Sensory, Topnotch Flashcards
Characteristic of sensory receptors: Specific sensation, specific receptor
Differential sensitivity
Characteristic of sensory receptors: Specific sensation, specific pathway
Labeled line principle
Characteristic of sensory receptors: Change in a way receptor responds to sequential or prolonged stimulation
Adaptation
Receptor for continuous stimulus strength (detects steady stimulus)
Slowly-adapting receptor
Slowly-adapting receptor is aka
Tonic receptor
Receptor for detecting change in stimulus strength (detects onset and offset of stimulus)
Rapidly-adapting receptor
Rapidly-adapting receptor is aka
Phasic receptor
Tonic vs phasic receptor: Has a predictive function
Phasic
Slowly-adapting receptor examples (5)
1) Golgi tendon
2) Muscle spindle
3) Slow pain receptor
4) Baroreceptor
5) Chemoreceptor
Rapidly-adapting receptor example
Pacinian corpuscle
Regions of the skin where stimuli can change the firing rate of the sensory neurons
Receptive field
Type of receptive field: Smaller with well-defined border
Type 1
Type of receptive field: Wider with poorly-defined border
Type 2
Tactile receptor: Found in the skin
Free nerve endings
Tactile receptor: Non-hairy skin especially the lips and fingertips
Meissner’s corpuscles (FA1)
Tactile receptor: Expanded tip tactile receptor that combine to form Iggo Dome Receptors
Merkel Discs (SA1)
Tactile receptor: Found in hair base
Hair end organs
Tactile receptor: Found in deep skin, internal tissues, and joint capsules
Ruffini end organs (SA2)
Tactile receptor: Onion-like structure in skin and deep fascia
Pacinian corpuscles (FA2)
Tactile receptor: Multi-branched and encapsulated
Ruffini end organs
Tactile receptor: Touch and pressure
Free nerve endings
Tactile receptor: Movement of objects and low frequency vibration
Meissner corpuscles
Tactile receptor: Continuous touch
Merkel discs
Tactile receptor: Movement of object on skin
Hair end organs
Tactile receptor: Pressure
Ruffini end organs
Tactile receptor: Localizing touch
Merkel discs
Tactile receptor: Degree of joint rotation
Ruffini end organs
Tactile receptor: High-frequency vibration
Pacinian corpuscles
Tactile receptor: Determine texture
Merkel discs
Tactile receptor: 2-point tactile discrimination
Meissner corpuscles
Tactile receptor: Stretch
Ruffini
Cell body of first order neurons are found in
Dorsal root or cranial nerve ganglia
Cell body of second order neurons are found in
Spinal cord or brainstem
Cell body of third order neurons are found in
Thalamus
Cell body of fourth order neurons are found in
Sensory cortex
2 somatosensory pathways
1) Dorsal column medial lemniscus pathway
2) Anterolateral/spinothalamic tract
Dorsal column medial lemniscus: Fibers
Large myelinated
Dorsal column medial lemniscus: Conduction velocity
30-110 m/s
Dorsal column medial lemniscus: Temporal and spatial fidelity
Present
Dorsal column medial lemniscus: Decussation
Near medulla
Dorsal column medial lemniscus: Sensations
Those requiring high degree of localisation and fine gradation of intensity
Anterolateral system: Fibers
Smaller myelinated
Anterolateral system: Conduction velocity
8-40 m/s
Anterolateral system: Fidelity and accuracy
Less
Anterolateral system: Decussation
Immediately
Anterolateral system: Sensations
1) Pain
2) Temp
3) Tickle and itch
4) Sexual
Relay station for sensation
Thalamus
Thalamic nucleus of dorsal column-medial lemniscal pathway
VPL
Thalamic nucleus of trigeminothalamic pathway
VPM
Thalamic nucleus of anterolateral system
VPI
Largest areas in the homunculus (3)
1) Face
2) Hands
3) Fingers
T/F Pain receptors have little or no adaptation
T
Fast pain is felt after how many seconds of stimulus
0.1
Slow pain is felt after how many seconds of stimulus
1
Referred pain is due to sharing of
2nd order neurons in the spinal cord of VISCERAL and DERMATOMAL pain fibers
Endogenous analgesia system inhibits pain at what level
Spinal cord
2 systems of endogenous analgesia
1) Opiod-mediated (BED-beta endorphins, enkephalins, dynorphins)
2) Non-opiod mediated (stress)
Temperature gradations
Freesing cold > cold > cool > indifferent > warm > hot > burning hot
Warmth receptors
Free nerve endings
Cold receptors
A delta
Pain receptors are stimulated at what temp
Less than 15 degrees or > 43C
Pain receptors adapt only between what temp
20-40C
Visual system detects and interprets electromagnetic waves between
400-750nm
Eye: Outer layer (3)
1) Conjunctiva
2) Cornea
3) Sclera
Eye: Middle layer (2)
1) Iris
2) Choroid
Eye: Inner layer
Retina
5 layers of the cornea
ABCDE
1) Anterior epithelium
2) Basement membrane or anterior-limiting membrane
3) Corneal stroma (thickest)
4) Descemet membrane or posterior-limiting membrane
5) Endothelium
Cornea: Anterior epithelium, lining
Stratified squamous non-keratinizing
Main refractive medium of the eye
Cornea
Sclera covers posterior ___ of globe
5/6
2 muscles of iris
1) Sphincter pupillae (miosis via M)
2) Dilator pupillae (mydriasis via a1)
Photoreceptor for color
CCC
Cones
Color
Center of retina
Photoreceptor for dim light
Rods at the periphery of retina
Ability to bend light
Refractive power
Measure of refractive power
Diopters
T/F Lens has a constant refractive power determined by zonula fibers
F, variable
Relaxed ciliary muscles: Tension from suspensory muscles
Increased
Relaxed ciliary muscles: Shape of lens
Flat
Contracted ciliary muscles: Tension from suspensory muscles
Decreased
Contracted ciliary muscles: Shape of lens
Spherical
Shape of lens for distant vision
Flat
Shape of lens for near vision
Spherical
Snellen fraction
Testing distance (6 ft or 20m) / Smallest line patient can read on the chart
Legal blindness
20/200 or less than 10 degrees of visual field in better eye
20/20 vision is achieved at what age
2-4 y/o
Layers of tear film
1) Lipid
2) Aqueous (most abundant)
3) Mucin
Automatic adjustment in the focal length of the lens to permit retinal focus at varying distances
Accommodation
Accommodation provides an additional ___ diopters
14
Maintains shape of eye
Intraocular fluid
3 chambers of the eye
1) Anterior
2) Posterior
3) Vitreous space
Anterior chamber of the eye is ___ mm deep
3-4
Rate of aqueous humor production
0.25 mL every 10 hours
Aqueous humor: Produced by
Ciliary body
Aqueous humor: Exits into
Canal of Schlemm
Main determinant of IOP
Aqueous humor
Normal IOP
8-21 mmHg
Gold standard for measurement of IOP
Applanation/Goldmann tonometry
Composition of vitreous humour (4)
1) Water (99%)
2) Collagen
3) Hyaluronic acid
4) Soluble protein
Amount of vitreous humor
4mL
Aqueous humor flow
1) Ciliary body
2) Posterior chamber
3) Pupil
4) Anterior chamber
5) Trabecular meshwork
6) Anterior chamber angle
7) Canal of Schlemm
8) Uveoscleral veins
Effect of light on photoreceptors
Hyperpolarization
Point of sharpest vision
Macula lutea
Area of central vision
Macula lutea
Location of macula lutea
2 disc diameters TEMPORAL to the optic disk
Yellow spot in the retina
Fovea centralis
Depression in the macula
Fovea centralis
Area of highest visual resolution
Fovea centralis
Area of the retina with highest cone density
Fovea centralis
Anatomic blind spot
Optic disc
Protrusion of optic disc into the vitreous space due to increased ICP
Papilledema
Macular degeneration refers to deterioration of which layer of the retina
Pigment epithelium
In albinism, which part of the retina lacks melanin
Pigment epithelium
Area in the retina where rods and cones are absent
Optic disc
Normal cup/disc ratio
0.3
Normal arrangement of retinal vessels in the optic disc
Artery nasal to vein
Normal artery:vein diameter ratio
2:3
Interneuron that connects rods and cones with ganglion cells
Bipolar cells
Known as contrast detectors of the eye
Bipolar cells
Retinal glial cell
Mueller cell
Cells that maintains internal geometry of the retina
Mueller cells
Output cell of the retina: Color
P cells
Output cell of the retina: Illumination
IlluMination: M cells
Output cell of the retina: Unknown function
eWan: W cells
Output cell of the retina: Form
Porm: P cells
Output cell of the retina: Fine details
Pine details: P cells
Output cell of the retina: Movement
Movement: M cells
Cells whose axons form the optic nerve
Mueller cells
Rods vs Cones: Contains 1 type of photopigment
Rods
Rods vs Cones: Contains 3 types of photopigment
Cones
Rods vs Cones: Greater amount of photopigment
Rods
Rods vs Cones: More sensitive
Rods
Rods vs Cones: Adapts more rapidly
Cones
Rods vs Cones: Higher visual acuity
Cones
Rods vs Cones: Not present in fovea
Rods
Condition in which light rays converge in front of the retina
LMN
Long eyeball, myopia, near-sighted
Condition in which light rays converge behind the retina
Short eyeball, hyperopia, far-sighted
Condition in which light rays converge at the retina
Emmetropia
Condition brought about by irregular curvature of the cornea
Astigmatism
Age-related loss of accommodation
Presbyopia
First sign of vitamin A deficiency
Nyctalopia (night blindness)
Corrective lenses: Myopia
Concave or negative
Corrective lenses: Hyperopia
Convex or positive
Corrective lenses: Presbyopia
Bifocals
Corrective lenses: Astigmatism
Cylindrical
Speed of sound waves in air
335 m/sec
Sound waves: Frequency is measured in
Hertz
Sound waves: Pressure is measured in
Decibels
Sound waves: Frequency that human ears can detect
20-20000 cycles per sec
Low frequency vs high frequency: More damaging to the organ of Corti
Low
Age-related bilateral symmetrical progressive sensorineural hearing loss
Presbycussis
Occupational hearing loss occurs after > 10 years of exposure to what dB
85 dB
Sound pressure that will cause pain and possible permanent damage
120 dB
Fluid in the scala media
Endolymph, high in potassium (PISO: Potassium, endo)
Fluid in the scala vestibuli
Perilymph, high in sodium (PISO: Sodium, peri)
Function of the pinna
Collect sound
2 muscles found in the middle ear
1) Stapedius
2) Tensor tympani
Smallest muscle in the body
Stapedius
Related bone: Stapedius
Stapes
Related bone: Tensor tympani
Malleus
CN: Stapedius
VII
CN: Tensor tympani
V3
Connection between outer and middle ear
Tympanic membrane
Function of middle ear
Impedance matching
Function of attenuation reflex/acoustic reflex (2)
1) Protects cochlea from loud/damaging sounds
2) Masks background noise
Function of basilar membrane
Frequency analyzer
2 components of the vestibular apparatus
1) Otolith organs
2) Semicircular canals
Otolith organs (2)
1) Utricle
2) Saccule
Semicircular canals (3)
1) Anterior
2) Posterior
3) Lateral
Otolith organs: Sensory organ
Macule (stataconia and hair cells)
Otolith organs: Detects changes in
Head orientation with respect to gravity
Otolith organs: For what movements
1) Linear acceleration
2) Angular acceleration (sometimes)
Semicircular canals: Sensory organ
Crista ampullaris
Semicircular canals: Detects changes in
Rate and direction of head
Semicircular canals: For what movements (2)
1) Angular acceleration
2) Predictive in maintenance of equilibrium
of taste receptor cells
50-150
Taste receptor cells are replaced every
10 days
T/F Taste receptors are true neurons
F
Location of taste buds
1) Fungiform papillae (anterior)
2) Foliate papillae (lateral)
3) Circumvallate papillae (base)
Taste: Caused by various organic chemicals
Sweet
Taste: Caused by ionized salts, mainly Na
Salty
Taste: Caused by acids
Sour
Taste: Caused by MSG (proteinaceous meaty flavor)
Umami
Taste: Caused by organic substances
Bitter
Taste: More sensitive than other tastes
Bitter
of olfactory receptors
60M
Olfactory receptor cells are replaced every
60 days
T/F Olfactory receptors are true neurons
T
Fibers for olfaction
Unmyelinated C fibers
Only sense that does not have a relay station in the thalamus
Olfactory
Located at the superior part of the nostril, innervated by CN V that detects noxious/painful stimuli
Olfactory membrane
