Intro To Sensory System Flashcards
Types of sensory receptors
Chemoreceptors (pH oxygen etc)
Mechanoreceptors (baroreceptors osmoreceptors etc)
Photoreceptors
Thermoreceptors
Nociceptors (pain knowledge of limbs)
Two main areas of sensory physiology
Sensation - sensing environment
Perceptions - interpretation of these signals
Physiochemical and psychological process
Where do most sensory pathways go
They go to the thalamus
Thalamus relays info to visual cortex
Has multiple functions:
Acts as translator, inputs processed, sensory info relayed to cerebral cortex
How many layers to the eye
3 concentric layers:
Outer,middle, and inner layer
Outer cornea and sclera
Middle iris ciliary body and choroid
Inner retina which contains photoreceptors
Inside is vitreous chamber
Light modified in two ways before it hits the retina in the back
Light guest modulated by pupils depending on how bright light is
Accommodation where lens changes shape to adjust refractive power so image is focused on retina
Iris has two muscles what they do
Inner circular muscle constricts pupil parasympathetic
Outer radial muscle dilates pupil
sympathetic
Retina has 3 layers
Inner layer with ganglion neurones
Middle layer with bipolar neurons
Outer layer with rods and cones (photoreceptors)
Cones mainly found in fovea and low sensitivity used for bright conditions
Rods are high sensitivity used more in darkness and three rods to bipolar cells
Convergence is when..
Is when rods are stimulated in low light
Rods have high sensitivity but low resolution
What is phototransduction
Light is absorbed by photo pigments
Rods have rhodopsin
Cones have RGB
Rhodopsin is destroyed by bright light and rods have to make new ones
What’s in the external ear?
You have the Pinna directing sound into EAR CANAL and the tympanic membrane aka ear drum (connective tissue membrane)
What is the eustacian tube?
Links ear to throat to allow pressure equilibrium
Eg when on a plane or driving
As pressure can rupture ear drum and membrane can’t vibrate
Infections can cause swelling
What’s in the middle ear
Small air filled mucosa lined cavity malleus connected to ear drum hits the incus leading vibration to stapes which is connected to the oval window
What is in the inner ear
Inner ear is fluid filled and oval and round windows keep fluid seperate from middle ear and this is all located behind eye socket
Two sections - bony labelled with fluid
Membranous tubes surrounded by endolymph fluid (these fluids conduct sound vibrations)
Three major structures of the inner ear
Cochlea containing sensory receptors
Vestibule and semicircular canals
Branches of cranial nerve lead from inner ear to brain
What is the organ of corti
Found in the cochlea it has three rows of outer hair cells and one row of inner hair cells
Vibrations bend the hairs via an electromechanical force
Loudness affects the vibrations of the basilar membrane increasing frequency of action potentials
Low frequencies travel further down the cochlea and affect hair cells (multiple tones activate different areas simultaneously)
