BSI Lecture 64 Special Senses Flashcards
What type of light are the photoreceptors of the eye only sensitive to?
electromagnetic radiation (EM)
The eye is sensitive to only wavelengths between ___ and ___ light.
Blue (400nm just before ultraviolet)/ red (700nm just after infrared)
What are the 3 layers of the eye?
Fibrous (Sclera (connective tissue), cornea)
Vascular
Inner
What part of the lens focuses/refracts lights
Cornea (more so than the lens) / Lens
What is the function of the pigmentation in the choroid?
To absorb light and prevent reflection
When the ciliary muscles contract (decrease tension on zonular fibers) what is the shape of the lens?
Convex, this is to focus more light for near vision
What part of the eye has the greatest number of photoreceptors?
Fovea centralis
What is the “blind spot” part of the eye?
optic disc (this is where the optic nerve (CNII) and blood vessels enter/leave the eye)
What are the fluid parts of the eyes and where are they found in the eye?
Aqueous Humor (between iris and cornea), Vitreous humor (posterior part of eye)
What does the lacrimal gland produce?
Lacrimal apparatus (tears, which contains mucus antibodies and antibacterial enzyme lysozyme)
What are the tarsal glands (meibomian glands)?
Modified sebaceous skin oil gland (oily secretions slows evaporation of the tears)
What is the shape of the lens when the SNS is active?
Flat ( optimizing it for far vision in poor light)
What mechanism do photoreceptors use for light?
Mechanism 2 (GPRs), activates phosphodiesterase to convert cGMP to GMP
What is the name of the ligand/chromophore in photoreceptors that when light energy is received, changes conformation?
Retinal
What are the name of the GPR and G-protein in photoreceptors?
GPRs (opsin), G-protein (Gt)
What are the 2 types of photoreceptors and their function?
Rods (light)
Cones (colors, red, blue, green)
What part of the thalamus do optic fibers go to?
Lateral geniculate nucleus (LGN), they then go to the visual cortices in the occipital lobe.
The 6 skeletal muscles that control the eye produce 2 types of eye movements, what are they?
Small/fast movements (saccades, help search the image for the most important features and to prevent bleaching)
Slow movements are used to track moving objects and require interaction with the vestibular system
_____ is due to excessive intraocular pressure and causes blindness by destroying the optic nerve.
Glaucoma
What are the 3 tiny bones of the ear?
Malleus, Incus, Stapes