Visual Receptor Organs and Their Functions in Animals

This presentation explains the structure, function, and evolution of visual receptor organs in animals. It covers simple eyespots, compound eyes, ans camera-type eyes, highlighting how different species adapt their vision for survival and environmental needs.

1. VISUAL RECEPTOR ORGAN S IN ANIMALS NEELAMADHAB MAHAVIDYALAYA, KANTILO, NAYAGARH By Manoj Kumar Mansingh

2. SENSE ORGANS Introduction: Animals, including humans, have sensory organs that allow them to detect changes in their environments.

3. SENSE ORGANS Senses tell animals what they need to know about their environment. Sensory Organs are any part of the body that receives signals from the environment. They help to keep them out of danger and enable them to find food and shelter.

4. SENSE ORGANS Types Of Sense Organs: We have all heard about the five senses i.e see, 1.eyes, 2.ears, 3.nose  4.tongue 5.skin Each sense organ contains different receptors. To see we use our eyes, to hear we use our ears, to smell we use our nose, to taste we use our tongue, and we touch with the help of skin. Vision receptor is one of them;

5. Centre For Sensory Information

6. Receptors Exteroceptors: Detect stimuli near outer body surface Interoceptors : Detect stimuli from inside the body Proprioceptors: Detect stimuli deep within the body WHAT IS RECEPTOR: an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerve.

7. Interoceptors Taste Smell pH Distension Spasm Flow Cold Warmth Touch Pressure Special senses Hearing Vision Exteroceptors

8. Proprioceptors Located in skeletal muscles, tendons, ligaments, and joint capsules. Provide information to CNS on posture, orientation in space, pressure, etc. Fibers are heavily myelinated for rapid transmission.

9. ANIMAL SENSES : Sensory Organs Many animals have the same type of sense organs as humans.

10. Vision Introduction: Vision is that sense that enables animals to see the world around them. Animals require vision to survive, find food, protect themselves from predators, seek shelter, and so on. The eye, along with its multiple parts and in coordination with the brain, produces vision. Parts of the eye :( from outside to Inside ) 1- Eyelashes and eyelids 2-Cornea 3-Aqueous humor 4-Iris 5-Pupil 6-Lens 7-Vitreous humor 8-Retina 9-Optic nerve 10-Sclera

11. Classification of Vision Monochromacy- only 1 type of cone cells. Eg .: Marine mammals, Owl Monkry and Australian sea lion . Dichromacy - 2 types of cone cells. Eg .: Cats, Dogs, Horses and Cattle . Trichromacy - 3 types of cone cells. Eg .: Birds , Fish , Amphibians and Reptiles . Infrared Vision - Eg .: Snakes

12. ANIMAL SENSES : Sensory Organs In some cases, animals do not have all the sense organs that humans have.

13. Visual Receptors Organ In Non-Chordates Cockroach: The photoreceptor organ of insects are simple eyes or ocelli and compound eyes. But in cockroach, usually compound eyes are found… Thus, a compound eye consists of a large number of visual units or ommatidia and 2000 such visual units are found in a compound eye of cockroach [Mosaic View]

14. Visual Receptors Organ In Non-Chordates Spiders: Spiders  usually have eight eyes (some have six or fewer), but few have good  eyesight . Some  spiders  have median eyes that can detect polarized light and they use this ability to navigate while hunting. Typical fields of view of the three main eye pairs of a modern salticid spider.  Right:  Yellow: Anterior median (AM or primary) eyes. Pink: anterior lateral (AL) eyes, including region of binocular overlap. Light blue: posterior lateral (PL) eyes. Dashed lines indicate range of movement of the AM eye tubes.  Below:  Red: Boomerang-shaped AM retina. Green: AL eye fields of view. Purple: PL eye fields of view. 

15. Visual Receptors Organ In Chordates Fish: Fish normally adjust focus by moving the lens closer to of further from the retina. Some fish can see ultraviolet and some are sensitive to polarized light.

16. Visual Receptors Organ In Chordates Snake: Snakes  do not see colors, but their eyes are equipped with a combination of light receptors. rods that provide low-light but fuzzy  vision , and cones that produce clear images. With the exception of a few species that  have  adapted to daytime hunting, most snakes do  not see well. Generally they can see shapes but not details.   Nocturnal  reptiles  usually have smaller eyes than diurnal ones, but relatively large pupillary and lens aperture and cornea. This improves their light-gathering ability, but at the same time reduces visual acuity. Snake Man

17. Visual Receptors Organ In Chordates Birds: Vision is the most important sense for birds, since good eyesight is essential for safe flight, and this group has a number of adaptations which give visual acuity superior to that of other vertebrate groups. Having two eyes means animals  can  see a three dimensional image of what's around them. Parrots, pigeons and other  birds  with eyes on the sides of their heads have a much bigger field of  vision , of about 300 degrees. Amazingly, this means that they can  see in front and a long way to the side, at the same time.

18. Structure Of Eye Of Mammalia

19. Muscles of the Eye

20. Parts of the Eye T he eye is a slightly asymmetrical globe , about an inch in diameter . The front part othe eye includes : The iris (the pigmented part ) T he cornea (a clear dome over the iris ) T he pupil (the black circular opening in the itis that lets light in ) T he sclera (the white part ) T he conjunctiva ( an invisible , clear layer of tissue covering the front of the eye , except the cornea )

21. Parts of the Eye Sclera : a tough white layer of connective tissue that covers all of the eyeball except the cornea . - Conjunctiva : external cover of the sclera – keeps the eye moist . Cornea : transparent covering of the front of the eye . - Allows for the passsage of light in to the eye and functions as a fixed lens .

22. Parts of the Eye Choroid : thin , pigmented layer lining the interior surface of the sclera . - Prevents light rays from scattering and distorting the image . - Anteriorly it forms the iris . *The iris regulates the size op the pupil . Retina : lines the interior surface of the choroid . - Contains photoreceptors . * Except at the optic disk ( where the optic nerve attaches ).

23. Mechanism OF Eye Visual function involves a combination of may factors , including : T he field of view D epth perception ( ability to judge distances ) P erception of M otion and C olour differentiation . LIGHT from Object Conjunctiva Cornea Aqueous humor Lens Vitreous humor RETINA NERVE IMPULSE Rods and Cones on Retina Synapse Bipolar nerve cells Ganglions Optic nerves Occipital lobe of BRAIN.

24. Common Eye Disorders Examples: Short-Sightedness, Long-Sightedness, Astigmatism, Cataract, Night-Blindness, Conjunctivitis, And Xerophthalmia. These are abnormalities in normal functioning of the eye. Below are brief discussion about them

25. Common Eye Disorders Short-Sightedness: Also referred to as myopia. People with this eye defect see near object clearly but not distanced object. A diverging or concave lens is suitable for correcting it.

26. Common Eye Disorders Long-Sightedness: It’s also known as Hyper- Metropia . Distanced object are seen clearly while nearby objects appears blurred. Long-Sightedness can be best corrected using a convex lens. It will be converge the image formed behind the retina to be focused on the retina.

27. Common Eye Disorders Astigmatism: Opticians confirmed the presence of this defect in all eye. In some cases the cornea isn’t even thus a distorted/stretched image is formed while some cases horizontal objects are blurred.

28. Common Eye Disorders Cataract: Common to aged people, a condition when the lens becomes cloudy due to advancing age. Using a suitable lens or changing the lens with an artificial one will correct this defect

29. Common Eye Disorders Night-Blindness: It causes victim not to see clearly at night or when the light is dim.

30. Common Eye Disorders Conjunctivitis: It happens when the conjunctiva is inflamed.

31. Common Eye Disorders Xerophthalmia: This eye defect is caused when vitamin A isn’t sufficient in the eye. It’s very possible it leads to blindness.

32. Care Of Eye The eye should be cared for very meticulously as it has been considered as the light of the body, we should avoid direct contact with dirty fingers also we should see the optician quickly as soon as we notice any abnormalities in normal functioning of the eye.

33. Eye Patients Of the 37 million people across the globe who are blind, over 15 million are from Odisha and other states of India. On the other hand, while India needs 2.5 lakh donated eyes every year. The country’s 109 eye banks manage to collect a maximum of just 25,000 eyes, 30% of which can’t be used.

34. Conclusion Thus by having a better understanding of vision in different species, it becomes easier for us to prevent, diagnose and treat any such conditions which may interfere with normal vision in our patients

35. ZOOLOGY DEPARTMENT