Neuroanatomy Flashcards
1
Q
What are ascending tracts?
A
Sensory info from peripheral nerves is transmitted to the cerebral cortex. Also called somatosensory pathways.
2
Q
Two types of ascending tracts?
A
Conscious: Dorsal column lemniscal and anteriolateral
Unconscious: spinocerebellar tracts
3
Q
How are the two cerebral hemispheres connected?
A
Via the corpus collosum,
4
Q
What are the ventricles? Route the CSF takes?
A
The lateral ventricle, with inferior, Anterior, Dorsal and Posterior horn.
Through the interventricular foramen (or foramen of monroe), to the third ventricle.
Down the aquaduct to the forth ventricle.
Down the central canal to spinal cord.
5
Q
What is the function of the CSF?
A
- Buoyancy- reduces the weight of the brain from 1.4kg (male) or 1.2kg female to 25g.
- Protection- cushions from physical damage
- Chemical homeostasis- keeps exc K+ low
6
Q
Where is CSF produced?
A
Ependymal cells in Choroid plexus found in all the ventricles
7
Q
How is the CSF recycled?
A
500ml made but only 150ml present.
reabsorbed through arachnoid granulations into the superior sagittal sinus to venous circulation.
8
Q
Where is the third ventricle? e.g. structures near
A
Either side of the third ventricle is the thalamus, connected by the interthalamic adhesion.
9
Q
Where is the forth ventricle? e.g. structures near
A
located in the brainstem, between the pons and the medulla oblongata, cerebellum posterior to
10
Q
What is the Diaphragma sellae?
A
Flat piece of dura mater that roofs the pituitary gland (held in the hypophyseous fossa or sellae turcica of sphenoid)
11
Q
What spaces surround the dura mater in the spinal canal?
A
Extradural space above the dura mater
Subdural space below the dura mater
12
Q
What space is there in both the spinal canal and brain meninges?
A
Subarachnoid space below the arachnoid (so above the pia)
13
Q
If the lateral sulcus is pulled apart what can be seen?
A
Insula
14
Q
What are the layers brain to scalp?
A
Brain, Pia, arachnoid, dura (meningeal then endosteal), skull, periosteum, epicranial aponeurosis, scalp.
15
Q
Area where neurons enter the thalamus?
A
fornix (from the hippocampus to hypothalamus)
16
Q
Anterior to posterior areas of the corpus collosum?
A
Rostrum, Genu, body, Splenium
17
Q
What separates the anterior horns of ventricles?
A
Septum pellucidum
18
Q
Where is the parietal-occipital sulcus?
A
separating the parietal and occipital lobes.
19
Q
Where is the lateral aperture located? Median?
A
The forth ventricle from posterior makes a diamond shape, the two lateral points are named the lateral aperture.
The median is the inferior point where it converges onto the central canal.
20
Q
Where is the brains longitudinal fissure?
A
in midsagittal plane, splits the two hemispheres in two.
21
Q
Where is the brains lateral fissure/ sulcus?
A
Separates the temporal lobe from parietal and frontal. (if pull apart can see insula)
22
Q
Function of insula?
A
Body homeostasis
23
Q
Wheres the central sulcus?
A
Coronal cross section splitting the frontal lobe from the parietal. Before this sulcus is the precentral gyrus, and posterior to is the postcentral gyrus
24
Q
The cerebellum derives from which developemental structure?
A
metencephalon
25
The cerebellum lies at the same level just posterior to what structure?
the pons, separated by the forth ventricle.
26
The two cerebellum hemispheres are connected by?
the vermis
27
Distribution of white and grey matter in the brain, cerebellum and spinal cord?
Brain and cerebellum grey is on surface and white in centre, but for the spinal cord this is the opposite so grey butterfly structure surrounded by the white matter.
28
What are the three cerebellal lobes?
anterior, posterior(or middle) and flocculonodular
29
What fissures divide the cerebellal lobes?
Primary fissure between anterior and posterior
| Posterolateral between the flocculonodular and posterior
30
Functional divisions of the cerebellum?
Cerebrocerebellum (Pontocerebellum), spinocerebellum, vestibulocerebellum
31
Function of the largest functional division of the cerebellum?
cerebrocerebellum: lateral hemisphere forms, planning movements and motor learning, inputs via cerebrum and pontine nucleus, outputs to thalamus and red nucleus. Fine co-ordination of movement by inhibiting excess.
32
spinocerebellum function?
Vermis and intermediate zones make up. Regulating body movements allowing body and posture corrections, and recieves proprioception info
33
Vestibulocerebellum function?
Involved in balance, occular reflexes, and fixation on a target, spatial orientation and muscle tone. Recieves Inputs from the vestibular system and outputs to the vestibular nuclei.
34
What are the structures that join the cerebellum to the
Cerebellar Peduncles: Superior, inferior and middle
35
flocculonodular lobe is made up of which two structures?
Flocculus and Nodulus
36
Middle cerebellar peduncle function?
Joins the cerebellum to the pons. Fibres from the pontine nucleus run through.
37
Inferior cerebellar peduncle function?
Connects cerebellum to the medulla oblongata and spinal cord.
Spinocerebellar Tracts go through and axons from the olivary nucleus
38
Superior cerebellar peduncle function?
connects the cerebellum to the midbrain.
| contains cerebellothalamic fibres and cerebellorubral
39
What is the infundibulum?
The pituitary stalk, which connects it to the hypothalamus
40
Superior (or upper) sinus position? Function?
Runs along the margin of falx cerebri, allowing blood to drain from lateral of anterior hemispheres to the confulence of sinuses.
e.g. CSF drains through arachnoid granules into, and back to venous circulation.
41
Inferior or lower sagittal sinus position? Function?
Vein beneath the cerebral hemispheres, along the inferior boarder of the falx cerebri, just above the corpus callosum. Blood drains posterior through, converging with the great cerebral vein to become the straight, and to the confluence of sinuses.
42
What is the confluence of sinuses?
Where the superior sagittal sinus, straight sinus (inferior sagittal and great cardiac converge to) and occipital sinus drain to.
Located at the internal occipital protuberance
43
Where does the blood/CSF drain to after the confluence of sinuses?
Transverse sinus, to sigmoid then internal jugular vein
44
What are the cavernous sinuses?
Drains into the inferior and superior petrosal sinuses into the sigmoid, and eventually the internal jugular vein.
Recieves blood from the inferior and superior ophthalamic veins.
45
What are the cerebellar folia?
Folds of cortex, increases the surface area
46
What is the cerebellar vermis?
Separates the two hemispheres. Associated with the body posture and locomotion. Part of the spinocerebellum.
Can't be seen when brain is in tact, as is on superior surface.
47
Function of the anterior cerebellum lobes?
Unconcious proprioception.
48
Function of the posterior cerebellum lobes?
Fine motor control, terminating excess involuntary movements via the GABA inhibition.
49
Where is the flocculonodular lobe?
Made up of flocculus + Nodule (connecting the two more lateral flocculus together)
Located on the anterior inferior of the cerebellum.
50
Function of the floculonodular lobe of cerebellum?
Connects to the vestibular nuclei, integrates vestibular info and body position to influence eye movements and balance.
51
cerebellum tonsil?
small bumps on the inferior of the cerebellum
52
CSF can flow from the forth ventricle to arachnoid granules through what?
Lateral aperture openings (paired) in forth ventricle, and single median aperture
53
Composition of myelin?
40% water, 32% lipids, 8% protein, 20% other.
54
Brainstem three components?
Midbrain, pons, medulla oblongata.
55
Function of the olives?
contain olivary nuclei.
Superior: considered part of the pons and auditory system, aiding in perception of sound
Inferior: part of olivo-cerebellar system, helping with motor learning and function.
56
Location of the olives?
Pair of swellings located on the anterior surface of medulla oblongata, lateral to the pyramids (and ventrolateeral sulcus) and medial to the posterolateral sulcus.
57
Where are the pyramidal tracts in medulla?
Pair of swellings between the anterior median fissure and the ventrolateral sulcus (more laterally) running down the medulla.
58
Anterior surface of medulla oblongata structures medial to lateral?
Anterior fissure (with decussation below), pyramids, ventrolateral sulcus, olives, posterolateral sulcus.
59
The anterior fissure is a continuous line down the medulla oblongata except for one interruption which is..?
The decussation of the pyramids
60
In a cross section through the medulla horizontally what is behind (dorsal) to the pyramids?
the inferior olives
61
importance of the pre-central gyrus?
It is just anterior to central sulcus, primary motor control strip. Controls voluntary movements. Pyramidal tracts nuclei are located here.
62
Importance of the post-central gyrus?
Located just posterior of the central sulcus. Primary somatosensory cortex of parietal lobe, the main area for touch reception. Homunculus map of this info.
63
In the posteriolateral sulcus which three cranial nerves exit?
glossopharyngeal IX, Vagus X, and accessory XI
64
importance of the pre-central gyrus?
It is just anterior to central sulcus, motor control strip. Controls voluntary movements. Pyramidal tracts nuclei are located here.
65
importance of the Dura mater structures?
Holds the dural sinus between the endosteal and meningeal layer.
66
What/where is the Crus Cerebri?
White matter of the Cerebrum Peduncle. Of the midbrain, transmits motor tracts from the cerebrum to cerebellum, involved in alertness and arousal.
67
Features and locations of structures in a horizontal slice of the midbrain? PUG
Anterior/ventral: Crus cerebri wiht pyramidal tracts, then black strip of the substantia Nigra, Red nucleus, (lateral) next is the medial, spinal and trigeminal lemnisci, more medially reticular formation, oculomotor nuclei and periaqueductal grey.
In the centre of this is the cerebral aqueduct.
Furthest dorsal/posterior is the superior or inferior colliculus.
68
What/where is the Crus Cerebri?
White matter of the Cerebrum Peduncle. Of the midbrain, contains cortico-spinal tracts originating from the motor cortex and controls voluntary movement
69
Function of the pyramidal tracts?
Corticobulbar tract: impulses from the brain to cranial nerves, motor info to move face etc.
Corticospinal tracts: to S.C, transmit volunatry movement to body.
70
Function of the red nucleus?
Modulate movements, gait particularly in most vertebrates but the presence of the corticospinal tract take over in primates, so mainly functions to modulate movements and for example swinging arms during walking.
71
Function of the substantia nigra?
Terminates excess movements, e.g. loss of dopamine producing neurons here leads to parkinsons.
72
Where is the tectum?
The most posterior of the midbrain, houses the 4 colliculi.
73
Superior and inferior to the colliculi are what structures?
Superior is the pineal gland, inferior the trochlea nerve emerges.
74
From between the two cerebral peduncles of midbrain which CN emerges?
Occulomotor
75
Blood is supplied to the brain via which two arteries?
Internal carotid artery and vertebral arteries arising from the neck and linked by the circle of willis from which branches arise to supply the brain.
76
Blood supply to the cerebellum?
Branch off of the vertebral artery called the inferior cerebellar, and posterior cerebellar off the basilar artery
77
Where does the internal carotid artery arise from?
originates from the common carotid as it bificates into left and right, at the level of C4
78
Where do the vertebral arteries arise from?
Subclavian, and enter the cranial cavity through the foramen magnum.
79
What branches are given off the vertebral arteries? Supplies?
Converge to?
Meningeal- supplies the falx cerebelli
A and P spinal arteries- supplies spinal cord
Posterior inferior cerebellar- cerebellum7
Converge to basilar artery
80
What arteries form the circle of willis?
From basiliar artery splits into P communicating.
| Internal carotid then splits into the P communicating, A communicating (form the circle) and middle cerebral off.
81
What arteries supply the cerebrum? Arise from?
Anterior cerebral off the circle of willis Anterior comunicating artery.
Middle cerebral off the circle of willis opposite internal carotid joining
Posterior cerbral branches off the basilar artery just before P. communicating.
82
Cerebrum, cerebellum and brainstem drain into? Located?
Dural venous sinuses into internal jugular vein
| Located between the periosteal and meningeal (brain side) of the dura.
83
What sinuses are found in the falx cerebri? Converging?
Superior sagittal sinus along superior margin
Inferior sagittal sinus along the inferior margin
Straight sinus posterior inferior
Converging to the confluence of sinuses.
84
What two veins join into the straight sinus?
Inferior sagittal sinus and great cerebral vein.
85
After the confluence of sinuses where does the blood drain to?
the transverse sinus continues bi-laterally (Left and Right), curving into the sigmoid sinus to meet the opening of the internal jugular vein.
86
As well as the sigmoid sinus, what other sinuses drain into the internal jugular? Draining from where?
Superior and Inferior petrosal sinuses.
The ophthalamic veins found either side of the sella turcica drain into the caverous sinus and into these petrosal sinuses before the internal jugular vein.
87
Function of the superior colliculi?
Preliminiary visual processng, and control of eye movements
88
Function of the inferior colliculi?
```
Auditory processing (eyes superior to ears)
Projects to the medial geniculate nucleus of thalamus
```
89
Function of tegmentum?
Inhibitory relay centre of excess movement e.g. substaintia nigra in
90
Cerebral aquaduct function?
CSF transport from the third to the forth ventricle
91
Function of the Gracile tubercle/ nucleus?
One of the dorsal column nuclei, aiding with sensation of fine touch and proprioception.
Dorsal Root ganglia- GN- Thalamus
92
What is the dorsal column?
dorsal column/medial lemniscus pathway
Sensory pathwayconveys fine touch, vibration, two point discrimination, proprioception.
From body to cerebrum.
93
Neurons of the dorsal column?
First order: Dorsal root ganglia to the gracile nucleus, or cuneate.
Second order: Then to the thalamus.
Third order: Thalamus to postcentral gyrus
94
Where is the cavernous sinus?
Inferior to the brain, just below the optic chiasm and internal carotid artery. It is lateral to the sellae turcica of the sphenoid (where pituitary sits in).
95
What is the cavernous sinus?
it is a dural venous sinus, so where blood from the brain drains to. From here it dains into the Superior and Inferior petrosal sinuses to the sigmoid to the internal jugular vein.
96
What structures pass through the lateral wall of the cavernous sinus?
```
Oculomotor nerve (III)
Trochlea (IV)
Opthalamic nerve of trigeminal (V)
Maxillary nerve of trigeminal (V)
Trigeminal ganglion of Maxillary and Opthalamic
```
97
What structures pass through the medial portion on the cavernous sinus?
```
Abducens Nerve (VI)
Internal carotid artery and internal carotid plexus neves travelling with.
```
98
What can a tumour of the pituitary gland cause? Why?
Can affect vision, as it may compress on the optic chaism. Can lose lateral vision, or if even bigger can push into the cavernous sinus - greater problems.
99
Where does the pituitary sit in relation to the cranial nerves?
The pituitary is medial to the cranial nerves in the cavernous sinus.
100
What is bells palsy?
it is a condition which results in facial paralysis of muscles on the affected side. Caused by disfunction of the cranial nerve, e.g. post upper repsiratory tract infection inflammed.
Normally self resolving.
101
Which nerve may a dentist apply anaesthetic to before extracting a tooth?
Remus of the mandible, block the mandibular branch of the trigeminal.
102
WHat are descending tracts?
Sending motor info from the cortex to muscles.
Motor cortex of brain- UMN-(no longer part of descending tract) LMN- muscle
All upper motor neurons.
103
Two types of descending tracts?
pyramidal: Tracts running from the cortex to spinal cord or brainstem. volntary control of body/face.
Extrapyramidal: Brain stem to spinal cord, involunatry automatic control of muscles e.g. muscle tone, posture, balance, locomotion.
104
Two types of pyramidal tracts?
Corticospinal: Body
Corticobulbar: Face and Neck
105
Types of Extrapyramidal tracts? (4)
Vestibulospinal: From vestbulonuclei to SC about balance etc
Reticulospinal: Medial from pons- facilitates voluntary movement, lateral from MO- supresses voluntary movement
Rubrospinal: from red nucleus, fine control of hand
Tectospinal: SC of tectum, head movements
106
The basal ganglia is .... shaped from the lateral view.
tadpole- it curves from the putamen and global pellucidum anteriosuperior to the head then posterior in the body and then back round as the tail. The amygdala is then on the tail.
107
The (neo)striatum = ......+.....
Caudate + putamen
108
The putamen lies .... to the global pallidus
lateral
109
Layers in from the insula?
Insula, Extreme capsule, Calustrum, External capsule
110
The large head of the caudate nucleus is almost completely separated from the putamen by the ......, except for at the ......
internal capsule
| nuclear accumbens
111
Striatal afferents come from where?
Cerebral cortex
112
Striatal afferents come from where?
Cerebral cortex
with motor mainly to the putamen.
Thalamostriatal projection from thalamus
Nigrostriatal projection from the substantia nigra
113
The substantia nigra is not part of the basal ganglia but is part of the ..... but through the ...... projection transmits to it with .....
Brainstem tegmentum
Nigrostriatal projection
Dopamine
114
Why are the caudate and putamen considered a functional unit as the striatum?
Because their function is very similar, both input to the basal ganglia, recieving afferents from the cortex, and efferents are projected to the globus pallidus and substantia nigra (pars reticula).
115
What is the amygdala?
Not part of the basal ganglia but is part of the limbic, its an integrative centre for emotions
116
What is the anterior commissure?
located n front of the fornix, white matter connecting 2 temporal lobes across midline. Transports pain
117
What is the posterior commissure?
on upper end of cerebral aquaduct. Bilateral pupillary reflex,
118
What is the interthalamic adhesion?
Between two thalamus halves over the 3rd ventricle.
119
Nerve fibres that radiate from the the brainstem to the cortex?
Corona radiata
120
4 structures in the Diencephalon?
Thalamus, hypothalamus, epithalamus, subthalamus.
121
What is the epithalamus?
Of a midsagittal section, it's posterior to the thalamus, includes the pineal gland in, connecting the limbic to other parts of the brain.
122
What is the pineal gland?
endocrine gland thats part of the epithalamus, and produces melatonin.
123
What does the hypothalamus do?
Links the nervous system to the endocrine via the pituitary.
Regulates: Body temp, hunger, thirst behaviour, and releasing hormones from the pituitary.
124
What does the thalamus do?
Relay centre for motor and sensory info from s.c. to the cortex. Controls consciousness, sleep and sensory interpretation
125
What does the sub-thalamic nucleus do? Where is it?
part of the diencephalon below the thalamus. Unknown function but dysfunction causes a increase in impulsivity.
