Week 1: Gross Anatomy Flashcards
Function of;
- Cornea
- Iris
- Pupil
- Lens
- Ciliary Muscles
- Fovea
- Retina
- Cornea: Protects eye from light
- Iris: Coloured muscle regulates pupil size
- Pupil: Regulates light input
- Lens: Focuses images on retina
- Ciliary Muscles: Controls shape of lens accommodation
- Fovea: point of central focus contains most cones
- Retina: Contains photoreceptors
Sagittal
Divides body into left and right
Transverse/Horizontal
Divides body into superior and inferior (top and bottom)
Coronal / Frontal
Divides body into front and back
Anterior
At or near the front (of the body)
Posterior
At or near the back of the body
Lateral
Further from the middle of the body
Medial
Nearer the middle of the body
Superior
Towards the head or top of the body (above)
Inferior
Further from the head/top (so below)
- Orbit to the cranial cavity=
- Orbit to the maxillary sinus=
- Orbit to the nasal cavity and paranasal sinus=
- Orbit to the infra-temporal fossa (near cheekbone)=
- Inferior
- Superior
- Lateral
- Medial
Eyeball length: sagittal vertical diameter
Eyeball Axil Length from cornea to retinal surface
Approx 23.7mm vertical
Approx 24mm, 25mm including tissues
Growth of eyeball from birth to 3
16mm at birth to 22.5mm by 3 y/o
Eyeball full size at 13
Eyeball position within the orbit in newborns
The angle and distance between the two eyes changes during growth as skull/orbit expand especially in infancy and childhood.
- at 2 month embryo: 180 degrees
- 3 month embryo: 105 degrees
- birth: 71 degrees
- adult: 68 degrees
Fibrous tunic
Cornea and sclera
Vascular tunic
Iris, ciliary body, choroid
Cornea function
Refracts light as enters the eye
Sclera function
White of the eye, provides shape and protects inner segments of eye
Iris
Coloured proteins, regulates amount of light entering eye
Ciliary body function
Secretes aqueous humour and alters shape of lens for accommodation (looking near and far)
Retina function
Receives light and converts it into receptor potentials and nerve impulses which output to the brain via the optic nerve
Lens function
Refracts light
Function of aqueous humour
Helps maintain shape of eyeball, jelly-like and supplies oxygen and nutrients to lens and cornea
Vitreous humour function
Liquid helps maintain the shape of eyeball and keeps retina attached to choroid
