Senses (Ch 22&23) Flashcards
Sensory receptor
detects info about changes in internal and external environment
5 types of sensory receptors
- mechanoreceptors
- chemoreceptors
- photoreceptors
- thermoreceptors
5.electroreceptors
Mechanoreceptors
transduce mechanical energy
ex: hearing and touch
Chemoreceptors
chemical compounds
Ex: taste and smell
photoreceptors
transduce light energy
Use pigments to absorb light energy
Ex: sight
Thermoreceptors
recognize hot and cold
Ex: pit organ in snakes: it can sense hot and cold, thus snake can sense its warm blooded prey
Electroreceptors
detect electrical fields
ex: shark has this around the head. It detects fish heartbeat (Ampullae of Lorenzini)
Sclera
curved, tough, forms outer coat of eyeball
supporting wall of eyeball
white , outer surface of eye
Gives eyes its shape
Choroid
layer outside retina
-Sheet of cells filled w/ black pigment that absorb light
-Prevent light from being reflected back into photoreceptors in retina
cornea
Lines inner surface of back of eye
=Consists of specialized receptors that absorb light and send signals related to properties of light + brain
= has transduction process
transduction
When light reaches back of eye, it stimulates a layer of specialized receptors that convert light into a message that the brain can interpret
Iris
Round muscle that adjusts the size of pupil
Gives eyes their characteristic colour
Cornea
Clear layer that covers front portion of the eye
Helps to eye’s ability to focus
Pupil
Regulates amount of light that enters by changing its size (size regulated by iris)
what happens to pupil when it dilate and constrict
expand, shrink
lens
Clear structure that focuses light onto the back of eye by accomodation
accomodation
change shape to make image stay focused (having the light that hits retina stay focus)
Macula
area in back of eye, center of retina
Region of sharpest vision b/c it has greatest receptor cells density
Where cones is most concentrated
optic nerve
transmits image to the brain via complex signals
Where signals from rods and cones travel