The special senses

Question 1

Where is information from sense organ processed?

Answer 1

-CNS- conscious or unconscious

Question 2

What are the special senses?

Answer 2

-Sight, hearing, taste, smell

Question 3

What system deal with taste?

Answer 3

-Gustatory

Question 4

What system deals with smell?

Answer 4

-Olfactory

Question 5

What are the accessory structures of the eye?

Answer 5

-Eyebrows, eyelids, eyelashes, conjunctiva, lacrimal, apparatus, extrinsic eye muscles

Question 6

What is the lacrimal apparatus?

Answer 6

-Gland that is responsible for tears a part of the PNS

Question 7

What is the conjunctiva?

Answer 7

-Transparent mucous membrane covering the cornea

Question 8

What are the three tissue layers of the eye wall?

Answer 8

-Fibrous layer (outer), vascular layer and nervous tissue layer (inner)

Question 9

What does the fibrous layer of the eye contain?

Answer 9

-Sclera (white of the eye) and cornea (front of the eye)

Question 10

What does the vascular layer of the eye contain?

Answer 10

-Choroid (melanin containing cells), colliery body (cilliary muscles to change thickness of lens), iris (coloured and control pupil size)

Question 11

What does the nervous tissue layer of the eye contain?

Answer 11

-The retina, outer pigmented to prevent light reflection and inner sensory retina

Question 12

What are the chambers of the anterior segment?

Answer 12

-Anterior chamber, posterior chamber

Question 13

How does light pass through the eye?

Answer 13

-Iris allows light into the eye, focused by the cornea, lens and humors onto the retina through the vitreous humour,between sons, ganglion cells and bipolar cells to photoreceptors next to the pigmented layer. Ganglion cell axons run on internal surface and converge at posterior of the eye to form optic nerve

Question 14

What are the two types of photoreceptors ?

Answer 14

-Rods and cones

Question 15

What are the features of the rod cells?

Answer 15

-More sensitive to light, allow vision in dim light by only black and white and not sharp

Question 16

What are the features of cone cells?

Answer 16

-High acuity, so bright light needed. Colour vision, separated into 3 subtypes-blue, red and green

Question 17

What is the anterior chamber?

Answer 17

-Chamber between cornea and iris

Question 18

What is the posterior chamber?

Answer 18

-Chamber between iris and lens

Question 19

What is the chamber in the posterior segment?

Answer 19

-Vitreous chamber

Question 20

What is the vitreous humor?

Answer 20

-Jelly like tissue that maintains and refracts in the posterior cavity

Question 21

What is the aqueous humor ?

Answer 21

-Fills the anterior segment-it is a watery liquid that is continuously replaces and refracted light and maintains pressure

Question 22

What are the regions of the retina?

Answer 22

-Macula and optic disc

Question 23

What is the macula?

Answer 23

-Area of high rod and cone density and contains the fovea which contains the highest density of cones

Question 24

What is the optic disc?

Answer 24

-Where blood vessels enter the cell

Question 25

What are the layers of the retina?

Answer 25

-Outer pigmented layer and inner neural layer

Question 26

What are the features of the outer pigmented layer of the retina?

Answer 26

-Produce melanocytes and contain melanin

Question 27

What are the features of the neural layer of the retina?

Answer 27

-Contain 3 main types of Neuron-photoreceptors, bipolar cells and ganglion cells

Question 28

What are the regions of the posterior retina?

Answer 28

-Macula-high res colour vision, contains fovea where highest density of cones for focused vision -Optic disc-where blood vessels enter the eye, axons from the retina meet and exit as the optic nerve - no photoreceptors

Question 29

Explain the process of phototransduction?

Answer 29

-Rhodopsin is composed of opsin and retinal, light causes retinal to change shape activating the rhodopsin which changes cells resulting in vision. Retinal detached from opsin and ATP is needed to bring retinal back to its original form and the process repeats

Question 30

What are the parts of the ear?

Answer 30

-Outer ear, middle ear, inner ear

Question 31

What does the outer ear contain?

Answer 31

-Pinna and external auditory canal

Question 32

What does the middle ear contain?

Answer 32

-Tympanic membrane, malleus (hammer), incus and stapes

Question 33

What does the inner ear contain?

Answer 33

-Mechanoreceptors for hearing and balance, vestibular apparatus, semicircular canals, cochlea (organs of corti)

Question 34

What are the features of the middle ear?

Answer 34

-Air filled, oval and round window connect to the inner ear -TM causes ossicles middle ear to mover malleus (attached to TM), incus, stapes (touches window), ossicles for a lever system, transmits vibrations from TM to fluids of inner ear

Question 35

What are the 3 chambers of the inner ear?

Answer 35

-Cochlea, hearing -Vestibule, equilibrium -Semicircular canals, equilibrium, filled with perilymph and endolymph fluids

Question 36

What canals make up the cochlea?

Answer 36

-Vestibular, tympanic and cochlear canals separated by basilar membrane

Question 37

What are the features of the organ of corti?

Answer 37

-Specialised sensory hair cells called sterocilia, seated of basilar membrane, reach to tectorial membrane, base of hair cells attached to neurone

Question 38

How does the cochlea work?

Answer 38

-Soundwaves cause the basilar membrane to move and the tectorial membrane to stay rigid which causes the sterocilia to bend which causes the mechanoreceptor to depolarise and neurotransmission occurs in connective neuron through the cochlea nerve

Question 39

Explain the process of sound transmission through the ear?

Answer 39

-Sound waves vibrate the tympanic membrane, auditory auspices vibrate causing amplification, stapes connected to oval window sends vibration into cochlea, press pushes on basilar membrane and energy waves dissipate at round window, hair cells bend and transmission of signal occurs, neurotransmission activates sensory neurons and action potentials are sent to the brain

Question 40

Explain the auditory pathway in the brain?

Answer 40

-Sensory axons from the cochlear ganglion terminate in the brainstem, axons from the neurons in the cochlear nucleus project to other brainstem nuclei or inferior colliculus, axons from the inferior colliculus project to the thalamus and thalamus neurons project to the auditory cortex