Sensory Physiology Flashcards
Specific sensations, specific receptors
Differential Sensitivity
Specific sensations, specific pathways
Labeled line principle
Change in a way a receptor responds to sequential or prolonged stimulation
Adaptation
For continuous stimulus strength (detects steady stimulus)
Slowly-adapting receptor (Tonic Receptors)
Slowly-adapting receptor (Tonic Receptors)
Muscle spindle, Golgi tendon, slow pain receptor, baroreceptor, chemoreceptors
For detecting change in stimulus strength (detects onset and offset of stimulus)
Rapidly-adapting Receptors (Phasic Receptors)
Rapidly-adapting Receptors (Phasic Receptors)
Pacing an Corpuscle
Receptor potential in a Pacinian Corpuscle
If depolarizing, brings the membrane potential closer to threshold
Smaller receptive field with well-defined border
Type 1
Wider receptive field with poorly-defined borders
Type 2
2 point discrimination receptor?
Type 1 receptor field
Stationary
Merkel’s
Moving
Me issuers
Touch & pressure in the skin
Free Nerve Endings
Movement of objects & low frequency vibration
In non-hairy skin esp. Fingertips and lips
Meissner’s Corpuscle (FA1)
Gives steady-state signals for continuous touch
Localizing touch sensation and to determine texture
Combine to form Dome Receptors
Expanded tip tactile receptor
Merkel’s Disc (SA1)
Movement of object on the skin
Hair-end organ
Heavy & prolonged touch (pressure) and to signal degree of joint rotation
In deep skin, internal tissues & joint capsules, multi-branched, encapsulated, slowly-adapting
Ruffini’s end organs (SA2)
Detects high-frequency vibration
Onion-like structure in skin & deep fascia
Pacinian Corpuscles (FA2)
Transducers stimulus to electrical signal
Sensory Receptors
Cell Body: Dorsal Root or Cranial Nerve Ganglia
First-Order Neurons
Cell Body: Spinal Cord or Brainstem
Second-Order Neurons
Cell Body:Thalamus
Third ORder Neurons
Cell body: Sensory Cortex
Fourth-Order Neurons
Uses large myelinated fibers (group II), conduction velocity 30-110 m/s
Dorsal Column-Medial Lemniscus Pathway
cRosses near the medulla
Dorsal Column-Medial Lemniscus Pathway
Uses smaller myelinated fibers (group III, IV) 8-40 m/s
Antero-Lateral System (Spinothalamic Tract)
Relay station for sensation
Thalamus
VPL nuclei
Dorsal Column-Medial Lemniscus Pathway
VPM
TrigeminoThalamic pathway
VPI nuclei
Anterolateral system
Neurotransmitters for pain
Glutamate & substance P
Fast pain
Aka first/sharp/pricking/acute/electric pain
Type A delta fibers
Fast pain
Neurotransmitter for Fast Pain
Glutamate
Slow Pain
Aka second/aching/throbbing/nauseous/chronic pain
Type C fiber
Slow pain
Neurotransmitter for Slow Pain
Substance P
Due to sharing of 2nd order neurons in the spinal cord of visceral pain fibers and skin pain fibers
Referred pain
Warmth Receptors
Free nerve endings, Type C fibers
Cold Receptors
Type A delta fibers, some Type C
Pain Receptors
<15 deg C or > 43 deg C
Distant objects
Lens should be flat
Tensed suspensions ligament
Relaxed ciliary muscle
Nearby Objects
Lens should be spherical
Relaxed suspensions ligament
Contracted ciliary muscles
Gelatinous with little flow
Behind the lens
Vitreous Humor
Produced by Ciliary body
Exits into Canal of Schlemm
Free flowing
Main determinant of IOP
Aqueous Humor
Flow of Aqueous Humor
Ciliary body - posterior chamber - pupil - anterior chamber - trabecular mesh work - anterior chamber angle - canal of Schlemm - uveoscleral veins
Area of central vision with slight thickening and pale color
Macula Lutea
Depression in macula Lutea with the highest visual resolution (highest cone density)
Fovea
Lacks rods & cones (anatomic blind spot)
Optic Disk
What do you call the protrusion of the optic disc into the vitreous space due to increased ICP?
Papillae a
Daylight
Cones
Dark
Rods
Converts 11-cigs retinal to all-trans retinal
Pigment epithelium
Absorb stray light and preventing light from scattering
Pigment epithelium
Absorb in Optic Disk; synapses with bipolar cells
Rods & Cones
Interneuron that connects Rods & Cones with Ganglion Cells
Contrast Detectors
Bipolar cells
Inter neurons that form local circuits with bipolar cells
Amacrine cells, Horizontal cells
Retinal glial cell
Maintains internal geometry of the retina ganglion cell
Mueller Cells
P cells
Color, form, fine details
M Cells
Illumination, movement
W Cells
Unknown function
Cutting of structure on the left side causes total blindness in the left eye?
Optic nerve
Causes bitemporal hemianopsia
Optic chasm
Cutting which structure on the left causes right homonymous hemianopsia?
Optic tract
Lesion on which structure on the left causes superior right homonymous quadrant anoxia
Meyer’s/temporal loop
Lesion on which on the left causes inferior right homonymous quadrant anoxia
Parietal lobe
Lesion on which structure on the left causes inferior right homonymous hemianopsia
Geniculocalcarine tract
Lesion on which structure on the left causes right homonymous hemianopsia with macular sparing
Calcarine fissure
Total loss of vision in the right eye
Optic nerve
Non-homonymous bitemporal hemianopsia
Optic chiasm
Contra lateral (left) homonymous hemianopsia
Optic tract
Superior left homonymous quadrant anoxia
Temporal lobe (Meyer’s Loop)
Inferior left homonymous quadrantanopia
Parietal Lobe
Contralateral (left) homonymous hemianopia
Geniculocalcarine tract
Superior left homonymous quadrantanopia (with macular sparing)
Inferior bank of calcarine fissure
Inferior left homonymous quadrantanopia (with macular sparing)
Superior bank of calcarine fissure
Contralateral (left) homonymous hemianopia (with macular sparing)
Both banks of calcarine fissure
Which type of cell in the visual cortex responds best to a moving bar of light?
Complex
Which type of cell in the visual cortex responds best to a stationary bar of light?
Simple
Which type of cell in the visual cortex responds best to lines, curves and angles?
Hyper complex
All of the following are found in the visual cortex except? A. Simple cells B. Complex C. Hypercomplex D. Bipolar cells
Bipolar cells
Which of the following. Is a step in photoreceptors in the rods?
Metarhodopsin II activates transduction
All of the following processes in photoreceptors are correct except?
A. Light converts 11-cis rhodopsin to all trans rhodopsin
B. Metarhodopsin II activates transducin
C. Transducin activates phosphodiesterase decreasing cGMP
D. CGMP decreases closing Na channels causing the membrane to depolarize
D. Hyperpolarizes
Light rays converge in front of the retina (long eyeball)
Myopia (biconcave lens)
Light rays converge behind of the retina (short eyeball)
Hyperopia (convex lens)
Irregular curvature of the cornea
Astigmatism (cylindrical lens)
Age-related loss of accommodation (near point moves farther away)
Presbyopia (convex lens)
First sign of Vitamin A deficiency
Nyctalopia
Normal vision
Emmetropia
Biconcave lens
Myopia
Convex lens
Hyperopia
Presbyopia
Cylindrical lens
Astigmatism
Sound pressure
Decibels
Sound frequency
Hertz
What is the age-related progressive sensorineural hearing loss?
Presbycusis
Occupational hearing loss occurs after >10 year exposure to which sound pressure
> 85 dB
What sound pressure causes pain & possible permanent damage?
120 dB
Conversation
60 dB
Workplace 8 hours
> 85-90 dB
Occupational hearing loss
Sx after 10 years
> 90 dB
OHL
Irreversible sensory neural hearing loss
100-110 dB
For sound collection, localization
Pinnacle
Impedance matching
Auditory ossicles
Endolymph
Scalia media, high in potassium
Peri lymph
Scalia vestibule, scalar tympani, high sodium
What are the two muscles found in the middle ear?
Tensor tympani (malleus) StaOedipus (stapes)
What is the connection between outer & middle ear?
Eustachian tube
What is the function of the middle ear?
Impedance matching
What is the function of the attenuation reflex?
Protects cochlea from loud/damaging sounds
Masks background noise
Otoliths organs
Utricle & saccule
For linear acceleration & sometime angular acceleration
Utricle & Saccule
Anterior, posterior, lateral canals
Semicircular Canals
For angular acceleration
Semicircular canals
Located on anterior and lateral part of the tongue
Fungi form & Foliate papillae
Located at the base of the tongue
Circumvallate papillae