VISION 1

Question 1

WHAT IS VISION?

Answer 1

Process by which light reflected from external objects are translated
into a mental image.

Question 2

HOW MANY STEPS IN VISION PROCESS?

Answer 2

This process consists of 3 steps:

1. light enters the eye and is focused by a lens on to the retina.
2. retinal photoreceptors transduce light energy into electrical signal.
3. processing of the electrical signals through neural pathways.

Question 3

IN WHAT PART OF THE EYE MOST FOCUSING OF LIGHT TAKES PLACE AND WHY?

Answer 3

Cornea - BECAUSE IT IS WHERE LIGHTHITS THE EYE. MOST FOCUSING TAKES PLACE HERE here due to air/cornea density differences

Question 4

WHAT DOES THE The pupil ADJUST?

Answer 4

the amount of light entering.

Question 5

WHAT FOCUSES LIGHT IN THE RETINA?

Answer 5

Changes in the shape of the lens

Question 6

WHAT DOES CONTRACTION OF ciliary muscles DO?

Answer 6

determines the amount of tension that the zonular fibers (ligaments) exert on the lens:

Question 7

HOW CILIARY MUSCLES ADJUST FOR CLOSE VS FAR OBJECTS

Answer 7

contracted = less tension, more rounded lens (focus on near object),
relaxed = more tension, more flattened lens (focus on distant object).

Question 8

WHAT TYPE OF CELLS generate graded potentials

Answer 8

PHOTORECEPTORS AND BIPOLAR CELLS GENERATE

Question 9

WHAT TYPE OF CELLS always generate action potentials.

Answer 9

Ganglion cells always generate action potentials.

Question 10

WHY ARE RODS USED FOR NIGHT VISION?

Answer 10

B/c they exhibit convergence, rods give low resolution sight at low levels of
illumination. Rods contain rhodopsin and are more numerous than cones.

Question 11

WHY ARE Cones are used for daylight vision.?

Answer 11

B/C Cones are in a 1:1 ratio to bipolar and ganglion cells. Cones give high resolution sight at high levels of illumination.

Question 12

THE Basic function of a sensory receptor is

Answer 12

to detect
change in the environment (called a stimulus) and
convert the energy (heat, light, pressure, etc) of
the stimulus into electrical signals (action
potentials) in the nervous system. This conversion

Question 13

WHAT IS TRANSDUCTION?

Answer 13

CONVERSION OF A STIMULUS INTO ELECTRICAL SIGNAL FOR THE BRAIN

Question 14

WHAT DO Somatosensory pathways carry?

Answer 14

information about pain, temperature, touch, pressure, vibration, position of the body parts, and their movements.

Question 15

The visual system detects

Answer 15

the shape and color of
objects and the movement of objects in the
external environment.

Question 16

IS LIGHT DETECTED BY THE VISUAL SYSTEM?

Answer 16

NO

Question 17

HOW IS Light is detected ?

Answer 17

Light is detected by different cells (rods, cones) in the eye and sent via the optic nerve to the visual cortex for
processing.