapidly several times
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25
Q

should there be difference in sensation felt between slow and fast stimuli when testing hair root plexus?

A

flicking hair rapidly will cause more frequent nerve impulses while gently moving the hair will send less frequent nerve impulses

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26
Q

should there be difference in sensation felt when two or three hairs are touched simultaneously when testing hair root plexuses?

A

Yes, stronger stimulus because more receptors are stimulated

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27
Q

what is tactile localization?

A

the ability to determine which portion of skin has been touched

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28
Q

why do some areas of the body have greater tactile sensitivity than others?

A

there are greater numbers of sensory receptors that detect tactile sensations in those body areas than other body areas

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29
Q

describe the relationship between receptor density and sensitivity

A

the greater the receptor density, the greater the sensitivity

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30
Q

describe the procedure for testing tactile localization

A
  1. subject closes eyes, arms held loosely away from body, elbows vent, one palm facing up with fingers spread while other hand hold green marker, tester touches subject’s fingertip w/ red marker
  2. subject tries to touch exact point w/ green marker, measure distance error
  3. repeat two times, aiming for same red spot and recording distance error
  4. repeat procedure on upper anterior forearm w/ no hair
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31
Q

which body areas have smallest area of localization?

A

fingertips

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32
Q

Can the ability to localize stimulus improve w/ subsequent attempts?

A

No, receptor density does not change

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33
Q

Describe the procedure for the two-point discrimination test

A
  1. subject’s eyes closed, start w/ closed caliper arms, tester should touch subjects palm w/ both points simultaneously w/ equal light pressure and ask if subject feels 1 or 2 pts.
  2. increase distance btwn caliper pts, continue until subject reports 2 pts contact is felt, measure distance
  3. repeat procedure w/ fingertip, back of hand, upper anterior forearm, back of neck, and forehead/cheek
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34
Q

what is the two-point threshold?

A

distance that two distinct and separate points of contact are felt

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35
Q

which body areas have the lowest two-point threshold?

A

fingertips

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36
Q

which body areas have highest two-point threshold?

A

back of head

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37
Q

describe the distribution of touch receptors in areas of body w/ lowest and highest two-point touch thresholds

A

areas w/ lowest two-point touch threshold have high density of cutaneous mechanoreceptors

areas w/ highest two-point touch threshold have low density of cutaneous mechanoreceptors

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38
Q

what type of touch receptors respond to two-point touch threshold test?

A
  • cutaneous mechanoreceptors
  • tactile corpuscles
  • tactile discs
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39
Q

what detects thermal sensations?

A

free nerve endings

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40
Q

what are cold receptors?

A

free nerve endings in stratum basale that detect 10-35°C

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41
Q

what are warm receptors?

A

free nerve endings in dermis that detect 30-45°C

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42
Q

describe thermal receptor distribution test

A
  1. draw rectangle 4x10mm on anterior surface of subject forearm w/ marker, diving rectangle into 10 squares, avoid hairy areas
  2. subject’s eyes closed, tester dried cold probe and touches small square w/ dry cold probe
  3. if cold, mark “c” on square, if no cold, “x”, if no touch felt, “o”
  4. repeat procedure on other 9 squares
  5. repeat procedure w/ dry warm probe, if hot, “h”
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43
Q

explain results of thermal receptor distribution test in terms of specificity and distribution of hot and cold receptors

A

warm and cold receptors distributed independently, there are more cold receptors on skin, hot receptors do not perceive warm stimuli as accurately as cold receptors

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44
Q

what are nociceptors?

A

free nerve endings that detect pain

  • found in all body tissues except brain
  • stimulated by chemical/physical damage to tissue
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45
Q

what is proprioception?

A

sense of body position in a three dimensional space

  • enables you to walk w/o looking at feet, or touch ear w/o looking at mirror
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46
Q

where are proprioceptors found?

A
  • synovial joints
  • tendons
  • skeletal muscles
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47
Q

what are proprioceptors?

A

nerve endings that convey info abt position of a joint, degree of muscle contraction, and amount of tension in tendons

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48
Q

which major parts of brain receive input from proprioceptors?

A
  • cerebellum
  • brainstem
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49
Q

describe procedure for testing proprioception?

A
  1. using pencil, draw small circle (1cm diameter) in middle of sheet of paper
  2. using red pen, place tip in middle of circle, remain in position w/ eyes closed for 15s, only elbow and pen touches table
  3. w/ eyes closed, lift pen 5-8cm off paper and make mark in circle, repeat until 10 marks made on paper
  4. repeat procedure w/ non-dominant hand and blue pen
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50
Q

why is there a difference in accuracy between dominant hand and non-dominant hand when testing for proprioception?

A
  • dominant hand more accurate, higher density of proprioceptors
  • more sensitive to pressure and tension changes
  • brain hemisphere that controls dominant hand more developed for motor skills
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51
Q

where are sensory receptors for olfaction?

A

in olfactory epithelium lining roof of nasal cavity

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52
Q

what classification are sensory receptors for olfaction?

A

chemoreceptors - responds to chemicals in solution

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53
Q

what do olfactory glands in lamina propria secrete?

A

mucus

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54
Q

how are odorant molecules smelled by olfactory cilia?

A

odorant molecules diffuse through air to nose and dissolve in mucus to stimulate olfactory cilia

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55
Q

describe pathway of olfactory stimuli to olfactory nerve

A

air → nose → dissolve in mucus → olfactory cilia

olfactory sensory neurons’ axons → cribriform plate of ethmoid bone → olfactory bulbs

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56
Q

what are olfactory cilia?

A

hairs that project from dendrites of olfactory sensory neurons

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57
Q

why do colds or allergies affect sense of smell

A
  • olfactory sensory neurons are affected/destroyed by pathogens
  • too much mucus blocks odorant molecules from coming into contact w/ olfactory cilia
  • inflammation obstructs olfactory epithelium
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58
Q

what is the olfactory tract?

A

bundle of axons extending posteriorly from olfactory bulb to olfactory regions of cerebral cortex

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59
Q

what is the olfactory bulb?

A

swollen ends of olfactory nerve, synapses w/ axons of olfactory sensory neurons coming from olfactory epithelium, conveys olfactory info to brain

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60
Q

what is the ethmoid bone?

A

bone where olfactory nerves pass through, contains cribriform plate and cribriform foramina

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61
Q

what is the cribriform plate?

A

process on ethmoid bone where cribriform foramina are located, where olfactory nerves pass through

  • olfactory epithelium covers inferior surface of cribriform plate
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62
Q

what is the nasal cavity?

A

cavity containing olfactory epithelium that occupies its superior portion

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63
Q

what are the olfactory glands?

A

glands that produce mucus carried to surface of epithelium by ducts
- within connective tissue that supports olfactory epithelium
- innervated by parasympathetic fibres of facial (VII) nerve

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64
Q

what is the mucus made by olfactory glands?

A

mucus moistens olfactory epithelium surface, dissolves odorant molecules so transduction of olfactory stimuli can occur

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65
Q

what are olfactory sensory neurons?

A

bipolar sensory neurons found in olfactory epithelium that transduces odors into neural signals, responds to chemical stimulation of odorant molecules by producing receptor potentials

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66
Q

what are odorant molecules?

A

chemicals that bind to and stimulate olfactory sensory neurons by coming into contact w/ olfactory cilia

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67
Q

Describe procedure for testing olfactory adaptation

A
  1. Vial A: peppermint, Vial B: pepprmint+cloves
  2. smell each vial and identify odours
  3. smell Vial A continuously for 4min and note time until no longer notice smell
  4. Quickly switch to Vial B and note what odor is smelled
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68
Q

what happened in terms of adaptation of the smell receptors in the olfactory adaptation test?

A
  • olfactory sensory receptors send receptor potentials at lower amplitude than initially due to maintained, constant stimulus
  • lower amplitude = less frequent nerve impulses
  • perception of sensation fades/disappears
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69
Q

when does olfactory adaptation occur in real life?

A

olfactory sensory neurons adapt by 50% in 1st sec after stimulation but adapt very slowly thereafter

  • complete insensitivity to certain strong odours occur ~1min after exposure
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70
Q

is olfactory adaption desirable?

A

Yes, can allow us to focus on other stimuli in a strong-smelling environment

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71
Q

where are sensory receptors for gustation located?

A

in taste buds of tongue, soft palate, pharynx, and epiglottis

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72
Q

what are taste buds?

A

onion-shaped groups of cells located in stratified squamous epithelium of tongue, on lingual papillae

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73
Q

what are lingual papillae?

A

elevated areas of tongue

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74
Q

what are gustatory epithelial cells?

A

epithelial cells w gustatory microvilli (hairs) that projects through taste pore at apical end of taste bud

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75
Q

what classification of receptors are taste buds?

A

chemoreceptors; food molecules must be dissolved in saliva to make contact w/ gustatory microvilli

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76
Q

what happens at basal end of taste buds?

A

gustatory epithelial cells synapse w/ dendrites of 1st order taste neuron that has contact w many gustatory epithelial cells in several taste buds

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77
Q

what are the cranial nerves that transmit from sensory information from taste buds to brain?

A
  • Facial (VII) nerve
  • Glossopharyngeal (IX) nerve
  • Vagus (X) nerve
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78
Q

describe the procedure for testing the effect of smell on taste

A
  1. subject sniffs vials w/ peppermint and clove oil and try to identify them
  2. subject dries tongue, closes eyes, and plugs nose; tester dips new cotton swab in cloves, and touches anterior 1/3 of tongue w/ swab and note if subject can detect the flavour
  3. have subject unplug nose and note change in sensation, rinse mouth
  4. have subject sit w/ eyes closed and mouth open, tester dips new swab in peppermint and new swab in cloves, hold peppermint under nose while simultaneously touching clove on tongue and note flavour subject tastes
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79
Q

is smell or taste more important in proper identification of strong substance?

A

smell, smells trick us into thinking we are tasting that substance

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80
Q

describe the procedure for testing chemoreception in gustation

A
  1. dry tongue surface w/ paper towel and place freshly unwrapped candy on anterior 1/3 tongue, keeping mouth open
  2. time how long it takes to taste the candy
  3. remove candy, rinse mouth
  4. repeat experiment w/ well moistened mouth, use new candy if you wish
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81
Q

what conclusions can you draw about chemoreception and gustation in their respective test?

A

IDK

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82
Q

what are the two types of receptors found in the retina?

A
  • rods
  • cones
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83
Q

how is the eye protected?

A
  • eyelids, eyelashes, eyebrows
  • lubrication system of tear glands and ducts
84
Q

what is the lacrimal gland?

A

secretory cells located at superior anterolateral portion of each orbit

  • secretes tears into excretory ducts that open onto surface of conjunctiva
85
Q

what is the lacrimal sac?

A

superior expanded portion of the nasolacrimal duct that receives the tears from a lacrimal canal

  • in lacrimal fossa of lacrimal bone
86
Q

describe the path tears take from lacrimal glands to excretion

A

lacrimal gland → lacrimal canaliculi → lacrimal sac → nasolacrimal duct

87
Q

what is the eyelid?

A

palpebrae

  • shades eyes during sleep
  • protects eyes from excessive light and foreign objects
  • spreads lubricating secretions over eyeballs
88
Q

what is the pupil?

A

hole in center of iris
- autonomic reflexes regulate pupil diameter in response to light lvls

89
Q

what is the iris?

A

colored muscle of eyeball that regulates amount of light entering eyeball through pupil
- suspended btwn cornea and lens
- attached at its outer margin by ciliary processes

90
Q

what is the sclera?

A

“whites” of the eye
- layer of dense connective tissue, mainly collagen fibres and fibroblasts
- gives eyeball its shape, makes it more rigid, protects inner parts
- covers entire eyeball except cornea
- serves as attachment site for extrinsic eye muscles

91
Q

what innervates superior rectus?

A

oculomotor (III) nerve

92
Q

what innervates inferior rectus?

A

oculomotor (III) nerve

93
Q

what innervates lateral rectus?

A

abducens (VI) nerve

94
Q

what innervates medial rectus?

A

oculomotor (III) nerve

95
Q

what innervates superior oblique?

A

trochlear (IV) nerve

96
Q

what innervates inferior oblique?

A

oculomotor (III) nerve

97
Q

superior rectus

A

elevates, adducts, and medially rotates eyeballs

98
Q

inferior rectus

A

depresses, adducts, and laterally rotates eyeballs

99
Q

lateral rectus

A

abducts eyeballs

100
Q

medial rectus

A

adducts eyeballs

101
Q

superior oblique

A

depresses, abducts, and laterally rotates eyeballs

102
Q

inferior oblique

A

elevates, abducts, and laterally rotates eyeballs

103
Q

what is ciliary body?

A

what the choroid becomes in anterior portion of vascular tunic of eyeball
- dark-brown, contains melanocytes
- contains ciliary muscles that alters shape of lens to adapt for near/far vision

104
Q

what are the ciliary muscles?

A

circular band of smooth muscle

  • contraction/relaxation changes tightness of zonular fibres, altering shape of lens to adapt for near/far vision
105
Q

what are the ciliary processes?

A

folds on internal surface of ciliary body

  • contains blood capillaries that secrete aqueous humour
106
Q

what is the anterior segment of the eye?

A

space btwn cornea and lens that contains aqueous humour, maintaining shape of eyeball, suppliying oxygen to lens and cornea

107
Q

what is aqueous humour?

A

transparent, watery liquid that nourishes lens and cornea

  • replaced completely every ~90min
108
Q

what is the anterior chamber of the eye?

A
  • part of anterior segment, space btwn cornea and iris
109
Q

what is the posterior chamber of the eye?

A
  • part of anterior segment, space btwn zonular fibres&lens and iris
110
Q

what is the cornea?

A

nonvascular, curved, and transparent fibrous coat covering the iris that helps focus light onto retina

  • central part receives oxygen from air
  • admits and refracts light
111
Q

what is the lens?

A

cavity of eyeball, behind pupil and iris that helps focus images on retina to facilitate clear vision

  • crystallins in cells of lens make up refractive media of the lens
112
Q

what are the zonular fibres of the lens?

A

suspensory ligaments
- thin, hollow fibrils that extends from ciliary processes and attached to the lens
- ciliary muscle changes their tightness, adapting eyes for near/far vision by altering shape of lens

113
Q

what is the bulbar conjunctiva?

A

thin, protective mucous membrane of nonkeratinized stratified squamous epithelium w/ goblet cells supported by areolar CT
- passes from eyelids onto eyeball surface, covering entirety of sclera but not cornea

114
Q

what is the retina?

A

inner layer of eyeball consisting of nervous tissue that receives light and transduces it into receptor potentials and nerve impulses
- beginning of visual pathway
- consists of pigmented layer of epithelial cells that contact choroid

115
Q

what is the choroid?

A

highly vascularized layer that lines most of internal surface of retina
- blood vessels provide nutrients to posterior surface of retina
- melanocytes in choroid absorbs stray light rays, so image cast on retina is sharp & clear

116
Q

what is the macula?

A

“yellow spot” in exact center of posterior portion of retina, at visual axis of eye
- contains receptors for linear acceleration/deceleration and head tilt

117
Q

what is the fovea centralis?

A

small depression in center of macula only containing cones
- area of highest visual acuity (sharpness of vision)

118
Q

what is the optic disc?

A

site where optic (II) nerve exits eyeball, no photoreceptors found so light rays focused here won’t be interpreted as an image

119
Q

what is the optic (II) nerve?

A
  • exits eyeball through optic disc
  • receives visual input from eyeball and transducts to brain for conscious processing
120
Q

what is the posterior segment of the eyeball?

A

posterior portion of eyeball lying btwn retina and lens
- contains vitreous humour

121
Q

what is the vitreous humour?

A

transparent, jellylike substance that holds retina flush against the choroid, giving retina even surface for reception of clear images
- mainly water, collagen fibres, and hyaluronic acid
- contains phagocytic cells, removing debris and keeping eyes unobstructed

122
Q

which photoreceptors are involved in visual acuity?

A

cones

123
Q

which photoreceptors are used to see in low light conditions?

A

rods

124
Q

what is the Snellen eye chart?

A

chart that tests a person’s visual acuity/ their ability to see objects clearly at various distances

125
Q

what is 20/20 vision?

A

normal vision

at a 20ft distance, a person w/ normal vision can read small 20/20 line on Snellen eye chart

126
Q

what is emmetropia?

A

normal vision (20/20)

127
Q

what is 20/100 vision?

A

difficulty seeing distant objects, you can see at 20ft what a person w/ normal vision can see at 100ft

128
Q

what is myopia?

A

nearsightedness, lens of a person is unable to focus distant objects on retina, distant object is focused in front of retina and appears blurry

129
Q

what is 20/15 vision?

A

objects you can clearly see at 20 ft are seen clearly by person w/ normal vision at 15ft

130
Q

what is hyperopia?

A

farsightedness, lens of a person may focus nearby objects behind the retina, nearby objects appear blurry

131
Q

describe the procedure for testing visual acuity

A
  1. subject stands 20ft from chart, covering left eye and reading each row of letters from left to right beginning at top of chart while tester tests for accuracy
  2. check line that was last read accurately
  3. have subject cover right eye and read chart w/ left eye
  4. repeat test w/ both eyes open
132
Q

describe the test for colour blindness?

A

the book for congenital colour vision tests for colour blindness

133
Q

what is colour blindness?

A

absence/deficiency of one of three photopigments located in the cones

  • can be inherited/acquired
134
Q

what is the cause of red-green colour blindness?

A

missing red/green photopigment in cones, preventing affected person from distinguishing red from green

  • sex-linked recessive trait, passed on from mother to son via X-chromosome
135
Q

what is astigmatism?

A

condition caused by irregular curvature of cornea/lens, images appear blurry/distorted due to improper focusing

136
Q

describe procedure for testing astigmatism

A
  1. start 10ft from astigmatism chart and cover one eye, noting any disparity of thickness of the line groups
  2. switch eyes and repeat procedure
137
Q

describe the procedure for testing the blind spot

A
  1. hold page of star and circle ~50cm from face
  2. close right eye and focus left eye on black dot, not letting it wander from dot
  3. slowly bring page closer to face until star disappears
  4. note distance page is from space
  5. slowly bring page even closer and note if star reappears
  6. move book away, star should disappear and reappear
  7. switch eyes in same manner, staring at star instead
138
Q

what are intrinsic muscles of the eye?

A

muscles found inside eye
ex. ciliary muscles, circular and radial muscles of iris

139
Q

what are extrinsic muscles of the eye?

A

muscles attached to outer surface (sclera) of eye

ex. rectus and oblique muscles

140
Q

what do the extrinsic muscles accomplish?

A

attached to exterior of eye, makes it possible to keep moving object focused on fovea centralis

141
Q

what happens when the eye is focusing on a close object?

A

ciliary muscles contracted, lens is more curved

142
Q

what happens when the eye is focusing on a distant object?

A

ciliary muscles relaxed, lens is flat

143
Q

describe the procedure for testing the accommodation pupillary reflex

A
  1. have subject stare at far wall for 1min
  2. tester observes diameter of subject’s pupils from front w/o blocking subject’s view
  3. while observing pupil size, tester holds an object 6-10in from subject’s face and have them read few words from object
144
Q

how does size of pupil change as a person switches from looking at distance object to near object

A

pupil constricted to direct light waves from close object to fovea (accommodation)

145
Q

what is convergence?

A

medial rotation of eyeballs as an object moves closer to us, allowing light rays to strike same points on both retinas

146
Q

describe procedure for testing convergence reflex

A
  1. have subject stare at far wall for 1min
  2. tester observes diameter of subject’s pupils from front w/o blocking subject’s view
  3. while observing pupil size, tester holds a pencil 6-10in from subject’s face
147
Q

describe the path soundwaves take through eye

A

external acoustic meatus → tympanic membrane → auditory ossicle → vestibular window

148
Q

what happens after sound waves travel to vestibular window?

A

perilymph and endolymph in cochlea move, resulting pressure waves cause microvilli on hair cells to bend, triggering receptor potential

nerve impulses travel via cochlear branch of CN (VIII) to thalamus to be processed and interpreted as sound

149
Q

what happens to pressure built up inside cochlea?

A

released via cochlear window into middle ear

150
Q

what is the auricle?

A

flap of elastic cartilage, part of external ear

  • attached to head by ligaments and muscles
  • collects soundwaves and channels them inward
151
Q

what is the helix?

A

rim of auricle

152
Q

what is the lobule?

A

inferior portion of auricle

153
Q

what is the external acoustic meatus?

A

curved tube in temporal bone that leads to middle ear

  • directs soundwaves to tympanic membrane
154
Q

what is the tympanic membrane?

A

thin, semitransparent partition of fibrous connective tissue btwn external acoustic meatus and middle ear

  • vibration from soundwaves to tympanic membrane cause malleus to vibrate
155
Q

what are the auditory ossicles?

A

smallest bones of body, joined by synovial joints, transmits and amplifies vibrations from tympanic membrane to vestibular window

156
Q

what is the malleus?

A

attached to internal surface of tympanic membrane
- articulates w/ body of incus

157
Q

what is the incus?

A

articulates w/ head of stapes

158
Q

what is the stapes?

A

fits into vestibular window

159
Q

what is the vestibular window?

A

small, membrane-covered opening btwn middle and inner ear where foot plate of stapes fits

160
Q

what is the cochlear window?

A

small opening btwn middle and internal ear

  • directly inferior to vestibular window
  • covered by 2ndary tympanic membrane
161
Q

what is the eustachian tube?

A

connects tympanic cavity w/ nasopharynx

  • opens during swallowing/yawning
  • allows pressure in tympanic cavity to equalize w/ atmospheric pressure
162
Q

what is the vestibular branch of the vestibulocochlear (VIII) nerve?

A

contains 1st order sensory neurons and efferent neurons that synapse w/ receptors for equilibrium

163
Q

what is the cochlear branch of the vestibulocochlear (VIII) nerve?

A

contains 1st order sensory neurons and motor neurons that synapse w/ inner and outer hair cells on spiral organ for hearing

164
Q

what are the semicircular ducts?

A

portions of membranous labyrinth that lie inside the bony semicircular canal, connecting w/ utricle of vestibule

  • contains receptors for detecting rotational deceleration/acceleration
165
Q

what are the semicircular canals?

A

3 bony channels that contain receptors for equilibrium

166
Q

what are ampullae?

A

swollen enlargements at end of each semicircular canal
- contains cristae

167
Q

what are cristae?

A

small elevations in ampulla of each semicircular duct
- contains receptors for rotational acceleration/deceleration

168
Q

what is the cochlea?

A

winding, cone-shaped tube forming portion of inner ear
- transmits vibrations to spiral organ

169
Q

what is the cochlear duct?

A

scala media

membranous cochlea consisting of spirally arranged tube enclosed in cochlea & lying along its outer wall

170
Q

what is the scala vestibuli?

A

superior spiral-shaped channel of the bony cochlea
- ends at the vestibular window

171
Q

what is the scala tympani?

A

inferior spiral-shaped channel of bony cochlea
- ends at cochlear window

172
Q

what is the vestibular membrane?

A

membrane that separates cochlear duct from scala vestibuli

173
Q

what is the basilar membrane?

A

membrane in cochlea that separates cochlear duct from scala tympani
- on which spiral organ rests
- bodies of hair cells rest on basilar membrane

174
Q

what is the spiral organ?

A

organ of Corti

organ of hearing, consists of hair cells that produce receptor potentials from vibrations, eliciting nerve impulses in cochlear branch of CN VIII

175
Q

what is the tectorial membrane?

A

gelatinous membrane projecting over & in contact w/ hair cells of spinal organ
- ends of stereocilia of hair cells embedded in tectorial membrane

176
Q

what is the vestibule?

A

small space in bony labyrinth of inner ear, contains utricle

177
Q

what is the utricle?

A

two sacs inside membranous labyrinth of vestibule

  • contains receptor organs for linear acceleration/deceleration that occurs in head tilt and horizontal direction
178
Q

what is the saccule?

A

inferior & smaller of the chambers in the membranous labyrinth inside vestibule of inner ear

  • contains receptors for linear acceleration/deceleration that occurs in vertical direction
179
Q

what is the macula?

A

small, thickened region on utricle wall & saccule wall

  • contains receptors for linear acceleration/deceleration and head tilt
180
Q

what are otoliths?

A

calcium carbonate crystals embedded in otholithic membrane, detects linear acceleration/deceleration and head position

181
Q

Describe procedure for examining structures of outer ear using otoscope

A
  1. determine which diameter tip will fit comfortable in subject’s external acoustic meatus
  2. clean in and out of top w/ alcohol and attach to otoscope handle
  3. tester holds lit otoscope and inserts tip of otoscope into external acoustic meatus while grasping subject’s upper auricle pulling it up and back
  4. examine tympanic membrane, noting shape, colour, blood vessels, hair, earwax
  5. remove and clean tip of otoscope w/ alcohol, ensure light is switched off
182
Q

describe procedure for testing auditory acuity

A
  1. have subject sit in quiet location w/ eyes closed and plug left ear
  2. tester holds softly ticking clock very close to right ear
  3. slowly move clock directly away from ear until subject indicated ticking no longer heard
  4. measure distance at which ticking no longer heard
  5. repeat w/ other ear
183
Q

describe the procedure for testing auditory localization

A
184
Q

what happens if you cup your hands behind ears to gather sound during the auditory localization test?

A

sound is resonated, sounds echo-like, background noise reduced, enhancing ability to determine position of sound

185
Q

describe procedure for testing vertical acceleration/deceleration

A

going up and down elevator

186
Q

what are the receptors being tested when going up and down an elevator?

A

receptors in saccule of vestibule

187
Q

describe procedure for testing horizontal acceleration/deceleration

A

have subject stand upright w/ eyes closed

have subject tilt head forward, raising chin up again

188
Q

what receptors are being tested by tilting head forward and raising chin up?

A

receptors in utricle of semicircular canal

189
Q

describe procedure for testing receptors for rotational acceleration/deceleration

A

multiple rotations (10 turns in 20 seconds)

190
Q

what happens when you turn multiple times in a short period?

A

endolymph in semicircular ducts continue to move after subject’s body stops rotation

vertigo and dizziness can occur

191
Q

what receptors are being tested when turning multiple times in a short period of time?

A

cristae on ampullae on semicircular ducts

192
Q

describe function of sensory receptors

A

they receive external/internal stimuli from environment and transduce them into receptor potentials

193
Q

what are 3 somatic sensations that are detected by free nerve endings?

A
  • pain
  • temperature
  • itching
  • tickling
194
Q

what are 3 somatic sensations detected by encapsulated nerve endings?

A
  • pressure
  • vibration
  • some touch sensations
195
Q

why might lack of cutaneous receptors be dangerous?

A

sensations on skin will be gone, reflexes and responses to evasive stimuli will be gone and take longer to happen

196
Q

several minutes after applying perfume, you notice you cannot smell it anymore. should you apply more?

A

No, sensory adaptation occurred in only your olfactory receptors, others’ haven’t

197
Q

what is the sensory limb of the pupillary light reflex?

A

optic (II) nerve

198
Q

what is the motor limb of the pupillary light reflex?

A

parasympathetic fibres of oculomotor (III) nerve

199
Q

briefly describe the pupillary light reflex test

A

shine a flashlight into each eye noting the direct and consensual constriction of pupils

200
Q

what is the swinging flashlight test?

A

used to test relative sensory pupillary defect

swinging flashlight back and forth btwn the 2 eyes identifies if one pupil has less light perception than the other

201
Q

describe procedure for swinging flashlight test

A

shine flashlight at one eye noting size of both pupils, then swing flashlight to other eye

202
Q

what is the abnormal response to the swinging flashlight test?

A

if both pupils dilate after flashlight shines on one eye, then that eye has perceives less light stimulus than opposite eye, indicating defect in sensory pathway

203
Q

what are vergence eye movements?

A

when eyes move simultaneously inward (convergence) or outward (divergence)

204
Q

briefly describe the accomodation test

A

patient is asked to follow an object that is brought from distance to tip of their nose

205
Q

what happens when a distant object is brought closer?

A
  • eyes converge
  • pupils constrict
  • lens round up
206
Q

which areas are the smallest and most dense sensory units found in?

A

areas w/ the greatest somatosensory cortical representation (the areas of the body that are biggest on the somatosensory homunculus)

  • lips
  • fingers

A-BIOL1191 LAB (4 decks)

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