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Flashcards in Neuro Lectures Deck (108):
1

What does pupil diameter change in response to?

-Changes in light intensity
-Proximity of object
-State of arousal (sympathetic NS)

2

Name afferent limbs of eye

Retina (photosensitive ganglion cells), Optic Nerve, Decussation at chiasm (stimulation of one eye therefore causes pupil response in both eyes), Optic Tracts

3

Name efferent limbs of eye

Edinger-Westphal Nucleus in mid brain, Parasympathetic fibres in 3rd CN, Synapse in ciliary ganglion in orbit, Short ciliary nerves innervate sphincter muscle

4

Define Tracts

Location of a pathway e.g. spinothalamic tract

5

Define Commissures

Tract connecting one hemisphere to the other e.g. anterior commissure

6

Define Lemnisci

Narrow strip of fibres e.g. medial lemniscus

7

Define Funiculi

'rope' or 'cord' e.g. lateral funiculus

8

Define Fasiculi

'bundle' e.g. gracile fasiculus

9

Define Capsule

Sheet of white matter fibre that borders a nucleus of grey matter

10

Define Column

Longitudinally running fibres that are separated by other structures e.g. dorsal column

11

Define White Matter

The paler tissue of the brain and spinal cord, consisting mainly of nerve fibres with their myelin sheaths

12

Define Grey Matter

The darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites

13

Define cortex

Laminated grey matter on outside of brain, e.g. motor cortex

14

Define Nuclei

Collections of nerve cell bodies within the CNS e.g. arcuate nucleus

15

Define Ganglia

Collections of nerve cell bodies outside the CNS (e.g. dorsal root ganglia) and some in CNS that have a capsule (e.g. basal ganglia)

16

Define Afferents

Axons taking information towards the CNS e.g. sensory fibres

17

Define Efferents

Axons taking information to another site e.g. motor fibres

18

Define Reticular

'Netlike' - where grey and white matter mix e.g. reticular formation of brainstem

19

Define Coronal Plain (vertical/frontal)

Parallel with coronal suture

20

Name the horizontal plane

Axial

21

Define Sagittal (parasagittal)

Parallel with sagittal suture

22

Define Ipsilateral

Same side [of brain]

23

Define Contrallateral

Opposite side

24

Define Medial

Towards midline

25

Define Median

at midline

26

Define Lateral

away from midline

27

Define Rostral

Towards nose/anterior

28

Define Caudal

Towards tail/posterior

29

In brain stem and cord, define Dorsal

Posterior

30

In brain stem and cord, define Ventral

Anterior

31

In cerebrum, define Dorsal

Superior (as folds in embryology from posterior position)

32

In cerebrum, define Ventral

Inferior (as folds in embryology from anterior/ventral)

33

Define Sulci

Grooves

34

Define Gyri (Gyrus)

Ridges

35

Functions of 'Control and Command centre' in the brain

-Receives sensory information (conscious and subconscious)
-Provides motor output (conscious and subconscious)
-Integration

36

Parts involved in consciousness

Thought, Emotion, Memory, Planning etc

37

Where is the motor cortex

Pre-central gyrus

38

Where is the sensory cortex

Post-central gyrus

39

Characteristics of the frontal lobe

-Voluntary movement on opposite side of body
-Frontal lobe of dominant hemisphere controls speech and writing
-Intellectual functioning, thought processes, reasoning, memory
(-Also contains Inhibitory centres regarding thought processing/reasoning)

40

Characteristics of Parietal Lobe

Receives and interprets sensations, including pain, touch, pressure, size, shape and body-part awareness

41

Characteristics of Temporal Lobe

Understanding spoken words, sounds as well as memory and emotion. (Damage here means can still hear words but not understand them)

42

Characteristics of Occipital Lobe

Understanding Visual images and the meaning of written words

43

What directly underlies the cortex

White Matter

44

Give examples of grey matter structures deep in the white matter surrounding the ventricles

-Thalamus
-Hypothalamus
-Basal Ganglia (Caudate nucleus, Putamen, Globus Pallidus)

45

Role of Thalamus

Relay centre directing inputs to cortical areas

46

Role of Hypothalamus

ANS links endocrine system to the brain - homeostasis

47

Role of basal ganglia

Motor control, cognition and non-motor behaviour

48

Role of cerebellum

Involved in the co-ordiantion of voluntary motor movement, balance and equilibrium and muscle tone.
(Co-ordinates movement and balance)

49

Describe location of cerebellum

-Lies over dorsal surface of brain stem and attached by 3 peduncles (Superior, Middle, Inferior)
-IVth ventricle (forms part of its roof) separates dorsal brainstem

50

What separates the cerebellum from the dorsal brainstem

IVth ventricle (forms part of its roof)

51

What makes up the cerebellum

Made up of folded cortex, white matter and deep inner nuclei. Cortex is folded into many transverse folia.

52

Results of cerebellar injury

Movements that are slow and uncoordinated such as:
-Loss of coordination of motor movement (asynergia)
-Movement tremors (intention temor)
-Weak muscles (hypotonia)
-Abnormal eye movements (nystagmus)

53

Functions of the brainstem

-Special senses
-Sensory and motor [innervation?] for head and neck via cranial nerves
-Autonomic regulation of the body
-Regulates Consciousness
-Pathway between brain and spinal cord

54

Name parts of the brain stem

-Midbain
-Pons (bridge to the cerebellum)
-Medulla oblongata (continuous with the cord)

55

Describe the midbrain (parts)

Midbrain surrounds cerebral aqueduct. Made up of Tectum (superior and inferior colliculi) and Cerebral peduncle (tegmenjtum and crus cerebri)

56

What are 2 types of specialised cell in the CNS

-Nerve cells/neuron(es); many types e.g. pyramidal, stellate, basket, Golgi, Purkinje, chandelier etc.
-Neuroglia; e.g. astrocytes, oligodendrocytes, microglia, (ependyma)

57

What is sound?

The displacement of air particles following a sinusoidal pattern of compression and rarefacation

58

In sound what is affected by amplitude and frequency of a wave?

Amplitude (height of wave) refers to volume (how loud)
Frequency refers to pitch

59

What is average human range of hearing?

20Hz - 20kHz

60

What are main mediums sound travels through in inner, middle and outer ear?

Inner - fluid
Middle - air
Outer - air

61

What structures make up the outer ear

Pinna (cartillagenous structure) and ear cannal

62

In embryology, what forms the outer ear and when in development does this happen?

Formed from the pharyngeal arches 1 and 2 (6x Hillocks of His).
Formed between 10th and 18th week in utero

63

What is the purpose of ear folds and pinna

direct sound waves towards the ear canal

64

What is the ratio of cartilage to bone in ear canal?

Cartilage - 1/3
Bone - 2/3
Therefore ratio of 1:2 respectively

65

The outer ear also comprises the ear drum - what is the proper term for this and how large is it

Tympanic Membrane
8x10mm diameter, 14mg, 84-55mm^2

66

Which bones make up the middle ear

Malleus, Incus & Stapes (in that order from outer to inner ear and in order of size)

67

What muscles make up the middle ear

Tensor Tympani & Stapedius

68

Which tubular structure also comprises the middle ear?

Eustachian Tube

69

Whats the role of the middle ear?

Acoustic impedance match between air and fluid- filled inner ear.
Amplification of the airbone sound vibration to make sound louder (as energy loss from air to fluid):
Ratio Area Tympanic M : Stapes 14:1
Lever action of ossicles - handle of malleus is 1.3 times longer than long process of incus
Total gain 18.3:1 or 20 - 35 dB

70

What is the fold increase in pressure from TM to inner ear?

200 fold increase down ossicular chain

71

What are the role of the muscles in the middle ear?

Protection of the inner ear from acoustic trauma and stiffens the ossicular chain
(Stapedius stimulated acoustically)

72

In a man what is the average reaction time to a thunderclap (not shotgun)?

25ms

73

Which muscle of middle ear undergoes voluntary and involuntary control?

Tensor Tympani

74

What is the role of the Eustachian Tube?

Ventilation of the middle ear space and drainage of secretions.

75

What is the inner ear and what is another term for it?

Vestibulocochlear apparatus
A set of fluid filled sacs encased in bone.

76

Describe the cochlear

In inner ear - responsible for hearing.
2.5 turns fluid filled bony tube.
2 openings (round + oval window).
3 compartments.
2 Ionic fluids

77

Name the 3 compartments of the cochlear

Scala Tympani
Scala Media
Scala Vestibuli

78

What innervates the inner ear

Vestibulocochlear nerve

79

What (in the inner ear) is responsible for balance

Labyrinth

80

What are the 2 cochlear fluids

-Endolymph (High K+)
-Perilymph (like ECF and CSF, is Na+ rich)

81

In cochlear, what maintains the concentration gradient?

- Na/K-ATPase
- NKCC1 CIC-K chlorine channels

82

What can result from ion channel abnormalities?

Deafness

83

Describe the basilar membrane of the cochlear

Narrow at base and Wide at apex
Stiff at base and Floppy at apex
High frequencies detected at base and Low frequencies at apex

84

In organ of Corti describe the mobility of the membranes

Tectorial membrane - fixed
Basilar membrane - mobile
Displacement of the basilar membrane causes movement of specialized mechanical transducing cells
--Base attached to basilar membrane Stereocillia anchored to tectorial membrane

85

Describe briefly the hair cells of inner ear

Inner Hair Cells- Mechanical transduction
Outer Hair Cells- fine tuning
Also base attached basilar membrane and stereocilia (shearing forces here) anchored to tectorial membrane.

86

Describe to process of how sound wave changes to to nerve impulse (from inner ear)

-Movement of the sterocilia
(-Rapid response required)
-Mechanically gated K+ channels opened causing depolarisation (K+ rich endolymph)
-Release of neurotransmitter - Glutamate (and others)
-Repolarization through K+ efflux (into K+ poor perilymph)

87

How do outer hair cells of inner ear work?

Outer hair cells can alter the stiffness of the basilar membrane to ensure maximal stimulation at one site and dampened response at another. This increases resolution.

88

How is sound information encoded?

Frequency (pitch) - encoded in nerves by location along the basilar membrane
Intensity (loudness) - encoded in nerves by numbers responding and by firing rate.
-Sound Transduction by Inner Hair Cells (and OHCs), Amplification by outer hair cells.

89

Briefly describe the path from the auditory fibre to brain

Auditory fibre of spiral ganglion. Spiral Ganglion to Cochlear nerve (VIII). Via Central Auditory Pathway of brain.

90

Describe the Central Auditory Pathway of brain

Cochlea via VIIIth nerve to cochlear nucleus -> superior olive. (Bilateral central auditory pathway; Binaural stimulation occurs at superior olive and all regions above.)
Goes to lateral leminiscus to Inferior colliculus to medial geniculate body to auditory cortex.

91

What are MSO neurons

Coincident detectors that respond only when excitatory signals arrive simultaneously. Anatomical differences in connectivity allow each MSO neuron to be sensitive to sound source from particular location - 'localising sound'

92

in hearing loss, what is a defective inner ear referred to as?

Sensorineural Hearing Loss

93

What does 'conductive hearing loss' refer to?

Defective outer/middle ear

94

Define Pain (IASP)

an unpleasant and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
(subjective sensation)

95

What is the minimum time for pain to be considered chronic?

12 weeks

96

Define Nociceptive Pain

Pain that arises from actual or threatened damage to non-neural tissue and is due to activation of nociceptors - can sense internal or external pain.

97

Define Neuropathic Pain

Pain initiated or caused by a primary lesion or dysfunction of NS

98

Define Pain (NeuPSIG)

Pain arising as a direct consequence of a lesion or disease of the somato-sensory system.

99

How is disease differentiated by pain?

Disease differentiates pain caused by neuroplastic changes in response to strong nociceptive stimulation

100

Define Nociceptors

Sensory neurons that are found in any area of the body that can sense pain either externally or internally. Most are poly-modal (thermal/chemical/mechanical)

101

What is dorsal root ganglion composed of?

Cell bodies of nerve fibres that are sensory (afferent)

102

Describe Nociceptor transduction

Peripheral terminals of nociceptors have numerous different types of transducers/receptors present. These can be selectively activated by a wide range of noxious mechanical, thermal and chemical stimuli. If stimulus is stimualtes a t/r, generator potential occurs. If gp causes sufficient (threshold) depolarisation of peripheral nerve membrane, an afferent volley of APs are generated which travel up axon to central dorsal horn.
When reaches central terminal of the nociceptor, it results in the release of synaptic transmitters including Glutamate (amino acid) and substance-P/CGRP (peptides)
A beta lacks peptides, C-fibres contain both.

103

What are neurotransmitters in nociceptive conduction

glutamate and substance-P/CGRP

104

Do Prostaglandins cause pain?

Prostaglandins by themselves don't cause pain but lower the threshold of C fiber nociceptors. Therefore lower concentrations of bradykinin and histamine are required to activate the nociceptor.

105

In what case would peripheral terminals of small diameter neurons be excited

In conditions of tissue inflammation as example where peripheral terminals are excited by a wise range of endogenous chemical mediators.
Case of primary hyperalgesia

106

How are characteristics of receptors changed inside a cell so that they are more receptive or reactive?

Phosphorylation

107

Whats the role of the insular cortex

plays a role in perception, motor control, self awareness and interpersonal experience
may play a part in addiction

108

Where is the cingulate cortex and what is it associated with?

-located in the medial aspect of the cerebral hemispheres
-intricately linked with limbic system associated with emotion formation and processsing, learning and memory.