Neuro Lectures Flashcards
(108 cards)
1
Q
What does pupil diameter change in response to?
A
- Changes in light intensity
- Proximity of object
- State of arousal (sympathetic NS)
2
Q
Name afferent limbs of eye
A
Retina (photosensitive ganglion cells), Optic Nerve, Decussation at chiasm (stimulation of one eye therefore causes pupil response in both eyes), Optic Tracts
3
Q
Name efferent limbs of eye
A
Edinger-Westphal Nucleus in mid brain, Parasympathetic fibres in 3rd CN, Synapse in ciliary ganglion in orbit, Short ciliary nerves innervate sphincter muscle
4
Q
Define Tracts
A
Location of a pathway e.g. spinothalamic tract
5
Q
Define Commissures
A
Tract connecting one hemisphere to the other e.g. anterior commissure
6
Q
Define Lemnisci
A
Narrow strip of fibres e.g. medial lemniscus
7
Q
Define Funiculi
A
‘rope’ or ‘cord’ e.g. lateral funiculus
8
Q
Define Fasiculi
A
‘bundle’ e.g. gracile fasiculus
9
Q
Define Capsule
A
Sheet of white matter fibre that borders a nucleus of grey matter
10
Q
Define Column
A
Longitudinally running fibres that are separated by other structures e.g. dorsal column
11
Q
Define White Matter
A
The paler tissue of the brain and spinal cord, consisting mainly of nerve fibres with their myelin sheaths
12
Q
Define Grey Matter
A
The darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites
13
Q
Define cortex
A
Laminated grey matter on outside of brain, e.g. motor cortex
14
Q
Define Nuclei
A
Collections of nerve cell bodies within the CNS e.g. arcuate nucleus
15
Q
Define Ganglia
A
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
Q
Define Afferents
A
Axons taking information towards the CNS e.g. sensory fibres
17
Q
Define Efferents
A
Axons taking information to another site e.g. motor fibres
18
Q
Define Reticular
A
‘Netlike’ - where grey and white matter mix e.g. reticular formation of brainstem
19
Q
Define Coronal Plain (vertical/frontal)
A
Parallel with coronal suture
20
Q
Name the horizontal plane
A
Axial
21
Q
Define Sagittal (parasagittal)
A
Parallel with sagittal suture
22
Q
Define Ipsilateral
A
Same side [of brain]
23
Q
Define Contrallateral
A
Opposite side
24
Q
Define Medial
A
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.
