Physiology Flashcards

1
Q

Aqueous humour - where is it produced?

A

Ciliary body

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2
Q

Aqueous humour - where is it secreted from?

A

Ciliary process (internal folds of ciliary body)

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3
Q

Aqueous humour pathway

A

Secreted into posterior chamber (nourishes lens)

Passes through the pupil to the anterior chamber (nourishes cornea)

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4
Q

Aqueous humour - where does it drain

A

Scleral venous sinus through the canal of schlemm

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5
Q

Aqueous humour is mainly found in the ANTERIOR/POSTERIOR segment of the eye?

A

Anterior

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6
Q

Aqueous humour - function

A

Maintains intra-ocular pressure

- the IOP depends on the balance between the production and reabsorption of aqueous humour

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7
Q

Vitreous humour - definition

A

Clear fluid with a jelly like consistency

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8
Q

Vitreous humour is mainly found in the ANTERIOR/POSTERIOR segment of the eye?

A

Posterior

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9
Q

Where are photoreceptors found

A

Posterior part of the retina

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10
Q

Photoreceptors - functions

A

Converts light into neural signals that can stimulate biological processes

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11
Q

2 types of photoreceptors

A

Rods

Cones

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12
Q

There is increased visual acuity if there are MORE/LESS photoreceptors present

A

More

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13
Q

There is increased visual acuity if the photoreceptors are spaced very close together. True or false?

A

True

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14
Q

Rods - light conditions

A

Dim light
When light conditions are not good
Low levels of light
Night vision, peripheral vision

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15
Q

Rods - where are they located

A

Peripheral retina

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16
Q

Rods - photoreceptor spacing

A

Large spacing between photoreceptors

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17
Q

Rods - high/low light sensitivity

A

High

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18
Q

Rods - high/low visual acuity

A

Low

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19
Q

Cones - light conditions

A

Bright light
Normal daylight
For seeing things in colour
Detail

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20
Q

Cones - where are they located

A

Central retina

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21
Q

Cones - photoreceptor spacing

A

Minimal spacing between photoreceptors

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22
Q

Cones - high/low light sensitivity

A

Low

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23
Q

Cones - high/low visual acuity

A

High

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24
Q

Colour vision - rods/cones

A

Cones

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25
Q

Short wave cone produces which colour?

A

Blue

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26
Q

Middle wave cone produces which colour?

A

Green

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27
Q

Long wave cone produces which colour?

A

Red

28
Q

When exposed to light, Na+ levels increase/decrease ?

A

Decrease

- due to the closure of cGMP gated Na+ channel

29
Q

Decreased Na+ levels causes the membrane potential to become more positive/negative?

A

Negative

- Vm hyperpolarises

30
Q

In the absence of light, Na+ levels increase/decrease?

A

Increase

- due to the opening of cGMP gated Na+ channel

31
Q

Increased Na+ levels causes the membrane potential to become more positive/negative?

A

Positive

- Vm depolarises

32
Q

What are the visual pigment molecules called?

A

Rhodopsin

33
Q

2 components of rhodopsin

A

Retinal (vitamina A derivative)

Opsin (GPCR)

34
Q

Where in the retina is the fovea located?

A

In the centre of the retina, inside the macula

35
Q

Infant presents with a visual problem in one eye. What is the initial management?

A

Put eye patch over GOOD eye.
Make the patient use their bad eye to force the brain to rely on signals from the bad eye. This helps the brain develop properly

36
Q

Emmetropia - definition

A

No refractive error

The eye has no visual defects

37
Q

Hyperopia - definition

A

Vision is better for distant than for near objects

farsightedness

38
Q

Hyperopia - parallel rays are focussed in front of / behind the retina ?

A

Behind

39
Q

Myopia - definition

A

Vision is bette for near than for far away objects

short sightedness

40
Q

Myopia - visual images come in to focus in front of / behind the retina ?

A

In front of

41
Q

Everything from the right visual field hits the eye at the ____ retina of the right eye and the ____ retina of the left eye

A

Nasal retina - right eye

Temporal retina - left eye

42
Q

Light from objects in the right visual field is processed by the RIGHT/LEFT primary visual cortex

A

Left

43
Q

Light from objects in the lower visual field is processed by the UPPER/LOWER part of the primary visual cortex

A

Upper

44
Q

What happens when we blink

A

Lacrimal fluid runs over the eye and this prevents the eye from drying out.
Helps remove foreign bodies from the eye

45
Q

Which nerves (sympathetic/parasympathetic) cause dilation of the pupil?

A

Sympathetic

46
Q

How does light reach the retina?

A

It goes through the pupils

47
Q

Dilated pupil allows more/less light to reach the retina?

A

More

48
Q

Which muscle is responsible for pupillary dilation?

A

Dilator pupillae muscle

49
Q

Location of the dilator pupillae muscle

A

Located around the external circumference of the iris

50
Q

Mydratic pupil

A

An abnormally sustained pupillary dilation

51
Q

Mydratic pupil - causes

A

eye drops (drugs)
diseases
trauma
CNIII pathology (constrictors not working at all)

52
Q

Constricted pupil allows more/less light to reach the retina?

A

Less

53
Q

Which nerves (sympathetic/parasympathetic) cause constriction of the pupil?

A

Parasympathetic

54
Q

Which muscles is responsible for constriction of the pupil?

A

Sphincter pupillae muscle

55
Q

Location of the sphincter pupillae muscle

A

It encircles the pupil

Around the internal circumference of the iris

56
Q

Mitotic pupil

A

Abnormally sustained pupillary constriction

57
Q

Mitotic pupil - causes

A

Diseases (Horner’s syndrome)

Opiate drugs

58
Q

Pupillary light reflex (direct)

A

Shine a torch into one eye

Direct light reflex (constriction) in the stimulated eye

59
Q

Pupillary light reflex (consensual)

A

Shine a torch into one eye

Constriction occurs in the non-stimulated eye

60
Q

Which nerves (sympathetic/parasympathetic) are responsible for far (distant) vision

A

Sympathetic nerves

61
Q

In far (distant) vision, the ciliary muscle contracts/relaxes ?

A

Relaxes

62
Q

In far (distant) vision, the suspensory ligaments contract/relax

A

Contract

63
Q

In far (distant) vision, the lens is flat/spherical

A

Flat

64
Q

Which nerves (sympathetic/parasympathetic) are responsible for near vision

A

Parasympathetic nerves

65
Q

In near vision, the ciliary muscle contracts/relaxes?

A

Contracts

66
Q

In near vision, the suspensory ligaments contract/relax?

A

Relax

67
Q

In near vision, the lens is flat/spherical

A

Spherical