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MD4001 > Week 3 > Flashcards

Week 3 Flashcards

1
Q

What do the pharyngeal arches initially appear as?

A

Tissue bulges separated by clefts (as the cranial neuropore closes)

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2
Q

What do the pharyngeal arches consist of?

A

Mesoderm core, ectoderm external cleft, internal endodermal pouch

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3
Q

What do each pharyngeal arch (1,2,3,4 5 disappears, 6) give rise to?

A

Distinct sets of structures in head & neck

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4
Q

Describe the development of early face/jaw from frontonasal prominence 1st pharyngeal arch?

A
  • 24days stomodeum is closed by oropharyngeal membrane, which later ruptures
  • 1st arch has smaller upper maxillary prominence & larger lower mandibular prominence
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5
Q

What are the 2 mains sources of the pharyngeal arch mesenchyme core?

A
  1. Mesoderm

2. Neural crest

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6
Q

What 4 things does the pharyngeal arch mesenchyme core give rise to?

A
  1. Muscle (brachial muscles)
  2. Cartilage element
  3. Artery
  4. Cranial nerve
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7
Q

What are ill defined “segments” of paraxial mesoderm in the head region rostral to somites also called?

A

Somitomeres

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8
Q

Describe the movement of Paraxial mesoderm & what it forms?

A

Migrates into pharyngeal arches & elsewhere to form mostly muscle tissue of the head (& some connective tissue/bone)

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9
Q

Describe the movement of the neural crest cells & what they form?

A

Ventral flow around placodes & into pharyngeal arches, giving rise to mesenchyme, ganglia & nerves

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10
Q

What are Ectodermal Placodes?

A

Thickening of ectoderm that help give rise to sensory neurons/ganglia

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11
Q

What are the major blood vessels derived from the pharyngeal arches (aortic arch)?

A
  • 1st & 2nd Aortic arch: 2nd disappear, 1st is maxillary artery
  • 3rd Aortic arch: common & proximal internal carotid artery
  • 4th Aortic arch: right subclavian artery, left aortic arch
  • 5th Aortic arch: disappear
  • 6th Aortic arch: right pulmonary, left pulmonary & forms the ductus arteriosus
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12
Q

What bones of the head, face & neck do lateral plate mesoderm give rise to (mesenchymal)?

A

Laryngeals

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13
Q

What bones of the head, face & neck do paraxial mesoderm give rise of (mesenchymal)?

A
  • Parietal
  • Pet. temporal
  • Occipitals
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14
Q

What muscles come from the cranial somitomeres of 1st pharyngeal arch (“mandibular arch”)?

A
  • Mastication
  • Ant. belly of digastric
  • Mylohyoid
  • Tensor tympani
  • Tensor veli palatini
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15
Q

What are the skeletal structures from the 1st pharyngeal arch (“mandibular arch”)?

A
  • Maxilla
  • Zygomatic bone
  • Mandible
  • Malleus
  • Incus
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16
Q

What are the nerves derived from the 1st pharyngeal arch (“mandibular arch”)?

A
  • Skin of the face supplied by V1, V2, V3

- Trigeminal V3 muscles of mastication

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17
Q

What muscles come from the cranial somitomeres of 2nd pharyngeal arch (“hyoid arch”)?

A
  • Facial expression
  • Stylohyoid
  • Stapedius
  • Post. belly of digastric
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18
Q

What are the skeletal structures from the 2nd pharyngeal arch (“hyoid arch”)?

A
  • Stapes
  • Styloid process
  • Stylohyoid ligament
  • Lesser horn of hyoid, upper part body of hyoid
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19
Q

What is the nerve derived from the 2nd pharyngeal arch (“hyoid arch”)?

A

Facial VII

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20
Q

What arteries comes from 2nd pharyngeal arch?

A

Hyoid & stapedial arteries

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21
Q

What muscle comes from the cranial somitomeres of 3rd pharyngeal arch?

A

Stylopharyngeus

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22
Q

What skeletal structure comes from the 3rd pharyngeal arch?

A

Greater horn of hyoid, lower part body of hyoid

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23
Q

What is the nerve derived from the 3rd pharyngeal arch?

A

Glossopharyngeal IX

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24
Q

What muscles come from the somites of 4th & 6th pharyngeal arches?

A
  • All muscles of pharynx (4th) except stylopharyngeus
  • All muscles of palate (4th) except tensor veli
  • Cricothyroid (4th)
  • All larynx muscles (6th)
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25
Q

What are the skeletal structure from the 4th & 6th pharyngeal arches?

A
  • Epiglottis
  • Laryngeal cartilages
  • Thyroid
  • Cuneiform corniculte
  • Arytenoids
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26
Q

What nerve is derived from the 4th & 5th pharyngeal arches?

A
  • Vagus X

- Superior laryngeal branch supplies 4th arch

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27
Q

What does paraxial mesoderm give rise to in the head, neck & face?

A
  • All voluntary muscles
  • Arteries,
  • Neurocranium
  • Meninges
  • Dorsal skin
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28
Q

What does the neural crest give rise to in the head, neck & face?

A
  • Pharyngeal arch skeleton
  • Viscerocranium
  • Glandular connective tissue
  • Parts of neurocranium, teeth
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29
Q

What does Ectodermal Placodes & Neural Crest form in the head, neck & face?

A

Cranial neurons of sensory ganglia (V, VII, IX, X) & sensory apparatus (eyes/nose)

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30
Q

What does the 1st pharyngeal pouch develop into (internal endoderm)?

A

Primitive tympanic cavity

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31
Q

What does the 2nd pharyngeal pouch develop into (internal endoderm)?

A

Palatine tonsil/tonsillar fissure

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32
Q

What does the 3rd pharyngeal pouch develop into (internal endoderm)?

A

Parathyroid (inferior) & thymus (migrates)

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33
Q

What does the 4th pharyngeal pouch develop into (internal endoderm)?

A

Parathyroid gland (superior) & Ultimobranchial body (calcitonin producing parafollicular (C) cells of thyroid)

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34
Q

What can happen during migration of thymus, parathyroid glands & ultimobranchial body?

A
  • Thymus can remain in neck (ectopic thymus)

- Inferior parathyroids can be variable in position (ectopic parathyroid)

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35
Q

What does the 1st pharyngeal cleft give rise to?

A
  • DORSAL PART: external auditory meatus & external tympanic membrane
  • DEEPEST PART: tympanic membrane
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36
Q

What happens to the 2nd, 3rd & 4th pharyngeal clefts?

A

Lose contact with exterior forming cervical sinus, the sinus usually disappears

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37
Q

What are the pharyngeal cleft anomalies?

A

Cysts (adults) & fistulas/sinuses (children) anterior to sternocleidomastoid

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38
Q

What are key controllers of rostrocaudal patterning in the head?

A

HOX genes

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39
Q

What is the hindbrain region that neural crest cells migrate from called?

A

Rhombomeres

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40
Q

What provides guidance cues for sensory cranial nerves growing back from ganglia?

A

Expression of transcription factor OTX & HOX genes to migrate to pharyngeal arches

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41
Q

What do local patterns of endoderm signals do to neural crest cells?

A

Specifies mesenchymal expression pattern & arch characteristics

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42
Q

What pharyngeal arch is affected in Treacher Collins Syndrome (autosomal dominant)?

A

Failure of formation/apoptosis of neural crest cells & migration into 1st/2nd pharyngeal arches

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43
Q

What protein is defected in Treacher Collins Syndrome (autosomal dominant)?

A

Treacle (TCOF1 gene)

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44
Q

What are the signs & symptoms of Treacher Collins Syndrome (autosomal dominant)?

A
  • Abnormal eye shape
  • Micrognathia
  • Conductive hearing loss
  • Underdeveloped zygoma
  • Malformed ears
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45
Q

What is the physiology behind Di George Syndrome?

A

3rd & 4th pouches fail to develop & thymus & parathyroids are defective

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46
Q

What are the signs & symptoms of Di George Syndrome (CATCH-22)?

A
  • Cardiac abnormality
  • Abnormal facies
  • Thymic aplasia
  • Cleft palate
  • Hypocalcaemia
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47
Q

What is holoprosencephalon spectrum?

A

Congenital brain malformation of incomplete separation of the 2 hemispheres

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48
Q

What gene is mutated in holoprosencephalon spectrum?

A

Sonic Hedgehog (SHH)

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49
Q

What are the signs of inadequate SHH function?

A
  • Narrowing & Fusion

- Cyclopia

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50
Q

What are the signs of excess SHH function?

A
  • Widening structures duplicated

- Diprosopus

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51
Q

What is Craniosynostosis syndromes (Apert & Crouzon syndromes)?

A

1+ fibrous sutures in infant skull prematurely fuses by ossifying

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52
Q

What 3 genes are often mutated in Craniosynostosis syndromes?

A
  1. FGFR’s
  2. TWIST transcription factor
  3. EPHRIN-B1
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53
Q

What are the anterior & posterior structures of the eyeball?

A
  • Ant: Cornea, Iris, Lens, Conjunctiva

- Post: Retina/optic disc

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54
Q

What are the connections in the vision pathway?

A
  • Optic nerve
  • Chiasm
  • Optic tract
  • Lateral Geniculate Nucleus (LGN)
  • Radiation
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55
Q

Describe Trachoma infection of the eye?

A
  • Caused by Chlamydia

- 4th major cause of blindness in the world

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56
Q

What are the 3 most common causes of world visual impairment?

A
  • Uncorrected refractive error: URE (42%)
  • Cataract 33%
  • Glaucoma 2%
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57
Q

What are the 3 most common causes of world blindness?

A
  • Cataract 51%
  • Glaucoma 8%
  • Age related macular degeneration (AMD) 5%
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58
Q

What are the 6 layers of the cornea?

A
  1. Epithelium
  2. Bowman’s membrane
  3. Stroma
  4. Descemet’s membrane
  5. Endothelium
  6. Tear film
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59
Q

What is the role of endothelium in the cornea?

A

Keeps the cornea clear

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60
Q

What are the 3 layers of the tear film?

A
  1. Oily LIPID outer layer to reduce evaporation
  2. AQUEOUS middle layer containing lysozymes & antibodies
  3. MUCIN layer containing glycoprotein (lubricates for good coverage)
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61
Q

What are the 3 functions of the tear layer?

A
  1. Wash eye debris
  2. Provide dissolved O2 to cornea external epithelium
  3. Lubrication
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62
Q

What does the cornea provide for the eye?

A

Major light focusing element of the eye- 40D of “fixed” power

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63
Q

What can side effect happen during cataract surgery?

A

Corneal oedema

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64
Q

How is the whole eye ball refraction (60D) split up?

A
  1. Cornea: 40D

2. Lens: 20D

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65
Q

What is the equation for dioptric power of the eye?

A

Power= 1/focal length

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66
Q

What is the equation for power of the cornea in air & under water?

A

Power= (n2-n1)/r

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67
Q

What happens during lens accommodation when focusing on close objects?

A

Ciliary muscles contract to slacken zonule fibres

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68
Q

What is the “near triad” for lens accommodation?

A
  1. Miosis
  2. Convergence
  3. Accommodation
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69
Q

What is Presbyopia?

A

Failure to accommodate when you are older due to lends hardening, main type of URE

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70
Q

What is Myopia?

A

Short-sightedness, growing epidemic in industrialised regions esp. Asia & associated with retinal detachment

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71
Q

What is Hypermetropia?

A

Long-sightedness, associated with squint & lazy eye (amblyopia) & cute closed angle glaucoma

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72
Q

How do you correct Myopia?

A

To stop image focusing before the retina, use a concave lens

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73
Q

What are the 2 different types of cataract surgeries?

A
  1. Small incision cataract surgery (SICs)

2. Phacoemulsification surgery

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74
Q

What does the anterior & posterior chamber of the eyeball contain?

A

Aqueous humor

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75
Q

What are the 4 different layers in the retina?

A
  1. Outer nuclear
  2. Plexiform
  3. Ganglion cell
  4. Outer nuclear
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76
Q

Where does information from rods & cones go?

A

Converge to ganglion cells in ganglion cell layer of retina

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77
Q

What do lateral & amacrine cells in the plexiform layer of retina do?

A

Provide initial processing of visual signal

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78
Q

Describe characteristics of Rods?

A
  • High convergence
  • One type (vision in greyscale)
  • Very light sensitive
  • Widespread distribution in retina
  • Broad spectral sensitivity
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79
Q

Describe characteristics of Cones?

A
  • Low convergence
  • 3 types (blue, green, red)
  • Only 1/30th the sensitivity of rods
  • Concentrated in macula
  • Narrow spectral sensitivity
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80
Q

Where are rods most numerous in the retina?

A

Peripherally

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81
Q

Where are cones most numerous in the retina?

A

Fovea

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82
Q

What range of wavelength is visible light?

A

400-700nm

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83
Q

Photoreceptors are depolarised in the ____ & hyperpolarised in the ____?

A
  • Dark

- Light

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84
Q

At our eyes most sensitive wavelength, how many photons of light can they detect?

A

5

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85
Q

What protein is found in all rods & cones?

A

Retinal (derived from Vit A)

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86
Q

What is Retinal protein bound to under unstimulated conditions?

A

Opsin protein

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87
Q

What are 3 colours with rod retinal binding an opsin called?

A

Rhodopsin

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88
Q

What happens when light hits retinal?

A

Changes conformation & appears bleached

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89
Q

When is the retina metabolically more active?

A

When asleep

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90
Q

Describe Cone fatigue?

A
  • Staring at specific colour for 2 long, cells that detect that frequency of light will fatigue
  • After image is result of photoreceptors not being “in balance”
  • As photoreceptors become less tired (10-30sec) after image disappears
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91
Q

What is Emmert’s Law?

A

Things the same size on the retina appear a different size depending on the distant you are viewing hem & how far away you “think” you are viewing them

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92
Q

Whats the difference between “ON” or “OFF” bipolar cells?

A
  • “ON” neurotransmitter release in light

- “OFF” is opposite

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93
Q

What do Horizontal & Amacrine cells do?

A

Connect bipolar cells & allow for summation of information to allow detection of edges & contrast

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94
Q

Where does the visual information go?

A

Convergence from photoreceptors –> Bipolar cells –> Ganglion cell –> BRAIN

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95
Q

How does the ganglion cell transfer retinal information to the brain?

A

Optic nerve –> Chiasm –> Optic tract

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96
Q

What is the lateral geniculate nucleus (LGN)?

A
  • Part of thalamus
  • Major relay station for sensory info
  • Sends info to occipital lobe
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97
Q

What is the optic nerve?

A
  • Collection of all ganglion cells
  • Exits back of eye through hole in sclera
  • Head can be see at back of eye (optic disc)
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98
Q

What can cause total blindness of the right eye?

A

Complete lesion of right optic nerve

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99
Q

What can chiasmal lesions cause?

A

Bitemporal hemianopia

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100
Q

What does lesion of the left optic tract cause?

least common site

A

Right homonymous hemianopia

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101
Q

What does lesion of inferior optic radiations in temporal lobe cause?

A

Right homonymous superior quadrantanopia

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102
Q

What visual defect does lesion of the left hemisphere cause?

A
  • Right homonymous hemianopia

- Pupillary light reflex is not impaired if it is beyond the tract

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103
Q

What visual defect does lesion of the left occipital lobe cause?

A

Right incomplete homonymous hemianopia

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104
Q

What 2 things can cause chasmal lesions & what fibres are most vulnerable?

A
  1. Pituitary tumour- decussating fibres

2. Craniopharyngioma- posteriorly crossing fibres

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105
Q

What is evolved to allow creation of stereovision (3D)?

A

Chiasma

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106
Q

What could be used to assist in stereovision if chiasma was not evolved?

A

Corpus callosum

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107
Q

In quadrantanopias what does damage to posterior lobe cause according to “PIST”?

A

Inferior visual field loss

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108
Q

In quadrantanopias what does damage to temporal lobe cause according to “PIST”?

A

Superior visual field loss

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109
Q

When is bilateral lower quadrantanopia (lower visual field loss) most common?

A

Premature babies

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110
Q

What happens to brain growth in the last 3-4months of gestation?

A

“Flowering” of dendritic tree occurs

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111
Q

How many synapses are being created every second?

A

14 million

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112
Q

What are the characteristics of vascular ischaemic damage in “watershed areas” of premature baby’s brain?

A

Peri-ventricular leucomalacia (PVL)

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113
Q

Describe children’s visual problems who have cerebral palsy & PVL?

A

Children with spastic diplegia can have difficulty with talks involving lower field

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114
Q

What hemianopia affects reading english the most?

A

Right homonymous hemianopia

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115
Q

How many layers does the lateral geniculate nucleus have?

A

6

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116
Q

What layers in the lateral geniculate nucleus does information from the ipsilateral eye go to?

A

LGN layers 2, 3 & 5

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117
Q

What layers of the lateral geniculate nucleus does information from the contralateral eye go to?

A

LGN layers 1, 4 & 6

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118
Q

What layers of the lateral geniculate nucleus receive signals that travel by the magnocelluplar pathway?

A

LGN layers 1 & 2

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119
Q

What layers of the lateral geniculate nucleus receive signals that travel by the parvocellular pathway?

A

LGN layers 3, 4, 5 & 6

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120
Q

What are line of Gennari?

A

Myelinated fibres running from LGN to synapse in layer 4 of the “striate” cortex

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121
Q

What are the 4 function of the occipital lobe?

A
  1. Relay station
  2. Retinotopic map
  3. Neural tuning is present
  4. Specific populations of cells respond to: colour, spatial frequency, orientation
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122
Q

What is the striate cortex?

A

Main receiving area for visual signals from LGN, divided into 6 layers- 1 (nearest the surface) to 6 (deepest)

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123
Q

Describe the layers of striate cortex area V1?

A
  • Superficial: cytochrome oxidase bolbs

- Deep: Ocular dominance columns (right & left eye)

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124
Q

What is the right side of the temporal lobe for?

A

Faces & route finding

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125
Q

What is the left side of the temporal lobe for?

A

Words & shapes

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126
Q

What is Prosopagnosia?

A

Loss of face recognition

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127
Q

What is Topographic agnosia?

A

Loss of route finding

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128
Q

What is alexia?

A

Inability to read words

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129
Q

What is the pupillary light reflex?

A

Controls diameter of the pupil in response to intensity of light that falls on retinal ganglion cells of the retina in back of the eye, assisting in adaptation to various levels of lightness/darkness

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130
Q

What is the scalp?

A

Skin & subcutaneous tissue from superior nuchal line of occipital bone to supraorbital margins of frontal bone, extends over temporal fascia to zygomatic arch

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131
Q

Describe the 5 layers of the “SCALP”?

A
  1. Skin: outermost
  2. Connective tissue: subcutaneous rich in neurovascular
  3. epicranial Aponeurosis: suturing to close wounds
  4. Loose connective tissue: separates scalp proper (1st 3 layers) from pericranium & calvaria
  5. Pericranium: external periosteal
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132
Q

What does the skin of the scalp contain?

A
  • Hair follicles, sweat & sebaceous glands

- Thickest over occipital bone

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133
Q

What does the epicranial aponeurosis of the scalp contain?

A
  • Tendon & muscle of occipitofrontalis

- Prevents superficial wounds from gaping

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134
Q

What does loose connective tissue of the scalp contain?

A

Spaces susceptible to distension with fluid or infection spread (eyelids, root of nose)

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135
Q

Whats the clinical significance of the layers of the scalp?

A

Between aponeurosis & pericranium there are potential spaces for accumulation of fluid (blood) or spread of infection

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136
Q

Why can fluid/infection spread to eyelids or root of nose?

A

Frontal belly of occipitofrontalis inserts into skin & subcutaneous tissue NOT BONE

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137
Q

How can scalp infections spread to intracranial structures?

A

Via emissary veins

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138
Q

What is the cutaneous/sensory nerve supply of the scalp?

A
  • CN V1: supraorbital, supratrochlear
  • CN V2: zygomaticotemporal
  • CN V3: auriculotemporal
  • Cervical nerve C2: greater & lesser occipital
  • Cervical nerve C3: 3rd occipital
  • Cervical nerve C2 & C3: great auricular
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139
Q

Describe the Ramsay Hunt Syndrome?

A 
- Varicella zoster virus
reactivation in
geniculate ganglion (CN VII)
- Erythematous, vesicular rash in & around external auditory canal
- Otalgia & acute facial palsy
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140
Q

What its the cutaneous & motor innervation of auricle & external acoustic meatus?

A
  • Cutaneous: superficial same as scalp, deep CN VII & CN X
  • Motor: CN VII
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141
Q

Describe the characteristic symptoms of reactivation of varicella zoster virus in trigeminal ganglion (shingles)?

A
  • CN V1 distribution

- Erythematous, vesicular, crusting rash & burning sensation, conjunctivitis, keratitis & uveitis

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142
Q

What is Hutchinson’s sign?

A

Cutaneous involvement of tip of nose (external nasal branch of nasociliary nerve)

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143
Q

What is the arterial supply to the scalp?

A

Internal (anterior) & external (lateral & posterior) carotid

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144
Q

Where do the veins of the scalp drain into?

A

External jugular vein, except occipital vein that drains to internal jugular

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145
Q

What is the clinical consequence of scalp arterial anastomoses?

A

Lie superficially & can lead to profuse bleeding when lacerated

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146
Q

What is the anterior & posterior lymphatic drainage of the scalp?

A
  • ANT: pre-auricular & parotid nodes

- POST: mastoid & occipital nodes drain to deep cervical

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147
Q

What are the 4 muscles of mastication (1st pharyngeal derivatives)?

A
  1. Temporalis
  2. Masseter
  3. Medial pterygoid
  4. Lateral pterygoid
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148
Q

What is the motor innervation of the muscles of mastication?

A

Motor root of CN V that emerges with CN V3 (anterior trunk except medial pterygoid that comes from main trunk)

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149
Q

Describe the location of Temporalis muscle?

A
  • From temporal fossa & fascia
  • Inserts at mandible coronoid process (medial surface) & anterior border/ramus of mandible
  • Fan shape
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150
Q

What motion does the temporalis muscle provide?

A

Retract & elevate mandible (assists in closing mouth)

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151
Q

Describe the location of the Masseter muscle?

A
  • From inferior border of zygomatic arch & maxillary process of zygomatic bone
  • Inserts at angle & lateral surface of mandible ramus
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152
Q

What motion does the Masseter muscle provide?

A

Elevate the mandible (powerful)

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153
Q

Describe the location of the medial pterygoid muscle?

A
  • From medial surface of lateral plate of pterygoid process & pyramidal process of palantine bone & tuberosity of pyramidal process of maxilla
  • Inserts to medial surface of mandible near angle inferior to mandibular foramen
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154
Q

What motion does the Medial Pterygoid muscle provide?

A

Elevate the mandible & assist with lateral movements

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155
Q

Describe the location of the lateral pterygoid muscles?

A
  • From roof of infratemporal fossa & crest of wing of sphenoid bone & lateral plate of pterygoid process
  • Inserts at condylar process of mandible, capsule of TMJ & articular disc
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156
Q

What motion does the lateral pterygoid muscle provide?

A
  • Protrude mandible
  • Assist medial pterygoid with lateral movements
  • Depress mandible
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157
Q

What are the 5 muscles of fascial expression?

derived from 2nd pharyngeal arch

A
  1. Buccinator
  2. Orbicularis oris
  3. Orbicularis oculi
  4. Occipitofrontalis
  5. Platysma
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158
Q

What are the 5 muscles of facial expression innervated by?

A

Branches of CN VII

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159
Q

Describe the location of Buccinator muscle?

A
  • From posterior alveolar processes of maxilla/mandible & from pterygomandibular raphe
  • Merge with orbicularis oris
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160
Q

What motion does the Buccinator muscle provide?

A
  • Press cheeks against molar teeth
  • Works with tongue to keep food between occlusal surfaces of teeth & out oral vestibule
  • Smiling
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161
Q

Where is the parotid duct located?

A

On top of masseter before piercing buccinator en route to oral cavity

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162
Q

Why is the buccal fat pad larger in infants?

A

Reinforce cheeks & inhibit cheek collapse during feeding

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163
Q

Describe the location of the Orbicularis oris muscle?

A
  • From buccinator/surrounding muscles & medial mandible/maxilla
  • Inserts into mucous membrane of lips
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164
Q

What motion does the orbicularis oris provide?

A
  • Close &/or protrude lips
  • With buccinator & tongue keeps food between occlusal surfaces of teeth
  • Assists in whistling
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165
Q

Describe the location of the Platysma muscle?

A
  • From subcutaneous tissue of infra & supraclavicular regions
  • Inserts at base of mandible, merges with orbicularis oris, skin of cheek & lower lip, angle of mouth
166
Q

What motion does the Platysma muscle provide?

A
  • Tense skin of inferior face/neck

- Depress mandible

167
Q

Describe the location of the 2 bellies of the Occupitofrontalis muscle?

A
  • FRONTAL belly: epicranial aponeurosis & the skin/subcutaneous tissue of eyebrows & forehead
  • OCCIPITAL belly: lateral 2/3 superior nuchal line & epicranial aponeurosis
168
Q

What motion does the Occupitofrontalis muscle provide?

A
  • Retract scalp (occipital belly)
  • Wrinkle forehead
  • Elevate eyebrows (frontal belly)
169
Q

Describe the location of the 2 parts of the Orbicularis oculi muscle?

A
  • PALPRBRAL from medial palpebral lig & into lateral palpebral raphe
  • ORBITAL from nasal part of frontal bone, frontal process of maxilla & medial palpebral lig & inserts into skin around orbit
170
Q

What motion does the orbicularis oculi provide?

A
  • Close eyelids gently (involuntary or blinking reflex in palpebral part)
  • Tightly close eyelids (voluntary orbital part)
171
Q

What are the 4 dilator muscles which insert into angle of mouth (modiolus)?

A
  1. Levator anguli oris
  2. Zygomaticus major
  3. Risorius
  4. Depressor anguli oris
172
Q

What are the 3 dilator muscles which insert into upper or lower lips?

A
  1. Levator labii superioris
  2. Zygomaticus minor
  3. Depressor labii inferioris
173
Q

What muscle flares the nostrils?

A

Levator labii superioris alaeque nasi

174
Q

What 2 muscles wrinkles skin over dorsal of the nose?

A
  1. Procerus

2. Transverse part of nasalis

175
Q

What are the 3 muscles of facial expression that are related to the ear?

A
  1. Superior auricular
  2. Anterior auricular
  3. Posterior auricular
    (ALL SUPPLIED BY CN VII)
176
Q

What is the lymphatic drainage of the ear muscles of facial expression?

A

Via parotid, mastoid & deep cervical nodes

177
Q

List the 6 layers of the eyelids?

A
  1. Skin
  2. Connective tissue
  3. Muscle (orbicularis oculi)
  4. Orbital septum
  5. Tarsus
  6. Conjunctiva
178
Q

What are the spaces between eyelids called?

A

Palpebral fissure

179
Q

Describe the orbital septum?

A

Anterior border of orbit continuous with periosteum

180
Q

What is preseptal cellulitis?

A

Infection of skin/subcutaneous tissue anterior to orbital septum

181
Q

What are the clinical consequences of orbital cellulitis?

A
  • Infection posterior to orbital septum
    - Pain on eye movements that are restricted & proptosis (bulging of the eye)
    - Threatens vision & risk of infection spread to cavernous sinus/meninges/brain
182
Q

What is Conjunctivitis (pink eye)?

A

Inflammation of membrane covering posterior surface of the eyelid & eyeball

183
Q

What is the sensory innervation of the eyelids?

A

CN V1 & V2

184
Q

What is the vascular supply of the eyelids?

A
  • External & internal carotid arteries

- Veins following arteries

185
Q

What is the lymphatic drainage of the eyelids?

A

Parotid nodes

186
Q

Where is the majority of the blood supply to the face from?

A

External carotid artery (branch of ophthalmic) with some from internal carotid artery

187
Q

What 2 places can the facial pulses be felt?

A
  1. Facial artery at inf border of mandible

2. Transverse facial artery ant to auricle

188
Q

What is the venous drainage of the face?

A
  • FACIAL vein into Internal jugular vein

- TRANSVERSE FACIAL vein drains upper face

189
Q

Describe the danger triangle of the face?

A
  • No valves in external facial veins
  • Blood flows in both directions
  • Deep veins drain to cavernous sinus
  • Skin infections here may spread as intracranial infections
190
Q

Name 3 means of lymphatic drainage of the face?

A
  1. Pre-auricular & parotid
  2. Submandibular
  3. Submental
191
Q

What is the innervation of the Medial Pterygoid muscle?

A

MAIN TRUNK of CN V3

192
Q

What are the 3 functional groups of the basal nuclei?

A
  1. Input nuclei: inputs from cortex & thalamus
  2. Intrinsic nuclei: relay info between input & output nuclei
  3. Output nuclei: send info to thalamus
193
Q

What 2 structures are associated with the input nuclei function of the basal nuclei?

A
  1. Caudate nucleus

2. Putamen

194
Q

What 3 structures are associated with the intrinsic nuclei function of the basal nuclei?

A
  1. Globus Pallidus (external)
  2. Subthalamic nucleus
  3. Substantia nigra (pars compacta)
195
Q

What 2 structures are associated with the output nuclei function of the basal nuclei?

A
  1. Globus Pallidus (internal)

2. Substantia nigra (pars reticulata)

196
Q

List the 5 subcortical structures of the basal nuclei?

A
  1. Caudate nucleus (includes nucleus acumbens)
  2. Putamen
  3. Globus Pallidus
  4. Subthalamic nucleus
  5. Substantia nigra
197
Q

What 3 basal nuclei structures make up the neostriatum/striatum/corpus striatum?

A
  1. Caudate nucleus
  2. Putamen
  3. Globus Pallidus
198
Q

What are the 3 functions of the basal nuclei?

A
  1. Refinement & initiation of motor output (Motor loop)
  2. Emotional & reward aspects of motor output (limbic)
  3. Influence on behaviour & learning (behavioural loop)
199
Q

What problems can lesions in the basal ganglia cause?

A

Problems “getting going”- ataxia

200
Q

What happens in the direct pathway in basal ganglia for movement?

A

“The accelerator”- medial Globus Pallidus acts as a brake to movement

201
Q

List the 4 steps involved in the direct pathway of basal ganglia for movement?

A
  1. Cerebral cortex excited neostriatum with glutamate
  2. Neostriatum inhibits Globus Pallidus medial lobe with GABA
  3. Medial lobe inhibits thalamus (GABA), but as its activity is reduced the thalamus activity increases
  4. Results in increased cerebral stimulation & increased movement
202
Q

What happens in the indirect pathway in basal ganglia for movement?

A

“The brake”- medial Globus Pallidus acts like a brake

203
Q

List the 6 steps involved in the indirect pathway of basal ganglia for movement?

A
  1. Cerebral cortex excites neostriatum with glutamate
  2. Neostriatum inhibits Globus Pallidus lateral lobe with GABA
  3. Lateral lobe inhibits subthalamic nucleus (GABA), it is inhibited so the subthalamic nucleus activity rises
  4. Subthalamic nucleus increases normal excitation of medial lobe of Globus Pallidus which increases activity
  5. Results in increased inhibition of thalamus & reduction in cerebral stimulation
  6. Reduced movement
204
Q

Where is dopamine produced?

A

Substantia nigra (pars compacta)

205
Q

Cortical activity is influenced by direct & indirect pathways ______?

A

Simultaneously

206
Q

How does dopamine modulate the movement system in basal ganglia?

A

Depends on what dopamine receptor they join with, can inhibit the indirect pathway or excite the direct pathway- both INCREASE movement

207
Q

Why are clinical signs of basal ganglia lesions contralateral to the side of lesion?

A

Basal ganglia doesn’t cross, but the corticospinal tract crosses to the contralateral side and basal ganglia modulates the motor cortex

208
Q

What does TRAP stand for in Parkinsonism disease (hypokinetic disease)?

A
  • Tremor
  • Rigidity
  • Akinesia
  • Posture
209
Q

What is the physiology behind Parkinson’s disease (hypokinetic disease)?

A

Progressive degeneration of the dopaminergic neurons of the substantia nigra

210
Q

How does a loss of dopamine lead to hypokinesia?

A
  1. Decrease in direct pathway activity (decreased movement)

2. Increase in the indirect pathway activity (decreased movement)

211
Q

What are the 2 places targeted for deep brain stimulation for Parkinson’s disease?

A
  1. Globus Pallidus medial lobe (internal)

2. Subthalamic nucleus

212
Q

Describe the hyperkinetic disorder called Hemiballismus?

lesion of indirect pathway

A
  • Lesion of subthalamic nucleus
  • No stimulation of globus pallidus (internal)
  • Violent projectile movement of limb contralateral to lesion
213
Q

Describe the physiology behind the hyperkinetic disorder called Chorea?
(lesion of indirect pathway)

A
  • Lesion of striatum (putamen)
  • Initially, loss of GABAergic cells that project to globus pallidus (external)
  • Later, stratal cholinergic cells begin to die
214
Q

What are the clinical signs of Chorea (hyperkinetic disorder)?

A

Rapid, involuntary & purposeless jerks of irregular & variable location on body

215
Q

What is Huntington’s chorea due to?

A

Excessive CAG repeats on chromosome 4

216
Q

Describe the hyperkinetic disorder called Athetosis?

A
  • Lesion in Globus Pallidus

- Spontaneous & often continuous writhing movements of a hand, arm, neck or face

217
Q

Describe the hyperkinetic disorder called Wilson’s disease?

A
  • Lenticular degeneration due to copper accumulation

- Dystonia & tremor

218
Q

Describe the hyperkinetic disorder called Dystonia?

A
  • Lesions in lentiform nucleus

- Increased/sustained muscle contractions, twisting of trunk/extremities & abnormal postures

219
Q

What makes up the Lentiform nucleus?

A

Putamen & Globus Pallidus

220
Q

Describe the cause of Huntington’s disease (basal ganglia disease)?

A
  • Mutation causing malformed protein: Huntingtins
  • Loss of enkephalinergic & GABAergic neurons in neostriatum, leading to decrease in activity of the indirect pathway (increased movement)
221
Q

What 4 things is Huntington’s disease characterised by?

A
  1. Wildly flailing limbs & contorted posture
  2. Reduced ability to saccade
  3. Abnormal emotional responses (later stages)
  4. Reduced cognitive ability (later stages)
222
Q

What is the average life expectancy of Huntington’s disease after onset of symptoms?

A

15yrs

223
Q

What is death of Huntington’s diseased patient usually due to?

A

Respiratory infections

224
Q

What syndrome is also thought to be a hyperkinetic disease of the basal ganglia?

A

Tourette’s Syndrome

225
Q

Describe the axes of the orbit?

A
  • Medial walls almost parallel
  • Lateral walls at 90o
  • Bases anterolaterallly
  • Apices posteromedially
226
Q

What does the tendinous ring of the orbit give rise to?

A

4 recti muscles

227
Q

What nerves pass through the superior orbital fissure “LFTSNIA”?

A
  • Lacrimal nerve CN V1
  • Frontal nerve CN V1
  • Trochlear nerve IV
  • Superior branch of CN III
  • Nasociliary nerve CN V1
  • Inferior branch of CN III
  • Abducens nerve VI
228
Q

What lies within the optic canal?

A
  • Optic nerve (CN II)

- Central retinal artery & vein (end/terminal artery)

229
Q

What are the contents of the orbit?

A
  • Extraocular muscles
  • Eyelids & lacrimal apparatus
  • Retrobulbar fat
230
Q

What is the Orbicularis Oculi muscle innervated by?

A

Temporal & Zygomatic branches of CN VII

231
Q

What can malfunctions of the orbicularis oculi muscle lead to?

A

Sagging of lower eyelid, leakage of tears & dry eyes with the potential for corneal ulceration

232
Q

What is the clinical consequence of the meninges & subarachnoid space extending from skull along CN II to sclera?

A

Raised intracranial pressure can therefore slow retinal venous drainage via the central retinal vein causing papilloedema

233
Q

What is the clinical significance of the central retinal artery?

A

If occluded due to transient causes (amaurosis fugax) it can lead to painless temporary loss of vision in affected eye

234
Q

What does the tarsal plate of the eyelid contain?

A

Tarsal (meibomian) glands that lubricate the lids (cyst)

235
Q

What does the eyelashes of the eyelid contain?

A

Ciliary (sebaceous) glands (sty)

236
Q

Describe the lacrimal apparatus & route of tears?

A
  • Tears gather in lacrimal caruncle

- Drain via puncture –> canaliculi –> lacrimal sac –> nasolacrimal duct –> inferior nasal meatus

237
Q

List the extraocular muscles from superior to inferior?

A
  • Superior oblique
  • Levator palpabrae superioris
  • Superior rectus
  • Medial rectus
  • Lateral rectus
  • Inferior oblique
  • Inferior rectus
238
Q

What eye movement does the superior rectus provide?

A

Pulls eye upwards

239
Q

What eye movement does the inferior rectus provide?

A

Pulls eye downwards

240
Q

What eye movement does the medial rectus provide?

A

Pulls eye medially

241
Q

Where does the inferior & superior rectus pass?

A

Posteriorly & medially

242
Q

What gaze renders the rectus eye muscles efficient & oblique eye muscles inefficient?

A

Divergent gaze (distally forwards & slightly lateral)

243
Q

What are the extra ocular muscles dependent upon?

A
  • Direction of the gaze
  • Position of eye
  • Action of other muscles
244
Q

What eye movements does the superior oblique provide?

A

Pulls back of eye upwards & medially, turning eye inferiorly & laterally

245
Q

What eye movements does the inferior oblique provide?

A

Turns eye superiorly & laterally

246
Q

How many axes of movement/diretions can the eyes do?

A

3

247
Q

What muscles control left & right eye to look right?

A
  • RIGHT EYE: lateral rectus

- LEFT EYE: medial rectus

248
Q

What nerve supplies the lateral rectus?

A

CN VI (abducens)

249
Q

What is the side effect in the eyes when there is injury to the right CN VI?

A

Diplopia when looking right & eye would not abduct fully

250
Q

What can lack of synchronous movements of the eyes cause?

A

Double vision (diplopia)

251
Q

What muscles help to make the left & right eye look upwards & right?

A
  • RIGHT EYE: inferior oblique turns eye superolaterally

- LEFT EYE: superior rectus turns eye superiorly & medially

252
Q

What muscles help to make the left & right eye look directly superiorly?

A

For BOTH EYES: superior rectus & inferior oblique

253
Q

What muscles help to make the left & right eye look downwards & right?

A
  • RIGHT EYE: superior oblique turns eye inferolaterally

- LEFT EYE: inferior rectus turns eye inferiorly & medially

254
Q

What muscles help to make the left & right eye look directly inferiorly?

A

For BOTH EYES: inferior rectus & superior oblique

255
Q

What gaze renders the rectus eye muscles inefficient & oblique eye muscles efficient?

A

Convergence gaze

256
Q

How are the eye muscles clinically assessed?

A

“H” test & testing muscles in their most efficient position will show any weakness

257
Q

When looking laterally, what muscles can elevate & depress the eye?

A

Superior & inferior recti

258
Q

When looking medially, what muscles can elevate & depress the eye?

A

Superior & inferior obliques

259
Q

What happens in the eye “H” test if there is a CN VI lesion?

A

Lateral rectus will not work, giving obvious signs

260
Q

What happens in the eye “H” test if there is a CN III lesion?

A

Pupil signs & eye movements will be limited, lateral rectus & superior oblique take over, so eye will look downwards & outwards

261
Q

What nerve supplied the superior oblique?

A

CN IV (trochlear)

262
Q

What is a clinical sign of injury to CN IV?

A

Patient cannot look medially & inferiorly so therefore struggle to walk downstairs / read a book

263
Q

Where does the ophthalmic artery branch from?

A

Internal carotid artery

264
Q

What 3 structures does the ophthalmic artery supply?

A
  1. Eye
  2. Part of nasal cavity
  3. Forehead
265
Q

Describe the venous drainage of the orbit & how its important clinically?

A

Supra & infraorbital veins anastomose with superficial veins of face & forehead, therefore infections may spread to cavernous sinus

266
Q

What 3 pathologies could cause internal acoustic meatus narrowing?

A
  1. Acoustic neuroma
  2. Mastoiditis
  3. Paget’s disease
267
Q

What are the clinical signs of tumours in internal acoustic meatus & at cerebellopontine angle?

A

They impinge upon CN VII & VIII giving ipsilateral facial signs (possibly effect CN V)

268
Q

What can fractures of the cranial base affect?

A
  • Ear
  • Eye
  • Nose
  • Petrous temporal bone
  • Orbit
  • Cribriform plate
269
Q

Describe the external structure of the ear?

A

Auricle & external acoustic meatus of cartilage & bone leading sound waves to tympanic membrane

270
Q

Describe the middle structure of the ear?

A

Ossicles mechanically transmitting sound, connected to pharynx by auditory tube

271
Q

Describe the internal structure of the ear?

A

Semi- circular canals (motion) & cochlea (hearing) converting mechanical signals to electrical carried by CN VIII

272
Q

What groove lies posterior to petrous temporal bone & mastoid process?

A

Groove for sigmoid venous sinus

273
Q

What apparatus lies within the petrous temporal bone?

A

Vestibulocochlear apparatus

274
Q

Describe the structure of the auricle in the external ear?

A

Elastic cartilage for support & “catching” sound & funnelling it into the external acoustic meatus

275
Q

What is the external acoustic meatus lined by?

A

Skin with hairs containing ceruminous glands (modified sweat glands) that secrete ear wax

276
Q

What needs to be done to the sinuous course of the external acoustic meatus during examination?

A

Straightened for examination of tympanic membrane by pulling ear superiorly, posteriorly & slightly laterally

277
Q

What nerve supplies the internal surface of tympanic membrane & middle ear?

A

CN IX

278
Q

Describe the structure of the tympanic membrane?

A
  • Held within temporal bone by fibrocartilaginous ring
  • Lies at angle, facing downwards & anteriorly
  • External skin, then a thin fascia & then
    mucous membrane internally
279
Q

What is used to examine the tympanic membrane?

A

Otoscope

280
Q

What does the tympanic cavity extend superiorly to?

A

Epitympanic recess

281
Q

Where does the tensor tympani arise & attach?

CN V3 via nerve to medial pterygoid

A

Within canal of petrous temporal bone above auditory tube & attaches to handle of malleus

282
Q

Where does the Stapedius (CN VII) arise & attach?

A

Within pyramid & attaches to neck of stapes

283
Q

What does loss of Stapedius function cause?

A

Hyperacusis

284
Q

What do both Tensor tympani & stapedius muscles prevent?

A

Excessive movement of the ossicles

285
Q

Describe the route of the auditory tube?

A

From medial wall of middle ear to nasopharynx (sensation by CN IX)

286
Q

Describe the auditory tube?

A

Bony canal but then tube is cartilaginous lying between petrous temporal bone & greater wing of sphenoid

287
Q

What does the cartilage of the auditory tube give origin to?

A

Levator & tensor palati that pull tube open for pressure equalisation of the middle ear (swallow while ascending in aeroplane)

288
Q

What is the clinical significance of the position of tubal tonsil?

A

Swelling may obstruct the tube causing otitis media (middle ear infection)

289
Q

The tubal tonsil & cartilage cause ________ in the nasopharynx?

A

Elevation

290
Q

What can chronic middle ear infection (otitis media) cause?

A

Damage ossicles causing conductive deafness & these may even spread to mastoid air cells or beyond

291
Q

Describe the anatomical relations of the middle ear?

A
  • Thin bony roof between middle ear & middle cranial fossa (infection)
  • Chorda tympani lies deep to upper portion of tympanic membrane
292
Q

Describe the inner ear structure?

A

Bony labyrinth containing membranous labyrinth, perilymph & endolymph

293
Q

What lies lateral to the inner ear?

A

Narrow box-like cavity of middle ear

294
Q

What do the cochlear & vestibular aqueducts allow?

A

Membranous labyrinth to connect with subarachnoid space for reabsorption of peri & endolymph

295
Q

Describe the vestibular part of CN VIII in the inner ear bony labyrinth?

A

Leaves semicircular canals, utricle & saccule of labyrinth & it has cell bodies clustered in ganglia in internal acoustic meatus

296
Q

What is the cochlear part of CN VIII derived from?

A

Organ of Corti in the cochlea

297
Q

Describe the anterior & posterior chambers of the eyeball?

A
  • Separated by iris
  • Communicate via pupil
  • Contain aqueous humour
298
Q

Describe the layers of the eyeball?

A
  • Sclera forms outer fibrous layer (replaced by the cornea anteriorly)
  • Then the vascular choroid layer before the innermost retina
299
Q

What does the choroid continue as in the anterior segment of the eyeball?

A

Ciliary body which forms a supportive ring around the lens & iris

300
Q

What happens when the ciliaris muscle in the anterior segment of the eyeball contracts?
(parasympathetic, CN III, Edinger-Westphal nucleus)

A

Ring shrinks, suspensory ligaments relax, & lens becomes rounded (accommodation for close vision)

301
Q

What 2 muscles does the iris have?

A
  1. Sphincter pupillae (parasympathetic, CN III, Edinger-Westphal nucleus)
  2. Dilator pupillae (sympathetic)
302
Q

What secretes aqueous humour?

A

Ciliary body

303
Q

How is the aqueous humour reabsorbed?

A

By scleral venous sinus (canal of Schlemm)

304
Q

What results in Glaucoma?

A

Excess pressure: drugs that constrict the pupil may ‘pull’ the venous sinus open & help

305
Q

Describe the optic disc from an ophthalmoscopic view?

A
  • ‘Entry’ of optic nerve & central retinal vein with artery which is an end/terminal artery (obstruction= blindness)
  • Lacks photoreceptors & often referred to as the ‘blind spot’
306
Q

Describe the clinical macula from an ophthalmoscopic view?

A

Corresponding to the anatomical fovea centralis which is the region of greatest visual sensitivity (thinnest retina)

307
Q

Describe the retina from an ophthalmoscopic view?

A
  • Anteriorly retina is non-optic but optic posterolaterally

- Inner neural layer may separate (detached retina)

308
Q

How to the rods in the retina look from an ophthalmoscopic view?

A

Dim light, not colour

309
Q

How do the cones in the retina look from an ophthalmoscopic view?

A

Bright light & colour

310
Q

What gives rise to the fibres of the optic nerve (CN II)?

A

Receptors in the retina

311
Q

What can strokes damaging the optic radiation/occipital cortex result in?

A

Loss of upper/lower parts of appropriate visual field= QUADRANTANOPIA

312
Q

What is the origin of foramen ceacum?

A

Midline thyroid

313
Q

Describe the development of the tongue?

A
  • Swellings develop (lateral lingual x2, tuberculum impar, copula, epiglottal)
  • 1st arch body of the tongue
  • Tissue of 3rd arch overgrows 2nd arch
  • Terminal sulcus becomes junction between 1st & 3rd arch mesenchyme
314
Q

What is the general sensation of the anterior 2/3 of the tongue, derived from the 1st arch?

A

Trigeminal (V)

315
Q

What is the general sensation of the posterior 1/3 of the tongue, derived from 3rd arch?

A

Glossopharyngeal (IX)

316
Q

What is the general sensation of the epiglottis/root, derived from 4th arch?

A

Vagus (X)- superior laryngeal nerve

317
Q

What is the nucleus of tractus solitarius in the brainstem for?

A

Taste

VII ant 1/3 tongue, IX post 1/3 tongue, X epiglottis

318
Q

What is the commissural nucleus in the brainstem for?

A

Cardiovascular reflexes

IX carotid sinus/body, X aortic arch & viscera

319
Q

What is the hypoglossal muscle derived from?

A

Somites

320
Q

Where does the thyroid originate from?

A

Foramen caecum caudal to the tuberculum impar (foregut endoderm origin), then migrates anteriorly

321
Q

What is the tract of thyroid migration marked by?

A

Thyroglossal duct (connects thyroid with tongue)

322
Q

What can cause Thyroid dsygenesis (abnormal development)?

A

Mutations in transcription factors PAX8 & TITF1 (expressed as bud descends)

323
Q

What do follicular cells secrete?

A

Triiodothyronine & Thyroxine

324
Q

Where are calcitonin producing parafollicular cells derived from?

A

4th pouch (ultimobranchialbody)

325
Q

Describe a Thyroglossal cyst?

A
  • Remnant of thyroglossal duct
  • Close to midline, most found in hyoid bone region
  • Moves upwards on tongue protrusion
326
Q

What % of Thyroglossal cysts are associated with the hyoid bone?

A

80%

327
Q

What pharyngeal arch are the facial prominences from?

A

1st arch

328
Q

Describe the development of the face?

A
  • Around stomodeum
  • Maxillary prominences grow -» midline
  • Nasal pits form surrounded by medial/lateral prominences
    10th week
329
Q

How is the upper lip formed?

A

By Maxillary prominences & fusion of Medial nasal prominences (philtrum)

330
Q

What is the 4th & 6th pharyngeal arch innervation?

A
  • 4th superior laryngeal

- 6th recurrent laryngeal

331
Q

What innervates the frontonasal prominence?

A

Trigeminal nerve

332
Q

What is the primary development of the palate?

A

Maxillary process fusion (1st arch) –> Intermaxillary segment forms philtrum/4 incisors/primary palate

333
Q

What is the secondary development of the palate?

A
  • Maxillary process –> palatine shelf
  • Palatine shelf flips “above” tongue
  • Fusion in midline and with nasal septum
334
Q

Where is cleft lips & cleft palates more/less prevalent in the World?

A
  • More in asia

- Less in africa

335
Q

What type of cleft lip is most common?

A

Unilateral

336
Q

What % of cleft lip cases also have a cleft palate?

A

Over 50%

337
Q

What are the associated defects for cleft lips & cleft palates?

A
  • SYNDROMIC: Treacher Collins & Van der Woude

- Many genes identified as affected in these syndromes (coding & non-coding regions)

338
Q

What is it called when cleft lips & cleft palates are not associated with other defects?

A

NON SYNDROMIC

339
Q

List the environmental causative factors for cleft lips & cleft palate?

A
  • Maternal age
  • Medications antiepileptic agents /corticosteroids,
  • Smoking, Alcohol during pregnancy
  • Maternal illness
  • Maternal diabetes
  • Lack of dietary folic acid
340
Q

List the genetic causative factors for cleft lips & cleft palate?

A
  • Aberrant gene variants are inherited from mother or father

- Inheritance is variable, often not strictly Mendelian probably because of environmental factors

341
Q

What are the 2 gene mutations identified for cleft lips & cleft palates?

A
  1. PHF8 mutated in Siderius X-linked mental retardation
    codes histone lysine demethylase
  2. IRF6 mutated in Van der Woude syndrome
342
Q

List the negative effects cleft lips & palates have on people?

A
  • Difficulty feeding
  • Hearing problems “glue ear”, ear infections
  • Speech problems
  • Dental anomalies
  • Social & psychological issues
343
Q

How can cleft lips & palates be corrected?

A
  • Surgery from 2-6 months

- Further operations to improve speech & correct bone growth

344
Q

What is the purpose of the oval window of the cochlea during transmission of sound waves?

A

Acts as a pressure release

345
Q

What do we mean by cognition?

A

The acquisition, retention & use of information that allows successful behaviour in our complex & changing environment

346
Q

What 6 concepts does cognition encompass?

A
  1. Perception (not the same as sensation)
  2. Attention
  3. Memory & learning
  4. Emotion & social cognition
  5. Symbolic representations (language etc.)
  6. Reasoning & problem solving
347
Q

What do primary areas receive?

A

Unprocessed modality data, association areas (also called higher-order areas) & sub-cortical components function to determine the perceptual qualities of the modality

348
Q

What does the integration of modal qualities from higher-order cortex with themselves & from other sensory modalities allow for?

A

Appreciation of music, detection of danger, integration of other peoples behaviour

349
Q

What is used to determine what is happening & where its happening?

A

Combination of processed sensory perceptions (vision, temp, sound)

350
Q

What do sub-cortical structures & association fibres do to the information?

A

Move it through association cortices for processing & integration to become either a reflex or cognitive state

351
Q

Describe the 3 steps to multi-sensory integration for motor output?

A
  1. Sensory info about environs & body project to primary cortical areas (visual, somatosensory, auditory)
  2. Processed & unprocessed info then passed to sensory association areas in parietal & temporal lobes for integration
  3. Integrated info shared with supplementary motor cortex (processing info about intent in association with other frontal lobe areas) & thence to the pre- & motor cortex to make sensory input into planned integrated motor events
352
Q

What is the McGurk Effect?

A

Visual sensory information is interpreted & is dominant over auditory processed information (fooled senses)

353
Q

What is Synaesthesia?

A

Combo of sensory experiences from 1 sensory domain with those from another, or the mixing of 2 modalities of the same sensory domain (seeing colour come out a muscical instrument)

354
Q

What is the most commonly studied Synaesthesia?

A

Colour-graphemic synaesthesia where specific black & white shapes are perceived in colour

355
Q

What are the 2 areas in the brain for speaking works?

A
  1. Primary motor cortex

2. Broca’s area

356
Q

What are the 2 areas in the brain for hearing words?

A
  1. Auditory cortex

2. Wernicke’s area

357
Q

What hemisphere is dominant for speech in most people (Wada test)?

A

Left hemisphere

358
Q

What way does the brain work to say written words?

A

Visual info passed to Wernicke’s area via angular gyrus, & so on to Broca’s area etc.

359
Q

How can Aphasia (inability to understand or produce speech) occur?

A

When the link between 2 areas (the arcuate faciculus) is damaged, & is typified by reduced ability to repeat spoken words

360
Q

How does the brain work for the basis of hearing, understanding & repeating spoken words?

A
  1. Afferent info arrives at auditory cortex & Wernicke’s area (left temporal lobe)
  2. Wernicke’s area comprehends words & passes the info to Broca’s area for sentence construction & syntax
  3. Broca’s area stimulates motor cortex to control the lips & tongue etc.
361
Q

What is Wernicke’s aphasia?

A
  • Speech fluent but nonsensical
  • Wrong or invented words
  • Comprehension lost
  • Here’s other people speak gibberish
362
Q

What is Broca’s aphasia?

A
  • Also known as motor/non-fluent aphasia
  • Difficulty speaking (stuttering to find the right word)
  • Patients aware they are making little sense
  • No problem responding to the spoken/written word
363
Q

What is the function of Broca’s area?

A

Motor programs for generation of language & sentence construction

364
Q

What is the function of Wernicke’s area?

A

Language comprehension

365
Q

How are Broca’s & Wernicke’s areas linked?

A

Arcuate faciculus

366
Q

What side of the brain is able to contribute to emotional content of language?

A

Right side

367
Q

What does dysfunction of right side of the brain near Broca’s & Wernicke’s areas cause?

A

Aprosodias- robotic or monotonic speech patterns

368
Q

What do congenitally deaf patients with damage approximating to left brain language centres show?

A

Signing deficits & comprehension deficits

369
Q

What dominant hemisphere do most right handed people have (95%)?

A

Left hemisphere

370
Q

What dominant hemisphere do most left handed people have?

A

Right hemisphere

371
Q

Where is language produced & speech comprehended in the brain?

A

Dominant side of the brain (mostly the left)

372
Q

How do you perform a Wada test?

now normally achieved using fMRI

A
  • 1 side of brain is anaesthetized via appropriate internal carotid & subject is tested for speech
  • If the dominant side remains awake, speech is unaffected
373
Q

When can split brain patients not verbally identify objects & why?

A
  1. When felt behind the screen with left hand as its controlled by right brain
  2. Seen with only left visual field was it cannot communicate with right brain
374
Q

How can the right brain communicate in split brain patients?

A

Independently by drawing (visual task) or holding up fingers (if the hidden task was counting)

375
Q

Describe Positron emission tomography (PET) for testing cortical function?

A
  • Requires a cyclotron
  • Poor spatial resolution
  • Can localise a neurotransmitter system
376
Q

Describe how & why MRI can be used to test cortical function?

A

Variations in hydrogen density provide the tone of the image

377
Q

Describe how & why fMRI can be used to test cortical function?

A
  • Imaging blood flow based on amount of haemoglobin /oxyhaemoglobin detected within an area
  • As neural activity increases so does requirement for glucose & blood flow
378
Q

What are meningitis symptoms in babies?

A
  • Tense/bulging soft spot on their head
  • Refusing to feed
  • Irritable when picked up, with a high pitched or moaning cry
  • Stiff body with jerky movements, or else floppy & lifeless
379
Q

What is the definition of encephalitis?

A

Inflammation of the brain

380
Q

What is the definition of Sepsis?

A
  • Whole-body inflammation

- Systemic inflammatory response syndrome (SIRS)

381
Q

What is the blood-cerebrospinal fluid (CSF) barrier?

A
  • Similar barrier at arachnoid membrane & in ventricles

- Breach by infectious agents causes meningitis

382
Q

What 3 ways can pathogens cross the brain barriers resulting in a typical inflammatory response associated with infection?

A
  1. Growing across & infecting cells comprising barrier
  2. Passive transfer in intracellular vacuoles
  3. Carriage across in infected white blood cells
383
Q

What are the lab investigations to confirm meningitis?

A
  • BLOOD: culture, NAAT, glucose, FBC, U&E, clotting

- CSF: white cell count, gram stain, Ziehl-Neelsen stain, India ink, NAAT

384
Q

What are the 4 commonest bacteria which cause meningitis?

A
  1. Neisseria meningitidis
  2. Haemophilus influenzae
  3. Streptococcus pneumoniae
  4. Mycobacterium tuberculosis
385
Q

What are the 3 commonest viruses which cause meningitis?

A
  1. Enteroviruses
  2. Herpes simplex 1 & 2
  3. Paramyxovirus
386
Q

What is the commonest fungus which causes meningitis?

A

Cryptococcus neoformans

387
Q

What are the 3 commonest protozoa which cause meningitis?

A
  1. Amoebae
  2. Naegleria
  3. Acanthamoeba
388
Q

What are the 5 virulence factors of bacterial meningitis?

A
  1. Anti-phagocytic polysaccharide capsule 2. Endotoxin
  2. IgA protease
  3. Outer membrane proteins (OMPs)
  4. Pili (fimbriae)
389
Q

Describe the effect on CSF with bacterial meningitis?

A
  • Turbid appearance
  • Polymorphs
  • Increased protein
  • Reduced glucose
  • Gram negative stain
  • Neutrophilia
390
Q

Describe the effect on CSF with viral meningitis?

A
  • Clear appearance
  • Lymphocytes
  • Slight increase in protein
  • Normal glucose
  • Normal white cell count
391
Q

What 3 pathogens commonly cause bacterial meningitis in neonates?

A
  1. Escherichia coli
  2. Group B Streptococcus
  3. Listeria monocytogenes
392
Q

What 2 pathogens commonly cause bacterial meningitis in <5yrs old?

A
  1. Neisseria meningitidis 2. Haemophilus influenzae
393
Q

What pathogen commonly causes bacterial meningitis in young adults?

A

Neisseria meningitidis

394
Q

What 2 pathogens commonly cause meningitis in older people?

A
  1. Streptococcus pneumoniae

2. Listeria monocytogenes

395
Q

What 2 pathogens commonly causes meningitis in immunosuppressed people?

A
  1. Mycobacterium tuberculosis

2. Cryptococcus neoformans

396
Q

What are the possible complications with bacterial meningitis?

A
  • Sepsis
  • Intellectual deficit
  • Deafness
  • Arthritis
  • Skin necrosis
397
Q

How do you treat suspected meningococcal infection?

A
  • IV/IM Penicillin (by GP on pre-admission)

- IV Ceftriaxone (on admission)

398
Q

List the 6 different vaccines available for bacterial meningitis?

A
  1. MenC (meningococcal group C)
  2. Hib (Haemophilus influenzae type B)
  3. BCG (Mycobacterium tuberculosis)
  4. Strep. Pneumoniae (pneumonococcal)
  5. MenB (meningococcal group B)
  6. Men ACWY (quadrivalent)
399
Q

How should you notify when you have a patient who is positive for meningitis?

A
  1. Reference Laboratories
  2. Public Health Action
  3. Public Awareness
400
Q

Describe Viral meningitis?

A
  • Milder disease than bacterial but more common
  • NAAT is diagnostic tool
  • Identify in faeces, urine, CSF, serology
  • No specific treatment
  • Aciclovir (herpes)
  • Use of vaccination (polio)
401
Q

Describe Tuberculous meningitis?

A
  • Frequently associated with miliary TB
  • Usually develops when Rich focus discharges contents in sub-arachnoid space
  • Acid-fast bacilli in CSF smear
  • CSF NAAT & culture
  • Treatment: rifampicin, isonazid, pyrazinamide, ethambutol
  • Vaccine: BCG
402
Q

What is usually the origin for encephalitis?

A

Viral (through blood or neurons)

403
Q

What is primary encephalitis?

A

First exposure to virus results in virus directly

affecting brain / spinal cord

404
Q

What is secondary encephalitis?

A

Virus first infects another part of body, then affects CNS when reactivated

405
Q

What are the signs of cerebral dysfunction in encephalitis?

A
  • Abnormal behaviour
  • Seizures
  • Altered consciousness - Nausea
  • Vomiting
  • Fever
406
Q

Describe the development of a brain abscess?

A
  • Begin as diffuse inflammation of brain matter progressing to focal lesion
  • From pia mater suppuration
407
Q

How are brain abscesses diagnosed?

A

Culture from aspirated pus (visualised by MRI or CT scans)

408
Q

What are the 3 predisposing factors for brain abscesses?

A
  1. Otitis media
  2. Mastoiditis
  3. Sinusitis
409
Q

What 2 different oral-nasopharyngeal microbiota can cause brain abscesses?

A
  1. Aerobic (S. aureus, Strep. milleri)

2. Anaerobic (Bacteroides sp., Fusobacterium sp.)

410
Q

What 2 are the different causes of brain abscesses in the immunocompromised?

A
  1. Protozoa (Toxoplasma gondii)

2. Fungi (Candida sp., Nocardia sp., Aspergillus sp.)

411
Q

What are transmissible spongiform encephalopathies (TSE’s)?

A

Prion diseases

412
Q

What 2 ways can Transmissible Spongiform Encephalopathies (TSEs) affect humans?

A
  1. Creutzfeldt-Jakob disease (CJD)

2. New variant Creutzfeldt-Jakob disease (nvCJD)

MD4001 (11 decks)

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