What are the 2 types of cells in the retina? What is the use of each?
Rods - night vision Cones - colour vision. 3 types: red blue green.
What is the name of the left and right visual fields of the retina?
Nasal and temporal hemiretina
What are the 3 types of interneurones in the retina?
bipolar, horizontal and amacrine
How do rods and cones interact with interneurones?
Rods converge on one single bipolar cell Cones have a 1 cone to 1 interneuron interaction
What is the visual pathway?
Eye --> optic nerve --> optic chiasm --> optic tract --> lateral geniculate nucleus --> optic radiation --> visual cortex
What are the 2 types of ganglion cells in the retina?
Magnocellular and parvocellular
Where is the lateral geniculate nucleus found?
What is the magnocellular and parvocellular pathway sensitive to?
Magnocellular - luminance contrast and motion Parvocellular - colour contrast, fine detail
What is lazy eye known as medically? How is it caused?
amblyopia Caused by abnormal binocular input early in life e.g. strabismus, anisometropia (refractive difference between eyes), deprivation (congenital cataract, ptosis etc)
What is strabismus, anisometropia, and deprivation/
strabismus - Lack of coordination of eyes anisometropia (refractive difference between eyes), deprivation (congenital cataract, ptosis etc)
Where is the highest density of cones located in the retina?
What controls the sphincter and dilator pupillae?
sphincter pupillae - CN III dilator pupillae - sympathetic
What is horners syndrome? Symptoms?
disruption of cervical sympathetics small pupil (miosis), partial ptosis, anhydrosis
What can cause a non-homonymous bitemporal hemianopia?
pituitary adenoma compressing optic chiasm
What would happen if the right temporal lobe was damaged?
Loss of vision in superior quadrant of the left visual hemifield. Superior left homonymous quadrantanopia.
What is macular sparing and why does it occur in damage to the visual cortex?
occurs due to areas of visual cortex receiving blood from calcarine and branhces of MCA, allowing macular to be spared if one artery is occluded.