Sensory System Flashcards
two main functions
- Detection of the signal
2. Quantitative features
detection of the signal
- can occur without the animal being away
- discrimination power of sensory input
- estimation = quality needs to be determined (modality) what it is
Quantitative features
- intensity of the signal
- brain will assess if the individual needs to be aware
- duration and frequency determined
- spatial location
How do you get a response
signal gets converted into an action potential
- it is interpreted in the brain based on the stimulation from the signal
what are the classifications of receptors based on location
- telereceptors ( hearing and sight )
- exteroreceptors ( external changes like temp and pressure)
- interoceptors ( internal changes )
sensory coding
- receptor conveys type of info it is sending
- conveys intensity of the stimulus ( more stronger signals = more frequent APs)
- send info about the location and receptive field characteristic of the receptor
will all stimulus give signals?
no - if it doesnt pass the threshold it is not seen as there
Chemoreceptors
chemical signals ( taste and smell)
- sweet and salty have different receptors
- internal variables : pH, blood oxygen
mechanoreceptors
touch, hearing, balance, and figures body position and blood pressure
Photoreceptors
light
vision
thermoreceptors
temperature and changes
Polymodal receptors
sharks: ampullae of lorenzini
touch and temperature
nociceptors
temperature pression, chemical products, perception of pain (humans)
primary reception structures
- perceived by terminal end
- afferent level ( out goes in)
nociceptors
thermoreceptors
photoreceptors
mechanoreceptors
touch receptors
chemoreceptors
secondary reception structure
mechanoreceptors used for balance and audition
they have cilia and chemoreceptors end of neuro synapse with non nervous sensitive cells
can aquatic animals sense smell
no
how does smelling occur
- chemicals dissolve in the mucus layer
- change into AP for brain to understand
- axons send the AP
- transductions arrive at the terminal end of the dendrites
- activated g olf protein moves through membrane and activates adelhynate cuclase which converts ATP to cAMP
- G protein changes to become active and energetic
- cAMP is now secondary messenger it goes into sodium channel and activates it
- sodium causes depolarization to open sodium and calcium channels
- cAMP changes to cAM
Pheromones
- take in air to sample molecules
- little circle in palette where air is sucked into (also helps detect gender)
- can affect behaviour of organisms
photoreceptor layout
- rods: elongated cilium and between 600-900 receptors (better for nocturnal animals)
- cones: center of cornea and 200-300 receptors
Rods
more photopigment slow response high amplification saturating response non directionally selective highly convergent retinal pathways high sensitivity low acuity achromatic: one type of pigment
cones
less photopigment fast response less amplification non saturating response directionally selective highly convergent retinal pathways lower absolute sensitivity high actuity chromatic: three types of pigment
different mechanoreceptors
proprioceptors
baroreceptors
osmoreceptors
proprioceptors
body ability to sense change ( self movement and body position)
Baroreceptors
changes in pressure
sense for internal and external environment
osmoreceptors
changes in osmolarity
tactile receptors
merkel: braille reading
- paccini: sensitive to pressure and found deep within the skin and some organs
- Ruffini: located in skin and joints. work together with proprioceptors to maintain balance and change body positions
- root hair plexus
primary mechanoreceptors
dendritic extensions of afferent neurons bipolar spiral wound around the muscle fiber, spindles
what is the junction between muscle and tendon
golgi tendon organ
secondary mechano receptors
hair cell receptors involved in the sense of hearing and equilibrium
magnetoreception
field used by different species
can be followed N/S but they dont know which is which
- used for homing
-maghemite gives direction
electroreceptors
- mainly present in most fish and amphibians
- ability to percieve natural electric signals or stimuli
- almost exclusively in aquatic/amphibian animals
what are electroreceptors used for
- electrolocation
- electrocommunication
why do sharks rely on electric field
- used to determine what their prey is
- most electric sensitive
- ampullae of lorezini
- may use it to navigate ocean
active electroreception
- animal senses its surrounding environment by generating electric fields and detecting distortion in the fields using electroreceptor organs
- different categories
- different muscles
- can count for up to 30% of the energy production
passive electroreception
- animal senses the weak bioelectric fields generated by other animals and use it to locate them
- sharks use this and some fish have it in the gill membrane
- solely by ampullary electroreceptors
can also be found in the lateral line in fish
what part of the fish body emits the signal/sound
the tail
what kind of change do pit organs sense in snakes and how sensitive
temperature
very sensitive - 1/100th
what are some transient receptor potential (TRP)
TRPV 2 (~50ºC) TRPV 3/4 (between 22 - 40 ºC) TRPM 8 (below 22ºC)
