Bio107-ch15EYE Flashcards
Sensory receptors provide
external and internal environmental information to the CNS
Sensory receptors act as
transducers
Transducers convert
energy into depolarization
through action potential
Receptors produce _____ potentials that may stimulate ______ potentials
graded
action
Sensory receptors are ______ selective
highly
Chemoreceptors
detect changes in chemical environment
taste buds, olfactory epithelium
Photoreceptors
detect light
Thermoreceptors
temperature
Mechanoreceptors
mechanical distortion or pressure
Propioceptors
position of muscles and joints
Nociceptors
pain
Osmoreceptors
solute concentration
Sensory adaption/receptor ______ its response to stimulus over time
decreases
Tonic adaption
receptors do NOT adapt or adapt slowly
pain receptors
Phasic adaption
receptors ADAPT rapidly
odor, touch
The eye:
Light perception
rods and cones in retina
Light regulation
iris
Accommodation
focus
Interpretation
CNS
In the eye, light rays enter through the _____, then pass to the ______
cornea
retina
Fovea centralis (3)
- focal point at the back of the eye
- has the greatest acuity
- cont. only CONES
Sclera
white part of eye
Choroid
contains a lot of blood vessels
dark/black outline in pic
Retina
contains the rods that take in light
Optic Nerve
blind spot because there’s no rods/cones
a cranial nerve
Suspensory ligament (3)
- helps stretch or relax ligaments
- helps determine light
- invuluntary
Iris
- colored part
2. determined by MYLONALYTES
Anterior chamber
front space of eye
Posterior chamber
back space of eye
Cornea
clear lens
Pupil
- a hole/black tunnel
2. where the light travels through to the fovea
Lens
suspense the eye
Aqueous humor
clear
as you get older or diseased it can turn grey
Vitreous humor
helps deal with pressure in the eye
Refraction
bending of light rays
Refracted first by the _____ then by the _____
cornea
lens
Visual Axis
straight through the eye and to the back
light rays that pass directly to the central fovea follow this
Accomodation
focusing of the lens for clearer vision
Distance vision the lens is
FLAT from front to back
Near vision the lens is
THICK from front to back
Contraction makes the lens
thicker
close = contraction
Relaxation pulls the lens
flat
distance = relaxation
Myopic eye
nearsighted
Hyperopic eye
farsighted
Emmetropic
normal, healthy eye, perfect vision
Abstigma
abnormal in the cornea and/or lens
Iris deals with
light regulation and regulates the size of the pupil
Contracted iris
small pupil size
Dilated iris
larger pupil size
Light is perceived by (2)
- Visual Rods
2. Visial Cones
Rhodopsin
photopigment (visual purple)
in RODS*
Things about RODS (5)
- High sensitivity- helps at night time
- More photopigment
- Slow response, long integration time
- Low acuity- does NOT help you see
- Achromatic- ONE type of ROD pigment
Things about CONES (5)
- Low sensitivity- for day vision
- Less photopigment
- Fast response, short integration time
- High acuity
- Chromatic- 3 types of CONES each with a different pigment
Role of Vitamin A (4)
- eye health
- effects rods more than cones
- night blindness
- causes a decrease in retinal
Color vision:
3 types of cones
- blue cone
- green cone
- red cone
If missing one of the 3 types of CONES, then
colorblind
Colorblindness is passed along the
X chromosome
mostly men are affected