Special Senses Flashcards
Sensation definition
action potential that reaches the brain through sensory neurons
Perception definition
interpretation of the stimuli after the brain is aware of the sensation
what is the process of sensory reception?
- sensory transduction
- amplification
- transmission
- integration
What is sensory transduction?
conversion of stimulus energy into a change in the membrane potential
what does transduction result in?
a graded membrane - receptor potential
if it passes threshold, it will lead to an action potential
what is a receptor potential?
graded potentials produced in response to a stimuli
what performs sensory transduction?
sensory receptors
what are sensory receptors?
specialized neurons that can detect the stimulus and convert it to a receptor potential (graded membrane potential)
What are the two main types of sensory receptors?
exteroreceptors
interoreceptors
What is an exteroreceptor?
sensory receptors that detects stimuli outside the body
What is an interoreceptor?
sensory receptors that detects stimuli within the body
what are the types of exteroreceptors?
- photoreceptors
- chemoreceptors
- mechanoreceptors
- nociceptors
- thermoreceptors
What is the stimuli and sensory organ for photoreceptors?
light - eyes
What is the stimuli and sensory organ for mechanoreceptors?
pressure, movement - skin, muscles, ears
What is the stimuli and sensory organ for nociceptors?
pain - skin
What is the stimuli and sensory organ for thermoreceptors?
temperature - skin
What is the stimuli and sensory organ for chemoreceptors?
chemicals - nose, tongue
what is amplification?
the strengthening of stimulus energy that is otherwise too weak to be carried into the nervous system
what can amplification be performed by?
by the sensory receptors or other parts
what is transmission?
conduction of impulses to the CNS
what can perform transmission?
- sensory receptor - transduce, and transmit, acting like the afferent neuron
- sensory (afferent) neuron: sensory receptors will synapse with the afferent neuron which will then tansmit
what is integration?
processing of information that occurs in the central nervous system, in particular the lobes of the brain
what is sensory adaptation?
a type of integration where there is a decrease in responsiveness with continued stimulation
what are the 4 special Senses with their specialized organs?
- vision - eyes
- hearing - ears
- smell - nose
- taste - tongue
What is the 1 somatic sense and its organ?
tough - skin
what does the iris do?
regulates the amount of light entering the pupil
what do the cornea and lens do?
lenses help focus the image on the retina
Cornea has the larger body of nerve bundles and is extremely sensitive to pain
What are the 3 tissue layers of the eye?
- sclera muscles
- choroid: blood vessels
- retina: light sensitive cells
what does the optic nerve do?
neurons send visual stimuli to the brain
what 2 types of cells does the retina consist of?
rodes and conves
where is the retina?
the back of the eye
what does the retina do?
converts light signal into an electrical signal that is transmitted through the optic nerve to the occipital lobe of the brain
When do cone cells function best?
in bright light - requires more light to stimulate
What do cone cells do?
distinguish colours in daylight
what do rod cells detect?
detects black, white and shades of grey - explains why night vision is in black and white
when do rod cells function?
- function in less intense light like the night
can be triggered by as few as 6 photons of light
what are examples of photoreceptors?
rod and cone cells?
what are photoreceptors?
specialized neurons that perform phototransduction
converts light energy to receptor potential
what do photoreceptors contain?
disks which are similar to thylakoids in chloroplast