8:35:00 am -
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sensory
"used to provide animals with information regarding their environment to make appropriate response"
environment???
- mechanical (pressure, sound, touch) PST
- chemical (sense, taste) ST
- electromagnetic (light, heat, magnetism) LHM
sensory receptor:
- pineal gland
- lateral line
- eyes
- chemical sensory
- otolith
1. eyes
- function
*collect light
*focus image to the retina
*transform image to the neural signals
-how to reduce lighting???
*pupillary operculum expands/ contract to adjust the amount of the light
*nictitating membranes cover up to reduce too much light.
-how to adjust low/high light??
*low.
^cones contract
^rods closer to light and not shield by melanin
*high
^opposite occurs
^cones closer to light
^rods extended n shield by melanin
-how to focusing on images???
*made by changing lens shape
*made by changing distance between retina and lens
2. pineal gland
-component???
*pinealocytes (photoreceptor cells)
*ganglian cells (second order neurons)
*glial cells (supporting cells)
-function
*detect light
*produce melatonin
-blind cave fish
*larvae detect the light and show a shadow response
3. chemical sensory
-types
*olfaction - smell
*gustation - taste
-OLFACTION
*nare??
^small opening near the mouth
^inside the nare are bilateral structure with numerous epithellia cells called lamellae
^number of lamellae depends on age and size of fish
GUSTATION
* based in taste buds
* cover entire body
*exposure of heavy metal quickly destroy taste buds but can recover when placed back in pristine water
*barbel is the modified structure for gustation
4. lateral line
*mechanorecemtive organ
*function
-detect vibration
-detect changes in pressure
-helps predator locate prey
-helps prey avoid predator
5. otolith
*located just behind the brain
*why have otolith???
-more dense than water
-move more slowly than the fish body
*function
-sensitive to gravity
-sensitive to acceleration
-aids in fish balance
*important of otolith
-determine the natural diet of predators
-determine places where fish live
-assist in determining fish age (darkslow n lightfast)
hahahahahahaha korang belaja la jugak malam ni k... :)