Senses and vision

Question 1

Sensation is the capacity to ____ a particular ____ or ____ stimulus.
Involves ____ organs and ____ nerves.

Answer 1

detect, physical, chemical sensory, afferent

Question 2

Perception is the ____ experience and ____ of ____ information. Involves ____ in the ____ nervous system.

Answer 2

conscious, interpretation, sensory
neurons, central

Question 3

A stimulus is a thing or ____ that evokes a specific ____ reaction in an ____ or ____

Answer 3

event
functional
organ
tissue

Question 4

What is transduction?

Answer 4

Each sensory organ deploys a specific mechanism to transform chemical or physical attributes of stimuli to neuronal activity

Question 5

Each sensory organ deploys a specific mechanism to transform chemical or physical attributes of stimuli to what?

Answer 5

Neuronal activity. This is called stimulus transduction

Question 6

Give some examples of physical and chemical stimuli

Answer 6

Physical = sound visible light, heat, magnetic field, UV light
Chemical = taste, odour, pheromones

Question 7

Weakly electric fishes produce and detect small current flows around them. What is this called? What is this called when used to communicate with conspecifics?

Answer 7

Electrolocation
Electrocommunication

Question 8

What is the purpose of cockeyed squid having asymmetrical eyes?

Answer 8

Large eye looking upward to detect predators against dim sunlight
Small eye looking downward to detect prey bioluminescent signals

Question 9

Sensory receptors are cells that specialise in ____ ____ stimuli (physical or chemical) into ____ (electical) ____

Answer 9

converting, external, neural, activity

Question 10

What do the following detect, and what activity are they linked to?
1. Photoreceptors
2. Mechanoreceptors
3. Chemoreceptors
4. Nociceptors

Answer 10

1. Detect light | vision
2. Detect movement | sound, texture, blood pressure, muscle stretch
3. Detect chemical compounds | smell, taste
4. Detect tissue damage | pain

Question 11

A receptor threshold is the ____ stimulus ____ that is ____.

Answer 11

minimum, intensity, detected

Question 12

What are three things that can affect how we perceive the same sensory experience?

Answer 12

Context, emotional state, memories

Question 13

What is meant by “visual light”?

Answer 13

Section of the electromagnetic spectrum that the human eye can detect

Question 14

Describe the role of the following in the eye…
1. Iris - o____ and c____ to allow more or less l____ through the p____
2. Cornea and lens - f____ the light into the r____, where the image is r____
3. Optic disc - allows v____ going in and out, and the optic n____ to carry visual information to the b____

Answer 14

1. Opens and closes to allow more or less light through the pupil
2. Focus the light into the retina, where the image is recreated
3. Allows vessels going in. and out, and the optic nerve to carry visual information to the brain

Question 15

The fovea is mainly covered by d____ p____ c____

Answer 15

Densely packed cones (acute vision during daylight)

Question 16

The periphery is covered by r____, which are more s____ to l____ than c____.

Answer 16

Rods, which are more sensitive to light than cones (sense very dim light)

Question 17

What are the three types of cones?
1. B____
2. G____
3. R____
Each type is s____ to a specific w____ b____

Answer 17

Blue, green and red
Each type is sensitive to a specific wavelength band

Question 18

Photoreceptors are depolarised in the dark, releasing what?

Answer 18

Glutamate
Light makes them hyper polarise, reducing glutamate release

Question 19

What are the three cell layers in the eye?
1. G____ cell layer
2. B____ cell layer
3. P____ layer

Answer 19

1. Ganglion cell layer
2. Bipolar cell layer
3. Photoreceptor layer

Question 20

Photoreceptors and bipolar cells do not fire action potentials. Instead they do what to affect the probability of neurotransmitter release?
C____ their m____ p____

Answer 20

Change their membrane potential

Question 21

In vertebrate retinas, what are the two types of bipolar cells?
O____ and o____

Answer 21

ON and OFF

Question 22

How many photoreceptors are the bipolar cells connected to in the fovea and the peripheral retina?

Answer 22

Fovea - one bipolar cell connected to one photoreceptor
Peripheral retina - one bipolar cell connects with several photoreceptors

Question 23

Both eyes collect light from both sides of the visual field. Where does visual information coming from each side of the visual field get conveyed to?

Answer 23

The visual information coming from the right side of the visual field is conveyed into the left hemisphere.
The one from the left side of the visual field is analysed in the right hemisphere

Question 24

What are the three neural routes to the visual brain?
1. R _ _ _ _ _ h _ _ _ t _ _ _ _ _ _ tract
2. G _ _ _ c _ _ _ s _ _ _ _ _ _ pathway
3. T _ _ _ _ p _ _ _ _ _ _ _ pathway

Answer 24

1. Retinohypotalamic tract
2. Geniculostriate pathway
3. Tectopulvinar pathway

Question 25

Discuss the retinohypotalamic tract
Around __% of g____ cells express a p____.
These neurons are not connected to ____ and project to the s______ nucleus of the h______.
Involved in regulating the c____ rhythm and controlling p____ reflex that expands or contracts the pupil to c____ the amount of l____ reaching the r____.
Not involved in visual p____.

Answer 25

1, ganglion, pigment
photoreceptors, suprachiasmatic nucleus, hypothalamus.
circadian, pupillary, control, light, retina.
perception

Question 26

Discuss the geniculostriate pathway
Upon reaching the ____ cortex, neural information diverges into:
1. D____ stream - analyses the ____, guides ____ relative to objects
2. V____ stream - analyses the ____, object ____ (colour, shape, size, texture).
Necessary for the ____ experience of vision.

Answer 26

visual
Dorsal, how, movement
Ventral, what, identification
conscious

Question 27

Discuss the tectopulvinar pathways
The only pathway present in f____, a____ and r____.
Information through ____ cells from the ____ periphery, with no ____ information.
Analyses ____ information of objects.
Explains the ____ ability of patients with ____.

Answer 27

fish, amphibians and reptiles ganglion, retina, color
spatial
visual, blindsight

Question 28

What are the two major functions of the brain?
1. Controls m____ of m____, producing u____ behaviours
2. R____ body’s i____ e____

Answer 28

1. Controls movement of muscles, producing useful behaviours
2. Regulates body’s internal environment

Question 29

What is rhodopsin?

Answer 29

Photopigment that reacts with light