Lab 3 Flashcards
Glaucoma
Occurs when aqueous humor does not adequately drain and thus pressure increases in the eye until the retina and optic nerve can be compressed and damaged
Presbyopia
As age, lens becomes more dense and less elastic, thus decreasing the ability of the lens to bulge for near vision
As a result, must hold things farther to focus on them
Cataracts
Hardening and clouding over of the lens
Usually a consequence of age
Can be caused by diabetes mellitus, smoking, and excessive sunlight exposure
Treatment is typically replacement of the lens with an artificial one
Extrinsic eye muscles
Lateral rectus muscle: Abducens Nerve VI (motor) (LR6)
Superior oblique muscle: Trochlear Nerve VI (motor) (SO4)
Inferior oblique muscle, Superior rectus, inferior rectus, medial rectus: Oculomotor Nerve III (Motor) (O3)
Superior oblique muscle: depresses eye and turns laterally
Inferior oblique muscle: elevates eye and turns laterally
Unlabelled:
https://cdn-useast.purposegames.com/images/game/bg/54/WiQgA6sb3bs.png?s=1400
Labelled: https://teachmeanatomy.info/wp-content/uploads/The-Extraocular-Muscles-of-the-Eye.jpg
Cones vs Rods
Two types of photoreceptor cells in mammalian eye
Cones: Color differentiation; Found in fovea
Rods: Contrast resolution; Distributed evenly throughout remainder of retina
Optic disc
Where the nerves and retinal blood vessels enter and exit; Completely devoid of receptors; Referred to as the blind spot
Visual field
Light from right field of view is processed in left primary visual cortex of the occipital brain lobe
Light from left field of view is processed in right primary visual cortex of occipital brain lobe
Optic chiasm
Connects brain lobes to opposite eye
Location where fibers cross over from the medial field of each eye to the other side of the brain
After optic chiasm the fibers run through optic tract before signal is sent to primary visual cortex for conscious perception of the image
Saccadic masking
During rapid movement, the brain selectively blocks visual processing
Red-green colorblindness
Overwhelmingly affect the red cones or the green cones; Collectively known as Congenital color vision deficiencies because they reduce the ability to distinguish those two colors
Red cones
Protan: Defect in red cones
Protanomaly: Some altered sensitivity in red cone function
Protanopia: Complete red cone deficiency
Green cones
Deutan: Defect in green cones
Deutanomaly: Some altered sensitivity in green cone function
Deutanopia: Complete green cone deficiency
Blue cones
Tritan: Defect in blue cones
Tritanopia: Completed blue cone deficiency
Altered sensitivity in blue cone function is not seen
Short-sightedness
Myopia
Focal point of image is before the light reaches the retina because the eyeball is too long
Concave lens is used
Long-sightedness
Hyperopia
Focal point of image is not reached by the time that the light reaches the retina because the eyeball is too short
Convex lens is used
Astigmatism
Blurred vision due to differences in the curvatures of the cornea or lens at varying locations
Human ear anatomy
Unlabelled: https://i.pinimg.com/564x/dc/d3/f3/dcd3f37c421b8d06690a3f2cb18691be.jpg
Labelled: https://med.uth.edu/orl/wp-content/uploads/sites/68/2017/10/EarDiagram.gif
Cochlea anatomy
Organ of Corti: Located in the scala media of the cochlea; Spiral organ
Scala media: Middle fluid-filled chamber within the cochlea
Scala tympani: Filled with fluid and located closest to middle ear
Scala vestibuli: Above scala media in the spiral organ of Corti
Vibrations in ear
Sound vibrates tympanic membrane
Vibration transferred to malleus, then incus, then stapes bones of middle ear
Inner ear cochlea transfers vibration to Vestibulocochlear nerve VIII (sensory)
Organ of Corti
Receptor organ of hearing
Housed in cochlea
Scala vestibuli
Begins at oval window and is continuous with vestibule
Part of bony labyrinth, so filled with perilymph
Scala media
Where organ of Corti is located
Part of membranous labyrinth, so filled with endolymph
Scala tympani
Terminates at the round window membrane
Part of bony labyrinth, so filled with perilymph
Perilymph fluid
Between bony and membranous labyrinths
Similar to cerebrospinal fluid
Endolymph
Fills membranous labyrinth
Similar to intracellular fluid
Otoconia
Also known as statoconia
Calcium carbonate crystals in the inner ear that help with balance
Gustation
Taste
One of two main chemical senses
Nociception
Perception of pain
Thermoception
Sense of heat and cold
Proprioception
Perception of body position
Tapetum lucidum
Reflective layer of tissue in many animals
Located behind retina
Helps animals see in low light or during night
How light flows through eye
Cornea (3/4 refraction occurs)
Pupil
Aqueous humor
Lens (1/4 refraction occurs)
Vitreous humor
Retina
Optic Nerve II (Sensory)
Avascular in eye
Cornea
lens
Vitreous humor
Vascular in eye
Retina
Choroid tunic
Pupil dilates
Low light/distant vision
Allow more light to enter eyes
Less refraction
Lens flattens
Pupillary muscle relaxes
Ciliary muscles relax
Sympathetic nervous system
Pupil constricts
Bright light/near vision
Less light enter eyes
More refraction
Pupillary muscles constrict
Ciliary muscles contract
Lens bulges
Parasympathetic nervous system
Detached retina
Occurs when neural components of retina release from the pigmented layer of the retina
Often caused by blow to head or sudden stopping of head
Can lead to permanent blindness since detachment removes photoreceptors from blood supply
