-
pheromone
signal between individuals that causes change in physiology or behavior
-
transduction
convert external stimulus to internal signal
-
How do you sense the environment?
- 1. transduction
- 2. amplification of signal
- 3. transmission to central nervous system
- 4. integration
-
nocireceptors
sense dangerous stimuli
-
thermoreceptors
sense temp
-
mechanoreceptors
sense touch or pressure
-
chemoreceptors
sense specific molecules/class of molecules
-
photoreceptors
sense specific waves of light
-
electroreceptors
detect electrical fields
-
depolarized
the interior of the cell becomes more positive
-
hyperpolarized
interior more negative than resting potential
-
How does the action potential react to changes in intensity of the sensory input?
it increases in firing rate
-
How does the brain interpret all of the electrical signals?
- receptor cells are very highly specific
- each sensory neuron sends its signal to a specific portion of the brain
-
frequency
number of pressure waves per second
-
pitches
different sound frequencies
-
statocyst
- helps to maintain correct orientation in space
- ex. if a crab is flipped over, the calcium-rich particle (statolith) presses against nerve hairs (setae) that signals the body to flip the crab back over
-
Effect of direct pressure on plasma membrane
- causes the ion channels to distort, either closing or opening the way for ion flow
- bending causes ions to open
-
Hair cells
- comprised of many stiff outgrowths (sterocilia) and one kinocilium
- depolarization due to pressure causes inflow of calcium, increasing amount of neurotransmitter released
-
Three main parts of the ear
- Outer ear
- Middle ear
- Inner ear
-
Fxn of outer ear
funnel sound into ear canal
-
tympanic membrane
- "eardrum"
- vibrates back and forth due according to sound wave
- vibrations pass to the ear ossicle (3 bones in middle ear)
-
Oval window
- separates middle and inner ear
- carries vibrations into the fluid inside a chamber called the cochlea
-
Fxn of middle ear
- amplifies sound
- tympanic membrane larger than oval window (same force, smaller size is more heavily affected)
- three ossicles act as levers, amplifying the vibrations
-
Basilar membrane
- membrane in middle chamber of cochlea
- certain parts vibrate differently according to the different frequencies
- brain receives signals from different hair cells and interprets them differently
-
How do elephants communicate?
infrasonic sounds (very low) that can travel very far
-
Echolocation
using sound echoes (sonar) to navigate
-
Compound eye
composed of hundreds of ommatidia (functional units of insect eyes)
-
Structure of vertebrate eye
- cornea - transparent sheet of connective tissue
- iris - colored, round muscle; controls amt of light entering the eye
- pupil - hole in the middle of iris
- retina - back of the eye; contains photoreceptor cells (rods or cones)
-
What is special about the vertebrate eye?
- the photoreceptors are placed in the far end of the eye, allowing light to pass through many layers of neurons before it reaches the cells
- this creates a blindspot where the axons have to exit the eye
-
Rod cells (in eye)
detect dim light
-
Cone cells (in eye)
detect color
-
fovea
place in retina that only has cones
-
opsin
transmembrane protein that contains retinal (pigment)
-
What causes color blindness?
- a deficiency in specific opsin (they only sense distinct wavelengths of light)
- blue, green, red (short, medium, long)
-
Gustation
sense of taste (through chemoreceptors)
-
umami
"meaty" sense from MSG
-
glomeruli
little balls that sense smell
|
|