Sensory Organs Flashcards
What are general senses?
Senses found all over the body (pain, pressure changes, etc)
What are special senses?
Senses that have specialized receptor cells within a specialized organ
Every sensation is connected to what?
Action potential
What do chemoreceptors respond to?
Chemicals — detect taste, smells, blood pH
What do photoreceptors respond to?
Light
What do mechanoreceptors respond to?
Physical forces: hearing motion, vibrations
What do thermoreceptors detect?
Change in temperature
What do nociceptors respond to?
Tissue damage (pain)
What is a receptive field and how does it relate to sensation?
An area of the body supplied by a single sensory neuron. Precision in detection depends on the size of the field
Where do we have smaller receptive fields?
Areas that require more nuance of sensation (face, hands, etc)
Sclera
The white fibrous outer layer of the eye
Cornea
The clear covering of 5-7 layers of non-keratinized epithelial tissue that allows light to pass through the anteriormost surface of the eye
Corneal Epithelium
Anterior-most layer of the cornea
Choroid
Highly vascular middle layer of the eye (dark part between sclera and retina)
Ciliary Body
Smooth hair-like muscle that controls the shape of the lens
Iris
Pigmented portion of the eye surrounding the pupil
Iris Diaphragm
Controls pupil dilation
Pupil
Open hole at the center of the iris that light passes through into the eye
Retina
The interior light-sensitive layer of the eye that contains photo-receptors (rod & cone cells)
Optic Disc
The spot on the retina where axons leave and blood vessels enters (the optic nerve connection)
Macula
Oval-shaped lightly pigmented area of higher resolution for color vision (little dot near optic disc)
Aqueous Humor
Clear, watery fluid that fills the space anterior to the lens
Lens
Transparent structure that focus light on the retina
Vitreous Body
Clear gel that fills the space posterior to the lens (inside retina and choroid)
What are the cells if the retina?
rod cells - rhodopsin for low light vision
cone cells - photopsins for color vision
bipolar cells - connect rod and cone cells to retinal ganglion
retinal ganglion cells - transmist image-forming and non-image forming info to the brain
The Auricle
The visible part of the war that collects sound waves
External Acoustic Meatus
Passage for sound that runs through the temporal bone
Tympanic Membrane
Aka the ear drum - transmits sound to the middle ear
Auditory Ossicles
Malleus - Superficial-most, hammer-shaped, attached to tympanic membrane
Incus - middle, anvil-shaped ossicle
stapes - deepest, stirrup-shaped ossicle attached to oval window
Auditory Tube
Connects middle ear to Pharynx (long tube doing down below cochlea)
What is the purpose of the auditory tube?
To equalize pressure
Oval Window
Small circular membrane in vestibule where stapes attaches
Vestibule
Midsection/Central Canal of inner ear
Semicircular canals
Swooping horn-like parts superior to vestibule that maintain equilibrium and detect rotation of the head
Cochlea
Snail-shaped cavity filled with fluid involved in hearing
Parts of the Cochlea
Vestibular duct (behind oval window)
Vestibular membrane (separates vestibular and cochlear ducts)
cochlear duct (contains the spiral organ)
basilar membrane (separates cochlear and tympanic ducts)
tympanic duct (behind round window)
Parts of the cochlear duct
hair cells - convert fluid movements to nerve signals
stereocilia - extensions on hair cells that send signals when bent and transmist via CN VIII
tectorial membrane - layers iver stereocilia of hair cells
How do sound waves travel through the ear?
Collected by the auricle into the external auditory meatus.
As the tympanic membrane moves the auditory ossicles (malleus to incus to stapes). Vibrations of the stapes causes the oval window to move back and forth, which generates waves in the vestibular duct
This causes displacement of the basilar membrane which moves the stereocilia and bends hair cells, which generates a nerve impulse in CN VIII
What are the parts of the tongue responsible for gustation (taste)?
lingual papillae - bumps on the tongue that grip and reposition food
taste buds - on the side of lingual papillae that detect taste stimuli
What are the 4 structures of olfaction (smell)?
olfactory neurons - have receptors that bind with chemicals in the air
olfactory nerves - are bundles of axons from olfactory neurons
olfactory bulb - structure where the olfactory nerves synapse
olfactory tracts - bilateral bundles of nerve fibers connected to the brain
