Skip to main content
Indietro

Anatomy & Physiology: Eye Structure and Function

I pulsanti di controllo sono stati cambiati in modalità "navigazione".
1/21

Termini in questo insieme (21)

  • Accessory structures of the eye
    Include bony orbits, fat cushion, conjunctiva, and lacrimal apparatus that protect, support, lubricate, and cleanse the eye.
  • Function of the conjunctiva
    A mucous membrane that lubricates the eye, reduces friction, and prevents dryness by covering the eyelids and anterior eyeball.
  • Components of the lacrimal apparatus
    Lacrimal gland, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct; produce and drain tears containing saline, mucus, lysozyme, and antibodies.
  • Layers of the eyeball
    Fibrous layer (sclera, cornea), vascular layer (choroid, ciliary body, iris), and inner layer (retina with pigmented and neural layers).
  • Function of the sclera
    White, protective outer layer that maintains the shape of the eyeball.
  • Role of the cornea
    Transparent part of the fibrous layer that allows light to enter the eye and provides most of the eye's refraction.
  • Components and functions of the vascular layer (uvea)
    Choroid supplies nutrients and prevents light scattering; ciliary body controls lens shape; iris regulates pupil size.
  • Structure and function of the retina
    Inner layer with pigmented and neural layers; neural layer contains photoreceptors (rods and cones), bipolar cells, and ganglion cells that detect light and transmit signals.
  • Photoreceptors in the retina
    Rods detect low-intensity light for night and peripheral vision; cones detect bright light for color and high-acuity vision.
  • Function of the fovea centralis
    Cone-rich area of the retina responsible for sharp, precise central vision.
  • Composition and role of the posterior segment
    Filled with vitreous humor, a gel-like substance that supports the eyeball and holds the retina in place.
  • Composition and role of the anterior segment
    Filled with aqueous humor, a fluid that maintains intraocular pressure, formed by ciliary processes and drained via the scleral venous sinus.
  • Lens structure and function
    Biconvex, suspended by ciliary zonule; adjustable refractive structure that focuses light on the retina by changing shape.
  • Refraction in the eye
    Bending of light by the cornea and lens to focus images on the retina; cornea provides most refraction, lens adjusts focus.
  • Accommodation for close vision
    Lens bulges, pupils constrict, and eyeballs converge to focus on near objects; controlled by cranial nerve III (oculomotor).
  • Distant vision focusing
    Lens remains flat; no special adjustments needed to focus on distant objects.
  • Common refractive errors
    Presbyopia (loss of lens elasticity), myopia (nearsightedness), hyperopia (farsightedness), and astigmatism (uneven cornea or lens curvature).
  • Phototransduction process
    Conversion of light into electrical signals by photoreceptors in the retina using visual pigments.
  • Visual pigments and opsins
    Retinal combines with opsins to form pigments: rhodopsin in rods; different opsins in cones sensitive to red, blue, or green light.
  • Signal transmission from retina to brain
    Ganglion cell axons form optic nerve; fibers cross at optic chiasma; signals continue via optic tracts to thalamus and visual cortex.
  • Other brain projections of visual signals
    Fibers reach midbrain pretectal nuclei and superior colliculi for visual reflexes, and suprachiasmatic nucleus for circadian rhythm regulation.