Neurology Flashcards
1
Q
What plane is this?
A
Coronal plane
2
Q
What plane is this?
A
Horizontal/transverse/axial plane
3
Q
What plane is this?
A
Sagittal plane
4
Q
What is the purple structure?
Label its parts:
A
Brainstem
5
Q
What is this?
A
Cerebellum
6
Q
What does the brainstem carry + function?
A
-Ascending sensory and descending motor tracts
-Breathing, consciousness, heart rate, sleep
7
Q
What are the functions of the cerebellum?
A
-Balance & coordination
-Gait, posture, motor learning, fine skills
8
Q
What is this?
A
9
Q
What does the thalamus do?
A
Sensory relay station
10
Q
What is this?
A
Hypothalamus
11
Q
What is the function of the hypothalamus?
A
-Homeostasis
-Temperature, food intake, water content, endocrine control, body cycles
12
Q
What are these?
A
Hippocampus & fornix
13
Q
in what lobe are the hippocampus and fornix and what are their functions?
A
-Temporal lobe
-Learning & memory, spatial navigation
14
Q
What is this?
A
Lateral ventricles (aqua)
15
Q
What is the function of the lateral ventricles?
A
Cerebrospinal fluid (CSF) production and recycling
16
Q
What is this?
A
Caudate nucleus
17
Q
What is the function of the caudate nucleus?
A
-Planning & execution of movement
-Memory, cognition, emotion
18
Q
What is this?
A
Putamen
19
Q
What is the function of the putamen?
A
-Regulation of movement c.f caudate
-Cognition and reward
20
Q
What is this?
A
Amygdala
21
Q
What are the functions of the amygdala?
A
Emotional learning & behaviour, fear, anxiety and aggression
22
Q
What is this?
A
White matter
23
Q
What does this show?
Label the diagram:
A
24
Q
What is the function of sub-cortical white matter?
A
Interconnects cortical and sub-cortical regions
25
What are the functions of the cortical grey matter?
-Higher processes - memory, thinking, problem solving, reasoning, consciousness, emotion
-Sensory processing
-Movement
26
Label this diagram:
27
What major landmarks can be identified to help locate brain structures?
-Corpus callosum
-Lateral sulcus
-Brainstem
28
How are myofibres arranged in skeletal muscle?
Fascicles
29
What connective tissues are in skeletal muscle?
-Epimysium
-Perimysium
-Endomysium
30
What surrounds each myofibre?
What is its role?
-Basement membrane
-Tensile strength, regeneration, development
31
What makes up the basement membrane surrounding myofibres?
-Collages
-Glycoproteins
-Proteoglycans
32
What three external things connect to skeletal muscle?
-Vascular supply
-Innervation
-Myotendinous junction - transmit force of contraction to tendon
33
What is the innervation to skeletal muscle?
-Each fibre innervated by one nerve
-Cell bodies in anterior horn of spinal cord or brainstem
34
What is a motor unit?
One neuron innervates multiple muscle fibres
35
What are neuromuscular junctions?
Neurotransmitter?
-Synapse - rapid transmission of depolarising impulse
-Acetyl choline - binds to post-synaptic AChR
36
Describe proprioception in skeletal muscle:
-Length and tension
-Muscle spindles - encapsulates intrafusal fibres
-Mediate stretch reflexes and propriorecpetion
-Golgi tendon organ
37
Label this diagram:
What does it show?
Skeletal muscles - control and sites of pathology
38
What is a myopathy?
Primary muscle disease
39
What are the 2 types of muscle fibre?
-Slow twitch (red fibres) - fatigue resistane
-Fast twitch - fatigue rapidly but generate a large peak of muscle tension
40
What are examples of slow and fast twitch muscle fibres?
-Slow: Type 1, oxidative
-Fast: - 2A glycolytic and oxidative (intermediate)
-2B glycolytic (white)
41
What does this show?
Motor unit
42
4 features of motor unit:
-Motor neuron (lower) and the fibres it innervates
-Neuron and its fibres of same type
-Fibre type dependant on neuron
-Size of motor unit varies between muscles
43
What does this show?
Denervation (loss of nerve supply)
44
What does this show?
Re-innervation (restoration of nerve supply)
45
What is utilised by the contractile apparatus?
What regenerates one of them?
-High ATP requirement
-Creatine phosphate as short term energy store
-CP replenished by creatine kinase
-CK release on muscle fibre damage (CK serum useful clinically)
46
What can be diagnosed via muscle biopsy and why?
-Mitochondrial cytopathy
-Affect muscle
-Ragged red fibres, ETC deficit, mitochondrial abnormal morphology
47
What maintains membrane stability in skeletal muscles?
Dystrophin and its associated proteins
48
Label this diagram:
49
What are dystrophies?
-Genetically determines
-Destructibe
-Mainly progressive disorders of muscle
-Defects in proteins conferring stability can be cause
50
What is the difference between the central and peripheral nervous system?
-CNS - Brain, spinal cord
-Peripheral - Division located outside the skull and spinal cord
51
What does somatic and autonomic mean?
-Somatic - of the body
-Autonomic - unconscious/automatic
52
What does somatic nervous system interact between?
53
What does autonomic nervous system interact between?
54
Where is the non-brain part of the central nervous system located?
Within vertebral column
55
What are the different divisions of the spinal CNS?
56
What are the two parts of the spinal CNS in each vertebrae?
57
What do dorsal and ventral roots contribute towards and what fibres are they?
-Dorsal root -> Afferent
-SENSORY (affected by the world)
-Ventral root -> Efferent
-MOTOR (having an effect on the world)
58
What is the first basic subdivision of the brain?
-Forebrain
-Midbrain
-Hindbrain
59
Label the basic 3 subdivisions of the brain:
60
What are the further sub-divisions of the forebrain?
-Telencephalon (cerebral cortex, basal ganglia, limbic system)
-Diencephalon (thalamus, hypothalamus)
61
What is the further sub-division of the midbrain?
Mesencephalon - tegmentum, tectum
62
What are the further sub-divisions of the hindbrain?
-Metencephalon (pons,cerebellum)
-Myelencephalon (medulla)
63
Label the further sub-divisions of the brain:
64
What does the brain compose of in terms of systems?
Brain comprises hierarchy of functional systems providing increasingly sophisticated competences
65
What does the medulla contain?
Tracts carrying signals between the rest of the brain and the body
66
What formation does the medulla contain and do?
-Caudal part of reticular formation
-Functions:
-Low level sensorimotor control (e.g. balance)
-Sleep/wakefulness
-Motor plant (movement, muscle tone)
-Reflexes of cardiac, circulatory, respiratory, excretory
67
Describe the pons and its functions:
-Relay from cortex and midbrain to cerebellum
-Contains millions of neuronal fibres
-Pontine reticular formation (pattern generators) - e.g. walking
68
What is the function of the cerebellum?
-"Motor errors" between intended movement and actual movement
-Adjusts synaptic weights to eliminate error
-Online correction during movement - motor learning
-Thought-exclusive for motor coordination
69
Label the parts of the midbrain:
What are they?
-Tegmentum - body of midbrain
-Tectum - roof of midbrain
70
What does the tectum do?
-Visual/spatial and auditory frequency maps
71
What is the tectum separated into?
-Superior colliculus:
-Sensitive to sensory change - orienting/defensive movements
-Inferior colliculus:
-Similar but for auditory events
-Connoliculi (little hills)
72
What is the tegmentum separated into?
-Periaqueductal gray
-Red nucleus
-Substantia nigra
73
Label the 3 parts of the tegmentum:
74
What are the functions of the periaqueductal gray of the tegmentum?
-Defensive behaviour role
-Role in pain (ascending and descending signals)
-Role in reproduction
75
What is the function of the red nucleus of the tegmentum?
76
What are the parts of the substantia nigra and their roles?
-Part of basal ganglia
-Sustantia nigra pars compacta (dopamine cells) - basal ganglia input
-Substantia nigra pars reticulata - basal ganglia output
77
What is the diencephalon divided into?
-Thalamus
-Hypothalamus
78
What is the relay structure of the thalamus:
-Specific nuclei - relay signals to cortex/limbic system for all sensations
-Non-specific nuclei - role in regulating state of sleep and wakefulness and levels of arousal
79
What is the role of the thalamus?
Important relays from basal ganglia and cerebellum back to cortex
80
What is the role of the hypothalamus?
-Regulates the pituitary gland which regulates hormonal secretion
-Interface between brain and hormones
-Hormonal control of motivated
-Hunger, thirst, temperature, pain, pleasure and sex
81
What are the sub-cortical portions of the cerebral cortex?
-Basal ganglia
-Limbic system
82
Describe the basal ganglia:
-Group of structures
-Loop organisation
-Thought to be involved in motor function since involvement in movement disorders
83
Describe the limbic system:
-Group of structures
-Emotion, motivation and emotional association with memory
-Influences formation of memory by integrating emotional states with memories of physical sensations
84
What parts make up the limbic system?
85
What is the function of the different limbic system parts?
86
What are the lobes of the brain?
-Frontal
-Temporal
-Parietal
-Occipital
87
Label this diagram:
88
Describe the structure of the cortical lobes of the brain:
-Gray matter (6 lobes) : cell bodies
-White matter : fibres/axons
-Biggest part of the brain in primates
89
What does the frontal lobe contain?
Precentral gyrus from which motor instructions (fine motor control) that are sent to muscles controlling hands and feet
90
What are the divisions of the frontal lobe?
-Primary motor cortex : Contains many of cells giving in origin to the descending motor pathways (initiation of voluntary movements)
-Premotor and supplementary motor areas : higher level motor plans and initiation of voluntary movements
91
What are functions of the frontal lobe?
-"executive planning":
-generating models of consequences of actions
-judgemental roles
-emotional modulation
-Working memory : short term info
-Control of behaviour depending on context or setting
-Prefrontal cortex
92
What does the prefrontal cortex do?
Generating sophisticated behavioural options that are mindful of consequences
93
What does the parietal lobe contain?
Postcentral gyrus which receives sensation from the rest of the body
94
Describe the parietal lobe:
-Primary somatosensory cortex
-Maintains representations of the body's and head's position in space
-Permits complicated spatio-temporal predictions e.g. catching something when you are moving
95
What does the temporal cortex contain?
Primary auditory cortex
96
Describe the temporal lobe:
-Inferotemporal cortex
-Recognition of faces and objects
-Important role in integrating sensory info from various parts of the body
-Interface between cortex and limbic system - association of affect/emotion with things
97
What does the occipital lobe contain?
Visual cortices
98
What are the two streams of the occipital lobe?
-Dorsal stream - vision for movement
-Ventral stream - vision for identification
99
How does the brain control behaviour?
-Sensory + selection + skill + memory + thought + emotion + motor = behaviour
-All actions will engage a bit of cortex interacting with a bit of basal ganglia, cerebellum and hippocampus all directing brainstem what to do
100
What is dystrophin?
-Large protein
-Confers stability to muscle cell membrane
101
Describe neuromuscular transmission:
102
Describe the basic histology of a peripheral nerve:
103
What does this show?
Axons within nerves can be myelinated or unmyelinated
104
In the PNS what is responsible for the myelin sheath?
-Schwann cells
-Each Schwann cell is responsible for one segment of myelin
-Allows saltatory conduction
105
What lie in between adjacent myelin segments?
-Nodes of Ranvier
-Where depolarisation of the membrane occurs
-Saltatory conduction
106
Describe axonal degeneration/regeneration (Wallerian degeneration):
107
Describe demyelination:
108
What is the range of human hearing?
-20-20KHz
-Range change during life
109
What are the components of the auditory system?
-Outer ear: air
-Middle ear: air
-Inner ear: fluid
-Central auditory pathways
110
What makes up the outer ear?
-Pinna
-Ear canal
111
Describe the pinna:
-Cartilaginous structure
-Formed from pharyngeal arches 1 & 2 (6x Hillocks of His) - 10th to 18th week in utero
-Direct soundwaves towards ear canal
-High pitch > low pitch
112
Describe the ear canal:
-1/3 cartilage
-2/3 bone
113
Label the structures of the outer ear:
114
What is this?
Describe it:
-Tympanic membrane
-8 x 10mm diameter
-84-55mm2
115
What makes up the middle ear?
-Bones: malleus, incus, stapes
-Muscles: tensor tympani, stapedius
-Tubes: eustachian tube
116
What does this show?
Bones of the middle ear
117
What is the role of the middle ear?
Acoustic impedance match between air and fluid-filled inner ear
118
How does the middle ear carry out its role (bones)?
-Amplification of the airborne sound vibration = makes it louder
-Area TM: Stapes 14:1
-Lever action of ossicles - handle of malleus is 1.3x longer than incus process
-Total gain = 20-35Db (18.3:1)
119
What is the increase in pressure generated in the inner ear?
200 fold increase boost in pressure from TM to inner ear
120
What is the role of muscles in the middle ear?
-Protection of the inner ear from acoustic trauma
-Stiffens ossicular chain
-Stapedius stimulated acoustically
121
Describe the nervous control of the muscles in the middle ear:
-Reflex arc: 3 or 4 neurones
-25ms
-Voluntary and involuntary control of tensor tympani
122
What is the role of the eustachian tube?
-Ventilation of the middle ear space
-Drainage of secretions
-Often dysfunctional in children
123
Label the structures of the middle ear:
124
What is contained within the inner ear?
Vestibulocochlear apparatus
125
Describe the vestibulocochlear apparatus and its innervation:
-Set of fluid filled sacs encased in bone
-Cochlear - hearing
-Labyrinth - balance
-Innervation - vestibulocochlear nerve
126
Describe the cochlear:
-2.5 turns
-2 openings (round & oval window)
-3 compartments
-2 ionic fluids
127
What are the 3 compartments of the cochlea?
-Scala tympanin
-Scala media
-Scala vestibuli
128
What are the 2 cochlear fluids?
-Endolymph: High K+
-Perilymph: Like ECF & CSF Na+ rich
129
How are gradients of cochlear fluids maintained?
-Na, K-ATPase
-NKCC1, CIC-K chlorine channels
130
Label this diagram of the cochlea:
131
Describe the basilar membrane:
-Narrow at base - stiff - high frequency detection
-Wide at apex - floppy - low frequency detection
132
Label this diagram to represent movement in inner ear:
What is it called?
Organ of corti
133
What does the basilar membrane cause?
-Displacement of basilar membrane causes movement of specialised mechanical transducing cells
-Hair cells
134
What are the two types of hair cell?
-Inner - mechanical transduction
-Outer - fine tuning
135
What is the structure of the hair cell of the ear?
-Base attached to basilar membrane
-Stereocillia anchored to tectorial membrane
-Shearing forces at sterocillia
136
What does this show?
Inner hair cell
137
What are neurons and their propagation?
-Specialised for electrical signalling
-Mainly formed during development
-Input via dendrite
-AP propagate along axon from axon hillock
138
How do neurones communicate?
-Via synapses
-Chemical - majority: neurotransmitters
-Electrical - less abundant: direct flow of ions that enable synchronized electrical activity e.g. brainstem
139
Describe chemical synaptic transmission:
-Axon potential depolarises synaptic terminal membrane
-Voltage-gated calcium channels open leading to calcium influx
-calcium influx triggers neurotransmitter release
140
What is the structure of an electrical synapse?
-Gap junctions mediate
-Direct movement of ions between two cells
141
Where are excitatory synapses often concentrated?
Dendritic spines
142
What is neural plasticity and why is it important?
-Changes in neuronal/synaptic structure and function in response to neural activity
-Basis of learning and memory
143
Describe features of dendritic spines:
-Dynamic structures - number, size composition
-Spine remodelling linked to neural activity
-Lower spine density linked to disease
144
Describe neuron heterogeneity:
Neurons differ in their:
-Size
-Morphology
-Neurotransmitter content
-Electrical properties
145
What are 2 examples of neuronal heterogeneity?
-Betz cells: upper motor, large, excitatory, long, pyramidal
-Medium spiny neurons: striatal interneurons, small, inhibitory
146
What does this show?
Arborisation of axons and dendrites
147
What are oligodendrocytes?
-Myelinating cells of the CNS
-Provide metabolic support for axons
148
What does myelin do?
-Insulates axon segments enabling rapid nerve conduction
-Myelin sheath segments interrupted by nodes of Ranvier - saltatory conduction
-Provide metabolic support for axons
149
How is the myelin sheath formed?
-Wrapping of axons by oligodendrocyte processes (membranes)
-Highly compacted - 70% lipid, 30% protein
-Myelin specific proteins used as markers
150
What are microglia?
-Resident immune cells of the CNS
-Originate from yolk sac progenitors that migrate to CNS
151
Describe the states and actions of the microglia:
-"resting state" highly ramified, motile processes survey environment
-Upon activation, retract processes, become amoeboid and motile
-proliferate at sites of injury - phagocytic
152
What are 4 features of microglia?
-immune surveillance
-Phagocytosis - debris/microbes
-Synaptic plasticity - pruning of spines
-good M2 and bad M1 microglia
153
What are astrocytes?
-Star like cells
-Most numerous glial cells in CNS
-Highly heterogeneous
-Common marker glial fibrillary acidic protein
154
What are the 5 functions of the astrocyte?
-Structural - define brain micro-architecture
-Envelope synapses
-Metabolic upport
-Neurovascular coupling - changes in cerebral blood flow
-Proliferate in disease
155
What is a nuclei in CNS?
Abundance of cell bodies
156
What do axons gather into and what are these called when they cross the midline in CNS?
-Tracts
-Commissures
157
What is grey matter abundant in?
-Neural cell bodies and processes
-Neutropil contains few cell bodies
158
What is white matter abundant of?
Myelinated tracts and commissures
159
What do cell bodies form in the PNS?
Ganglia
160
What do axons bundle into in the PNS?
Nerves
161
What are many PNS axons enveloped by?
Schwann cells
162
What forms the blood/brain barrier?
-Endothelial cell tight junctions
-Basement membrane (few fenestrations)
-Astrocyte end feet
-Pericytes (contractile-aid blood flow)
163
Describe the blood/brain barrier's features:
-Dyes in blood can't penetrate
-Sensitive to inflammation, hypertension, trauma and ischaemia
-Problem for drug delivery
164
What is special about circumventricular organs in the brain?
-Lack normal BBB
-Homeostatic & endocrine functions
165
What are ependymal cells?
-Epithelial-like
-Line ventricles & central canal of spinal cord
166
What are the functions of the ependymal cells?
-CSF production
-Flow & absorption
-Ciliated to facilitate flow
-Allow solute exchange between nervous tissue & CSF
167
What is choroid plexus?
-Frond-like projections in ventricles
-Formed from modified ependymal cells - villi form around network of capillaries
-Highly vascularised
168
What is the function of the choroid plexus?
-Main site CSF production by plasma filtration driven by solute secretion
-Gap junctions between cells form blood-CSF barrier
169
Describe the conversion of waves to electrical current in the ear:
-Movement of stereocilia
-Rapid response
-Mechanically gated K+ channels open cause depolarisation
-Results in opening of Ca2+ channels
-Neurotransmitter released - glutamate
-Repolarisation through K+ eflux into perilymph
170
What do nerves respond to on a basic level and is this a fully sound model?
Ear
-Each nerve responds maximally at a specific frequency
-Ability to discriminate different frequencies not fully explained in this frequency
171
What can outer hair cells alter and why is this important?
-Alter the stiffness of basilar membrane
-Ensures maximal stimulation at one site and dampened response at another
-Increase resolution
172
How is frequency (pitch) encoded?
In nerves by location along the basilar membrane
173
How is intensity (loudness) encoded?
In nerves by numbers responding and by firing rate
174
How is sound transduction encoded?
Inner hair cells (and OHC)
175
How is sound amplification encoded?
Outer hair cells
176
What is the nerve pathway from the ear to the brain?
-Auditory fibre - spiral ganglion
-Spiral ganglion -> cochlear nerve (VIII)
-Central auditory pathway
177
Label this diagram:
178
Describe the central auditory pathway:
-Cochlea -> brainstem via VIIIth nerve
-Brainstem -> medial geniculate body
-Medial geniculate body -> auditory cortex
179
Label the central auditory pathway:
180
Label the brainstem part of the central auditory pathway:
181
What does ITD stand for?
Interaural Time Differences
182
What is the central auditory pathway?
-8th nerve
-Cochlear nucleus
-Olive
-Lateral leminiscus
-Inferior colliculus
-Medial geniculate
-Auditory cortex
183
What does a defective outer/middle ear cause?
-Conductive hearing loss
-Treatment involves improving conduction or amplification
184
What does a defective inner ear cause?
-Sensorineural hearing loss
-Amplify/stimulate
185
What are the 4 key features of the blood brain barrier?
-Endothelial cell tight junctions
-Lack of BM fenestrations
-Astrocytic end feet
-Pericytes
186
What do these show?
Arterial territories
187
What is venous drainage of the brain?
-Veins drain into sinuses channels between 2 layers of dura
-Superior sagittal sinus
-Inferior sagittal sinus
188
What is the general vasculature of the spinal cord?
-Anterior spinal artery + vein
-Posterior spinal artery + vein
-Anterior + posterior radicular artery
189
What separates anterior vs posterior communication of circulation?
-Anterior = anterior communicating artery
-Posterior = basilar artery
190
Label this diagram:
191
Label this diagram:
192
What does the ventricular system contain?
CSF
193
What does interstitial fluid drain into?
-Into CSF via perivascular channels
Drains back via:
-Via arachnoid granulations
-Peripheral nerves to lymphatics
-Nasal mucosa lymphatics deep cervical lymph nodes
194
What are ependymal cells?
Have cilia to move CSF
195
Where is CSF produced?
Choroid plexus
196
What is this?
Brainstem
197
Label this diagram:
What does it show?
Midbrain
198
Label the cerebellum divisions:
NOT LOBES
.
199
What is the function of the archicerebellum floculonodular lobe?
-Balance
-Connected to vesibular nuclei and reticular nuclei
200
What is the function of the paleocerebellum?
Muscle tone and posture
201
What is the function of the neocerebellum?
Movements, coordination, muscle tone
202
What is the limbic system involved in?
-Memory
-Motivation
-Emotion
-Fight or flight
203
What is the hippocampus involved in?
Laying down memories
204
What is this?
Hippocampus
205
What is the thalamus composed of?
3 main groups of nuclei:
-Sensory relays
-Cerebellar and basal ganglia relays to motor frontal lobe
-Connected to associative and limbic areas of cerebral cortex
206
What does damage to the thalamus result in?
Loss of sensation, pain or movement disorders
207
What are the pathways through the basal ganglia?
Direct and indirect pathways of basal ganglia
208
Describe the hypothalamus:
-Multiple inputs
-Sits on top of pituitary gland and tells it what to do
209
Label this diagram:
210
What is the role of the spinothalamic tract and its pathway?
-Crude touch
-Pain
-Temperature
INPUT PATHWAY
211
What is the role of the corticospinal (pyramidal) tract and its pathway?
Movement
SOLE OUTPUT PATHWAY
212
What is the role of the dorsal column-medial lemniscus pathway?
-Vibrations
-Joint position
INPUT PATHWAY
213
How many extraocular muscles are there and their general functions?
-7 muscles
-Control movement of eyes
-Allow us to move our eyes without moving our head
-Conjugate movements (coordinated movements of both eyes) allow us to form one image
214
Where are the extraocular muscles?
Inside the orbit - attached to the outer surface of the eyeball
215
What is the natural orientation of the orbit?
-Orbit axis is off to an angle
-Does not line up with the optical axis (eye looking straight ahead)
216
What are the 7 extraocular muscles?
-1 lifts upper eyelid = levator palpabrae superioris (LPS)
-6 move eyeball
-4 recti
-2 obliques
217
What 3 cranial nerves are involved in extraocular muscle innervation?
-3 cranial nerves
-CN III -> Oculomotor
-CN IV -> Trochlea
-CN VI -> Abducens
218
How do you remember what cranial nerves innervate what extraocular muscles?
LR6 SO43
-Lateral rectus 6 (abducens)
-Superior Oblique 4 (trochlea)
-All rest 3 (oculomotor)
219
What is the origin and insertion of the extraocular muscles?
-Attached to orbital bones
-Insert onto the sclera (except LPS)
-LPS inserts upper eyelid
220
What does how the extraocular muscles move the eye depend on?
-Where muscle originates
-Where it inserts on eyeball
-Determines which way it will pull eyeball when it contracts
221
What movements of extraocular muscles are possible?
-Some only move eye in one direction
-Some in more than one direction
-Movement of eye involve several muscles acting together
222
Label this diagram of eye movements:
223
What is significant about the direction of muscle fibres of the orbit?
-Apex of orbit lies medially so optical axis does not coincide with orbital axis
-Direction of muscle fibres do not coincide with optical axis
224
What does the levator palpebrae superioris do?
-Inserts into upper eyelid and elevates it
-Innervated by oculomotor nerve (CN III) and sympathetic fibres
225
What can CN III injury cause?
226
Describe the medial and lateral recti muscles:
-Both only one action
-Medial rectus - moves eye medially (adducts)
-CN III
-Lateral rectus - moves eye laterally (abducts)
-CN VI
227
What can oculomotor nerve lesion lead to?
-Medial rectus weak
-Unopposed pull of lateral rectus
-Eye deviates laterally
-Diplopia
228
What can an abducens nerve lesion lead to?
-Lateral rectus weakness
-Unopposed pull of medial rectus
-Eye deviates medially
-Diplopia
229
Describe superior and inferior recti:
-More complex primary and secondary actions
-Superior: 1o elevates eye, 2o and medially rotate
-Inferior: 1o eye, 2o abducts and laterally rotate
-Both CN III
230
Describe super and inferior oblique:
-Superior : 1o medially rotates eye, 2o depresses and abducts
-Inferior: 1o laterally rotates eye, 2o elevates and abducts
231
Do extraocular muscles work by themselves with example?
-No they work together
-Looking down shows antagonistic movements of So and IR
232
Label which muscles provide which ocular movements:
233
What does the inner ear contain?
-Cochlea = sound
-Vestibular apparatus = balance
Vestibular structures:
-utricle and saccule
-3 semicircular ducts containing fluid
234
How are the semicircular ducts orientated?
What do they do?
-At right angles to each other
-Semicircular ducts and utricle contain sense organs for balance
235
What is in the semicircular ducts and what do they drain into?
-Endolymph fluid
-Empty into a sac called the utricle
236
Explain the function of the semicircular ducts:
-Detect movement of the head
-Head moves in one direction
-Endolymph, cupula and hair cells in ampulla bend in opposite direction
-Info sent centrally via 8th CN from right and left semicircular ducts to nuclei in medulla
237
Label these structures:
238
Describe the signal pathways from semicircular ducts when they reach the brain:
-Reach nuclei in brainstem
-Connections control posture, balance and conscious awareness of position
-Nuclei make connections with nuclei of CN III, IV and VI
-Coordinated head and eye movement
239
What is this called?
-Oculocephalic reflex
-Maintain fixed gaze whilst head is moving
240
Describe the oculocephalic reflex:
-Normally when head rotates the eyes move in the opposite direction and the gaze remains fixed
-Used to assess vestibular apparatus and brainstem
-Absent = eyes move in same direction as head = brainstem lesion
241
What is diplopia?
Double vision
242
What happens at the third week of embryonic development?
Gastrulation:
-Ectoderm: skin, NS
-Mesoderm: Notochord, muscular system
-Endoderm: epithelial lining of gut + resp system, liver, pancreas
243
What is the first stage of the development of the spinal cord?
Ectoderm thickens in midline to form the neural plate
244
Describe the formation of the neural tube up until the end of the 4th week:
245
When does the neural tube close?
-Normally at the end of the 4th embryonic week
-Failure to close can cause abnormalities of spinal cord (anencephaly, spina bifida)
NEURAL TUBE DEFECTS
246
What are lateral to the neural groove?
Presumptive neural crest cells
247
Label this diagram:
248
What do cells of the neurual crest go on to form?
-Sensory dorsal root ganglia of spinal cord and V/VII/IX/X
-Schwann cells
-Adrenal medulla
-Bony skull
-Meninges
249
What stages of brain development do these show?
4 and 6 weeks
250
What structures are present in the developing brain at 4 weeks?
-Prosencephalon - cerebral hemispheres & thalamic structures
-Mesencephalon - midbrain
-Rhombencephalon - medulla, pons, cerebellum
251
Label this diagram:
What does it show?
Brain development at 4th week
252
What do microcephaly and macrocephaly mean?
Reduced or increased head circumference
253
What does the CSF circulate through and what is its volume?
-Through subarachnoid spaces and ventricles
-120mLs
254
How is CSF produced and what is its function?
Where is it absorbed?
-Produced as filtrate of blood at choroid plexus in ventricles
-Absorbed via arachnoid granulations in superior sagittal sinus
-Cushions brain and helps circulate metabolites
255
What is hydrocephalus?
-Accumulation of CSF with increased intracranial pressure
-Can cause macrocephaly in children
-Obstructive (non-communicating - tumour, haemorrhage) or non obstructive (increased production)
256
What are the causes and responses in stress?
-Cause = stressor
-Response = stress
257
What is stress?
-As a response it is often characterised as either somatic (physical) or psychological (mind)
-Overlap and mediated by brain
-Preceptions are both somatic and psychological - different connected neuronal networks
258
What is somatic (physical) stress?
-Physical, emotional and subjective experiences
-Associated with damage of body tissue and bodily threat (pain & inflammation)
259
What is psychological stress?
Emotional strain or tension resulting from adverse or demanding circumstances, often involving anticipation
260
What are the two types of stress?
-Eustress (good stress) - beneficial and motivating: striving for a goal
-Distress (bad stress) - damaging and harmful: challenge is not resolved by coping or adaptation
Type of stressor less important than how it is experienced and how bearable
261
Label this diagram of stress:
262
Describe distress (previously psychological stress):
-Any uncomfortable emotional experience accompanied with predictable biochemical, physiological and behavioural changes
-Psychological & somatic responses when we must adapt to changing conditions
-individual perceives environmental demands exceed his adaptive capacity
263
Describe general adaptation syndrome (Selye):
-Stress - the non-specific response of the body to any demand for change
-Stress response in 3 phases:
-Alarm - stressor identified, body's response is state of alarm (fight or flight)
-Adaptation (resistance) - body engages defensive countermeasures
-Exhaustion - body runs out of defenses, resources depleted
264
What is allostasis?
How complex systems adapt (e.g. via SAM and HPA axis) in changing environments by changing set-points (adaptation through change)
265
What is allostatic load?
Cumulative exposure to stressors (and cost to the body of allostasis) which if unrelieved leads to systems 'wearing out'
Continued attempts to restore balance have long-term effects on physiological systems, including structural changes
266
What is acute stress?
-Short-lived response to a novel situation experienced by the body as a danger
-It is healthy & adaptive and necessary for survival
267
What is chronic stress?
Repeated or continued exposure to threatening or dangerous situations, especially those that cannot be controlled
-Some involve appraisal and conscious perception
268
What are important in stress?
Individual differences are important including differences in exposure to & perception of stress, experiences and physiological differences in stress response
269
What are the 5 elements of the human stress response?
-Biochemical
-Physiological
-Behavioural
-Cognitive
-Emotional
270
Describe stress responses:
-Generic and not stressor-specific
-Mediated via autonomic nervous system:
-Sympathetic-adrenal-medullary (SAM) system
-Hypothalmo-pituitary (HPA) axis
LEAD TO CHANGES THAT INFLUENCE FUTURE RESPONSES TO STRESS REFLECTING BRAIN PLASTICITY
271
What is the sympathomedullary pathway of stress?
272
What is the pituitary-adrenal system of stress?
273
What are the biochemical and molecular stress responses?
-Glucocorticoids (cortisol)
-Catecholamines (adrenaline & noradrenaline)
-Inflammation and immune response (important and complex, mediated and modified by adrenaline and cortisol)
274
What is the relationship between stress and immune suppression?
-Acute stress: immune suppression
-Chronic stress: partial immune suppression + low grade inflammatory response; effects on gene expression (balance between immune activation & autoimmunity disrupted in chronic stress response
275
Name some (fast) physiological stress responses:
276
Name some physical (somatic) effects of chronic stress:
277
Name some behavioural responses to stress:
278
name some cognitive responses to stress:
279
Name some emotional responses to stress:
280
What casual pathways are involved in stress?
-Stress is an interaction between person and environment, people vary
-Different parts of the brain mediate responses to different types of stressor
-Amygdala and hippocampus are key
281
What stress events do these show?
282
How are stress and illness related?
-Related to a host of illnesses esp cardio and GI (strong ANS connections)
-Exacerbated physical illnesses and slows recovery + higher susceptibility to infection
283
Is there a lot of evidence between stress and illness?
-Evidence of casual association limited
-Emerging evidence that stress increases immune ageing
-Exposure is greater in those experiencing deprivation and less healthy lifestyles
284
Name some diseases stress could be linked to?
285
What mental illnesses are linked to stress?
-PTSD
-Shell shock
286
What are some symptoms of PTSD?
287
What can help stress management?
288
What is natural selection?
-The differential survival and reproduction of individuals due to differences in phenotype
289
What is fitness?
How successful a organism is at reproducing
290
What is sexual selection?
Competition for mates
291
What is Darwin's theory of evolution?
-Natural selection - observation of more offspring are produced than can survive
-Traits vary (morphology, physiology, behaviour)
-Different survival rates + reproduction + passed on to generations
Darwinism = variation, selection, retention
292
Darwinian or evolutionary medicine in modern application:
-Understand health and disease
-Humans evolved for simple hunter-gatherer in small tribal bands - different. tomodern
-Why are we left with traits vulnerable to disease?
293
How does darwinism fit into evolutionary psychiatry?
-Mental processes naturally selected and important functions
-Evolution heritage lead to mental mechanisms (cognitive, motivational, affective, hedonic, linguistic, behavioural)
-Some mental conditions interfere with ability to perform functions they were selected for
-Disorder in evolutionary psychiatry must refer to dysfunctions that harm person in current environment and social circumstances
294
What does evolutionary psychiatry consider?
-Species perspective with related interests to E-Psych and medicine
-Human social brain evolution and proposes some human psychiatric mechanisms are consequences of adaptations to reproductive problems encountered in Pleistocene environments (Environment for evolutionary adaptation)
295
What are the important focuses of evolutionary psychiatry?
-Not why one individual has illness now
-Focuses on evolutionary significance of psychiatric vulnerability, symptoms and behaviours
296
Why should psychiatry consider evolution?
-Proposes evolutionary theories to account for widespread existence of:
-Substance misuse
-Borderline states and schizo
-Bipolar
-Dementia
-Neurodevelopmnet disorders
297
What is the cycle of Tinbergen's questions?
298
Label the diagram of Tinberg's questions:
299
What are Tinberg's 4 questions?
300
What are proximate and ultimate causation?
-Proximate - event closest responsible for observed result
-Ultlimate - evolutionary results
301
What are the end products of the human brain/mind?
-Behaviour patterns
-Emotions and cognitions
-Phenotypic characteristics of our brains that have been shaped by selection
302
What generate the end products of the brain/mind?
-Brain circuitry
-Genes
-Neurotransmitters
-Subservient systems that have evolved to generate those end products
303
What 5 things are pathways that mediate influence of evolutionary processes on disease vulnerability?
304
What pathways have mediated the influence of evolutionary processes on disease?
-Selected adaptations that help protect against injuries and infection:
-Pain, sickness illness behaviour
-Anxiety, depression
-Fever, lethargy, fatigue
-Nausea
-Itching
-Sneeze, vomit, cough
305
What is smoke detector principle?
-Explains why evolved systems regulating protective responses often give rise to false alarms
-Anxiety and panic attacks whos cost tend to be small relative to possible catastrophic costs if no response is expressed when danger is present
306
What is dunbar's number?
-Cognitive limit on number of people with whom one can maintain stable social relationships
307
What is compassion focused therapy?
-Therapy rooted in evolutionary and neuroscience approach to psychological processes
-Brains designed to function in certain ways, motives, emotions are products. ofevolution
308
what are. the3 types of emotion regulation system?
-Threat and protection
-Drive and excitement
-Contentment, soothing and social safeness
CFT aims on development. ofsoothing and social safeness system
309
What is stereopsis and what is required for it?
-3D vision
-Two eyes
310
How many layers of the eye are there and what are they?
-3
-Outer layer: sclera and cornea
-Middle layer: uvea
-Inner layer: retina
311
What makes up the outer layer of the eye?
-Sclera: tough fibrous outer coat, collagen
-Cornea: also made up of collagen
312
What are the features and function of the outer eye layer?
-light transmission - must be transparent
-Barrier to trauma and infection - tough
-Responsible for ~ 2/3 refractive power of the eye (43D)
313
What are the layers of the outer eye layer?
-5 layers
-Epithelium
-Bownman's layer
-Stroma
-Descemet's layer
-Endothelium
314
Label the layers of the outer layer of the eye:
315
What is the middle layer of the eye made up of?
-Iris
-Ciliary body
-Choroid
316
What is the iris?
-Coloured part of front of eye
-Contains dilator and sphincter pupillae muscles
-Pupillary reflexes
317
What is the ciliary body?
-Glandular epithelium produces aqueous humour
-Ciliary )smooth) muscle controls accommodation
318
Label:
319
What is the choroid?
-Blood supply to outer third of retina
-Heat sink
-Also called uveal tract
320
What makes up the inner layer of the eye?
-Retina
-Specialised organ of phototransduction
-Many layers
321
What main structures make up the retina?
-Macula lutea
-Fovea centralis
-Cones
-Rods
322
What are the layers of the retina?
323
What cells are present in the retina?
-Retinal photoreceptors
-Bipolar cells
-Amacrine & horizontal cells
-Mullers glial cells
-Retinal ganglion cells
324
What does the anterior segment of the eye contain and do?
-Aqueous humour
-Nutrition to lens and cornea
-Maintains intraocular pressure
325
Describe the lens of the eye:
-Biconvex
-Responsible ~ 1/3 refractive power of the eye (~20D)
-Accommodation
326
What is emmetropia?
Naturally occurring clear vision
327
What is hypermetropia?
-Underpowered to focus near objects on retina
-Corneal curvature too shallow
-Lens not flexible enough
-Axial length of eye too short
328
What is myopia?
-Overpowered so can't focus far objects on retina
-Corneal curvature too steep
-Axial length of eyeball too long
329
What is in the posterior segment of the eye?
-Vitreous humour
-Avascular visoelastic gel
-Hyaluronic acid (GAG)
-Collagen
330
What are the adnexae of the eye?
-Lids
-Conjuctiva
-Tear film
331
What are the basic components of all neurons?
-Dendrites
-Cell body/mass
-Axon
-Presynaptic terminals
332
What are the 4 different types of neurons?
333
What are the 2 types of neuronal transmission?
-Axonal
-Synaptic
334
Describe the important property of the neuronal cell membrane:
-Semi permeable
-Potassium and chloride readily permeable
-Sodium crosses with difficulty
-large organic proteins cant cross at all
335
What forces determine distribution of charge ions in a neuron?
-Diffusion
-Electrostatic pressure
336
What is the ion distribution of the neuronal cell?
-A- (anions/proteins) - restricted to inside
-K+ - mostly inside
-Na+ - mostly outside
-Cl- - mostly outside
337
Describe the sodium-potassium pump:
-AT to transport Na+ out and K+ in neuron
-3Na+/2K+
-Energy via ATP
338
What is the result of the sodium-potassium pump?
-Na+ high conc outside both forces pushing in
-Membrane and pump resists inwards Na+
-K+ & Cl- can move backwards and forwards across membrane to reach steady state determined by opposing diffusion and electrostatic pressure
-Some sodium back in but is pumped out
339
What is the final resting potential?
-70mV
340
What is the action potential?
-Neuron fires - sudden pulse where -ve resting potential is temp reversed
-Transmits info
-Depol + threshold
-Reversal of membrane potential
-Repolarisation to resting potential
-Refractory period
341
What is the first stage of an action potential?
342
Describe excitatory neurotransmitters:
-Depolarise the cell membrane
-increases probability of a action potential being elicited
-cause excitatory post synaptic potential (EPSP)
343
Describe inhibitory neurotransmitters:
-Hyperpolarise the cell membrane
-Decrease probability of an action potential being elicited
-Cause inhibitory post synaptic potential (IPSP)
344
When will an action potential be elicited?
-If membrane potential is depolarised beyond the threshold of excitation
345
What region is important in Postsynaptic potentials?
-Voltage charges spread away from point of origin - passive conduction
-Whether AP is generated depends of what reaches the axon hillock
346
What is this?
Axon hillock
347
What happens after the hillock has depolarised?
-ESPSs begin to depolarise cell membrane
-Threshold ~ -60mV
-When reached, Na+ channels open and polarity reverses to +30 inside
348
What does this diagram show?
Describe the process:
349
Describe the lids of the eye:
-Protect globe
-Anterior skin, eye lashes
-Meibomian glands
-Orbicularis oculi
-Tardal plate, tarsal conjuctiva
-Levator palpebrae superioris & sympathetic muscle
350
Describe the conjunctiva:
-Palpebral (tarsal) vs bulbar (ocular)
-Conjuctival fornix
-Limbal stem cells
-Mucous membrane (goblet)
-Lymphoid cells
351
Describe the tear film:
-3 layers
-Anterior lipid, middle aqueous, posterior mucous
-Protective
-Nutrition for cornea
352
What is the basic arterial supply of the eye?
-Internal carotid a. -> opthalmic a.
-Branches of opthalmic a. -> ocular + orbital group
-External carotid a. -> facial a. -> angular artery
353
What arterial supply to the eye is part of of the ocular group?
-Central retinal artery
-Posterior ciliary artery - > long + short
-Muscular artery -> anterior ciliary a.
354
Label the arterial supply to the eye:
355
What are these and what supplies them?
-Anterior ciliary a.
-Muscular artery
356
What arteries are part of the orbital group of the eye?
-Lacrimal a.
-Several other branches supply face and lids
357
What supplies blood to the inner 2/3 of retina?
-Inner 2/3 central retinal a.
-Branches into superior/inferior/temporal/nasal branches
358
What drains venous blood from the retina?
-Branch retinal veins
-Central retinal v.
-Opthalmic v.
-Cavernous sinus
-Internal jugular v.
359
Label the venous drainage of the eye:
360
What supplies blood to the outer 1/3 of the retina?
-Choroid
-Posterior ciliary a. -> choroidal a. -> choriocapillaris
-Blood-retinal barrier at RPE regulates movement of nutrition and solutes from choroid into subretinal space
361
What is the venous drainage of the outer 1/3 of retina?
-Vortex vains drain choroid
-One for each quadrant
-Superior drain to SOV, inferior drain to IOV
362
What do the superior and inferior ophthalmic veins drain into?
-Superior -> directly into cavernous sinus
-Inferior -> pterygoid venous plexus
-Valveless system - orbital cellulitis-facial infection can precipitate cavernous sinus thrombosis
363
Label the drainage of the ophthalmic veins:
364
What is the lymphatic drainage of the eye?
-No lymphatic drainage of globe
-Conjunctiva and lids do have lymphatic drainage to submandibular and pre-auricular nodes
365
What is the structure of rods and cones and their overall function?
-Outer segment contains discs containing light sensitive photopigment
-Inner segment made up of cell body, axon and synaptic terminals
-Phototransduction -> absorb light, send electrical signals
366
Describe photopigments:
-Lies in discs of outer segments
-Rods - rhodopsin
-Cones - opsin
367
Describe opsins:
-Transmembrane proteins which contain light sensitive molecule retinal
-Different opsin structures mean retinal absorbs different wavelengths of light
368
What does this show?
Different opsins absorb different wavelengths of light depending on their structure
369
What is the effect of a photon on a opsin molecule?
-Triggers conformational change to all-trans form
-Triggers changes in opsin structure
-Triggers a cascade within the cell
370
What is the first stage of phototransduction?
-Sodium ions diffuse into rod cells through an ion channel activated by CGMP
-Cells remain in a depolarised state
-Continuous release of neurotransmitter glutamate
371
What is the second stage of phototransduction?
-Retinal in rhodopsin absorbs light and its configuration changes
-Retinal activates transducin
-Transducin creates phosphodiesterase which breaks down CGMP
372
What is the third stage of phototransduction?
-Sodium channels close
-Less sodium enters the cell
-Cells become hyperpolarised due to exit of potassium from cell
-Glutamate release decreases
-Acts as a signal that light stimulus is present
-Arestin blocks rhodopsin from forming transudcin to create back to original state
373
What is the pathway of signals in the retina?
-Photoreceptor -> bipolar cell -> retinal ganglion cell
374
Label the pathway of signals in the retina:
375
First stage?
376
Second stage?
377
Third stage?
378
Fourth stage?
379
All stages?
380
Describe the basics of the visual pathway:
-Temporal & nasal retinas
-Left and right visual field
-Right and left vision made by crossing of fibres
381
Describe the pathways of nerves from the temporal and nasal retinas:
382
383
What is the visual field divided into and where would their pathways go?
-Left and right/ Upper and lower quadrants
384
Result of each of these?
385
What makes up the CNS?
-Brain + spinal cord
-Nuclei = collection of cell bodies in CNS
386
What is the PNS?
-Nervous system outside of CNS
-12 pairs cranial
-31 pairs spinal
-Ganglia = collection of cell bodies
387
Describe the cranial nerves:
-12 pairs
-Peripheral nerves
388
What info and how is transmitted by cranial nerves?
-Sensory/motor/autonomic between brain + head/neck
-Different combinations of fibre types: Motor, general sensory, autonomic)
-Some contain just 1
389
What are the cranial nerve names?
390
What can be used to remember whether cranial nerves are sensory, motor or both?
391
Which cranial nerves contain parasympathetic fibres?
1973
392
Which cranial nerves have nuclei?
-Nerve III-XII
-In the brainstem (MB, pons, MO)
393
What is the function of cranial nerve nuclei?
-Receive sensory/afferent input from periphery (blue)
-Contain cells whose axons convery motor/efferent signal to periphery (red)
-Some nerves with both components have two separate nuclei
-Parasympathetic arise from specific nuclei in brainstem
394
Describe CN1:
-Olfactory
-Function: smell
-Receptors: nasal cavity
-Axons: Trave, through cribriform plate -> olfactory bulb -> tracts -> temporal lobe
-Limbic system connections
395
Describe CN2:
-Optic
-Function: Vision
-Fibres travel from retina to primary visual cortex
396
Describe the optic chiasm:
-Info from nasal retinae decussates
-Info from temporal retinae remains ipsilateral
-Each optic tract contains info from contralateral visual field
397
What are the 4 things to test for CN2 testing?
1. Visual acuity
2. Visual fields
3. pupillary light reflex
4. Fundoscopy
398
What is the pupillary light reflex and what does it involve nerve wise?
-Normal reflex - both pupils constric when light shone in either eye
-Involves CN2 + Cn3
399
What do CN3,4,6 all have in common?
-All eye related
-All motor
-Control extraocular muscles
-Pass through superior orbital fissure to enter the orbit
400
Describe CN3:
-Oculomotor
-Innervates MR, SR, IR, IO, LPS
-Parasympathetic fibres to orbit for pupil constriction
-Midrain nuclei
-Nerves exit at junction between midbrain and pons
401
What are the afferent and efferent for the pupillary light reflex?
-Afferent (input) - CNII
-Efferent (output) - CNIII parasympathetic
402
What are the two different types of pupillary light response?
-Ipsilateral pupil constricts = direct response
-Contralateral pupil constricts = consensual response
403
How can you test CNIII?
-Eye movements
-Pupillary light reflex
-LPS
404
What are signs of lesion/problem with CNIII or pathway?
-Ptosis
-Lateral deviation of eye (unopposed lateral rectus)
-Dilated pupil that does not constrict
405
Describe CNIV:
-Trochlear
-Innervates SO
-Nuclei in midbrain
-isolated lesions rare
-Paralysis of So = diplopia on looking down
406
Describe CNVI:
-Abducens
-Innervates LR
-Nuclei in pons
-Paralysis of LR = medial deviation of eye
407
What is testing for CNVI?
-Paralysis of left LR = medial deviation of left eye
-Able to look right
-Unable to abduct left eye on looking left
408
Describe CNV:
-Trigeminal
-Attached to pons
-3 branches
-All contain sensory fibres -> extensive distribution in head
-Mandibular carrier motor fibres for muscles of mastication
409
What are the three branches of CNV (trigeminal)?
Where do they pass through in the skull?
-Ophthalmic: V1 - superior orbital fissure
-Maxillary: V2 - foramen rotundum
-Mandibular: V3 - foramen ovale
410
Describe the sensory fibres of CNV:
-Carry general sensation (touch, pressure, pain, temp)
-From dura, face and scalp, cornea, nose and mouth
-General sensation of anterior 2/3 of tongue
-Proprioception of TMJ joint
411
How do you test CNV?
-General sensation over the face (compare left and right)
-Test corneal reflex: Between CNV (corneal sensation) and CNVII (muscles of facial expression) - gently touching the cornea should result in blinking
412
Label which nerves innervate these parts of the face:
413
What can CNV pathology cause?
-Anaesthesia over sensory distribution of nerve
-Paralysis of mastication muscles
-Trigeminal neuralgia - pain in face sudden attacks (usually unilateral)
414
Describe CNVII:
-Facial
-Sensory, motor and parasympathetic
-Pontomedullary junction attachment at brainstem
-Two roots
-Complex course through temporal bone
415
What are the two roots of the facial nerve?
-Medial - motor fibres
-Lateral - sensory and parasympathetic fibres (nervus intermedius)
416
What do the different fibres of CNVII innervate?
-Special sensory - taste anterior 2/3 tongue
-Motor - muscles of facial expression
-parasympathetic - lacrimal gland, submandibular and sublingual glands
-Within parotid, terminal part divides into 5 branches
417
How can you test CNVII?
-Special sensory - taste senasion in anterior 2/3 tongue, lacrimation (dry eye)
-Motor:
-Observe face for weakness, asymmetry
-test muscles of 5 branches - frown = raise eyebrows, screw eyebrows, puff cheeks, smile
418
What injury/pathology can occur for CnVII?
-idiopathic (bells palsy) - nerve inflammation
-Tumour of parotid gland
-Acoustic neuroma
-Middle ear infection
-Wher it is depends on what branches are affected
419
What can be confused to do with pathology of CNVII?
-Stroke and Bell's palsy
-Stroke affects primary motor cortex
420
Describe the motor cortex in terms of facial movement:
-Part of motor cortex is dedicated to upper face and lower face
-Cell bodies of UMN reside in motor cortex
-Axons travel to facial motor nuclei in pons
421
Describe the motor neurons of the upper and lower face:
-UMN axons synapse with LMN cell bodies at facial motor nuclei (pons)
-Axons of UMN for upper and lower face cross midline and synapse with contralateral (opposite) facial motor nucleus
-facial motor nucleus also receives input from ipsilateral motor cortex which controls upper face
422
How can you tell between a UMN and LMN lesion with facial weakness?
-If UMN on one side are injured:
-Lower contralateral weakness
-Upper contralateral face not weak as it has dual innervation from both sides of motor cortex
-facial nerve lesion = all ipsilateral facial muscles weak
423
3 differences between somatic and autonomic nervous system:
424
What are the main systems of the parasympathetic nervous system?
425
What are the basic systems of the sympathetic nervous system?
426
What is the main difference between somatic and autonomic motor neurons?
-Somatic - 1 neuron from spinal cord to effector
-Autonomic - Ganglion with two neurons (pre and post ganglionic)
427
What are the neurotransmitters for somatic and autonomic motor neurons?
428
Are pre and postganglionic fibres myelinated?
-Pre - yes
-Post - no
429
What are the main functions of the autonomic nervous system?
-Thermoregulation
-Exercise
-Digestion
-Competition
-Sexual function
430
What effect does sympathetic NS have on heart, blood vessels, lungs and GIT?
431
What effect does parasympathetic NS have on heart, blood vessels, lungs and GIT?
432
Outputs of the ANS?
1. Parasympathetic
-Cranial outflow
-Sacral outflow
2. Sympathetic
3. Enteric
433
Where do parasympathetic fibres communicate via?
-'hitch a ride' on cranial nerves 3, 7, 9, 10
-Apart from sacral outflow, S1, 2
434
What do Sympathetic fibres communicate via?
-white and grey rami communicates, sympathetic chain
-splanchnic nerves to large thoraco-abdominal plexi
435
What does this show?
Sympathetic pathway
436
Label this autonomic pathway:
437
438
Describe the pathway of the sympathetic chain:
439
What is the white rami comunicantes?
Connect spinal nerve to sympathetic trunk
440
What part of the autonomic nervous system causes fight or flight?
Sympathetic interaction on adrenal medulla causing massive amplification
441
What is this?
Parasympathetic pathway
442
Label this parasympathetic pathway:
443
What is the cranial outflow pathways? (parasympathetic)
-Preganglionic fibres via:
-Cn III, VII, IX, X
-Cell bodies located in cranial nerve nuclei in the brains stem
444
Describe the basic pathway of the enteric nervous system:
445
What are the receptors and neurotransmitters of the autonomic nervous system?
446
What are the basic sub-types of noradrenaline receptors?
Alpha (1 + 2)
Beta 1-3
447
Is there just one receptor type of adrenergic receptor?
No, there are various different sub-types for each system of the body
448
What goes into the brainstem nuclei of the autonomic nervous system?
Various inputs
449
What is one of the most important receptor input of the autonomic nervous system?
-Carotid sinus receptors
-Baroreceptors
-Chemoreceptors
-Feedback
450
Describe the basics of the autonomic cardiovascular control:
451
What are the two basic groups of autonomic nervous system issues?
Primary - pure autonomic failure (parkinsons)
Secondary - alcohol induces, diabetes etc...
452
How can you test autonomic nervous system?
-Heart rate, blood pressure (beat by beat)
-Head up tilt test HUT
-Pupillometry
-Sweat measurement
453
What is pain affected by?
-Biological
-Psychological
-Social factors
454
What is the psychological background to pain?
-All pain is real and doesnt require actual tissue damage
-Brains way of telling us it thinks you are in danger
455
What components make up the cycle of pain in the body?
456
What is DIM and SIM in terms of pain?
-DIM - danger in me
-SIM - safety in me
457
How is pain created psychologically in the moment?
More credible evidence of DIM than SIM
458
What can happen with pain in the long term?
-Sensitisation
-Catastrophic thinking
-Injury = high consequence
459
Describe acute pain:
-Warning to protect from further physical damage
-Usually explained and treated
-temporary
460
Describe chronic pain:
-No useful warning purpose
-Usually no diagnosis or explanation
-Widespread and ongoing effect
461
What are the two common pathways of pain and activity?
-Take it easy trap
-Activity cycling
462
What are the three Ps of pain management?
-Pacing
-Prioritising
-Planning
463
464
What is this?
Motor cortex
465
466
What are features of lower motor neuron disorders?
-Weakness-flaccid
-Reduced tone
-Muscle wasting
=Absent deep tendon reflex
-Fasciculcations
467
What does this diagram show and label it
468
What do basal ganglia do?
-Process all information from vast amount of afferent info from muscle spindles
469
What is the physiology behind motor control?
470
What stimulates and inhibits basal ganglia?
471
What does this show?
Grey matter
Cell bodies of motor neurosn
472
Are peripheral neves motor or sensory?
Both!
473
What fibres do peripheral nerves carry?
-Motor and sensory
-Some carry autonomic fibres
Pathology can be axonal, demylination or both
474
475
Describe the steps of a neuromuscular junction:
476
What are the first 3 steps of neuromuscular junction?
477
What are the second three stages of neuromuscular junction?
478
What causes myasthenia gravis?
479
What makes up a skeletal muscle?
480
481
482
What do the light and dark bands look like during the cycle of skeletal muscle contraction?
483
What is the theory of skeletal muscle contraction called?
What are the different parts of it?
Sliding filament theory
484
What are the first two parts of sliding filament theory?
485
What are the third and fourth parts of the sliding filament theory?
486
487
How many muscle fibres make up a muscle and what is the structure of the fibres (general)?
488
What is this and what does it make up?
489
What makes up a myofibril?
490
491
492
493
494
What are association fibres?
White matter tracts connecting different parts of the same hemispheres?
495
496
What are the blue, green and red fibres called?
-Blue = association
-Green = commisural
-Red = projection
497
498
499
500
501
502
503
504
What is the insula and opercula?
-Floor of the lateral sulcus
-Disgust, emotion, homeostasis
505
What is this?
506
What are the main functions of the frontal lobes?
-Motor functions
-Problem solving
-Memory/judgement
-Impulse control
-Higher cognitive function
-Language
-Executive function
507
What is the visual representation of the motor cortex?
508
What is this?
509
What are the functions of the temporal lobes?
-Semantic processing (meaning and identity of things)
-Memory
-Language
-Primary auditory cortex
510
What is this?
511
What are the functions of the parietal lobes?
-Somatosensory
-Dominant perception (usually left)
-Language and mathematics
-Non-dominant (usually right)
-Visuospatial function
512
What is this?
513
What is the function of the occipital lobe?
Visual
514
How many layers does the neocortex have?
6
515
What are the inputs and outputs of the neocortex?
-Inputs:
-Cortical areas
-Input from thalamus
-Projections:
-Other cortical areas
-Brainstem and spinal cord
-Thalamus
516
What are Brodmann areas?
52 regions of the brain defined by their cytoarchitecture
517
What are these different areas:
-Green = Broca's area
-Blue = Wernicke's area
-Yellow = corpus callosum
518
Describe brain asymmetry:
-Dominance of the brain
-Overall left posterior and rightward anterior asymmetry
519
First layers of the coverings of the brain?
520
What are these levels of the coverings of the brain?
521
522
523
524
525
What does the arachnoid mater form?
Arachnoid cisterns
526
What are the key elements of the blood brain barrier?
-Endothelial cell tight junctions
-Lack of BM fenestrations
-Astrocytic end feet
-Pericytes
527
528
Label the vessels in red:
529
Label the vessels in blue:
530
Draw the loop of Henle:
531
What are these?
-Arterial territories
-Different areas of the brain separated based on their arterial supply
532
533
534
535
What do ependymal cells do?
-Epithelial layer lining the ventricles of the brain
-Function in the flow of cerebral spinal fluid
536
What is this mode of CSF drainage?
IMPORTANT
537
What is this mode of CSF drainage?
538
What is this mode of CSF drainage?
539
What is this mode of CSF drainage?
540
Label the blue:
541
label the yellow:
542
Label the yellow:
543
Label the green:
544
Label:
545
Label the purple:
546
Label the red:
547
Label the green:
548
Label the green:
549
Label the pink:
550
Label the pink:
(inferior pons)
551
Label the blue:
(inferior pons)
552
Label:
553
554
555
556
What is the archicerebellum and its connections?
-(oldest) flocculonodular lobe
-Balance
-Connected to vesibular nuclei and reticular nuclei
557
What is the paleocerebellum and its connections?
-Quite old
-Muscle tone and posture
-Afferent:
-Dorsal spinocerebellar tracts via inf cerebellar peduncle
-Ventral SC tract via superior CP
-Efferent:
-Globose and emboliform nuclei to red nucleus to rubrospinal tract
558
What is the neocerebellum and their connections?
-More complicated movements (coordination, muscle tone)
Afferent:
-Cerebral cortex to pontocerebellar fibres (decussate) via MCP
Efferent:
-Purks to dentate to red nucleus & ventral thalamus via SCP
559
Label the orange:
560
Label the green:
561
What are the conscious and unconscious tracts of the spinal cord?
Conscious -> DCML pathway and spinothalamic pathway
Unconscious -> spinocerebellar
562
What does the DCML pathway carry and how?
-Fine touch, vibration and proprioception
-Info travels via dorsal columns in spinal cord and. is transmitted through medial lemniscus in brainstem
563
What are the first order neurons of the DCML pathway?
-Sensory info from peripheral nerves to medulla
-upper limb = fasciculus cuneatus = nucleus cuneatus
-lower limb = fasciculus gracilis = nucleus graciilis
564
What are the second order neurons of the DCML?
-From cuneate gracilis nuclei fibres carry infor to 3rd order neurons
-Decussate in medulla -> contralateral thalamus
565
What are the third order neurons of the DCML?
-Transmit sensory info to thalamus and ipsilateral primary sensory cortex
566
Describe the spinothalamic tracts:
-Anterolateral system
2 tracts:
-Anterior spinothalamic tract - crude touch + pressure
-Lateral spinothalamic tract - pain + temp
567
What are the first order neurons of the spinothalamic tracts?
-Arise from sensory receptors in periphery
-Enter spinal cord and synapse in tip of dorsal horn
568
Describe the second order neurons of the spinothalamic tracts:
-Carry info from dorsal horn to thalamus
-fibres decussate in spinal cord
569
Describe the third order neurons of the spinothalamic tracts:
-From thalamus to ipsilateral primary sensory cortex
-pathways same for both tracts
-Alongisde each other
570
571
Describe the spinocerebellar tracts:
-Group of tracts carrying unconscious proprioceptive info
-Carried from muscles to cerebellum
-4 types
572
Describe the 4 spinocerebellar tracts and what they do:
-Posterior - lower limbs to ipsilateral cerebellum
-Cuneocerebellar - upper limbs to ipsilateral cerebellum
-Anterior - lower limbs to ipsilateral cerebellum, decussate twice
-Rostral - upper limb to ipsilateral cerebellum
573
What is the overview of the descending tracts?
-Pyrimidal tracts -> originate in cerebral cortex and carry motor fibres to spinal cord and brainstem (voluntary muscle control)
-Extrapyramidal tracts -> originate brainstem and carry motor fibres to spinal cord (involuntary and autonomic control of muscles)
574
Describe the corticospinal tracts:
-Pyramidal
-begins in cerebral cortex
-Inputs: primary motor cortex, premotor cortex, supplementary cortex
-Cortex -> descend internal capsule -> crus cerebri -> pons -> medulla
-Caudal medulla tract divides into 2
575
Describe the lateral and anterior corticospinal tracts:
-Lateral decussates then descends terminating in ventral horn
-Anterior remains ipsilateral to spinal cord and decussates and terminates in ventral jorn of upper thoracic levels
576
Describe the corticobulbar tracts:
-Pyramidal
-Begins in lateral primary motor cortex
-Inputs same as corticospinal
-Cortex -> descend internal capsule -> crus cerebri -> brainstem -> terminate motor nuclei of cranial nerves (facial + neck muscles)
-most fibres innervate motor neurons bilaterally except facial and hypoglossal
577
Describe the exceptions of the corticobulbar tracts:
Facial nerve:
-Contralateral innervation
-Only affects muscles in lower quadrant of face
Hypoglossal:
-Only contralateral
578
Describe the extrapyrimidal tracts:
-Originate in brainstem
-4 in total
-Rubrospinal and tectospinal decussate - others dont
579
Describe the vistibulospinal tract:
-Arise vestibular nuclei
-Medial and lateral tracts
-Supply ipsilateral info
-Control balance and posture
580
Describe the reticulospinal tract:
-Medial tract arises from pons
-Facilitate voluntary movements
-Increase muscle tone
-Lateral arise from medulla
-Inhibits voluntary movement
-Reduces muscle tone
581
Describe the rubrospinal tract:
-Arises red nucleus
-Decussate and then descend
-Role in fine control of hand movement
582
Describe the tectospinal tract:
-Arises superior colliculus
-Decussate then enter spinal cord
-Coordinates movements of the head in relation to vision stimuli
583
What fibres does CNVII contain and where are they connected to the brain?
-Sensory, motor and parasympathetic fibres
-Attached to the brainstem at the pontomedullary junction
584
What are the roots of CNVII?
Has two roots:
-Medial - motor fibres
-Lateral - sensory and parasympathetic fibres (the nervus intermedius)
-Complex course through temporal bone
585
What are the 3 fibre types of CNVII?
Special sensory - taste anterior 2/3 tongue
Motor - muscles of facial expression
Parasympathetic - lacrimal gland, submandibular and sublingual salivary glands
586
How can you test CN VII?
-Taste sensation of anterior 2/3 tongue
-Lacrimation (dry eye)
Motor:
-Observe facial weakness
-Muscles of expression
587
What kind of nerve is CNVIII?
Sensory nerve
588
Describe the vestibular afferents:
-Go to vestibular nuclei
-Connections to spinal cord, cerebellum, nuclei of CN III, IV and VI
-Cerebral cortex for posture, balance, eye movement, conscious perception of position of head
589
Describe the cochlear afferents:
-To 2 cochlear nuclei
-Primary auditory cortex (superior temporal gyrus) - conscious perception of sound
-Auditory association cortex (Wernicke's area) - interpretation
590
How can you test CNVIII?
Testing cochlear component:
-Crude testing - covering each ear and whispering into the other
Vestibular:
-Observing balance and gait
-Caloric testing
591
What fibres are in CN IX?
-Sensory, motor and parasympathetic fibres
-Attached to medulla via several small rootlets
592
What are the functions of the CN IX?
-Taste - posterior 1/3 of the tongue
-General sensation (touch, temp, pain) of:
-pharynx
-eustachian tube
-posterior 1/3 of tongue
-Afferents from carotid sinus (baroreceptors) and carotid body (chemoreceptors)
Parasympathetic fibres -> parotid gland
593
What fibres are in CNX?
-Sensory, motor and parasympathetic fibres
-Attached to the medulla via several small rootlets
594
Describe the sensory aspect of CNX:
-General sensation to pharynx, larynx, oesophagus, EAM, tympanic membrane
-Visceral afferents - thoracic and abdo viscera
-Afferents from the aortic bodies (chemoreceptors) and aortic arch (baroreceptors)
595
Describe the motor and parasympathetic fibres of CNX:
-Motor -> soft palate, pharynx and larynx - vital for swallowing and speech
-Parasympathetic - thoracic and abdo viscera
596
How can you test CNX?
Patient's voice:
-hoarseness or nasal sound
-elicit the gag reflex (afferents = IX, efferents = X)
-Elevation of palate ('ah')
597
What kind of nerve is XI?
Motor nerve
598
What are the parts of CN XI and their functions?
Cranial part: Rootlets arise from the medulla and leaves via the jugular foramen by joining vagus
Spinal part: From ventral horn spinal cord C1-5
-Travels up through foramen magnum
-Leaves again through jugular foramen
-Innervates sternocleidomastoid and trapezius
599
how can you test CN Xi?
Test SCM - turn head against resistance
-Trapezius - symmetry / atrophy?
600
Describe CNXII:
-Motor nerve -> muscles of the tongue
-Arises from the medulla, leaves through the hypoglossal canal
601
How do you test CNXII?
-Ask patient to stick their tongue out
-Deviation of tongue on one side?
-In lesion, ipsilateral tongue muscles are paralysed - contralateral musles still function and push tongue to weak side
602
What are the 3 types of pain?
-Nociceptive - actual damage to non-neural tissue (nociceptors)
-Neuropathic - lesion or disease of somatosensory NS
-Nociplastic - altered nociception despite no clear evidence of actual of threatened tissue damage (activation of peripheral nociceptors)
603
What is allodynia?
Pain due to a stimulus that does not normally provoke pain
604
What is dyesthesia?
Unpleasant abnormal sensation whether spontaneous or evoked
605
What are hyperalgesia and hypoalgesia?
-Hyper - increased pain from a stimulus that normally provokes pain
-Hypo - diminished pain in response to a normaly painful stimulus
606
What are hyperalgesia and hypoalgesia?
-Hyper - increased pain from a stimulus that normally provokes pain
-Hypo - diminished pain in response to a normaly painful stimulus
607
Describe the pain pathway generally (diagram):
608
Describe the different nerves in the sensory pain response:
609
610
What are nociceptors?
-Peripheral receptor for the pain system
-NOT simple touch and temperature which have their own specialised receptors cells
-Simply the free nerve endings of A-delta and C fibres (primary afferent neurons)
611
What is a special trait of nociceptors?
-Poly-modal
-Thermal/chemical/mechanical)
612
Describe the activation thresholds of nociceptors:
-Activation thresholds for mechanical and thermal stimulation are high compared to mechanoreceptors and thermoreceptors
-Extremes of pressure and temperature activate nociceptors
613
What are the types of nociceptors and where are they found?
-AΔ fibres
-C fibres
-Found in any area of the body that can sense pain either externally or internally
-External: skin/cornea/mucosa
-Internal: viscera/joints/muscles/connective tissue
614
Where do nociceptor cell bodies lie?
Either in:
-Dorsal root ganglion (body)
-Trigeminal ganglion (face/head/neck)
615
What are the two nociceptors responsible for?
A-delta - mediate initial fast pain of injury (protective withdrawal reflex)
C - dull, throbbing pain that accompanies inflammation following injury
616
What is the third type of nociceptor?
-Visceral nociceptors
-Similar to the other 2 types found in periphery
-Respond to distention and ischaemia rather than cutting and thermal damage
-Carried by alpha-delta and C fibres
617
Describe the dorsal root ganglion:
-present on dorsal root (sensory)
-comprised of cell bodies of nerve fibres that are sensory
-first order neurons
-pseudo-unipolar neurons
-can be source of pain pathology
618
What is the equivalent of the dorsal root ganglion of the head/neck?
Trigeminal ganglion is the equivalent for the face/head
619
What is the equivalent of the dorsal root ganglion of the head/neck?
Trigeminal ganglion is the equivalent for the face/head
620
621
What info is carried in the different types of sensory nerve fibres?
622
Describe the myelination of different sensory fibres:
623
Describe how diameter and speed differs between different sensory fibres:
624
What is this and describe it:
-Dorsal horn
-Posterior aspect of SC grey matter forms two horns called dorsal horns
-Contain distal nerve endings of primary afferents and cell bodies of second order neurons
-Also excitatory and inhibitory interneurons that transmit somatosensory info from the SC to brain
625
What do alpha-delta and C fibres do in the dorsal horn?
A-delta afferents synapse directly with secondary afferent which carry signal to thalamus
C fibres connect to secondary afferents via interneurons which are important in modulation of the pain signal
626
How do visceral afferents differ from a-delta and c fibres in the dorsal horn?
-Fewer primary afferents activate a larger number of second order neurons, resulting in poorer localisation of pain
-Also converge with somatic inputs, may account for referred pain
627
How do visceral afferents differ from a-delta and c fibres in the dorsal horn?
-Fewer primary afferents activate a larger number of second order neurons, resulting in poorer localisation of pain
-Also converge with somatic inputs, may account for referred pain
628
629
What are spinothalamc tracts?
-Sensory that carries pain, temperature and crude touch info from the body
-2nd order neurons
-Originate in spinal cord (substantia gelatinosa and nucleus proprius)
630
Describe the pathway of spinothalamic tract (STT):
-ORIGINATE SPINAL CORD
-DECUSSATE AT OR FEW LEVELS ABOVE THE SITE OF ENTRY (SPINAL SEGMENT)
-CROSS MIDLINE IN ANTERIOR COMMISSURE
-FORM ANTEROLATERAL TRACT
-TERMINATE IN THALAMUS (VENTRAL POSTERIOR LATERAL NUCLEUS)
-SOME AXONS TERMINATE IN RETICULAR FORMATION AND MIDBRAIN
631
What spinothalamic tracts carry what info?
-Lateral STT - pain + temp
-Anterior STT - crude touch
632
633
Describe the lateral spinothalamic tract:
-Neospinothalamic tract
-Runs superficially in the anterolateral white matter cord
-Ascends directly to the lateral thalamus
-Carries sensory, discriminative part of pain signal
634
Describe the medial spinothalamic tract:
-Paleospinothalamic tract
-Deeper in the cord, sending collaterals to the reticular activating system, periaqueductal grey and hypothalamus before terminating in medial nucleus
-General arousal and sversive component of pain experience
635
636
Describe the basics of the thalamus and its function:
-Midline paired symmetrical structure
-All sensations except olfactory relay/pass through
-Multiple nuclei: CPL, Medial group
-Reciprocal connections to all parts of cortex
637
What do the thalamic nuclei contain in the pain pathway and what do each do?
-Cell bodies of third order neurons - projetions which make up the final part of the nociceptive pathway
-Medial nuclei - emotional component
-Lateral nuclei - sensory component
638
What is this?
-Sensory cortex
-Brodmann area 3, 1, 2
-Every area on the body is represented in a spatial fashion sensory homonculus
639
What is the pain matrix?
-Certain areas are consistently activated in response to painful stimulus
-From the thalamus, third order neurons make multiple connections to the somatosensory crtices and deeoer midbrain structures
-Important ones are limbic system and anterior cingulate cortex
640
What is this and what does it do? (pain)
-Insula
-Degree of pain is judged
-Subjective aspect of pain perception
-Perception, motor control, self-awareness and interpersonal experience
641
What role does the amygdala play in pain and why?
-Learned emotional responses
-Important for emotional-affective dimension of pain and for pain-modulation
642
Describe the cingulate cortex and its aspect of pain:
-Medial aspect of cerebral hemispheres
-Linked with limbic system and associated with emotion formation and processing, learning and memory
-Maintains reciprocal connections with other pain processing areas
643
Describe peri-acqueductal gray, particularly with pain:
-Grey matter around cerebral aqueduct
-Input from cortical and sub-cortical areas
-Projects onto neurons in dorsal horn
-Bear opioid receptors
-Pathways include noradrenergic and serotonergic neurons
644
What can stimulus of the PAG result in?
Profound analgesia
645
Where do different pain-killers target?
