Chapter 16 - Sensory Flashcards
Modality
type of sensation
Photoreceptor
Light
Mechanoreceptor
Mechanical energy, ex. stretch or bending
hair cells of cochlea (hearing) also….touch, pressure, stretch, or tension
Thermoreceptor
heat or cold
Chemoreceptors
lfaction, gustation, & internal chemistry – Particle [ ] in extracellular fluid,
Nociceptor
pain
Law of Specific Nerve Energies
Receptors only respond to their modality.
i.e. taste receptors do not respond to light
Transduction
Transduction = change of energy, ex. stretch of mechanoreceptor becomes graded potential and possibly an action potential.
Adaption
So you can ignore stuff
Hair receptor
hair movement and very gentle touch
Merkel’s disc
light sustained touch
Pacinian corpuscle
Vibrations and deep pressure
Ruffini endings
deep pressure
Meissner’s corpuscle
light, fluttering touch
Acuity and Receptive Field Size
- Two receptive fields stimulated by two points of stimulation: two points felt
- Only one receptive field stimulated by the two points of stimulation the same distance apart is in: one point felt
Fast pain
Occurs on stimulation of mechanical and thermal nociceptors
Carried by small, myelinated A-delta fibers
Produces sharp, prickling sensation
Easily localized
Occurs first
Slow pain
Occurs on stimulation of polymodal nociceptors
Carried by small, unmyelinated C fibers Produces dull, aching, burning sensation
Poorly localized
Occurs second; persists for longer time; more unpleasant
How We Block Pain
Which of these is NOT one of the primary tastes?
Spicy
Primary tastes
bitter, salty, sweet, sour, umami
Each olfactory cell makes one kind of odor receptor that binds to one kind of odorant. How many different kinds of odor receptor cells are in your nose?
400
pitch
depends on frequency
intensity
depends on amplitude
timbre
depends on overtones
Vestibular Apparatus
3 Semicirc Canals + 2 Gravity Sensors (Utricle & Saccule)
Utricle
- Detects (1) changes in head position away from vertical and (2) horizontally directed linear acceleration and deceleration
- Movement Away from Horizontal
Or Horizontal Traveling - next slide
Saccule
- Detects (1) changes in head position away from horizontal and (2) vertically directed linear acceleration and deceleration
- Movement away from vertical or
vertical movements.
Ex. Get out of bed (horiz → vertical) or vertical traveling like riding elevator up & down.
Cupula
Accessory Structure for hair cells in Semicirc canals
Vestibular nuclei
Ex. Reading road signs from a moving vehicle. Tracking thrown ball with eyes. Keeping your balance while walking on boat deck.
Gustation
taste, CN VII, IX, X
Olfaction
smell, CN I
Somatosensory
eceptors, spinal cord & brainstem, thalamus, parietal lobe
Vision
photoreceptors depolarized in the dark, retinal processing, CN II, thalamus, occipital lobe
Auditory
cochlea, hair cells, CN VIII, brainstem, thalamus, temporal lobe Vestibular - also hair cells, CN VIII
Glaucoma
If fluid cannot drain via canal of Schlemm (Scleral Venous Sinus), pressures build up →
Parasympathetic stimulation
Circular muscles runs circulary
Sympathetic stimulation
Radial muscle runs radially
Refraction
bending of light rays
Cornea and lens do this
Accomodation
When the lens gets rounder for greater refraction for near objects
Far vision
flatter lens
Near vision
Rounder lens
Emmetripia
Normal vision
myopia
Nearsighted
Hyperopia
Farsighted
Outer segment of rod
For dim light
most common in peripheral retina
Outer segment of cone
for color
most common in fovea/central retina
require bright light
Rods
120 million per retina
More numerous in periphery
High sensitivity
Night vision
Low acuity
Much convergence in retinal pathways
Vision in shades of gray
Cones
6 million per retina
Concentrated in fovea
Low sensitivity
Day vision
High acuity
Little convergence in retinal pathways
Color vision
Corpuscle
(layers like an onion) makes the Pacinian corpuscle a phasic receptor.
