Chapter 2: Beginning Of The Perceptual Process

Question 1

FIrst step of the process

Answer 1

Light reflected from an object into the eye

Question 2

Virtual Process first four steps

Answer 2

1) The distal stimulus (aika the tree)
2) Light is reflected from the tree and enters the eye to create the proximal stimulus on the vision receptor
3) Receptors transform light into electrical signals
4) Electrical signals are ‘processed” as they travel through a network of neurons

Question 3

Visible light

Answer 3

The energy within the electromagnetic spectrum that humans can perceive, has wavelength from 400nm-700nm

Question 4

Electromagnetic spectrum

Answer 4

A continuum of electromagnetic energy that is produced by electric charges and is radiated as waves

Question 5

Wavelength

Answer 5

The distance between the peaks of the electromagnetic waves

Question 6

The eye (how it works)

Answer 6

Light reflected from objects in the environment enters the eye through the pupil and is focussed by the cornea and lens to form sharp images of the objects on the retina, the network of neurons that covers the back of the eye and that contains the receptors for vision

Question 7

2 types of visual receptors

Answer 7

Rods

Cones

Question 8

Outer segments

Answer 8

Part of the receptor that contains light-sensitive chemicals called visual pigments that react to light and trigger electrical signals

Question 9

Fovea

Answer 9

Only contains cones (when we look at an object, the objects image falls on the fovea)

Question 10

Peripheral retina

Answer 10

Includes all of the retina outside of the fovea, contains both rods and cones

Question 11

Macular degeneration

Answer 11

Common in older people
Destroys the cone rich fovea and a small area surrounding it, which creates a blind spot when seeing an object (loses sight of the object)

Question 12

Retina pigmentosa

Answer 12

Degeneration of the retina that is passed from one generation to the next, attacks peripheral rod receptors and results in poor vision in the peripheral vision field

Question 13

Blind spot

Answer 13

A spot where there is an absence of receptors where the nerve fibers leave the eye

Question 14

2-element optical system

Answer 14

cornea and lens

Question 15

Cornea

Answer 15

Transparent covering of the front of the eye

-accounts for 80 percent of the eye’s focussing power

Question 16

Lens

Answer 16

supplies remaining 20% of focussing power

-can change it shapes to adjust focus for objects at various distances

Question 17

Accommodation

Answer 17

Change in the len’s shape that occurs when the ciliary muscles at the front of the eye tighten and increase the curvature of the lens so it gets thicker

Question 18

Presbyopia

Answer 18

Unable to accommodate enough to see objects (due to hardening of lens and weakening of muscles)

Question 19

myopia (nearsightnedness)

Answer 19

an inability to see distant objects clearly (light rays come to focus in front of the retina)

Question 20

Refractive myopia

Answer 20

the cornea and or the lns bends the light too much

Question 21

Axial myopia

Answer 21

In which the eyeball is too long

Question 22

Hyperopia (farsightedness)

Answer 22

Can see distant objects clearly but have trouble seeing nearby objects because the focus point for parallel rays of light is located behind the retina, usually due to too small of an eyeball

Question 23

Transduction

Answer 23

The transformation of one form of energy into another form of energy

Question 24

Visual pigments have two parts

Answer 24

Long protein called Opsin

Small light sensitive component called retinal

Question 25

Isomerization

Answer 25

The retinal changing shape due to the pigment molecule absorbing light

Question 26

Dark Adaption

Answer 26

The process of increasing sensitivity in the dark

Question 27

Dark adaption is measured by

Answer 27

Determining a dark adaptation curve

Question 28

Rod monochromats

Answer 28

People who have no cones

Question 29

As soon as lights are extinguished...

Answer 29

Rods and cones begin to get more sensitive, but as cones are much more sensitive than rods at the beginning of dark adaptation, we see with our cones right after lights are turned off After 3-5 minutes the cones have reached maximum sensitivity (but rods are still adjusting and take about 7 minutes, reach maximum at about 20-30 mins)

Question 30

Rod-Cone break

Answer 30

The place where the rods begin to determine the dark adaption curve

Question 31

Visual pigment bleaching

Answer 31

The change in shape and separation from the opsin causes the molecule to become lighter in colour (process is called card name)

Question 32

2 important connections between perception and physiology

Answer 32

1) Our sensitivity to light depends on the concentration a chemical-the visual pigment 2) The speed at which our sensitivity increase in the dark depends on a chemical reaction - the regeneration of the visual pigment

Question 33

Electrical signals occur in structures called

Answer 33

neurons

Question 34

Components of a neuron

Answer 34

Cell Body: contains mechanisms to keep the cell alive Dendrites: Branch out from the cell body to receive electrical signals from other neurons Axon or nerve fiber: full of fluid that conducts electrical signals

Question 35

Sensory receptors

Answer 35

Neurons specialized to respond to environmental stimuli

Question 36

When the axon or nerve fiber is at rest, the difference in electrical potential between the tips of the two electrodes is:

Answer 36

- 70 millivolts (mV) | - this means that the inside of the axon is 70mV more negative than the outside

Question 37

Resting potential

Answer 37

As long as there are no signals in the neuron (refer to card above #36)

Question 38

Action potential

Answer 38

Neurons receptors are stimulated so that a signal is transmitted down the axon. As the signal passes the recording electrode, the charge inside the axon rises to +40mV compared to the outside -as the signal passes through the charge inside the fiber reverses course and starts becoming negative again

Question 39

Propagated response

Answer 39

Once the response is triggered, it travels all the way down the axon without decreasing in size (would be the same size even if moved, increasing from -70mV to +40mV)

Question 40

Changing the stimulus intensity does not affect the size of the action potentials but does affect the ___ of firing

Answer 40

rate

Question 41

Refractory period

Answer 41

The interval between the time one nerve impulse occurs and the next one can be generated in the axon -Refractory period is typically 1ms, so 500-800 impulses per second

Question 42

Spontaneous activity

Answer 42

Action potentials that occur in the absence of stimuli from the environment

Question 43

ions

Answer 43

molecules that carry an electrical charge

Question 44

The solution outside the axon of a neuron is rich in positively charged _____ (Na+) ions, whereas the solution inside the axon is rich in positively charged _________ (K+) ions

Answer 44

sodium | potassium

Question 45

Permeability

Answer 45

The ease with which a molecule can pass through the membrane The opening of sodium channels in the membrane represents an increase in the permeability

Question 46

Rising phase of the action potential

Answer 46

The increase in potential from -70mV to +40mV (polarized)

Question 47

Once the neuron reaches +40mV the sodium cannels close (membrane becomes impermeable to sodium) and the potassium channels open up

Answer 47

CRAZZZZY #BIO11

Question 48

Falling phase of the action potential

Answer 48

Going from +40mV to -70mV (repolarization)

Question 49

Synapse

Answer 49

The spaces between neurons

Question 50

Neurotransmitters

Answer 50

Flow into the synapse to small areas on the receiving neuron receptor sites that are sensitive to specific neurotransmitters

Question 51

Two types of responses at the receptor sites

Answer 51

Excitatory | Inhibitory

Question 52

Excitatory response

Answer 52

occurs when the inside of the neuron becomes more positive

Question 53

Depolarization

Answer 53

Process when the inside of the neuron becomes more positive Depolarization is an excitatory response

Question 54

Inhibitory response

Answer 54

occurs when the inside of the neuron becomes more negative, a process called hyperpolarization

Question 55

Hyperpolarization is a _____ response

Answer 55

inhibitory (as it causes the charge inside the axon to move away from the level of depolarization)

Question 56

Neural Circuits

Answer 56

interconnected groups of neurons - within the retina

Question 57

Two types of neurons that connect neurons across the retina (asides from bipolar cells and ganglion cells

Answer 57

Horizontal cells | Amacrine cells

Question 58

Neural convergence

Answer 58

Occurs when a number of neurons synapse onto a single neuron

Question 59

The greater convergence of the rods compared to the cones translate into two differences in perception

Answer 59

1) the rods result in better sensitivity than the cones | 2) The cones result in better detail vision than the rods

Question 60

Visual acuity

Answer 60

Referrers to the ability to see details (seeing small letters at eye doctor equals high acuity)

Question 61

High convergence results in high sensitivity but poor acuity (the rods)

Answer 61

WOW

Question 62

Low convergence results in low sensitivity but high acuity (Cones)

Answer 62

WOW

Question 63

Preferential lookin technique

Answer 63

Two stimuli are presented and the observer sees what one the child looks at longer

Question 64

Node of ranvier

Answer 64

Little gaps in myelin sheath used to facilitate speed