Neuro Flashcards
(132 cards)
1
Q
What are the first three embryological structures of the brain? What do they go on to form?
A
PROSENCEPHALON :
- Telencephalon: cerebral hemispheres
- Diencephalon: thalamus, hypothalamus
MESENCEPHALON:
= midbrain
RHOMBENCEPHALON:
- Metencephalon: cerebellum, pons
- Myelencephalon: medulla
2
Q
What is the meaning of rostral and caudal?
A
rostral: towards brain
caudal: towards tail
3
Q
Where do you find Broca’s area and Wernicke’s area?
A
Broca’s: frontal lobe
Wernicke’s: temporal lobe
4
Q
What is the function of Broca’s area and Wernicke’s area? What are the difference between the two aphasias?
A
Broca’s: motor speech (forming sentences)
Wernicke’s: comprehension of speech (making sure what you’re say makes sense)
Broca’s aphasia: problem forming words
Wernicke’s aphasia: word formation is fine but speech makes no logical sense
5
Q
What is the function of the frontal lobe?
A
contains motor cortex
social conduct
mood
language
6
Q
What is the function of the parietal lobe?
A
proprioception
contains somatosensory cortex
7
Q
What is the function of the temporal lobe?
A
auditory cortex
contains amygdala and hippocampus
8
Q
What is the function of the occipital lobe?
A
primary visual cortex
9
Q
What is the function of the amygdala?
A
feelings and emotion
10
Q
What is the function of the hippocampus?
A
emotional memory
learning
11
Q
What is the corpus callosum?
A
white matter bundle connecting the two hemispheres
12
Q
What separates the two hemispheres?
A
deep longitudinal fissure
13
Q
What fills the deep longitudinal fissure?
A
fold of dura mater called falx cerebri
14
Q
What separates the cerebellum and occipital lobe?
A
tentorium cerebelli
15
Q
What is contained within the grey and white matter?
A
Grey: neuronal cell bodies
White: glial cells + myelinated axons
16
Q
What are the layers of the scalp from outermost to innermost?
A
Skin Connective Tissue Aponeurosis Loose connective tissue Periosteum
17
Q
What is the name for the joins of the skull?
A
sutures
18
Q
What is the name of the roof of the skull?
A
Calvarium
19
Q
What layers make up the meninges from outermost to innermost?
A
Dura- Periosteal layer & Meningeal layer
Arachnoid
Pia
20
Q
What makes the dura mater different from the other meningeal layers?
A
the dura mater has it’s own vascular supply
21
Q
What is the blood supply to the dura?
A
middle meningeal artery
22
Q
How is the dura innervated?
A
Innervated by CN5- Trigeminal
23
Q
Where is the CSF found?
A
subarachnoid space
24
Q
How is CSF reabsorbed?
A
arachnoid granulations
25
Describe the blood flow through the circle of willis?
blood enters via:
- vertebral arteries up through basilar artery
- internal carotid arteries
blood leaves via:
anterior, middle and posterior cerebral artery
26
What cells surround the capillaries in the brain?
neurons
endothelial cells
astrocytes
pericytes
27
What parts of the brain are supplied by each cerebral artery?
Anterior: front portion
Middle: sides of brain
Posterior: back portion
28
How will stroke in the anterior cerebral artery present?
loss of contralateral motion and sensory function in lower limbs
29
How will stroke in he middle cerebral artery present?
loss of contralateral motion and sensory function in upper limbs and face
+ Broca's aphasia
30
How will stroke in the posterior cerebral artery present?
loss of vision
| opposing side homonymous hemianopia with macular sparing
31
What is homonymous hemianopia?
a visual field defect involving either the two right or the two left halves of the visual fields of both eyes
32
What is macular sparing?
visual field loss that preserves vision in the center of the visual field
33
Describe the process of venous drainage.
1. Choroid plexus makes CSF
2. CSF fills 2 lateral ventricles
3. Drains through foramen of Monroe
4. Into 3rd ventricle
5. Drains through cerebral aqueduct
6. Into 4th ventricle
7. Then drains into subarachnoid space, medially through foramen of magendie, laterally through foramen of luscka
8. Reabsorbed by arachnoid granulations
34
List the sinuses in order.
```
superior + inferior sagittal sinus
joined by falx cerebri
join at the confluence of sinuses
transverse sinus
sigmoid sinus
internal jugular vein
```
35
Name the structures in the cavernous sinus.
```
O: oculomotor nerve
T: trochlea nerve
O: opthalmic nerve
M: maxillary nerve
C: internal carotid artery
A: abducens nerve
```
36
What cranial nerves have parasympathetic fibres?
1973
37
Name the cranial nerves in order.
```
I Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal (V1= ophthalmic, V2= maxillary, V3= mandibular)
VI Abducens
VII Facial
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Accessory
XII Hypoglossal
```
38
What cranial nerves leave the skull via the cribriform plate?
olfactory nerve
39
What cranial nerves leave the skull via the optic canal?
Optic nerve
40
What cranial nerves leave the skull via the superior orbital fissure?
Occulomotor
Trochlea
Trigeminal- V1
Abducens
41
What cranial nerves leave the skull via the foramen rotundum?
Trigeminal- V2
42
What cranial nerves leave the skull via the foramen ovale?
Trigeminal- V3
43
What cranial nerves leave the skull via the internal acoustic meatus?
Facial
| Vestibulocochlear
44
What cranial nerves leave the skull via the jugular foramen?
glossopharyngeal
vagus
accessory
45
What cranial nerves leave the skull via the hypoglossal formamen?
hypoglossal
46
What is the function of the olfactory nerve?
smell
47
What is the function of the optic nerve?
vision
48
What is the function of the oculomotor nerve?
eye movement:
| extra-ocular muscles EXCEPT LR6SO4 (lateral rectus and superior oblique)
49
What is the function of the trochlear nerve?
innervates superior oblique
50
What is the function of the trigeminal nerve?
V1: Ophthalmic
innervates upper face, eyelids, lacrimal glands, ethmoid sinus, corneal reflex
V2: Maxillary
maxillary portion of face
upper teeth and lips
nasopharynx
```
V3: Mandibular
mandibular region of face
anterior 2/3 tongue
lower teeth and lips
pinna of ear
muscles of mastication
tensor tympani
tensor veli palatini
mylohyoid
```
51
What is the function of the abducens nerve?
lateral rectus
52
What is the function of the facial nerve?
sensory impulses from the face
buccinator
platysma
53
What is the function of the vestibulocochlear nerve?
sound
| balance
54
What is the function of the glossopharyngeal nerve?
pharynx, soft palate, pinna, posterior 1/3 tongue, carotid sinus, parotid gland, stylopharyngeus
55
What is the function of the vagus nerve?
```
aortic arch
thoracic viscera
larynx
abdominal viscera
pinna
epiglottis
soft palate
pharynx
GI tract
```
56
What is the function of the accessory nerve?
cranial: pharynx
spinal: sternocleidomastoid
57
What is the function of the hypoglossal nerve?
muscles of tongue
58
What are the two compartments of the eye?
aqueous body
| vitreous body
59
What photoreceptors are found in the eye and what do they do?
rod- detect dim light
| cones- colour vision
60
What makes up the outer eye?
Sclera- white of eye
| Cornea- first point of refraction
61
Make makes up the middle eye?
Iris
Choroid
Ciliary Body
Lens
62
What makes up the inner eye?
Retina
| Inner neural layer
63
What is found on the inner neural layer of the eye?
photoreceptors
light transducers
vitamin A storage
64
What makes up the ciliary body?
ciliary muscles
| suspensory ligaments
65
What makes up the iris?
sphincter pupillae
| dilator pupillae
66
What are the extra-ocular muscles and what do they each do?
```
Superior rectus- elevation
medial rectus- adduction
inferior rectus- depression
lateral rectus- abduction
inferior oblique- extorsion
superior oblique- intorsion
```
67
What is palsy?
weakness or problems with muscles
68
How will a lesion on the oculomotor nerve affect the eye?
depression and abduction of the eye
| eyelid drooped down
69
How will a lesion on the abducens nerve affect the eye?
can't laterally rotate (abduct)
70
How will a lesion on the trochlear nerve affect the eye?
eye extorted, appears slightly elevated
71
How will a pituitary tumour affect the eyes?
bitemporal hemianopia
72
What is bitemporal hemianopia?
a type of partial blindness where vision is missing in the outer half of both the right and left visual field
73
What makes up the external ear?
Auricle
External acoustic meatus
Tympanic membrane
74
What is the function of the auricle?
directs sound to external acoustic meatus
75
What is the function of the external acoustic meatus?
transmits sound to tympanic membrane
contains cerumen- prevents pathogens and insects reaching eardrum
76
What makes up the middle ear?
ossicles (malleus, incus, stapes)
stapedius and tensor tympanic muscles
middle ear cavity (Eustachian tube and oval window)
77
What is the order of the ossicles in the ear from outermost to innermost?
malleus, incus, stapes
78
What is the function of the stapedius muscle?
dampens the stapes to prevent excess vibration in response to loud sound
79
What is the function of the tensor tympani muscle?
tenses tympanic membrane to prevent excessive vibrations and dampens loud sounds
80
What is the function of the Eustachian tube?
connects middle ear to nasopharynx and equalises pressure either side of tympanic membrane
empties middle ear secretions into nasopharynx
81
What is the function of the oval window?
transfers mechanical vibrations from middle ear into fluid filled vibrations in the inner ear
82
What makes up the inner ear?
semi-circular canals
vestibule
cochlea
organ of corti
83
What is the function of the semi-circular canals?
detects change in dynamic equilibrium (balance)
84
What is the function of the vestibule?
detects changes in static equilibrium
85
What makes up the vestibule?
two membranous sacs: utricle and saccule
86
What makes up the cochlea?
scala tympani
scala vestibuli
scala media
87
What is the function of the organ of corti?
has 3 rows of outer hair cells and 1 row of inner hair cells which have stereocilia which bend when hit with a vibration, this converts mechanical energy into electrical energy to be picked up but the auditory nerve
88
What is the sound pathway?
```
sound
external acoustic meatus
vibration of tympanic membrane
vibration of ossicles
oval window
fluid-filled vibrations inside cochlea
organ of corti
basillar membrane
hair cell depolarisation
cochlear nerve
vestibulocochlear nerve
CNS
```
89
What are the 3 main pathways of the basal ganglia?
direct
indirect
nigrostriatal
90
What is the general function of the basal ganglia?
execution of smooth movements
91
What are the components of the basal ganglia?
```
putamen
caudate nucleus
thalamus
external globus pallidus
substantia nigra
internal globus pallidus
```
92
What makes up the striatum?
caudate nucleus
| globus pallidus
93
What makes up the lentiform nucleus?
globus pallidus
| putamen
94
What are the type divisions of the substantia nigra?
```
pars reticularis (SNr)
pars compacta (SNc)
```
95
What us the main physical difference between Parkinson's and Huntington's?
parkinsons- hypokinetic
| huntingtons- hyperkinetic
96
What causes Parkinson's?
loss of dopaminergic neurons in basal ganglia
| can lead to overactivity of indirect pathway OR under activity of direct pathway
97
What causes Huntingtons?
destruction of indirect pathway of basal ganglia (degeneration of striatum)
98
What is the function of the ascending and descending spinal tracts?
ascending: send sensory information towards brain
descending: sends motor information towards muscles
99
How many orders of neuron are they for ascending and descending tracts?
ascending: 4 orders
descending: 2 orders
100
What are the ascending spinal tracts and what do they each do?
DCML (dorsal column-medial lemniscus): fine touch, proprioception, vibration
Spinothalamic: crude touch, pain, temperature
Spinocerebellar: unconscious proprioception
101
What are the two divisions of the DCML tract?
fasciculus cuneatus- upper limbs
| fasciculus gracilis- lower limbs
102
What are the descending spinal tracts and what do they do?
PYRAMIDAL:
corticospinal: conscious muscle movement
corticobulbar: voluntary movement of face and neck muscles
```
4 EXTRA PYRAMIDAL:
vestibulospinal
reticulospinal
rubrospinal
tectospinal
```
103
Describe the pathway of the DCML spinal tract?
```
1st- dorsal root column, enters posterior column and ascends
synapse to 2nd
decussate at medulla
synapse to 3rd in thalamus
primary somatosensory cortex to 4th
```
104
What are the two divisions of the spinothalamic tract?
anterior: crude touch and pressure
lateral: pain and temperature
105
Describe the pathway of the spinothalamic tract.
1. 1st- dorsal root ganglion
2. enter spinal cord and ascend together ipsilaterally for 1-2 segments
3. synapse- 2nd order decussate across anterior white commissure
4. split into anterior and lateral tracts and ascend on contralateral spinal cord
5. DOES NOT DECUSSATE AT MEDULLA
6. synapse in thalamus to 3rd order, fibres travel to somatosensory cortex
7. synapse to 4th order and carries messages to different parts of cortex
106
Describe the pathway of the spinocerebellar tract.
1. 1st order- dorsal root ganglion into spinal cord
2. synapse to 2nd order neuron: splits and EITHER crosses spinal cord and goes up ventral tract contralaterally OR doesn't cross and ascends up the dorsal tract ipsilaterally
3. dorsal tract into cerebellar peduncle
4. both end up ipsilateral
107
What two types of neurons do we have in the descending tracts?
upper and lower motor neurons
108
What are the differences between the extrapyramidal descending tracts?
vestibulospinal + reticulospinal- do NOT decussate, ipsilateral innervation
rubrospinal+ tectospinal- DO decussate, contralateral innervation
109
What are the two divisions of the corticospinal tracts?
anterior and lateral
110
What proportion of corticospinal tracts decussate?
10% stay ipsilateral
| 90% decussate at medulla
111
What do the corticospinal and corticobulbar ascending tracts supply?
corticospinal: supplies musculature of body
corticobulbar: supplies musculature of head and neck
112
Where do neurons terminate in corticobulbar tract?
on motor nuclei of cranial nerves
113
What do the extrapyramidal tracts do?
rubrospinal: movement coordination
reticulospinal: posture adjustment especially during movement
vestibulospinal: posture and balance
tectospinal: movement in response to visual reflex
114
What is brown-sequard syndrome?
lesion of spinal cord
115
How does brown-sequard syndrome of the different tracts present?
corticospinal: ipsilateral paralysis
DCML: ipsilateral loss of fine touch, vibration and proprioception
spinothalamic: contralateral loss of pain, temp and crude touch
116
What is a motor unit?
an alpha motor neuron and extrafusal skeletal muscle fibres that it innervates
117
What do alpha motor neurons do?
controls muscle contraction for voluntary movement
118
What do gamma motor neurons do?
controls muscle contractions in response to external forces acting on muscles (stretch reflex for example)
119
How does the size of a motor unit correlate to its degree of control?
the smaller the unit, the finer the control
120
What is the most abundant muscle fibre and what innervates it?
extrafusal muscle
| innervated by alpha motor neurons
121
What are intrafusal muscles? What innervates them?
regulatory unit surrounded by extrafusal fibres
| innervated by gamma motor neurons
122
What is the function of intrafusal muscle fibres?
sense stretch- motors muscle length and rate of change
helps to prevents overstretching
these changes are detected by type 1a and type 2 sensory fibres
123
What is the stretch reflex?
when sensory neurons in an intrafusal unit detect overstretching
124
How does the stretch reflex work?
type 1a sensory fibres synapse with and excite alpha motor neurons from the same muscle and cause contraction of muscle to shorten length
type 2 sensory fibres synapse with and inhibit alpha motor neurons of the antagonistic muscle causing contraction
125
What are Golgi tendons?
tendons at the end of muscles that detect tension
have type 1b sensory fibres that are stimulated by the compression of muscle contraction and protects you from injuring yourself from too much tension
126
What is the inverse myotactic reflex?
inverse stretch reflex that protects from overload of muscle
if stimulated enough will cause inhibition/ relaxation of contracting muscle and stimulation of antagonistic muscle
127
What is resting potential? How is it established?
-70mV
established by Na+/K+ ATPase pump
128
Describe the permeability of axon membrane to Cl-, K+, Na+
membrane is semi-permeable
Cl- and K+ cross easily
Na+ crosses less readily
129
Why does myelination increase conduction along the axon?
electrical impulse jumps between nodes of ranvier (saltatory conduction)
130
What are the two refractory periods?
absolute refractory: no new action potentials can be generated
relative refractory: a new action potential may be generated if the stimulus is strong enough
131
What are the two types of synapse?
electrical
| chemical
132
What is the most common type of synapse?
chemical
