Chapter 9

Question 1

What do sensory receptor neurons do?

Answer 1

they transduce (convert) environmental energy (like light) into neural activity.

Question 2

For vision, the ____________ in the _____Convert light energy into chemical energy.

Answer 2

Photoreceptors; retina

Question 3

In the auditory system, ___ ________ ______ are first converted into mechanical energy, which activates the _________ receptors that produce action potentials.

Answer 3

Air pressure waves; auditory

Question 4

In the somatosensory system, mechanical energy activates receptors sensitive to ______, __________, or ______

Answer 4

Touch; pressure; pain

Question 5

For taste and olfaction, various chemical molecules in the ____ or in _____ fit themselves into receptors of various ______ to activate action potentials in the respective receptor neurons

Answer 5

Air; food. shapes

Question 6

Every sensory receptor organ and cell has a “receptive field,” what is this?

Answer 6

A specific part of the world to which it responds.
- each photoreceptor cell in the eye points in a slightly different direction (each has a unique receptive field)

Question 7

Color photoreceptors are _________ and __________ packed. Receptors for black-white vision are _________ and are more ________.

Answer 7

small; densely
larger; scattered

Question 8

vision passes through the _______, to the _________, and then to the _________ ________

Answer 8

retina, thalamus, cerebral cortex

Question 9

Auditory receptors (sounds) pass through the ear, then to the _______, then to the __________, then the _________, and then finally to the ________ _________-

Answer 9

Hindbrain, midbrain, thalamus, cerebral cortex

Question 10

Somatosensory receptors (touch) goes first to the ________ _______, then the __________, then the thalamus, and then the cerebral cortex.

Answer 10

Spinal chord, brainstem

Question 11

If a person “hears” the speech syllable ba, but sees someone articulating the syllable ga, what do they hear?

Answer 11

They hear a hybrid sound (like da)

Question 12

How do action potentials encode different sensations?

Answer 12

the receptors of a stimulus can be encoded by an increase or decrease in a neurons discharge rate

Question 13

What is Synthesis?

Answer 13

The mixing of senses
eg. shivering when hearing a certain sound

Question 14

In most mammals, the _________ represents the sensory field of each modality (vision hearing, touch, smell, taste)

Answer 14

Neocortex

Question 15

all mammans have at least one primary cortical area for each sensory system. What are additional areas called?

Answer 15

Secondary

Question 16

What is Perception?

Answer 16

interpretation of sensations

Question 17

Light energy travels from the outside world through the _______ and into the eye, where it strikes a light-sensitive surface, the ________, at the back of the eye.
From this stimulation of ______________ cells on the retina, we begin to construct a visual world.

Answer 17

Pupil; Retina
Photoreceptor

Question 18

What exactly do photoreceptor cells and the retina do?

Answer 18

They translate light into action potentials, discriminate wavelengths so we can distinguish color, and work in a range of light intensities (bright to dim)

Question 19

How does the brain initially perceive objects

Answer 19

upside down and backwards

Question 20

our vision is better in the center of the visual field than at the margins, or periphery, why?

Answer 20

because photoreceptors are more densely packed at the centre of the retina, a region known as the Fovea

Question 21

What is a Blind Spot?

Answer 21

A small area of the retina called the Optic Disc. This is an area where blood vessels enter/exit the eye, and where fibres are located (there are no photoreceptors)

Question 22

Why dont we usually have a problem with the Optic Disc?

Answer 22

because there are at different locations one each eye.

Question 23

What is Papilledma?

Answer 23

The swelling of the optic disc

Question 24

What are two causes for Papilledma?

Answer 24

1) Inter cranial pressure wither from a. tumor or infection
2) inflammation of the optic nerve itself (also called optic neuritis)

Question 25

What fluid surrounds the optic nerve

Answer 25

Cerebrospinal fluid (CSF)

Question 26

What are the two types of image-forming photoreceptors

Answer 26

Rods = function at low light levels
Cones = function at high levels of light

Question 27

Does the fovea only contain rods? or cones?

Answer 27

Only contains cones

Question 28

Cones have __ color pigments, whereas rods have __

Answer 28

3 (blue, green, red); 1

Question 29

The gene for red cone isn carried on the ___ chromosome, which is why females are more likely to see red more

Answer 29

X

Question 30

Photoreceptors are connected to ___ layers of retinal neurons.
The first layer contains all 3 cell types, _______, _________, and _______.

Horizontal cells link photoreceptors with ________ cells, and amacrine cells link bipolar cells with the cells in the ________ neural layer, the Retinal Ganglion Cells.

Answer 30

2
Bipolar; horizontal; and amacrine.
Bipolar cells; second

Question 31

What are Retinal Ganglion Cels (RGC’s)

Answer 31

A group of veinal neurons with axons that cluster at the optic disc, and from the optic nerve

Question 32

Other than M cells, the retina also contains Muller cells, what do these cells do?

Answer 32

they act as optical fibers

Question 32

What are the 2 types of RGC’s

Answer 32

Magnocellular cells
- large
- receive input from rods
- sensitive to light but not color
- found in the retina
Parvocellular cells
- smaller
- receive input from cones
- sensitive to color
- found in the fovea

Question 33

What is Optic Chiasm?

Answer 33

When the optic nerves cross

Question 34

What is the Geniculostriate System

Answer 34

This pathway goes from the retina to the LGN of the thalamus

Question 35

What is the Tectopulvinar system

Answer 35

runs from the eye to the midbrain tectum, then to the pulvinar

Question 36

What is the difference between the Ventral stream and the Dorsal stream

Answer 36

Ventral = pathway to the temporal lobe
Dorsal = pathway to the parietal lobe

Question 37

The LGN has 6 different layers, what numbers are on the Ipsilateral side (right side) and what numbers are on the contralateral side (left side)

Bonus: what does each side do

Answer 37

ipsilateral: 2, 3, 5
- receive fibers from the ipsilateral eye
contralateral: 1, 4, 6
- receive fibers from the contralateral eye