Eyes, Ears, Skin Flashcards
(107 cards)
What are the eyelids composed of?
Thin, elastic skin covering striated and smooth muscles
The eyelids protect the anterior portion of the eye.
Which cranial nerve innervates the upper eyelid?
Oculomotor nerve (CN III)
This nerve controls the movement of the upper eyelid.
What is the function of tears?
Protect cornea and sclera with lubrication, nutritional support, moisture, and protection from microbes
Tears also contain immunoglobulins that increase during allergic responses.
What is the conjunctiva?
A mucous membrane that provides a barrier to the external environment and nourishes the eye
Goblet cells in the conjunctiva secrete lubricating mucus.
What is the sclera?
The white of the eye, a dense, fibrous structure that helps maintain the shape of the eyeball
It protects the intraocular contents from trauma.
What is the cornea?
A transparent, avascular, dome-like structure covering the iris, pupil, and anterior chamber
The cornea plays a crucial role in focusing light onto the retina.
What is the role of the iris?
A highly vascularized, pigmented collection of fibers that surrounds the pupil
It controls the size of the pupil and thus the amount of light entering the eye.
What is accommodation in the context of vision?
The ability to focus for near vision and refocus for distance vision
Controlled by the ciliary body through zonular fibers and ciliary muscles.
What is the vitreous humor?
A clear, gelatinous substance that occupies about 2/3 of the eye’s volume
It helps maintain the shape of the eye.
What are rods responsible for?
Night vision or vision in low light
Rods are absent in the fovea.
What are cones responsible for?
Providing the best vision for bright light, color vision, and fine detail
Cones are distributed throughout the retina with the greatest concentration in the fovea.
Define presbyopia.
Impaired near vision often found in middle-aged and older people
Patients may need reading glasses or bifocals.
What does the optic nerve do?
Transmits impulses from the retina to the occipital lobe of the brain
It is known as the second cranial nerve (CN II).
What is the function of the Eustachian tube?
Connects the middle ear to the nasopharynx
It helps equalize pressure in the middle ear.
What is conductive hearing loss?
Loss of hearing due to interrupted sound transmission to the inner ear
It can occur because of obstruction or disease processes.
What is the organ of Corti?
The end organ of hearing located in the cochlea
It contains sensory cells that transduce sound vibrations into neural signals.
What is anisocoria?
Pupillary inequality of less than 1mm despite an equal response to light
It can be a benign variant or pathologic.
What is the red reflex?
A normal orange glow observed when light is applied to the pupil
Absence may indicate lens opacity, cataract, or detached retina.
What does a Snellen chart test assess?
Visual acuity
20/20 is considered the standard of normal vision.
True or False: The numerator in a Snellen chart test denotes the distance between the patient and the chart.
True
The denominator indicates the distance at which a normal eye can read the letters.
What are common symptoms that should be assessed in a vision examination?
Changes in vision, pain or discomfort, and discharge
A thorough medical, family, and social history should also be taken.
What is the tympanic membrane?
The membrane that separates the middle ear from the external auditory canal
Also known as the eardrum.
What is the function of the semicircular canals?
Contain the receptor organs for balance
They are part of the inner ear.
What is the cochlea?
A snail-shaped bony tube that forms part of the inner ear and contains the organ of Corti
It is essential for the sense of hearing.