Sensory System Flashcards
Parts of the Vertebrate Eye
Cornea Aqueous humor Iris Lense Choroid Sclera Retina (light sensors) Vitreous humor Fovea (where focusing occurs of object) optic nerve
What is the function of the retina?
Light sensors
What part of the eye does focusing occur
Fovea
What are the rods in eyes used for and where are they located?
Light sensitivity
concentrated edge or retina
What are cones used for and where are they located?
Color sensing
Retina
What is the part of the eye where most of the light is bent and where does the rest occur?
80% cornea
20% lens
What is accommodation of the eye?
In medicine, the ability of the eye to change its focus from distant to near objects (and vice versa). This process is achieved by the lens changing its shape. Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies.
Vision in water: what happens to light in the eye
Light does not get bent by cornea and all needs to be bend at the lens
Fish eyes Problem and solution
Problem : little refractive index difference between h20 and eye
also takes a while for them to transition between light and dark conditions
Solution: they have spherical layered lens and move the lens backwards and forwards to focus.
What is the tappet lucidum and what is its function
Light reflecting surface, minerals that reflect light, maximize light reflection
Marine Mammal eyes Problems and solution
problem: little refractive index difference between h20 and eye
Solution: spherical lenses like fish
Also need to see in air:
Flattened cornea (avoid cornea refraction in air)
-pinhole camera effects in air
Large pupillary range
Tapedum lucidum
How is stimulus intensity communicated?
More action potential
Draw the vertebrate eye:
How is the fish eye adapted?
How is the elephant seal eye adapted
Fish: must move their lens to focus light due to little refractive index difference between water and eye.
Mammals: have flattened corneas that help focus light. They also have large eyes and great pupillary range.
Both have taped lucidum and round lenses.
Hearing abilities of fish:
Measure particle movement.
Swim bladder conducts sounds
Otolith: flat surface remains stationary as the body moves and rubs against the sensory epathilium.
Cephalic and Lateral Lines
Neuromasts (hide between scales) on head and body, detect movement of displaced water molecules
Challenges of hearing in water
Sound conduction
sound localization: sound faster needs to be processed quicker
Hearing at depth
How do marine mammals hearing differ form terrestrial mammals?
External ear reduced or absent
ear closure mechanism for some species
different sound condition pathways
auditory bulla isolated or semi-fused to scull (helps process sound that is traveling faster on land than at sea).
What is the primary olfaction organ in fish?
Nares: Consisits of olfactory chambers line d with folds of olfactory epithelia (lamellae)
What organ do sharks use for electroreception? What are the two types?
Pit organs (detect electrical currents produced by muscle movement).
Two types: Tuberous and ampullary
Forms of navigation:
Landmarks
Path integration “dead reckoning”: known direction and distance, calculate position.
Compass: use of sun use of polarized light, stars, magnetic fields
Map sense: learned orientation or innate:
Describe 3 types of compasses animals use to Navigate:
Vision used:
Sun orient based on position of the sun.
Stars
Use of receptors
Magnetic fields
Navigation comparison between marine and terrestrial animals:
Cue type: more difficult to sea stars and orient with sun Ain water and no visual boundaries
Additional cues of water: waves and pressure, chemical cues, sound electrical
Ability to control bath is complicated with currents that cause drift.
How do salmon navigate back to their natal spawning grounds?
They use geomagnetic fields to get back to basic area and then cue in on chemical traits to find specific spot.
