EYEBALLS

Question 1

sensory input for eye
- involves _______________ cells (eg rods & cones)
- conduction of _________ from __________ ____________ to integration centre

Answer 1

• light-detecting
• signals, sensory receptors

Question 2

motor output: conduction of _________ from integration centre (__NS) to the __________ (muscle/gland cells) which carry out body’s ___________ to the ___________

Answer 2

signals, C, effectors, responses, stimulus

Question 2

integration: process by which ______ from environmental ___________ of sensory receptors is interpreted, then associated with appropriate _____________ of body, carried out in the CNS by _______ & ___________ in vertebrates

Answer 2

info, stimulation, responses, brain, spinal cord

Question 3

from receptor to effector, info is transmitted from 1 __________ to the next by a combi of ____________________ (nerve impulses) & ____________ (neurotransmitters)

Answer 3

neurone, electrical signals, chemicals

Question 4

PNS nerves communicate ________ & __________ signals between ______ & ___________________

Answer 4

motor, sensory, CNS, rest of body

Question 5

PNS stands for

Answer 5

peripheral nervous system

Question 5

eye is a _______ organ of _______ & contains ____________ for detecting _______ stimulus

Answer 5

sense, sight, receptors, light

Question 6

conjunctiva:
- thin transparent __________
- ________ _______ at front of eyeball against friction
- covers _______ (white of the eye) in front
- keeps eyeball moist
- continuous with skin of eyelids

Answer 6

• membrane
• protects cornea
• sclera

Question 6

each eyeball is attached to eye socket by 6 _______ ________ which allows eyeball to ________ slightly within socket

Answer 6

rectus muscles, rotate

Question 7

cornea (part of ______):
- anterior (front) end of _______ which forms small _______ in front of eye
- ___________ portion of _______ –> allows light to pass thru to reach ________
- refracts light into ______ (______ of the refraction occurs here)

Answer 7

sclera
- sclera, bulge
- transparent, sclera, retina
- pupil, most

Question 8

choroid
- contains _______ __________ that’s supplying ________ with oxy & nutrients
- pigmented ________ to prevent __________ __________ of light

Answer 8

• blood vessels, retina
• black, internal reflection

Question 8

sclera: tough _______ _______ layer of eyeball that __________ it against any mechanical injury

Answer 8

white outer, protects

Question 9

which parts of the eye is at wall of the eye

Answer 9

sclera, choroid, retina

Question 9

retina
- ____________ layer of eyeball that contains _________________ (rods & cones) that detect __________
- cones: _______________ in _______ light
- rods: __________ in _____ light

Answer 9

• innermost, photoreceptors, stimuli
• colour vision, bright
• vision, dim

Question 10

optic nerve transmits ________ ___________ (info) from _________________ to _________

Answer 10

nerve impulses, photoreceptors, brain

Question 11

iris (part of _______)
- __________ end of _________
- controls ______ of _______ hence controlling amt of _______ entering eye
- consists of 2 ______________ muscles (_________ & ________)
- gives eye its colour (like brown, blue, green)

Answer 11

choroid
- anterior, choroid
- size, pupil, light
- involuntary, circular, radial

Question 12

pupil: ______ in _______ of ____ that allows light to enter eye

Answer 12

hole, centre, iris

Question 13

lens: ________ light _____ onto ________ by changing ________ (its a transparent, __________ –> like this () structure & elastic hence able to change _________ & _______ to _________ light onto ______)

Answer 13

focuses, rays, retina, shape, biconvex, thickness, shape, refract, retina

Question 14

ciliary body
- supports lens
- contains ________ that control __________ of lens

Answer 14

muscles, curvature

Question 14

suspensory ligaments: holds _____ in position by attaching _____ to _______________

Answer 14

lens, lens, ciliary body

Question 15

vitreous humour
- supports lens
- ________ light _____ onto ________ & keeps eyeball ______
- ____________, jelly-like substance

Answer 15

• refracts, rays, retina, firm
• transparent

Question 16

aqueous humour
- _________ light & keeps eyeball _____
- maintains _______ of _________ chamber of eyeball
- ____________ & watery fluid

Answer 16

• refracts, firm
• shape, anterior
• transparent

Question 17

conjunctiva ____________ by tears

Answer 17

lubricated

Question 18

tears helps to reduce _________ when eyelids move

Answer 18

friction

Question 19

dust particles cause ________ production of tears; and excess tears drain into the naso-lachrymal duct which runs from inner corner of eye to _______

Answer 19

greater, nose

Question 20

retina - contains abt 125 million ____ cells & 6 million _____ cells - accounts for ____% of all sensory receptors in body --> eyes very impt

Answer 20

- rod, cone - 70

Question 21

fovea - images normally focused here - contains _____ ______ (which r densely packed) - part of _______ that's ______ sensitive to light - provides _______ _______ vision in _______ light (when images focused onto it) - has ________ conc. of ______

Answer 21

- only cones - retina, most - acute colour, bright - highest, cones

Question 22

other areas of retina: density of rods (provides vision in _____ light) much ________ than cones

Answer 22

dim, higher

Question 22

blind spot - found immediately over ______________ - no ___________________ hence no _________ when image falls on it

Answer 22

- optic nerve - photoreceptors, vision

Question 23

rods vs cones - rods: _____ sensitive to light but ______ distinguish colours (they enable us to see at night but only in black & white) - cones: _____ distinguish colours in ________ but _____ function in night vision

Answer 23

- more, don't - can, daylight, don't

Question 24

rods vs cones - rods: ________ sensitive to ____ light level - cones: sensitive to _____ light intensity (3 types - RGB - of cones for colour vision, all cones come tgt enabling spectrum to be seen on retina)

Answer 24

-highly, low - high

Question 25

rods vs cones - rods: ___________ in ____________ of retina - cones: _____________ in _______

Answer 25

- dispersed, periphery - concentrated, fovea

Question 26

rods vs cones - rods: images _______ & only in shades of _____ - cones: images _______ & __________

Answer 26

- blurry, grey - acute, coloured

Question 27

human visual system 1. reflected light rays from object enters eye thru ______ 2. rays refracted by ________, __________ ________, _____ & __________ _________ to focus on ________. lens makes fine __________ adjustments needed to _______ the rays 3. image of object formed on ________, stimulating the _________________, generating ________ ___________ which r _____________ to _______ via ________ ________ 4. ________ interprets impulses & we see object as it really is: right way up

Answer 27

1. pupil 2. cornea, aqueous humour, lens, vitreous humour, retina, bending, focus 3. retina, photoreceptors, nerve impulses, transmitted, brain, optic nerve 4. brain

Question 28

image formed on retina is - upside down: - back to front: - smaller in size than actual object:

Answer 28

- inverted - reversed - diminished

Question 29

pupil reflex: immediate change in _________ of pupil in response to __________ of light that falls on _________________ cells on ________, __________ conscious control

Answer 29

diameter, intensity, photoreceptor, retina, without

Question 30

pupil reflex (regulates entry of light) in high light intensity (bright light) - circular muscles of iris _________ while radial muscles of iris _______ - _________ pupil size (pupil __________) - _________ amt of light entering eye, preventing _________ to ____ & ______ of retina

Answer 30

- contract, relax - reduces, constricts - reduces, damage, rods, cones

Question 31

pupil reflex in high light intensity (bright light) SCCRR stands for?

Answer 31

Small pupil Circular Contract Radial Relax

Question 32

pupil reflex in low light intensity (dim light) - circular muscles of iris ______ while radial muscles of iris ________ - _________ pupil size (pupil ________) - as much light as possible enters eye --> we can see more _________

Answer 32

- relax, contract - enlarges, dilates - clearly

Question 33

pupil reflex in low light intensity (dim light) BCRRC stands for?

Answer 33

Big pupil (enlarged) Circular Relax Radial Contract

Question 34

pupil reflex: focusing adjustment of _____of eye so that _______ images of objects @ diff dist r formed on ________

Answer 34

lens, clear, retina

Question 35

Focusing light from distant object (more than 7m) 1. ________________ light rays reach eye 2. cornea ________ light rays 3. circular _________ muscle ________ 4. suspensory ligament ______ 5. lens become ________, _____ convex & _____ refractive 6. light ________ on _______ 7. ________________ stimulated 8. ______ _________ transmitted thru ___________ ___________in _______ ________ to _______ 9. _______ interprets __________ & person sees object

Answer 35

1. almost parallel 2. refracts 3. ciliary, relaxed 4. taut 5. thinner, less, less 6. focused, retina 7. photoreceptors 8. nerve impulses, optic nerve, brain 9. brain, impulses

Question 36

focusing light from near object 1. __________ light rays reach eye 2. cornea __________ light rays 3. circular _________ muscles ___________ 4. suspensory ligaments _______ 5. lens become _________, ______ convex & ______refractive 6. light ________ on ________ 7. ________________ stimulated 8. ______ _________ transmitted thru __________ __________ in _______ ________ to _______ 9. _______ interprets __________ & person sees object

Answer 36

1. diverging 2. refracts 3. ciliary, contracts 4. slack 5. thicker, more, more 6. focused, retina 7. photoreceptors 8. nerve impulses, sensory neurone, optic nerve, brain 9. brain, impulses

Question 37

pupil reflex (before the pupil dilation/constriction occurs) - when light intensity is increased/decreased, ___________________ in ________ are ___________ - _______ _________ r generated & transmitted along __________ __________ in the ______ _______ to brain - _______ __________ r transmitted along _______ ________ to iris - RRCC or RCCR occurs

Answer 37

- photoreceptors, retina, stimulated - nerve impulses, sensory neurone, optic nerve - nerve impulses, motor neurone