the senses

Question 1

types of sensory receptors

Answer 1

chemoreceptors
mechanoreceptors
photoreceptors
thermoreceptors
nociceptors

Question 2

name some diseases that affect the eye

Answer 2

Diabetic retinopathy
Age Related Macular Degeneration
Cataracts
Colour blindness
Night blindness
Dry eye
Glaucoma
Retinal Detachment
Allergic conjunctivitis
Viral, fungal and bacterial infections of the eye
Cancers of the eye: Retinoblastoma
Genetical conditions: Retinitis pigmentosa

Question 3

the two main areas of sensory physiology

Answer 3

sensation
sensory perception(how the signals are interpreted)

sensation is a physiovhemical process and perception is a psycological process

Question 4

functions of the thalamus

Answer 4

Relay Station for Sensory Information

sensory integration

helps regulate sleep and consciousness

Question 5

the three concentric layers of the eye body

Answer 5

Fibrous Tunic (Outer Layer): cornea, sclera

Vascular Tunic (Middle Layer): iris, ciliary body, choroid

Nervous Tunic (Inner Layer or Retina): retina, macula, optic disk

note that each of these layers has components of it’s own that contribute to eye function

Question 6

function of the ciliary muscle

Answer 6

changes lens shape by relaxing/contracting muscle

Question 7

the central point of the retina

Answer 7

FOVEA

Question 8

part of the eye that contains photoreceptors

Answer 8

retina

Question 9

cataracts

Answer 9

the clouding of the lens in the eye, leading to a decrease in vision quality

Question 10

how many smooth muscles does the iris have, name them

Answer 10

2

Inner circular muscle (involved in constriction)

Outer radial muscle (involved in dilation)

Question 11

the cells in the iris that determine the colour of the iris are called?

Answer 11

melanocytes

Question 12

what happens during the parasympathetic and sympathetic stimulations of the cilary muscle

Answer 12

parasympathetic stimulation leads to ciliary muscle contraction, which facilitates accommodation for near vision(like reading), while sympathetic stimulation results in ciliary muscle relaxation, adapting the eye for distance vision

note that c.muscle contraction affects the suspensory ligaments

Question 13

the two main types of of photoreceptors in the retina

Answer 13

cones(3 types of that) and rods(1 type of that)

Question 14

the lens is more flattened in near vision and more rounded in distance vision, true or false

Answer 14

false

Question 15

what happens to the suspensory ligaments attached to the lens as the ciliary muscle contracts and vice-versa?

Answer 15

they relax during c. muscle contraction and contract during it’s relaxation

Question 16

how is the pupil reflex test important

Answer 16

Can be used to assess Integrity of sensory and motor function of the eye

when carried out…: both pupils constrict regardless of which eye is being stimulated

Question 17

how many layers of neurons does the retina contain, name them

Answer 17

3

Inner layer (contains neurons called ganglion cells)

Middle layer (contains neurons called bipolar cells)

Outer layer (contains photoreceptors: rods + cones)

Question 18

the retina layers are in reverse order, true or false

note that this means Light has to Pass Through Inner & Middle Layers and blood vessels before reaching the photoreceptors

Answer 18

true

Question 19

outline some differences between rods and cones

photoreceptors in the retina

Answer 19

responsible for black and white vision while responsible for colour vision

Highest Conc. periphery of retina while Highest Conc. fovea

Low Visual Acuity while High Visual Acuity

Convergence with Bipolar cell: High while Convergence with Bipolar cell: Low

High Sensitivity while Low Sensitivity

low light conditions while high light conditions

Question 20

which photoreceptor is stimulated in low light conditions

Answer 20

rod

Question 21

rhodopsin

Answer 21

a light-sensitive pigment in the rods of the retina, crucial for low-light vision

Question 22

the two components of rhodopsin

Answer 22

Rhodopsin consists of a protein called opsin and a light-absorbing molecule called retinal

Question 23

remember that cones are photoreceptors

the three types of photopigments in cones

Answer 23

Cone Red Light
Cone Green Light
Cone Blue Light

Question 24

rhodopsin is not destroyed by bright light, is this true?

Answer 24

no, it is

Question 25

is rhodopsin regenerable

Answer 25

yes

Question 26

rubin’s vase

Answer 26

an optical illusion that depicts either a vase or two faces in profile, depending on how one perceives the image. It was created by the Danish psychologist Edgar Rubin in 1915.

Question 27

before light strikes the back of the retina, it is modified in two ways, outline these 2 ways

Answer 27

the light is first modulated by the pupils

Process where lens changes shape to adjust refractive power so image is focussed on retina (this is known as accomodation)

the modulation of pupil size helps optimize vision in different lighting environments.

Question 28

the mechanism of accomodation is reliant on the sympathetic nervous system, true or false

note that accomodation is when the lens of the eye can change its shape to focus on objects at different distances

Answer 28

false, it is reliant on the parasympathetic nervous system

Question 29

for distant vision, is there a parasympathetic stimulation of the ciliary muscle?

Answer 29

no

note that for near vision, this statement would be right

Question 30

cones are photoreceptors

high stimulus levels are required to use the cones , true or false

Answer 30

true

Question 31

the role of convergence of signals from rods in the detection of low light

convergence is the coordinated movement of both eyes inward, towards each other, to focus on a near object.

Answer 31

COnvergence allows multiple rod cells to synapse onto a single bipolar cell, which then transmits the signal to ganglion cells and eventually to the brain. This pooling of signals increases the likelihood of detecting a weak stimulus, enhancing the sensitivity of the visual system in dim light.

Question 32

rhodospin bleaching

Answer 32

the process where light breaks down rhodopsin pigment in the eye, leading to temporary vision loss.

Question 33

the largest component of the eye, and what is it filled with

Answer 33

vitreous chamber

the vitreous humor (a gel-like substance)

Question 34

outline the spectral properties of the three types of cones

Answer 34

cone blue lights have a short wavelength

cone green lights have a medium wavelength

cone red lights have a long wavelength

Question 35

tritanopia

Answer 35

type of color vision deficiency, often referred to as blue-yellow color blindness.

Individuals with tritanopia have difficulty distinguishing between shades of blue and green, as well as between yellow and red. This condition is caused by a malfunction or absence of the S-cone photoreceptors in the retina, which are responsible for perceiving short-wavelength light, primarily blue hues.

Question 36

deuteranopia

Answer 36

a form of color vision deficiency, commonly known as red-green color blindness.

individuals with deuteranopia have difficulty distinguishing between shades of red and green. This condition is caused by the malfunction or absence of M-cone photoreceptors in the retina, which are responsible for perceiving medium-wavelength light, particularly green hues

Question 37

protanopia

Answer 37

a type of color vision deficiency, commonly referred to as red-blindness

Individuals with protanopia have difficulty perceiving red hues due to the absence or malfunction of L-cone photoreceptors in the retina, which are responsible for perceiving long-wavelength light, particularly red hues