SlideShare a Scribd company logo
Yashpal Singh Chundawat
Jai Narain Vyas University, Jodhpur
Zoology Department
Refraction of light entering
the eye
Focusing of image on the
ratina by accommodation
of lens
Convergence of image
Photo-chemical activity in
retina and conversion into
neural impulse
01
02
03
04
2
Events
of Vision
05 Processing in brain and
perception
Overview Of Eye Anatomy
01
02
03
04
Sclera
# “White of the eye”. # Dense fibrous Connective tissue.
# Contains Blood Vessels and Insertion site for extrinsic Eye
Muscle.
Cornea
# Thin, transporting epithilium.
# Continuous with the sclera, covering iris and pupil.
Iris
# “Colored part” of the eye. # Creates and adjust the pupil.
# Contains blood vessels, pigment cells, loose connective
tissue and pupillary muscle. # Regulates amount of light.
Lens
# Focused image on the retina.
# Colsely-packed concentric columnar cells.
05 06 07 08
Ciliary Body
# Ring of smooth muscle around lens.
# Regulates the shape of the lens for
accommodation.
Suspensatory Ligaments
# Attach the ciliary body to the lens
Retina
# Lines the posterior part of the eye.
# Held in place by the Vitrous.
# Contains light-sensitive photoreceptors.
Choroid
# Pigmented to absorb exess light.
# Supplies the retina with nutrient and
oxygen via blood supply.
WHEN WE DECIDE TO LOOK AT SOMETHING, A
BRAINSTEM STRUCTURE CALLED PONS CALLED
INTO ACTION. IT CONTROLS EYE MOVEMENT ,
CONSTANTLY TELLING OUR EYE MUSCLES TO
MOVE TOWARD THE COREECT STIMULUS OF
LIGHT.
Accomodation
● The process of changing the shape ofthe lens while
focusing on the object.
● At rest focusing on distant object, needs to increase focal
power to focus on close object.
● The ciliary muscles contract and release tension in the
ligament and the lens becomes rounder.
● The increased curvature increaes the focal point closer to
the eye.
Lens Correction
Transduces light into neural signals and
passes on the information to other region
of the brain.
Displaced portion of the CNS contains the
light-sensitive cells.
The Ratina 9
In addition to Phtoreceptors contain 4
additional types of neurons that form an
orderly intricate neural circuit.
While ganglion cells communicate via
action potentials, the photoreceptorsand
other neurons communicate via
gradeynaotic potentials that are
conducted electrically.
Arranged with the light-senseing photoreceptors at the very posterior edge of the eye
where they are located near the PE and choroid which assiasts in regeneration.
11
The Retinal
Anatomy
Ganglion cells
- Axons generate the optic nerve.
- Send action potential to the thalamus.
1*106 cells in the retina.
Amacrine cells
- Synapse within the inner layer of the ratina.
- Interconnect bipolar cells and gagnglion cells.
- Regulate communication between the ganglion cells
and the photoreceptor.
Bipolar cells
- Directly connected photoreceptors
and gaglion cells in a radial direction.
Harizontal Cells
- Synapse within the outer layer of the retina.
- Interconnect photoreceptors with bipolar cells in a
horizontal direction.
-Mediate interactions over a wide area of the retina.
Photoreceptors
- Rods - Detect
amount of light
present.
- Cones - Detect color.
- Highest density of
cones at fovea.
Pigmented Epithilium
- Absorb excess light.
-Involved in photoreceptor
regeneration.
The Ratinal Anatomy
13
• Central area of the retina with cone-mediated
vision.
• Neurons are displaced laterally to the fovea to
minimize scattering.
• Very high resolution vision, due to 1:1:1 ratio of
photoreceptor : bipolar ganglion : ganglion cell.
• At the periphery the ratio of photoceptors to
ganglion cells is high, cover a large receptive field.
• Cone levels fall to a very low density outside the
fovea, where the rods take over.
• Peripheral vision is mediated by both rods and
cones.
Photoreceptors
Cones
# Higher threshold receptors for photopic vision and color
vision.
Rods
#Low threshold receptors for night vision (scotopic vision).
Rhodopsin/Visual purpule.
#Visula pigment present in rods.
#Rhodopsin = opsin + retinine(11-cis retina/vit A aldehyde).
Phototransduction
Phenomena of
conversion of
light energy into
nerve impulse
Light falls on ratina -->
cause photochemical
changes --> trigger
cascade of biochemical
reaction --> generation
of electrical impulses.
Photochemical
Changes
Rhodopsin
bleaching
Rhodopsin
regeneration
1. Activation of the receptor protein.
• In rods, that is rhodopsin.
1 Photon ------> 1 Rhodopsin
Opsin Prorein 11- trans-retinal
Confermational Charge
Transducin
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
POLARIZED STATE
RESTING POTENTIAL
- 60 mev
Transducin
Phosphodierase(PDE)
Transducin
Na+
Sodium Channels
Ligant gated ion channel Voltage Gated Ion Channel
Na+
GTP
cGMP
Na+
By the action on Guanyl Cyclase enzyme
Ligand gated
ion Channel
Voltage gated ion gates Open
Voltage gated
ion channel
Na+ Na+ Na+
Threshold
potential
- 30 mev
Terminal Synaptic Vessicle
(NEURO-TRANSMETERS)
POST
SYNAPTIC
PRE SYNAPTIC
BIPOLAR CELL
GAGNLIONIC CELL
29
REFERANCES
Our evolution
Ppt -
“EYE PHYSIOLOGY AND VISION”
BY Tabitha Schrufer
Ppt -“PHYSIOLOGY OF VISION”
Prof. Vajira Weerasinghe
University of Peradeniya
Textbook of
MEDICAL PHYSIOLOGY
G.K. Pal
www.Allaboutvision.com
Artical By : Adam Debrowski
30
Thank You

More Related Content

Similar to Molecular Physiology Of Vision

Retina & the vision
Retina & the visionRetina & the vision
Retina & the vision
Muhammad Haroon Stanikzai
 
PHYSIOLOGY OF RETINA.pptx
PHYSIOLOGY OF RETINA.pptxPHYSIOLOGY OF RETINA.pptx
PHYSIOLOGY OF RETINA.pptx
LavanyaMadabushi
 
160 report
160 report160 report
Nervous system
Nervous systemNervous system
Nervous system
Claudia Kopanovski
 
Physiology of Vision.ppt
Physiology of Vision.pptPhysiology of Vision.ppt
Physiology of Vision.ppt
ssuser7ec6af
 
anatomy of retina
anatomy of retinaanatomy of retina
anatomy of retina
Rifat Shamim
 
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdfVISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
TatendaMageja
 
EYE PRESENTATION Dr Sheeba.ppt
EYE PRESENTATION   Dr Sheeba.pptEYE PRESENTATION   Dr Sheeba.ppt
EYE PRESENTATION Dr Sheeba.ppt
Royal Dental College Library
 
Ch09
Ch09Ch09
Ch09
Jan Stern
 
Mounika seminar doc
Mounika seminar docMounika seminar doc
Mounika seminar doc
srikruthi9
 
eye.docx
eye.docxeye.docx
eye.docx
Safia Humayun
 
Physiology of sense organ EYE
Physiology of sense organ EYEPhysiology of sense organ EYE
Physiology of sense organ EYE
Sudipta Himel
 
Lab 15 Sheepeyediss
Lab 15 SheepeyedissLab 15 Sheepeyediss
Lab 15 Sheepeyediss
guest6d238a
 
Retina
RetinaRetina
Chapter6 Power Point Lecture
Chapter6 Power Point LectureChapter6 Power Point Lecture
Chapter6 Power Point Lecture
Gladys Escalante
 
retina and role in vision
retina and role in visionretina and role in vision
retina and role in vision
sandeepkumar14601
 
Sense organs
Sense organsSense organs
Sense organs
ROMAN BAJRANG
 
Mammalian eye
Mammalian eyeMammalian eye
Mammalian eye
Kankana Choudhury
 
Generator of vep
Generator of vepGenerator of vep
Generator of vep
Shehzad Hussain Raja
 
06 lec9
06 lec906 lec9

Similar to Molecular Physiology Of Vision (20)

Retina & the vision
Retina & the visionRetina & the vision
Retina & the vision
 
PHYSIOLOGY OF RETINA.pptx
PHYSIOLOGY OF RETINA.pptxPHYSIOLOGY OF RETINA.pptx
PHYSIOLOGY OF RETINA.pptx
 
160 report
160 report160 report
160 report
 
Nervous system
Nervous systemNervous system
Nervous system
 
Physiology of Vision.ppt
Physiology of Vision.pptPhysiology of Vision.ppt
Physiology of Vision.ppt
 
anatomy of retina
anatomy of retinaanatomy of retina
anatomy of retina
 
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdfVISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
VISION IN ANIMALS VETERINARY PHYSIOLOGY.pdf
 
EYE PRESENTATION Dr Sheeba.ppt
EYE PRESENTATION   Dr Sheeba.pptEYE PRESENTATION   Dr Sheeba.ppt
EYE PRESENTATION Dr Sheeba.ppt
 
Ch09
Ch09Ch09
Ch09
 
Mounika seminar doc
Mounika seminar docMounika seminar doc
Mounika seminar doc
 
eye.docx
eye.docxeye.docx
eye.docx
 
Physiology of sense organ EYE
Physiology of sense organ EYEPhysiology of sense organ EYE
Physiology of sense organ EYE
 
Lab 15 Sheepeyediss
Lab 15 SheepeyedissLab 15 Sheepeyediss
Lab 15 Sheepeyediss
 
Retina
RetinaRetina
Retina
 
Chapter6 Power Point Lecture
Chapter6 Power Point LectureChapter6 Power Point Lecture
Chapter6 Power Point Lecture
 
retina and role in vision
retina and role in visionretina and role in vision
retina and role in vision
 
Sense organs
Sense organsSense organs
Sense organs
 
Mammalian eye
Mammalian eyeMammalian eye
Mammalian eye
 
Generator of vep
Generator of vepGenerator of vep
Generator of vep
 
06 lec9
06 lec906 lec9
06 lec9
 

Recently uploaded

Sciences of Europe journal No 142 (2024)
Sciences of Europe journal No 142 (2024)Sciences of Europe journal No 142 (2024)
Sciences of Europe journal No 142 (2024)
Sciences of Europe
 
Methods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdfMethods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdf
PirithiRaju
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
Sérgio Sacani
 
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
ABHISHEK SONI NIMT INSTITUTE OF MEDICAL AND PARAMEDCIAL SCIENCES , GOVT PG COLLEGE NOIDA
 
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
vluwdy49
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
PirithiRaju
 
LEARNING TO LIVE WITH LAWS OF MOTION .pptx
LEARNING TO LIVE WITH LAWS OF MOTION .pptxLEARNING TO LIVE WITH LAWS OF MOTION .pptx
LEARNING TO LIVE WITH LAWS OF MOTION .pptx
yourprojectpartner05
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Sérgio Sacani
 
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
hozt8xgk
 
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSJAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
Sérgio Sacani
 
Applied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdfApplied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdf
University of Hertfordshire
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
University of Maribor
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
by6843629
 
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Leonel Morgado
 
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
frank0071
 
Pests of Storage_Identification_Dr.UPR.pdf
Pests of Storage_Identification_Dr.UPR.pdfPests of Storage_Identification_Dr.UPR.pdf
Pests of Storage_Identification_Dr.UPR.pdf
PirithiRaju
 
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
Advanced-Concepts-Team
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
Leonel Morgado
 
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Sérgio Sacani
 
23PH301 - Optics - Optical Lenses.pptx
23PH301 - Optics  -  Optical Lenses.pptx23PH301 - Optics  -  Optical Lenses.pptx
23PH301 - Optics - Optical Lenses.pptx
RDhivya6
 

Recently uploaded (20)

Sciences of Europe journal No 142 (2024)
Sciences of Europe journal No 142 (2024)Sciences of Europe journal No 142 (2024)
Sciences of Europe journal No 142 (2024)
 
Methods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdfMethods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdf
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
 
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
MICROBIAL INTERACTION PPT/ MICROBIAL INTERACTION AND THEIR TYPES // PLANT MIC...
 
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
 
LEARNING TO LIVE WITH LAWS OF MOTION .pptx
LEARNING TO LIVE WITH LAWS OF MOTION .pptxLEARNING TO LIVE WITH LAWS OF MOTION .pptx
LEARNING TO LIVE WITH LAWS OF MOTION .pptx
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
 
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
 
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSJAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDS
 
Applied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdfApplied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdf
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
 
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
 
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
 
Pests of Storage_Identification_Dr.UPR.pdf
Pests of Storage_Identification_Dr.UPR.pdfPests of Storage_Identification_Dr.UPR.pdf
Pests of Storage_Identification_Dr.UPR.pdf
 
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
 
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
 
23PH301 - Optics - Optical Lenses.pptx
23PH301 - Optics  -  Optical Lenses.pptx23PH301 - Optics  -  Optical Lenses.pptx
23PH301 - Optics - Optical Lenses.pptx
 

Molecular Physiology Of Vision

  • 1. Yashpal Singh Chundawat Jai Narain Vyas University, Jodhpur Zoology Department
  • 2. Refraction of light entering the eye Focusing of image on the ratina by accommodation of lens Convergence of image Photo-chemical activity in retina and conversion into neural impulse 01 02 03 04 2 Events of Vision 05 Processing in brain and perception
  • 3. Overview Of Eye Anatomy
  • 4. 01 02 03 04 Sclera # “White of the eye”. # Dense fibrous Connective tissue. # Contains Blood Vessels and Insertion site for extrinsic Eye Muscle. Cornea # Thin, transporting epithilium. # Continuous with the sclera, covering iris and pupil. Iris # “Colored part” of the eye. # Creates and adjust the pupil. # Contains blood vessels, pigment cells, loose connective tissue and pupillary muscle. # Regulates amount of light. Lens # Focused image on the retina. # Colsely-packed concentric columnar cells.
  • 5. 05 06 07 08 Ciliary Body # Ring of smooth muscle around lens. # Regulates the shape of the lens for accommodation. Suspensatory Ligaments # Attach the ciliary body to the lens Retina # Lines the posterior part of the eye. # Held in place by the Vitrous. # Contains light-sensitive photoreceptors. Choroid # Pigmented to absorb exess light. # Supplies the retina with nutrient and oxygen via blood supply.
  • 6. WHEN WE DECIDE TO LOOK AT SOMETHING, A BRAINSTEM STRUCTURE CALLED PONS CALLED INTO ACTION. IT CONTROLS EYE MOVEMENT , CONSTANTLY TELLING OUR EYE MUSCLES TO MOVE TOWARD THE COREECT STIMULUS OF LIGHT.
  • 7. Accomodation ● The process of changing the shape ofthe lens while focusing on the object. ● At rest focusing on distant object, needs to increase focal power to focus on close object. ● The ciliary muscles contract and release tension in the ligament and the lens becomes rounder. ● The increased curvature increaes the focal point closer to the eye.
  • 9. Transduces light into neural signals and passes on the information to other region of the brain. Displaced portion of the CNS contains the light-sensitive cells. The Ratina 9 In addition to Phtoreceptors contain 4 additional types of neurons that form an orderly intricate neural circuit. While ganglion cells communicate via action potentials, the photoreceptorsand other neurons communicate via gradeynaotic potentials that are conducted electrically. Arranged with the light-senseing photoreceptors at the very posterior edge of the eye where they are located near the PE and choroid which assiasts in regeneration.
  • 10.
  • 11. 11 The Retinal Anatomy Ganglion cells - Axons generate the optic nerve. - Send action potential to the thalamus. 1*106 cells in the retina. Amacrine cells - Synapse within the inner layer of the ratina. - Interconnect bipolar cells and gagnglion cells. - Regulate communication between the ganglion cells and the photoreceptor. Bipolar cells - Directly connected photoreceptors and gaglion cells in a radial direction. Harizontal Cells - Synapse within the outer layer of the retina. - Interconnect photoreceptors with bipolar cells in a horizontal direction. -Mediate interactions over a wide area of the retina.
  • 12. Photoreceptors - Rods - Detect amount of light present. - Cones - Detect color. - Highest density of cones at fovea. Pigmented Epithilium - Absorb excess light. -Involved in photoreceptor regeneration. The Ratinal Anatomy
  • 13. 13 • Central area of the retina with cone-mediated vision. • Neurons are displaced laterally to the fovea to minimize scattering. • Very high resolution vision, due to 1:1:1 ratio of photoreceptor : bipolar ganglion : ganglion cell. • At the periphery the ratio of photoceptors to ganglion cells is high, cover a large receptive field. • Cone levels fall to a very low density outside the fovea, where the rods take over. • Peripheral vision is mediated by both rods and cones.
  • 14. Photoreceptors Cones # Higher threshold receptors for photopic vision and color vision. Rods #Low threshold receptors for night vision (scotopic vision). Rhodopsin/Visual purpule. #Visula pigment present in rods. #Rhodopsin = opsin + retinine(11-cis retina/vit A aldehyde).
  • 15. Phototransduction Phenomena of conversion of light energy into nerve impulse Light falls on ratina --> cause photochemical changes --> trigger cascade of biochemical reaction --> generation of electrical impulses. Photochemical Changes Rhodopsin bleaching Rhodopsin regeneration
  • 16.
  • 17.
  • 18. 1. Activation of the receptor protein. • In rods, that is rhodopsin. 1 Photon ------> 1 Rhodopsin Opsin Prorein 11- trans-retinal Confermational Charge Transducin
  • 21. Sodium Channels Ligant gated ion channel Voltage Gated Ion Channel
  • 22. Na+ GTP cGMP Na+ By the action on Guanyl Cyclase enzyme Ligand gated ion Channel
  • 23. Voltage gated ion gates Open Voltage gated ion channel Na+ Na+ Na+ Threshold potential - 30 mev
  • 24.
  • 27.
  • 28.
  • 29. 29 REFERANCES Our evolution Ppt - “EYE PHYSIOLOGY AND VISION” BY Tabitha Schrufer Ppt -“PHYSIOLOGY OF VISION” Prof. Vajira Weerasinghe University of Peradeniya Textbook of MEDICAL PHYSIOLOGY G.K. Pal www.Allaboutvision.com Artical By : Adam Debrowski