The Visual System Part 1

Aqueous humor secreted from Ciliary body, Flos to Anterior Chamber, drains through Canal of Schlemm

_________

Intrinsic Muscles of the Eye: The Iris circular.....________ radial.....…________ Dilating pupil for eye exam: how to do it? Pharmacology of pupillary dilation: _________

Intrinsic Muscles of the Eye: Ciliary Muscle Ciliary muscle relaxed = tension on zonular fibers = tension on lens = flattened lens = _________________ Ciliary muscle contracted = tension on zonular fibers reduced = less tension on lens = lens becomes more spherical =__________________ Eye strain Using a Microscope or Binoculars

Near point of Accomodation 0.06 0.07 0.08 0.09 0.12 0.14 0.16 0.18 0.3 0.4

Demonstrate Convergence With Convergence Demonstrate Convergence

Extraocular muscles Motor innervation by CN III = __________ CN IV = __________ CN VI = __________ __________= misalignment of eyes Due to _______________________

Lateral geniculate nucleus a subdivision of the thalamus.              

Visual reflexes: ___________, ___________, ___________, ___________.

Clinical Case Study: Hyperprolactinemia, p. 627-8 of text

The Visual System Part 2

The Retina

What do you notice with regards to the connections in this complex circuit? What cells seem to have axons? What does this mean with regards to sensory coding?

S 15 Receptors for light detection More membrane = more photosensitive molecules = more sensitive to light Photoreceptor cells 4 light sensitive proteins: - 1 type of _____ - 3 types of ______, each with a single type

Visual Acuity 120,000,000 rods and 6,000,000 cones per retina 1,200,000 retinal ganglion cells & axons ____:___convergence ratio Fovea:

_______ Theory of Color Vision Differences in spectral sensitivity due to 4 types of ______. Web-based color deficiency test _______ Theory of Color Vision

“Bleaching” of photopigments _________ _________

What is the advantage of this multistep process? The cascade of events initiated by light in a photoreceptor. The result of the cascade is to close a cGMP-gated sodium channel, reducing the inward current and hyperpolarizing the membrane. Source: Kandel, Schwartz & Jessell, Principles of Neural Science, 4th Edn What is the advantage of this multistep process?

Hubel and Weisel Experiments Retinal Ganglion Cells Lateral Geniculate Neurons Visual Cortex Neurons Youtube

_____________in the Cortex Motion sensitive Color and shape sensitive