The document discusses the human sensory system, specifically vision. It describes the basic anatomy of the eye, including structures like the iris, cornea, lens, retina, and different types of light receptors (rods and cones). It explains how light enters the eye and is focused on the retina to form an image, which is then transmitted via the optic nerve to the brain for processing and perception of vision. The document also discusses monocular and binocular vision, and how the eye works as a complex optical system to collect light and regulate intensity.

1. PRINCIPLE SENSORY
SYSTEM
GROUP 1
AYESHA MEHBOOB
SUNDAS GILL
MARYAM YAQUB
FIZZA RAJA
SUMERA MALIK

2. What is a Sensory System?
O Window to physical energies. Give rise to
sensory perceptions.
O General plan of sensory pathways:
receptor, thalamus (diencephalon), cortex
(telencephalon).

3. Different sensory systems
O Vision
O Audition
O Somatosensory
O Taste
O Smell

4. Why do we have different SYSTEMS
when the neural activity is the same : action
potential
O Theory of specific sensory energies by
Johannes Muller, 1826. Labeled
pathways.

5. Vision
Introduction and structure of an eye
by
Ayesha Mehboob
Function of human eye
By
Sundas Saba Gill

7. THE EYE
O The eye is a complex sensory organ
consisting of various muscles, tissues,
and nerve sensors, which work together to
create the phenomenon we know as
vision:
The ability to see
O Complex eyes can distinguish shapes
and colors.

8. TYPES OF EYE
Eye types can be categorized into
1. Simple eyes: with one concave
photoreceptive surface, and
2. Compound eyes: which comprise a
number of individual lenses laid out on a
convex surface

9. O Any eye type can be adapted for almost
any behavior or environment.
O The only limitations specific to eye types
are that of resolution e.g.
The compound eyes achieving a resolution
better than 1°. Also, superposition eyes can
achieve greater sensitivity and apposition
eyes are better suited to dark-dwelling
creature

10. HUMAN EYES
O Human eye is an organ which reacts to
light for several purposes.
O As a conscious sense organ,
the eye allows vision.
O Rod and cone cells in the retina allow
conscious light perception and vision
including color differentiation and the
perception of depth.

11. O The human eye can distinguish about 10
million colors.
O light signals affect adjustment of the size
of the pupil.

12. STRUCTURE OF AN EYE

13. OUTER STRUCTURE

14. INNER STRUCTURE

15. Anatomy of eye
O Sclera: The white portion of the eye,
which is a dense tissue containing blood
vessels and providing a surface for
attaching the external muscles of the eye.
O Pupil: The round, black opening in the
center of the iris that allows light to pass
through the eye and onto the retina.

16. O Iris: The colored part of the outer eye.
This thin muscle constricts or dilates to
adjust the diameter of the pupil, thus
controlling the amount of light that enters
the eye.
O Cornea: The transparent tissue that
covers the front of the eye including the
pupil and iris.
O responsible for most of the eye’s focusing
abilities.

17. Aqueous humor : A liquid substance found
in the eye chambers, made mostly of water.
O delivers vital nutrients to the eyes
O maintain correct pressure balance in the
eye chamber
O Help in maintain its shape

18. O Ciliary muscle: is a muscle in an area of
the eye which helps people focus.
O It assist the lens of the eye to be flattened
or rounded to allow people to focus on
distant and near objects and maintain the
proper fluid pressure in the eye.

19. O Lens: After light enters through the pupil,
it passes through the lens, which focuses
the light and projects it onto the surface of
the retina in the back of the eye.
O vitreous humor: helps keep the retina in
place.
O transparent jelly-like mass located behind
the lens.
O helps to maintain the shape of the
posterior chamber of the eyeball.

20. O Retina: A light sensitive tissue that lines
the inner surface of the back of the eye.
O It transforms light that enters through the
pupil and passes through the lens into
nerve signals that are converted into an
image by the visual cortex of the brain

22. VISUAL FIELD
O All of these components function
simultaneously to allow us to see our
surroundings.
O The resulting picture, called the visual
field:
Combination of two primary types of vision
with distinct functions and characteristics

23. TYPES OF VISIONS
1. FOVEAL VISION (smallest portion of our
visual field)
O Objects within the scope of foveal vision
are clear and colorful.
2. PERIPHERAL VISION(The majority of
the scene we see)
O to detect movements and color and shape
contrasts.

24. TYPES OF LIGHT RECPTORS
O These two different types of vision are a result
of the two kinds of light receptor cells found in
the retina.
1. Cones: Foveal vision is created by cone
cells.
O that are tightly packed in a small area in the
center of the retina.
O only account for 6% of the total retinal light
receptors.
O Cone cells require the most light for creating a
clear, detailed image.

25. 2. Rods: The rod cells account for the other
94% of light receptors in the retina.
O They require less light.
O create the blurry, less colorful qualities of
peripheral vision.

26. BINOCULAR &
MONOCULAR VISION
O The visual fields of many organisms like
human , involve large areas of binocular
vision to improve depth perception.(3
dimension)
O vision using two eyes,
O In other organisms, eyes are located so
as to maximize the field of view, such as
in rabbits and horses, which
have monocular vision.

27. SUNDAS SABA GILL

28. ANATOMICAL PROCESS OF
VISION
1. The eye is a complex optical system
which collects light from the surrounding
environment,
2. regulates its intensity through
a diaphragm,
3. focuses it through an adjustable
assembly of lenses to form an image,

29. 4. converts this image into a set of
electrical signals
5. and transmits these signals to
the brain through complex neural
pathways that connect the eye via
the optic nerve to the visual cortex and
other areas of the brain.

30. In simple words:
O clear image of the visual world produce on
a sheet of photoreceptors called the
retina, which is part of the central nervous
system but located at the back of the eye.
O Photoreceptors gather visual information
and sending electrical signals to other
retinal neurons for initial processing

31. O The signals are then sent via the optic
nerve to other parts of brain, which
ultimately processes the image and allows
us to see.
O The image on the retina is reversed:
Objects to the right of center project images
to the left part of the retina and vice versa.