Special Senses: Anatomy & Physiology of the Eye and Hearing Disorders

These flashcards cover key concepts from the lecture on the anatomy and physiology of the eye as well as hearing disorders, aiding in exam preparation.

What is the function of the cornea in the eye?

The cornea is a transparent domelike structure that attracts light to enter the eyes.

What does the iris do?

The iris gives color to the eyes and helps in pupil constriction.

How does the pupil respond to changes in illumination?

The pupil constricts with increased light for protection and dilates with decreased light as an adaptive mechanism.

What is the role of the lens in vision?

The lens refracts light, adjusting for the distance of objects, which is known as accommodation.

What is the vitreous humor?

A jelly-like structure inside the eye that maintains its normal shape.

What does the aqueous humor do?

The aqueous humor is a liquid that maintains normal eye pressure.

What is the conjunctiva?

A clear membrane that protects the eye, covering the inside of the eyelid and the sclera.

What is the ciliary body's function?

The ciliary body produces the aqueous humor in the eye.

What is the function of the Canal of Schlemm?

It collects aqueous humor from the anterior chamber of the eyeball and delivers it to the veins.

What does the macula do?

The macula is an area of the retina responsible for central vision.

What are rods and cones?

Rods are photoreceptor cells for dim/night vision, while cones are receptors for daylight/bright vision.

How is visual acuity tested?

Visual acuity is tested using the Snellen chart, where normal vision is defined as 20/20.

What indicates normal color vision in the Ishihara test?

Reading 10 or more plates normally indicates normal color vision.

What is fluorescein angiography used for?

Fluorescein angiography uses a contrast agent to evaluate clinically significant conditions like neovascularization.

What does tonometry assess?

Tonometry detects increases in intraocular pressure (IOP), which can indicate glaucoma.

What distinguishes open-angle glaucoma from closed-angle glaucoma?

Open-angle glaucoma involves gradual blockage of the trabecular meshwork, while closed-angle glaucoma has a sudden blockage caused by the iris.

What are cataracts?

Cataracts are lens opacities or cloudiness caused by chemical changes in lens protein.

What is the treatment for macular degeneration?

Treatment may include photodynamic therapy and administration of verteporfin.

What are the symptoms of retinal detachment?

Symptoms include flashes of light, floaters, blurred vision, and curtain-like vision.

How to test for hearing loss using the Rinne and Weber tests?

Rinne's test compares air conduction (AC) to bone conduction (BC), while Weber's test checks for lateralization between ears.

What is Meniere's syndrome?

Meniere's syndrome is characterized by tinnitus, vertigo, and sensorineural hearing loss.

What is otosclerosis?

Otosclerosis is the formation of new bones in the ossicles of the middle ear, leading to conductive hearing loss.

What is the function of the sclera?

The sclera is the white, opaque, outer layer of the eye that protects internal structures and maintains the eyeball's shape.

How does the retina contribute to vision?

The retina is the innermost, light-sensitive layer of the eye containing photoreceptor cells that transmit visual signals to the brain.

What is the difference between myopia and hyperopia?

Myopia (nearsightedness) occurs when light focuses in front of the retina, while hyperopia (farsightedness) occurs when light focuses behind the retina.

What characterizes astigmatism?

Astigmatism is blurred vision caused by an irregular curvature of the cornea or lens, preventing light from focusing properly on the retina.

What is presbyopia?

Presbyopia is an age-related loss of lens elasticity, making it difficult to focus on near objects.

How is the Amsler grid used in ophthalmology?

The Amsler grid is a diagnostic tool used to detect and monitor macular degeneration by identifying distorted or missing areas in the central visual field.

What is the purpose of the Eustachian tube?

The Eustachian tube equalizes air pressure between the middle ear and the atmosphere to ensure the tympanic membrane can vibrate properly.

What are common signs of Otitis Media?

Common signs include ear pain, fever, and a red, bulging, or opaque tympanic membrane.

What does a negative Rinne test indicate?

A negative Rinne test occurs when bone conduction (BC) is equal to or greater than air conduction (BC \ge AC), suggesting conductive hearing loss.

What is the function of the optic nerve?

The optic nerve (Cranial Nerve II) transmits visual information from the retina to the brain's visual cortex.

What is the function of the choroid?

The choroid is a vascular layer between the retina and sclera that provides nourishment to the outer layers of the retina.

What is the fovea centralis?

The fovea centralis is a small pit in the macula containing a high concentration of cones, providing the sharpest visual acuity.

What is the role of the lacrimal apparatus?

The lacrimal apparatus is the system responsible for producing and draining tears to lubricate and protect the eye.

What is presbycusis?

Presbycusis is age-related sensorineural hearing loss involving the gradual loss of hearing, especially high frequencies.

How do the semicircular canals contribute to equilibrium?

The semicircular canals are inner ear structures that detect rotational head movement and maintain dynamic equilibrium.

What is the function of the cochlea?

The cochlea is the snail-shaped inner ear structure that converts sound vibrations into neural signals.

What is the function of the tympanic membrane?

The tympanic membrane, or eardrum, vibrates in response to sound waves and transmits them to the middle ear ossicles.

What causes conductive hearing loss?

Conductive hearing loss is caused by interference in sound wave transmission through the outer or middle ear, often due to cerumen or fluid.

What is sensorineural hearing loss?

Sensorineural hearing loss results from damage to the inner ear or the auditory nerve (Cranial Nerve VIII).

What are the 3 ossicles of the middle ear?

The 3 ossicles are the malleus, incus, and stapes, which amplify sound vibrations from the eardrum to the inner ear.