1. EYE AND VISION Pedro Amarante Andrade, PhD
LCSC06 BIOSCIENCES FOR SPEECH AND LANGUAGE THERAPY

2. VISION: THE EYE
Location
Size
Shape
Colour
Texture
Direction
Speed

3. ANATOMY

4. ANATOMY
Lens and Cornea remarkable level of transparency for organic structures that rivals inorganic materials such as glass
Neuroscience, Third Edition Purves et al pp. 230

5. ANATOMY Fluid-filled sphere Three layers: Retina (Neurons)
Choroid (blood sup.)
Ciliary muscle
Iris (adjust the pupil)
Sclera (outermost –
fibrous tissue, becomes the cornea)
Neuroscience, Third Edition Purves et al pp. 230

6. ANATOMY Liquid Fluid-filled sphere Anterior chamber:
Aqueous chamber
Posterior chamber:
Fluid is produced by the ciliary process and flows into the anterior chamber through the pupil
Neuroscience, Third Edition Purves et al pp. 230
Tortora G.J. and Derricskon B Principles of Anatomy and Physiology . pp. 609

7. ANATOMY Liquid

8. ANATOMY Liquid Fluid-filled sphere Behind the lens: Vitreous humor
80% of total volume
Maintain the eye shape
Contain phagocytic cells that remove blood and debris
Neuroscience, Third Edition Purves et al pp. 230

9. IMAGE FORMATION Refraction
Cornea and lens are responsible for focusing the image in the in the retina
Cornea (refraction) affected by being under water
Neuroscience, Third Edition Purves et al pp. 231
Neuroscience, Third Edition Purves et al pp. 232
Tortora G.J. and Derricskon B Principles of Anatomy and Physiology . pp. 615

10. IMAGE FORMATION Refraction
Cornea and lens are responsible for focusing the image in the in the retina

11. IMAGE FORMATION Accomodation
Far away objects
Nearby objects
Neuroscience, Third Edition Purves et al pp. 231
Adjustments on the size of Pupil

12. RETINA Part of the CNS Neuroscience, Third Edition. 2004.
Purves et al pp. 235
Neuroscience, Third Edition Purves et al pp. 230

13. RETINA Part of the CNS Neuroscience, Third Edition. 2004.
Purves et al pp. 235
Neuroscience, Third Edition Purves et al pp. 230

14. RETINA Five types of neurons: Photoreceptors; Bipolar; Ganglion;
Horizontal;
Amecrine
Neuroscience, Third Edition Purves et al pp. 235

15. RETINA Five types of neurons: Photoreceptors; Outer layer;
Human Physiology, An integrated approach, 5th edition
Dee Unglaud Silverthorn
Neuroscience, Third Edition Purves et al pp. 235

16. RETINA Five types of neurons: Photoreceptors; Bipolar;
Neuroscience, Third Edition Purves et al pp. 235

17. 1 million ganglion cells to 126 million photoreceptors
RETINA
Five types of neurons:
Photoreceptors;
Bipolar;
Ganglion;
1 million ganglion cells to 126 million photoreceptors
ACTION POTENTIAL
Neuroscience, Third Edition Purves et al pp. 235

18. RETINA Five types of neurons: Photoreceptors; Bipolar; Ganglion;
Horizontal;
Amecrine
(-) Maintain the visual system’s sensitivity to luminance contrast
(+) Sustained responses of bipolar cells to step changes in light intensity
Neuroscience, Third Edition Purves et al pp. 235

19. RETINA Rods and Cones Rods Cones LOW spatial resolution
Very Sensitive to light
Cones
HIGH spatial resolution
Insensitive to light
Neuroscience, Third Edition Purves et al pp. 241

20. RETINA Rods and Cones Rods Scotopic vision
LOW spatial resolution
Very Sensitive to light
Scotopic vision
At the lowest level of light;
Low resolution and no colour
Neuroscience, Third Edition Purves et al pp. 241

21. HIGH spatial resolution
RETINA Rods and Cones
Photopic vision
Dominant in determining what is seen in light
Cones
HIGH spatial resolution
Insensitive to light
Neuroscience, Third Edition Purves et al pp. 241

22. ELECTROMAGNETIC RADIATION
Energy is the form of waves that radiates from the sun;
White objects reflect all wavelengths
Black objects absorb all wavelengths
Tortora G.J. and Derricskon B Principles of Anatomy and Physiology . pp. 605

23. ELECTROMAGNETIC RADIATION

24. VISUAL PATHWAY Midbrain (neural circuits): Constriction of pupils
Coordination of head and eye movements
Patterns of sleep (circadian cycle)
Tortora G.J. and Derricskon B Principles of Anatomy and Physiology . pp. 619

25. VISUAL PATHWAY
Neuroscience, Third Edition Purves et al pp. 261

26. VISUAL PATHWAY
Neuroscience, Third Edition Purves et al pp. 268