Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ophthalmology > physiology > Flashcards

physiology Flashcards

1
Q

what is ICP

A

pressure within the cranial cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

pathophysiology of raised ICP

A

increased pressure in fluid surrounding the brain or an increase in the pressure within the brain itself

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

name some causes of raised ICP

A

brain tumours
head injuries
hydrocephalus
meningitis
stroke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

main complication of raised ICP

A

can cause damage to the brain or spinal chord by compressing them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what makes infants less affected by raised ICP

A

fontanelles and open suture lines means that they have potential for change in cranial size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the monro-kellie hypothesis

A

blood, brain and CSF are in equilibrium
if volume of one of the components increases, the volume of a different component must decrease to maintain equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens in brain herniation

A

the brain becomes displaced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

name some visual problems caused by raised ICP

A

double vision, blurred vision, loss of vision, pupillary changes, papilledema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the optic nerves

A

CNS tracts - paired anterior extensions of the forebrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are optic nerves formed by

A

the axons of the retinal ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

complication of raised ICP on the optic nerve

A

compression of the nerve, as well as the central artery and vein of the retina causes papilledema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

name 5 possible visual symptoms of papilledema

A
  • Transient visual obscurations (greying-out of vision)
  • Transient flickering
  • Blurring of vision
  • Constriction of the visual field
  • Decreased colour perception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are dural septae

A

folds of dura mata creates divisions in the cranial cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the role of dural septae

A

divide the cranial cavity into falx cerebri and tentorium cerebelli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

impact of raised ICP on the dural septae

A

brain can herniate through openings (tentorial notch, foramen magnum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

when will raised ICP affect the oculomotor nerve

A

if medial temporal lobe herniates through tentorial notch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

result of raised ICP on the oculomotor nerve (2)

A
  • paralysis of somatic motor innervation - 4 extra-ocular muscles and eyelid
  • paralysis of parasympathetic innervation of sphincter of pupil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

clinical sign of damage to the oculomotor nerve due to raised ICP

A

lose/slowness of pupillary light reflex, dilated pupil, ptosis, eye turned inferolaterally (‘down and out’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

why is the trochlear nerve susceptible to damage

A

small diameter with a long intracranial course

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

result of damage to the trochlear nerve due to raised ICP

A

paralysis of superior oblique muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

clinical presentation of damage to the trochlear nerve due to raised ICP

A

eye cannot move inferiomedially, resulting in diplopia when looking down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

result of damage to the abducent nerve due to raised ICP

A

paralysis of lateral rectus muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

clinical presentation of damage to the abducent nerve due to raised ICP

A

eye cannot move laterally in horizontal plane, resulting in medial deviation of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what creates the blood-ocular barrier

A

endothelium of capillaries in the iris, ciliary body and retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what creates the blood-aqueous barrier

A

capillaries of the iris and ciliary body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what creates the blood-retinal barrier

A

non-fenestrated capillaries of the retinal circulation andtight junctions between retinal epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the aqueous humour

A

clear fluid that flows through the anterior segment of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

name some ways we can overcome the blood-ocular barrier when administrating drugs (3)

A
  • alcohol or acetate makes steroid more hydrophobic
  • phosphate makes it more hydrophilic
  • various additives may be added to topical eye drops such as viscosity enhancers, permeation enhancers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is CSF

A

a clear, colourless fluid that surrounds the brain and the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the main component of CSF

A

water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

where is the CSF contained

A

within the subarachnoid space and the central canal of the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are the 3 main roles of CSF

A

mechanical protection
homeostatic function
circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

role of CSF in mechanical protection

A

shock-absorbing medium that protects brain tissue; brain ‘floats’ inside the cranial cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

role of CSF in homeostatic function

A

pH of CSF affects pulmonary ventilation and cerebral blood flow, transports hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

role of CSF in circulation

A

medium for minor exchange of nutrients and waste products between blood and brain tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what produces CSF

A

secretory epithelium of the choroid plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

where is the choroid plexus located

A

in the two lateral ventricles, and in the roof of the third and fourth ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what is the usual total volume of CSF

A

150ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is the choroid plexus

A

network of capillaries in the walls of the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

name the ions involved in CSF secretion (3)

A

Na+, Cl- and HCO3-

41
Q

state the flow of CSF (4)

A
  • choroid plexus of each lateral ventricle
  • third ventricle via narrow openings in interventricular foramina (more added)
  • flows through the aqueduct of the midbrain into 4th ventricle (more added)
  • enters subarachnoid space + circulates in the central canal of the spinal chord
42
Q

name the 4 main foramina of the ventricles of the brain

A
  • intraventricular Foramina (of Monroe)
  • cerebral Aqueduct (of Sylvius)
  • foramen of Magendie
  • foramina of Luschka
43
Q

what do the Interventricular foramen (Foramen of Monro) connect

A

the lateral ventricles to third ventricle

44
Q

how many foramina in the lateral ventricles of the brain

A

3

45
Q

what is another name for the foramen of megendie

A

median aperture

46
Q

what is another name for the foramina of luschka

A

lateral apertures

47
Q

how many foramina are found in the 4th ventricle of the brain

A

3

48
Q

what does the cerebral aqueduct connect

A

3rd to 4th ventricle

49
Q

what do the foramen of Magendie and Luschka connect

A

the 4th ventricle to the subarachnoid space

50
Q

how does CSF return to venous blood

A

through arachnoid granulations into the superior sagittal sinus

51
Q

what is the role of the blood brain barrier

A

protects the brain from neurotoxins and helps prevent infection from spreading to the brain

52
Q

how do we obtain CSF

A

via lumbar puncture

53
Q

what does normal CSF look like

A

clear and colourless, contains little protein, little immunoglobulins and only 1-5 cells/ml

54
Q

what is an epidural haematoma

A

arterial bleed between skull and dura

55
Q

what is a subdural haematoma

A

venous bleed between dura and arachnoid

56
Q

what is hydrocephalus

A

accumulation of CSF in the ventricular system or around the brain causing ventricular enlargement and increased CSF pressure

57
Q

what are the 2 main causes of hydrocephalus

A

obstruction of drainage or overproduction of CSF

58
Q

what is papilledema

A

optic disk swelling due to increased intercranial pressure

59
Q

how do we recognise raised intercranial pressure

A

transmitted to the subarachnoid space surrounding the optic nerve

60
Q

name the 3 main roles of the aqueous humour

A
  • provides oxygen and metabolites and contains bicarbonate
  • bicarbonate buffers the H+ produced by the cornea and lens by anaerobic glycolysis
  • very high in ascorbate, which is a powerful antioxidant
61
Q

where is the aqueous humour produced

A

in the epithelial later of the ciliary body

62
Q

describe the flow of the aqueous humour in the eye (2)

A
  • from the ciliary body into the posterior chamber
  • through the pupil into the anterior chamber
63
Q

drainage of aqueous humour

A
  • drains to the scleral venous sinus through a trabecular meshwork and the canal of Schlemm
  • a small amount diffuses through the vitreous being absorbed across the retinal pigment epithelium
64
Q

where is the canal of schlemm located

A

in the angle between the iris and cornea (iridocorneal angle)

65
Q

what lines the ciliary body and the posterior surface of the iris

A

a forward continuation of the pigment epithelium of the retina (PE) overlain by an inner nonpigmented epithelial (NPE) layer

66
Q

what drug can be used to reduce the production of aqueous humour

A

carbonic anhydrase inhibitors

67
Q

name 2 carbonic anhydrase inhibitors and how they’re administered

A

dorzolamide (eye drops)
acetazolamide (oral)

68
Q

name innate immune system components of the eye (3)

A

blink reflex
mucous layer
tears

69
Q

role of the blink reflex in protecting the eye

A

tears flush the surface of the eye

70
Q

how do tears act as a chemical barrier to protect the eye

A

antimicrobial agents e.g. lysozymes

71
Q

name the immune cells found in tears (3)

A

neutrophils, macrophages and conjunctival mast cells

72
Q

name the adaptive immune cell found in the eye

A

langerhans cells

73
Q

role of langerhans cells in the eye

A

principle antigen presenting cell for the external eye

74
Q

what is the only part of the eye with lymphatic drainage

A

conjunctiva

75
Q

what is immune privilege

A

being able to tolerate the introduction of antigens without eliciting an inflammatory response

76
Q

name some sites of the body that have immune privilege

A

brain/CNS, testes, placenta, eyes

77
Q

name the 5 areas of the eyes which have immune privilege

A

cornea
anterior chamber
lens
vitreous cavity
subretinal space

78
Q

what is sympathetic ophthalmia

A

rare, bilateral granulomatous uveitis

79
Q

what is the most common cause of sympathetic ophthalmia

A

trauma

80
Q

give an example of a type 1 hypersensitivity reaction in the eye

A

acute allergic conjunctivitis

81
Q

give an example of a type 2 hypersensitivity reaction in the eye

A

ocular cicatricial pemphigoid

82
Q

give an example of a type 3 hypersensitivity reaction in the eye

A

autoimmune corneal melting

83
Q

give an example of a type 4 hypersensitivity reaction in the eye

A

corneal graft rejection

84
Q

how is the retina divided

A

relative to the fovea into a nasal and temporal hemiretina

85
Q

what is contained in the left optic tract

A

fibres from the left temporal (lateral) retina, and the right nasal (medial) retina

86
Q

what is contained in the right optic tract

A

fibres from the right temporal retina, and the left nasal retina

87
Q

upper optic radiation

A

carries fibres from the superior retinal quadrants through the parietal lobe to reach the visual cortex

88
Q

lower optic radiation

A

carries fibres from the inferiorretinal quadrants through the temporal lobe to reach the visual cortex

89
Q

describe the direct pathway for visual signal transmission

A

photoreceptors to bipolar cells to ganglion cells
axons of ganglion cells merge to form the optic nerve

90
Q

role of horizontal cells in signal processing

A

receive input from photoreceptors and project to other photoreceptors and bipolar cells

91
Q

role of amacrine cells in signal processing

A

receive input from bipolar cells and project to ganglion cells, bipolar cells, and other amacrine cells

92
Q

role of photoreceptors

A

convert electromagnetic radiation to neural signals

93
Q

what are the 2 main types of photoreceptors

A

rods and cones

94
Q

resting membrane potential of photoreceptors

A

around 20 mV

95
Q

what is rhodopsin

A

visual pigment molecule

96
Q

what is visual acuity

A

the ability to distinguish 2 nearby points

97
Q

name 2 factors that affect visual acuity

A

photoreceptor spacing and refractive power

98
Q

role of cone receptors

A

colour receptors

99
Q

role of rod receptors

A

night vision and seeing in black and white

ophthalmology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions