The Special Senses

Question 1

Where are the special senses processed?

Answer 1

In the CNS

Question 2

What are the sensory systems?

Answer 2

Somatosensory system (pressure,warmth, vibration, limb position)
Sight (visual)
Hearing (auditory)
Taste (gustatory)
Smell (olfactory system)

Question 3

What are the accessory structures of the eye?

Answer 3

Eyebrows
Eyelids or palpabrae
Eyelashes
Conjunctiva
Lacrimal apparatus
Extrinsic eye muscle

Question 4

What are the characteristics of the conjunctiva?

Answer 4

Transparent mucous membrane
Important for lubrication and protection

Question 5

What are the structures of the lacrimal apparatus?

Answer 5

Lacrimal gland (responsible for tears)
Nasolarimal duct (goes to nasal cavity)

Question 6

What are the three layers of the eye wall?

Answer 6

Fibrous layer
Vascular layer
Nervous tissue layer

Question 7

What is contained within the fibrous layer?

Answer 7

Sclera (white of the eye)
Cornea (front of the eye)

Question 8

What is contained within the vascular layer?

Answer 8

Choroid (melanin containing cells)
Ciliary body (ciliary muscles change the thickness of the lens)
Iris (coloured part of the eye)

Question 9

What is contained within the nervous tissue layer?

Answer 9

Retina
-outer= pigmented retina scatters light
-inner= sensory retina

Question 10

What is the path of vision in the eye?

Answer 10

Iris allows light into the eye
Focused by the cornea, ,SNS, and humours onto the retina
The lights tricking the retina produces action potential that are relayed to the brain via the optic nerve

Question 11

What are the two chambers of the eye?

Answer 11

Anterior segment (front of lens)
Posterior segment (behind the lens)

Question 12

What is contained within the anterior segment of the eye?

Answer 12

Anterior chambers (between cornea and iris)
Posterior chambers (between iris and lens)
Aqueous humour (fills anterior segment) (maintains pressure, refracts light)

Question 13

What is contained within the posterior segment?

Answer 13

Vitreous chamber
Vitreous humour

Question 14

What are the two layers of the retina?

Answer 14

Outer thin pigmented layer (melanocytes)
Inner thicker neural layer (contain three types of neurones)

Question 15

What neurones are contained within the inner thicker neural layer of the retina?

Answer 15

Photoreceptors
Bipolar cells
Ganglion cells

Question 16

What are the regions of the (posterior) retina?

Answer 16

Macula (high res colour vision)
Optic disc (blood vessels enter eye, no photo receptors)

Question 17

What is the process of light passage through the eye?

Answer 17

Light passes through anterior cavity
Focused by lens
Passes through vitreous humour
Pass between axons, ganglion cells and bipolar cells
Reach photoreceptors next to pigmented layer

Question 18

What is the direction of travel of neuronal signal in the eye?

Answer 18

Photoreceptors synapse with bipolar cells
These synapse with ganglion cells
These run on internal surface and converge at posterior of the eye
These forms optic nerves which exits the eye

Question 19

What are the two types of photoreceptors cells?

Answer 19

Rod cells
Come cells

Question 20

What are the characteristics of rod cells?

Answer 20

Sensitive to light
Only black and white
Rhodopsin

Question 21

What are the characteristics of cone cells?

Answer 21

Need bright light
Colour vision

Question 22

What are the three sections of structures of photo receptor cell types?

Answer 22

Synaptic terminal
Inner segments
Outer segments

Question 23

What is the process of phototransduction?

Answer 23

1) light causes retinol to change shape, which activates rhodopsin
2) activated rhodopsin stimulates cell changes that result in vision
3) following rhodopsin activation, retinal detaches from opsin
4)energy from ATP is required to bring retinal back to original form
5) retinal recombined with opsin to form rhodopsin

Question 24

What is rhodopsin?

Answer 24

Protein opsin bound loosely to pigment called retinal

Question 25

What are the main three parts of the ear?

Answer 25

Outer ear Middle ear Inner ear

Question 26

What is contained within in the outer ear?

Answer 26

Pinna External auditory canal

Question 27

What is contained in the middle ear?

Answer 27

Tympanic membrane(ear drum) Malleus (hammer) Incus (anvil) Stapes (stirrup)

Question 28

What is contained within the inner ear?

Answer 28

Mechanoreceptors for hearing and balance Vestibular apparatus Semicircular apparatus Cochlea

Question 29

What are the two canals of the cochlea?

Answer 29

Middle (cochlear canal contains organ of corti) Basilar membrane

Question 30

What is the process of sound transmission in the ear?

Answer 30

1) sound waves vibrate tympanic membrane 2) auditory ossicles vibrate 3) stapes connected to oval window, sends vibration into cochlea 4) pressure wave pushes on basilar membrane of cochlea duct 5) hair cells bend, transmission of signal 6) neurotransmitters release activates sensory neurones, action potential to brain

Question 31

What structure are the ossicles?

Answer 31

Malleus Incus Stapes (3 bones that connect the ear drum to the inner ear)

Question 32

What is the purpose of the vestibular apparatus?

Answer 32

Make static equilibrium with two chambers (saccule and utricle) which control balance

Question 33

How is the middle ear and inner ear connected?

Answer 33

Oval window

Question 34

What does the Eustachian tube do?

Answer 34

Equalises pressure between middle ear and outer atmosphere Connects middle ear to pharynx

Question 35

Where are hair cells found in the ear?

Answer 35

Present on basilar membrane

Question 36

why stimulating different areas of your body give you different distances of a two-point system?

Answer 36

receptive fields are smaller in areas that are more sensitive, more than 2 receptive fields must be stimulated to recognise an individual stimuli.

Question 37

would a two-point test have a different outcome on someone with a damaged somatosensory cortex?

Answer 37

yes

Question 38

If someone had damage to their motor cortex would their results from the two point discrimination task be the same as if they had no damage?

Answer 38

Yes. If the damage was to the motor cortex the sensory pathways are still intact and the area of the brain interpreting the sensation is still intact

Question 39

what is the physiological reason that you have a blind spot?

Answer 39

where the optic nerve leaves the eye and there are no phoreceptors

Question 40

why cant you normally detect your blind spot?

Answer 40

brain fills in the details for you

Question 41

Explain why it is often possible to smell (or “taste”) medications, such as eyedrops, that have been placed into the eyes

Answer 41

Eyedrops drain through nasolacrimal duct into nasal cavity – much of what is considered taste is actually smell – much of what is considered taste is actually smell

Question 42

what is the term for drugs that bind to receptors and inhibit them?

Answer 42

antagonists

Question 43

what type of receptor is involved in the sensations of sound and balance?

Answer 43

mechanoreceptors

Question 44

what is the name of the organ in the inner ear that is most responsible for hearing?

Answer 44

organ of corti

Question 45

the parts of the vestibular apparatus that tell our brain about our movements through space are called the _____?

Answer 45

semicircular canals

Question 46

loud noises can cause action potentials to ____?

Answer 46

fire more frequently