neuro important Flashcards
1
Q
what does the arterial system of the brain originate from ?
A
internal carotid - anterior portion = 80%
vertebral arteries - posterior portion = 20%
2
Q
where are berry aneurysms most likely to form?
A
the junctions/connections between branches in the circle of Willis
3
Q
roughly what area of the brain does the anterior cerebral artery supply
A
anterior and middle portion of brain
4
Q
roughly what area of the brain does the middle cerebral artery supply?
A
lateral sides of brain
5
Q
roughly what area of the brain does the posterior cerebral artery supply ?
A
posterior portion of brain - occipital and some of temporal lobe
6
Q
what would be the effect of a lesion of the ACA
A
loss of contralateral motor and sensory functions of lower limbs
7
Q
what would be the effect of a lesion of the MCA
A
contralateral motor and sensory functions of upper limbs and face (+ Broca’s aphagia)
8
Q
what would be the effect of a lesion of the PCA
A
Vision (leads to opposing side homonymous hemianopia with Macular sparing)
9
Q
what structures are found in the cavernous sinus
A
(O TOM CAT) Oculomotor Trochlea Opthalmic Maxilliary Carotid (internal) Abducens (Trochlea)
10
Q
what is cranial nerve 1 and what is its function
A
olfactory
smell
11
Q
what is the pathway of CN I
A
olfactory epithelium -> olfactory bulb -> olfactory tract -> primary olfactory cortex (+ limbic system)
12
Q
what type of fibre is CN I (olfactory)
A
sensory
13
Q
what is CNII and what is it’s function
A
Optic
vision and sensory fibre for the pupillary light reflex and accommodation reflex
14
Q
what type of fibre is CN II (Optic)
A
sensory
15
Q
what is CN III and what is its function
A
Oculomotor
eye movement, pupillary light reflex and accommodation reflex
16
Q
what type of fibre is CN III (oculomotor)
A
somatic motor
Oculomotor nucleus -> extraocular muscles except LR6SO4
autonomic motor/parasympathetic
Edinger-Westphal Nucleus -> ciliary ganglion -> ciliary muscles + sphincter pupillae
17
Q
what is CN IV and what is its function
A
Trochlear
eye movement - superior oblique
18
Q
what is the pathway of CN IV
A
Posterior Midbrain -> exits posteriorly -> loops round anteriorly -> SOF -> SO
19
Q
what type of fibre is CN IV
A
motor
20
Q
what is cranial nerve V and what are its branches
A
Trigeminal
opthalmic, maxillary, mandibular
21
Q
describe the pathway of CN V
A
4 Nuclei along brainstem -> Trigeminal ganglion (Meckel’s cave) -> 3 branches
22
Q
what kind of fibres make up CN V
A
Both
motor (muscles of mastication)
somatic sensory (pain, touch, temp, proprioception)
23
Q
what are the functions of the V1-opthalmic branch of CNV
A
Somatic sensory: upper face, eyelids, lacrimal gland, and Ethmoid sinus
Autonomic sensory: sensory fibres for corneal reflex
24
Q
what are the functions of the V2-maxillary branch of CNV
A
Somatic sensory: maxillary portion of face, upper teeth and lips, and nasopharynx
25
what are the functions of the V3- mandibular branch of CNV
Somatic sensory: mandibular region of the face, ant anterior 2/3 of the tongue, lower teeth and lips, external ear
Somatic motor: muscles of mastication, Tensor tympani, tensor veli palatini, Mylohyoid, Ant. Belly of DIgastric
26
what is CN VI and what are its functions
Abducens
| eye movement - lateral rectus
27
describe the pathway of CN VI
Nucleus in pons anterior to facial colliculus -> exits through ponto-medullary junction -> SOF -> LR
28
what kind of fibres make up CN VI
motor
29
what is CN VII and what are its functions
facial
Sensory function: taste anterior 2/3 tongue, somatic sensation of external and middle ear
Motor function: Stylohyoid, Stapedius, post. Belly of Digastric, Muscles of facial expression
Autonomic motor function: motor - corneal reflex, lacrimal gland, Nasal gland, sublingual and submandibular salivary glands
30
what kind of fibres are in CN VII
sensory
motor
parasympathetic
31
what is CN VIII and what are its functions
vestibulocochlear
| sound, balance
32
describe the pathway of CN VIII
Organ of corti/Vestibular system -> Vestibular ganglion, spiral ganglion-> CN VIII -> IAM -> into ponto-medullary junction lateral to 6 and 7
33
what is cranial nerve IX and what are its functions
glossopharyngeal
Sensory: Pharynx, soft palate, external ear, posterior 1/3 of tongue, carotid sinus and body
Motor: stylopharyngeus
Parasympathetic: parotid gland
34
what is the origin of CN IX
3 nuclei in medulla
35
what fibres does CN IX carry
both motor and sensory + parasympathetic
36
what is CN X and what are its functions
vagus
Sensory: aortic arch, thoracic viscera, larynx, Abdominal Viscera, External ear and epiglottis (taste)
Motor: muscles of soft palate (swallowing), pharyngeal muscles (swallowing), and Laryngeal muscles (speech)
Parasympathetic: Thoracic viscera, GI tract
37
what is the origin of CN X
medulla
38
what fibres does CN X carry
both motor and sensory + parasympathetic
39
what is CN XI and what are its functions
accessory nerve
Cranial: accessory to CN X in innervating the Pharyngeal muscles
Spinal: sternocleidomastoid, trapezius
40
what is the origin of CN XI
Cranial component: medulla; Spinal component: C1-C5
41
what type of fibres does CN XI carry
motor
42
describe the pathway of CN XI
Spinal component the brain via the Foramen Magnum -> meets up with the cranial component -> exits via the Jugular Foramen
43
what is CN XII and what are its functions
hypoglossal
| muscles of tongue
44
what kind of fibres does CN XII carry
motor
45
what is the origin of CN XII
hypoglossal nucleus – medulla
46
what does the spinal trigeminal nucleus do
Receives sensory innervation from the face (CN V, VII, IX and X)
47
what is the nucleus ambiguus
Motor nucleus for muscles of the pharynx and Larynx (CN IX, X and XI)
48
what is the solitary tract nucleus
Taste nucleus (CN VII, IX and X)
49
describe the anatomy of the outer eye
Sclera (white part of eye)
| Cornea (first point of refraction)
50
describe the anatomy of the middle eye
Iris: contains the sphincter pupillae, dilator pupillae
Choroid
Ciliary body: ciliary muscles and suspensory ligaments
lens
51
describe the anatomy of the inner eye
Retina: detect light
Outer pigmented layer: contains melnin
Inner neural layer – photoreceptors, light transduction, vit A storage
52
action of lateral rectus
abduction
53
action of medial rectus
adduction
54
action of superior rectus
elevation, adduction and intorsion
55
action of inferior rectus
Depression, Abduction and extorsion
56
action of superior oblique
Intorsion, abduction, depression
57
action of inferior oblique
Extorsion, abduction, Elevation
58
what are the 2 synergistic pairs of eye muscles
SR + IO
| IR + SO
59
what is the effect of a CN III palsy
Depression and abduction of eye (down and out)
| Eye lid drooped down
60
what is the effect of a CN VI palsy
cant laterally rotate (abduct) eye
61
what is the effect of a CN IV palsy
eye extorted - appears slightly elevated
62
what parts of the ear are fluid or air filled
```
External ear (air-filled)
Middle ear (air-filled)
Inner ear (fluid-filled)
```
63
what are the aspects of the external ear
auricle, external acoustic meatus, tympanic membrane
64
what is the function of the auricle
directs sound into the external acoustic meatus
65
what is the function of the external acoustic meatus
Transmits sound into the tympanic membrane
| Contains cerumen: prevents pathogens and insects from reaching the tympanic membrane
66
what is the function of the tympanic membrane
Vibrates in response to sound -> transmits vibrations to ossicles
Separates external ear from middle ear
Attaches onto the Malleus bone
67
what are the components of the middle ear
ossicles, muscles (stapedius, tensor tympani), eustachian tube, oval window
68
describe the direction of vibrations through the ossicles
Malleus -> Incus -> Stapes -> Oval window -> inner ear
69
what does the stapedius do
dampens the stapes to prevent excess vibration in response to loud sound
70
what does tensor tympani do
tenses the tympanic membrane to prevent excessive vibrations -> dampens loud sounds
71
what does the eustachian tube do
Tube: connects middle ear to nasopharynx and equalises pressure either side of the tympanic membrane -> Empties middle ear secretions into nasopharynx
72
what does the oval window do
transfers mechanical vibrations from the middle ear into fluid filled vibrations in the inner ear
73
what are the components of the inner ear
semi-circular canals, vestibule, cochlea
74
function of semi-circular canals
Detects changes in dynamic equilibrium
75
role of vestibule
Utricle and saccule
| Detects changes in static equilibrium
76
components of cochlea
Scala vestibuli
Scala media/Cochlear duct- Organ of Corti
Scala tympani
77
what is the function of the basal ganglia
Execution of smooth movements – aka. Fine tunes movement plan
Stimulates desirable movement
Inhibits undesirable movement
Modulates movement
78
what makes up the striatum
caudate nucleus + putamen
79
what makes up the lentiform nucleus
globus pallidus + putamen
80
what are the 2 parts of the substantia nigra
```
Pars Reticularis (SNr)
Pars Compacta (SNc)
```
81
what is the direct pathway of the basal ganglia
Stimulates desirable movement
82
what is the indirect pathway of the basal ganglia
Inhibits undesirable movement
83
what is the nigrostriatal pathway of the basal ganglia
Modulates both direct and indirect pathways => movement amplification
84
what causes Parkinson's disease
hypokinetic
inactive substantia nigra compacta
overactivity of indirect pathway, underactivity of direct pathway
85
what causes huntingtons
hyperkinetic
| destruction of cells of the indirect pathway, indirect pathway inhibition, decreased movement inhibition
86
what are the ascending tracts
DCML
Spinothalamic
spinocerebellar
87
what does the DCML convey
fine touch, proprioception, vibration
88
what does the spinothalamic tract convey
crude touch, pain, temperature
89
what does the spinocerebellar tract convey
unconscious proprioception
90
what are the descending tracts
corticospinal
corticobulbar
extra pyramidal tracts
91
what is the corticospinal tract involved in
conscious muscle movement
92
what is the corticobulbar tract involved in
voluntary movement of face and neck muscles
93
what are the extra pyramidal tracts involved with
coordination, posture and muscle tone
94
what do ascending tracts carry
sensory information towards the brain (4 orders of neuron)
95
what do descending tracts carry
motor information towards the muscles (2 orders of neuron)
96
describe the pathway of the DCML
- Travels via the ipsilateral side to the nucleus
1. 1st - Dorsal root ganglion, enters posterior column
and ascends
2. SYNAPSE to 2nd.
3. Decussate at medulla
4. SYNAPSE to 3rd in Thalamus
5. Primary somatosensory cortex to 4th.
97
what does the anterior vs lateral spinothalamic tract convey
Anterior: crude touch and pressure.
| Lateral: pain and temperature
98
describe the pathway of the spinothalamic tract
1. 1st - Dorsal root ganglion, enter spinal cord and ascend together
ipsilaterally for 1-2 segments.
2. SYNAPSE. 2nd order decussate across anterior white commissure
- Split into anterior and lateral.
- Ascend on contralateral spinal cord.
- DOES NOT decussate at medulla.
3. SYNAPSE in Thalamus to 3rd order.
- Fibres travel to primary somatosensory cortex.
4. Synapse to 4th order which carry messages to various points in the
cortex.
99
describe the pathway of the spinocerebellar tract
1. First order: dorsal root ganglion into the spinal cord.
2. Synapse to a second order neuron.
- Splits and either crosses the spinal cord and goes up the
ventral tract CONTRALATERALLY. Or doesn’t cross and
ascends up the dorsal tract ipsilaterally.
3. Dorsal into inferior cerebellar peduncle.
4. Ventral into superior. Decussates within the cerebellum.
5. BOTH END UP IPSILATERAL.
100
describe the route of the corticospinal tracts
anterior and lateral tracts. 10% stay ipsilateral, 90% decussate at medulla. Supplies musculature of the body
101
describe the route of the corticobulbar tracts
neurones terminate on the motor nuclei of the cranial nerves
102
what are the 4 extra pyramidal tracts
vestibulospinal, reticulospinal, tectospinal and rubrospinal
103
describe the route of the extra pyramidal tracts
the vestibulospinal and reticulospinal tracts do not decussate, providing ipsilateral innervation.
The rubrospinal and tectospinal tracts do decussate and therefore provide contralateral innervation
104
what are the symptoms of Brown Sequard syndrome
loss of pain, temp and light touch on contralateral side (spinothalamic)
loss of vibration, motor, deep touch and position of ipsilateral side (Corticospinal/ DCML)
105
what makes up a motor unit
an alpha motor neuron + extrafusal skeletal muscle fibres it innervates
106
what do alpha motor neurones control
muscle contraction involved in voluntary movement
107
what do gamma motor neurones control
muscle contraction in response to external forces acting on the muscle
108
the smaller the motor unit ....
the finer the control
109
what are intrafusal muscle fibres
regulatory unit surrounded by extrafusal fibres
110
what is the role of intrafusal muscle fibres
```
- Sense stretch: monitors muscle length
and rate of change.
- Help to prevent overstretching of
muscles.
- Type 1a and type 2 sensory fibres
detect these changes.
- Innervated by gamma motor
neurons that help keep the intrafusal
unit taut so they can keep detecting
change
```
111
describe the stretch (myotatic) reflex
Stretch reflex: when sensory neurons in an intrafusal unit
detect over stretching.
type 1a - synapse and excite alpha motor neurones from same muscle - contraction
type 2 - synapse + inhibit alpha motor neurones of antagonistic muscle - relaxation
112
what do golgi tendons detect
tension
113
describe the role of the golgi tendons
```
- Have type 1B sensory fibres that are
stimulated by the compression of
muscle contraction.
- If there is too much muscle tension the
golgi tendon organ will inhibit the
muscle from creating any force (via a
reflex arc), thus protecting you from
injuring itself. As well as contracting the
antagonistic muscle.
```
114
what is the inverse stretch reflex
protects from the overload of muscle
if stimulated enough they will cause inhibition/relaxation of the contracting muscle and stimulation of the antagonistic muscle
115
what is the axon resting potential
-70mV
116
what do excitatory neurotransmitters do
Results in depolarisation of next neuron by bringing membrane potential closer
to threshold potential
- Generate excitatory post-synaptic potentials (EPSPs)
- Eg acetylcholine
- Increase the likelihood of a response
117
what to inhibitory neurotransmitters do
hyperpolarisation
membrane potential decreased to further from threshold, harder for action potential to begin, generate inhibitory post-synaptic potentials (IPSPs)
e.g. GABA
118
what does white matter contain
myelinated axons
119
what does grey matter contain
cell bodies and no myelin sheaths
120
what cells myelinate axons in the brain
oligodendrocytes
121
what are commissures
tracts connecting one hemisphere to the other, cross the midline
122
what are lemnisci
narrow strips of fibres
123
what is a funiculi
rope or cord
124
what is a capsule
sheet of white matter fibres that border a nucleus of grey matter
125
what are nuclei
collection of nerve cell bodies within the CNS e.g. arcuate nucleus
126
what are ganglia
collection of nerve cell bodies outside the CNS e.g. the dorsal root ganglia in the PNS
and some inside CNS that have capsule e.g. basal ganglia
127
what are afferents
axons taking information towards the CNS e.g. sensory fibres
128
what are efferents
axons taking information to another site from the CNS e.g. motor fibres
129
what does reticular mean
where grey and white matter mix e.g. brain stem
130
what are sulci
grooves
131
what are gyri
ridges
132
functions of the frontal lobe
voluntary movement on opposite side of body
dominant hemisphere controls speech (broca's area) and writing
intellectual functioning, thought processes, reasoning and memory
133
functions of the parietal lobe
receives and interprets sensations (pain, touch, pressure, size) and proprioception
134
functions of temporal lobe
understanding spoken word (Wernike's area), sounds, memory and emotion
135
functions of the occipital lobe
understanding visual images and meaning of written word
136
what are the grey matter structures
thalamus, hypothalamus, basal ganglia
137
lentiform nucleus =
globus + putamen
138
role of the thalamus
relay centre direction inputs to cortical areas
139
role of hypothalamus
links endocrine system to brain & involved in homeostasis
140
role of cerebellum
co-ordinates movement and balance
141
how is the cerebellum attached to the brain stem
3 peduncles:
superior - midbrain
middle - pons
inferior - medulla
142
how is the cerebellum separated from the dorsal brainstem?
4th ventricle - forms part of its roof
143
what is the cerebellum made up of
folded cortex, white matter and deep inner nuclei
144
how do cerebellar injuries present
slow, uncoordinated movements, intention tremor, weak muscles, nystagmus
145
anatomy of the midbrain
tectum - superior and inferior colliculi
cerebral peduncle - tegmentum & crus cerebri
surrounds the cerebral aqueduct
146
types of nerve cell
pyramidal, stellate, golgi, purkinje
147
types of neuroglia
astrocytes, oligodendrocytes, microglia
148
Neurulation
ectoderm - neural plate (3w) - differential mitosis - neural groove - detaches to form neural tube- neural crest cells laterally
149
what do neural crest cells develop into
schwaan cells, pigment cells, meninges, bony skull, adrenal medulla, dorsal root ganglia, CN V, VII, IX, X, dermis
150
which portion of the neural tube grows fastest
rostral - develops into spinal cord
151
what are the 3 primary brain vesicles in week 5
prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)
152
what are the secondary brain vesicles present at week 7
1. prosencephalon -> telencephalon + diencephalon
2. mesencephalon
3. rhombencephalon -> metencephalon + myelencephalon
153
what does the telencephalon give rise too in the mature brain
cerebral hemisphere & lateral ventricles
154
what does the diencephalon give rise too in the mature brain
thalamus, hypothalamus & 3rd ventricle
155
what does the mesencephalon give rise too in the mature brain
midbrain (colliculi) & aqueduct
156
what does the metencephalon give rise too in the mature brain
cerebellum, pons & upper part of 3rd ventricle
157
what does the myelencephalon give rise too in the mature brain
medulla, lower part of 4th ventricle
158
when does the neural tube usually close
week 4
159
what happens is the spinal cord fails to close
spinal cord - spina bifida
| cephalic region - anencephalus
160
what are some developmental milestones
```
w3 - eye
w10 - expansion, commissures
3m - basic structures
5m -myelination
7m - lobes
9m - gyri + sulci
```
161
what does the corpus callosum do
fibre bundle which connects left and right hemisphere
162
what percentage of neurons are in the cerebellum
70%
163
functions of the hippocampus
limbic system
construction of mental images
short term memory
spatial memory and navigation
164
what is anterograde tract tracing
transport from neural cell bodies to axon terminals
165
what is retrograde tract tracing
transport from axonal terminals to neuronal cell bodies
166
how do you detect brain activity
increased neural activity - increased neurotransmitters, need more O2 so blood - can be seen on imaging e.g. EEG
167
role of glial cells
surround the soma, axon and dendrites of neurones and provide them with physical and metabolic support e.g. oligodendrocytes, schwaan, astrocytes
168
role of astrocytes
help to regulate the composition of the ECF in the CNS by removing K+ and neurotransmitters (glutamate)
help form tight junctions - BBB
169
role of microglia
specialised macrophage-like cells that perform immune functions in the CNS
170
role of ependymal cells
line fluid filled cavities within the brain and spinal cord - regulate the production and flow of CSF
171
what are the features of the blood brain barrier
```
endothelial tight junctions
astrocyte end feet
pericytes
continuous basement membrane
specific transporters
```
172
what are circumventrular organs
lack the blood-brain barrier e.g. posterior pituitary
173
how do ventricles and subarachnoid space connect
cisterns
174
where does the CSF circulate
subarachnoid space
175
how is CSF produced
by ependymal cells in the choroid plexus of the lateral ventricles
176
what is hydrocephalus
abnormal accumulation of CSF in ventricular system
177
what causes multiple sclerosis
the degeneration of myelin and development of scar tissue which in turn disrupts and eventually blocks neurotransmission along myelinated axons
178
what are the 5 processes of synaptic transmission
```
manufacture
storage
release
interact with post-synaptic receptors
inactivation
```
179
what is temporal summation
input signals arrive from the same presynaptic cell at different times - summate - greater flow of ions into cell
180
what is spatial summation
where 2 inputs occur at different locations in the post synaptic neurone
181
name some examples of fast neurotransmitters
ACh
glutamate
GABA
182
name some examples of neuromodulators - longer, slower response
Dopamine
noradrenaline
serotonin
183
how do local anaesthetics work
interrupt axonal neurotransmission by blocking sodium channels
184
what are cholinergic neurons
neurones that release ACh
185
role of acetylcholinesterase
located on post and presynaptic membrane and rapidly destroys ACh, releasing choline & acetate
choline is transported back into presynaptic axon terminal for resynthesis of ACh
186
what are the 2 general types of ACh receptors
nicotine -neuromuscular junction
| muscarinic - brain and junctions of PNS
187
role of noradrenaline
transmitter in the peripheral heart and CNS
| affected by antidepressant drugs
188
what is dopamine
important transmitter in basal ganglia
189
what is the role of serotonin
has an excitatory effect on pathways that mediate sensations
190
what is glutamate
main excitatory neurotransmitter
191
what is GABA
main inhibitory neurotransmitter
192
what is L-DOPA
precursor for dopamine - able to cross BBB - parkinson's medication
193
what is the human hearing range
20-20000 Hz
194
what range is the ear most sensitive at
1000-4000 Hz
195
what is sensation of the middle ear provided by
CN IX - glossopharyngeal
196
what type of joints are found between the ossicles
synovial
197
what substance is the cochlea duct filled with
endolymph (high K+, low Na+)
198
how many rows of inner hair cells are there
1
199
how many rows of outer hair cells are there
4-5
200
describe the path of the cochlear branch of vestibulocochlear nerve (CNVIII)
cochlear nuclei -> superior olivary nucleus -> inferior colliculus -> medial geniculate body -> primary auditory cortex in Wernicke's area
201
where does the facial nerve CNVII exit the cranial cavity?
internal acoustic meatus behind the cochlea
202
what does the vestibule apparatus consist of
3 semi-circular canals, the utricle and saccule
203
what is the function of the semi circular canals
detect angular acceleration during the rotation of the head along 3 axis
204
what is the function of the utricle and saccule
provide information about linear acceleration of the head, and about the changes in head position in relation to gravity
205
what do rods detect
light and dark
206
what do cones detect
colour
207
what are the 3 layers of the tear film
anterior lipid
middle aqueous
posterior mucous
208
what are the layers through which a photon must travel through the eye
```
tear film
cornea
aqueous humour
lens
vitreous humour
ganglion cell
amacrine cell
bipolar cell
horizontal cell
cone & rods
pigmented epithelium
```
209
describe the blood supply of the eye
internal
9opthalmic, optic nerve) and external
(medial lid and orbit) carotid
210
describe the somatic nervous system
```
innervate skeletal muscle
single neurone between CNS and skeletal muscle cells
only excitatory
conscious
only ACh
```
211
describe the autonomic nervous system
innervate smooth & cardiac muscle, glands ect.
2 neurone chain
excitatory or inhibitory
involuntary
ACh before ganglion and ACh or noradrenaline after
212
describe the sympathetic division of the autonomic nervous system
fight or flight
T1-L2, sympathetic trunks
pre = ACH + nicotinic receptors
213
describe the parasympathetic division of the autonomic nervous system
pre = ACh + nicotinic receptors
| effector cell = ACh + muscarinic receptors
214
what are upper motor neurons
the descending pathways and neurones of the motor cortex
215
what are the lower motor neurones
PNS, alpha motor neurones
216
what is acute pain
less than 12 weeks
217
what is chronic pain
more than 12 weeks
218
what is nociceptive pain
pain that arises from actual or threatened damage to non-neuronal tissue and is due to the activation of nociceptors
219
what is neuropathic pain
pain initiated or caused by a primary lesion/ dysfunction of the nervous system
220
what are first order neurones/ primary afferent
enters through spinal or trigeminal nerve ipsilaterally synapses with 2nd order neuron in CNS
221
what are second order neurons
cell body in spinal cord/ brainstem
| decussates to other side of CNS and ascends to terminate at the thalamus
222
what is a third order neuron
cell body in thalamus - projects to somatosensory cortex
223
what are the afferent fibres of nociceptors
alpha delta fibres - thinly myelinates, touch, pressure, temp, fast pain
C fibre: unmyelinated, slow pain, temp, touch, pressure, itch - slowest conduction speed
224
what is the insula
lies within the brain via the sylvian fissure
| where degree of pain is judged - subjective
225
what is the cingulate gyrus
medial aspect of hemispheres
linked with limbic system
emotion, learning and memory
226
what is the periaqueductal grey
in midbrain
| receives input from somatosensory cortex - reduced pain sensation in extreme stress
227
what is substance P
peptide neurotransmitter involved in pain transmission , vasodilator , long lasting pain
228
why do substantia nigra appear black?
neuramelanin that is produced as a by-product of dopamine production
229
what do people with huntingtons lack
GABA
230
what are the functions of the limbic system?
learning & regulation and translation of out emotional state into appropriate behaviour
connected via papez circuit
231
what does the limbic system consist of
cingulate gyrus
hippocampus
parahippocampal gyrus
uncus, amygdala
232
what is responsible for explicit memory
episodic - hippocampus & midbrain
| semantic - frontal temporal lobe
233
what is responsible for implicit memory
skills- cerebellum + basal ganglia
reflexes - cerebellum
emotional - amygdala
234
what is the amygdala responsible for
emotional memory and output
| responsible for fear
235
what are the 2 inputs of the cerebellum
```
mossy fibres (middle peduncle)
climbing fibres (inferior peduncle)
```
236
what is the output of the cerebellum
purkinje cell axons
237
what are the names and numbers of the vertebral column
7 cervical
12 thoracic
5 lumbar
238
where are the dural venous sinuses located
between the periosteal and meningeal layers of dura mater
239
what structure do the dural venous sinuses drain into
internal jugular vein
240
where are the straight, superior and inferior sagittal sinuses found and where do they converge
found along the flax cerebri
| converge at the confluence of sinuses
241
what does the transverse sinus drain into
transverse -> sigmoidal -> internal jugular vein
242
what does the cavernous sinus drain into
cavernous -> superior + inferior petrosal -> internal jugular vein
243
where are the cerebral veins found and what do they drain into
subarachnoid space
| drain into dural venous sinuses
244
what supplies sensation to the middle ear?
glossopharyngeal nerve
245
describe the pathway of sound
auricle -> external auditory canal -> tympanic membrane -> ossicles (malleus, incus, stapes) -> oval window -> scala vestibuli -> majority to cochlea duct, rest to scala tympani where pressure is relieved by the round window
246
where does the basilar membrane lie
in the cochlea duct on the scala tympani surface
247
how does the frequency differ at the base and the apex of the basilar membrane
base - thin, high freq
apex - wide, low freq
248
what is the role of the inner hair cells in the cochlea
stereocillia extend into endolymph - convert movements into receptor potentials
249
what is the role of the outer hair cells in the cochlea
stereocillia in tectorial membrane - sharpen frequency tuning
when bent- TIP links open, K+ channels open and influx in -> causes Ca2+ channels to open and influx in -> release of glutamate -> AP
250
describe the path of the cochlea branch of vestibulocochlear nerve
cochlear nuclei -> superior olivary nucleus -> inferior colliculus -> medial geniculate body (via inferior brachium) -> primary auditory cortex
251
what substance fills the vestibular system
endolymph
252
describe how the semi-circular canals work
stereocilia are located at the capula near the ampulla
| head rotation bends stereocilia which affects glutamate release
253
describe how the utricle and saccule work
detect changes in gravity
saccule hair cells are at right angles to utricle hair cells
stereocilia covered by gelatinous substance with otoliths embedded
254
describe the components of the direct pathway
cerebral cortex -> striatum -x internal Globus pallidus + SNr -x thalamus -> excitatory inputs to cerebral cortex
255
describe the components of the indirect pathway
cerebral cortex -> striatum -x External Globus pallidus -x subthalamic nucleus -> SNr + internal globus pallidus -x thalamus -x inhibitory inputs to cerebral cortex
