Anatomy - Neuro COPY Flashcards
1
Q
Label this diagram:
A
2
Q
Label these bones:
A
3
Q
What does the anterior cranial fossa contain?
A
Frontal lobe of the brain
4
Q
What is in orange?
A
Orbital part of the frontal bone
5
Q
Label this diagram:
A
6
Q
What is this and what major structures make it up?
A
-Anterior cranial fossa
-Orbital part of frontal bone
-Ethmoid bone
-Lesser wing of sphenoid bone
7
Q
What does the middle cranial fossa contain?
A
-Temporal, parietal and occipital lobes of the brain
-Much deeper than the anterior cranial fossa
8
Q
Label this diagram:
What are these structures part of?
A
Middle cranial fossa
9
Q
Label this diagram:
What are these structures a part of?
A
Middle cranial fossa
10
Q
Label this diagram:
What are they a part of?
A
Middle cranial fossa
11
Q
CN for optic canal?
A
12
Q
CN for superior orbital fissure?
A
13
Q
CN for foramen rotundum?
A
14
Q
CN for foramen ovale?
A
15
Q
What is this?
A
Sella turcica
16
Q
What does the posterior cranial fossa contain?
A
-Cerebellum, pons and medulla oblongata
-Deepest of the 3 fossa
17
Q
Label this diagram:
What are these structures a part of?
A
Posterior cranial fossa
18
Q
What is this?
A
19
Q
What is this?
A
20
Q
What is this?
A
21
Q
Label these:
A
22
Q
What is this?
What does it connect?
A
-Levator palpebrae superioris
-Originates at posterior of orbit at common tendinous ring
-Inserts into upper eyelid
23
Q
What is this and where is it?
A
-Lacrimal gland
-Just inside lateral margin of orbit adjacent to lateral margin of levator palpebrae superioris
24
Q
What is this and where does it connect?
A
-Superior rectus
-Originates deep part of orbit at common tendinous ring
-Runs over the top of the eyeball and inserts anterior to the equator to the eyeball just behind the conjunctival sac
25
What is this?
26
Label this diagram and describe them:
-Superior oblique - originates posterior orbit and runs forwards to pass through trochlea and insert posterior eyeball
-Trochlea - structure superior oblique passes through
-Medial rectus muscle - running along length of medial aspect of orbit on a deeper plane than the superior oblique muscle
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What are these and what are they embedded?
Back of orbit
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What are these and what are they embedded in?
Back of orbit
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What are these?
30
What are these?
31
What are at the back of the orbit?
Nerve and arteries
-Optic nerve CII
-Ophthalmic artery - lateral to medial over optic nerve
-Central artery of retina - into optic nerve
-Superior opthalmic nerve
-Nasociliary nerve - attached ciliary ganglion CN V1
32
Label this diagram:
33
What is this?
-Inferior rectus muscle beneath subarachnoid space
34
What is this?
Oculomotor nerve CNIII
35
What is this?
Abducens nerve to lateral rectus
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Where do parasympathetic nerves arise and which innervate the eye?
-Oculomotor (CNIII) - branches to orbit
-Facial (CN VII) - branches to orbit
-Glossopharyngeal (CNIX)
-Vagus (X)
Sacral spinal segments 2,3,4
37
Describe parasympathetic fibres of the oculomotor nerve (CNIII):
-Originate Edinger-Westphal nucleus in mid-brain
-Travel into the branch to inferior oblique muscle
-Leave nerve to inferior oblique + enter ciliary ganglion gibing fibres that innervate ciliary muscle and sphincter pupillae
38
Describe the pathway of parasympathetic fibres of the facial nerve (CNVII):
-Leave nerve in middle ear
-Synapse in ganglion in pterygopalatine fossa and supply lacrimal gland
39
Describe the sympathetic outflow and specifically that of the orbit and eye:
-From spinal segments thoracic 1 to lumbar 2
-Pass into sympathetic trunks which run from base of skull to bottom of sacrum
-Symp fibres to orbot arise from T1, pass up sympathetic trunk through stellate ganglion to base of skull
-Leave superior cervical ganglion to supply dilator pupillae muscle and blood vessels
40
Describe extra-ocular muscle movement:
-Eye muscles work together with other eye muscles of the same eye and opposite to move eye in various directions
-A given extra-ocular muscle if working on its own in isolation would move front of eye in specific direction
41
Label this diagram:
Ciliary processes radiate from the lens
42
What is this?
Lateral to optic disc
Concentration of cones
43
Label this diagran:
44
What consists the brainstem?
-Midbrain
-pons
-Medulla Oblongata
45
What is the midbrain divided into?
What are they separated by?
-Tectum dorsal to aqueduct of midbrain & IVth ventricle
-Ventral tegmentum lies ventral to aqueduct of midbrain and IVth ventricle
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What is the medulla oblongata anatomically?
-Continuation of spinal cord within skull
-Begins foramen magnum
-Limited above by caudal border of pons abd bulbopontine sulcus
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What is this?
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What is this?
-Crus cerebri
-Two columns of descending fibres (e.g. corticospinal, corticobulbar)
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What is this?
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Label:
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Label:
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What is this and what does it form?
-Forms posterolateral margin of medulla
-Thick bundle of white matter passing through medulla
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What is the anterior median fissure?
-Partial division of medulla in ventral midline
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Label this diagram:
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Label this diagram:
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Label this diagram:
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Label this diagram of the cerebellum:
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Label this diagram:
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Label this diagram:
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What is this?
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Horizontal fissure
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label;
What do these two form?
Flocculo-nodular lobe
70
What is sent to superior cerebellar peduncle?
71
What is sent to middle peduncle?
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What is sent to inferior peduncle?
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What do each of the peduncles connect to?
Medulla - inferior
Pons - middle
Midbrain - superior
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What does this show?
Flocculonodular lobe
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Label this diagram:
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What is this?
Fourth ventricle
79
label these structures of the fourth ventricle:
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81
what is this?
-posterior median sulcus
-separates rhomboid fossa into triangular left and right parts
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what is this?
obex
83
what is this?
corpus callosum
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what is this?
third ventricle of brain
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what is this?
septum pellucidum
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permits CSF to flow from lateral ventricles to third ventricles
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flow of CSF from 3rd to 4th ventricle
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central sulcus
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paracentral lobule
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cingulate sulcus
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cingulate gyrus
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What types of fibres are different areas of the cortex connected by (white matter)?
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What are the two basic functions of uniting the two cerebral hemispheres?
- Bringing together separate representations of the two halves of the body, the visual field and the auditory surround
- Uniting areas of the cortex which have functions specialised to one hemisphere.
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What happens if the corpus callosum is separated?
104
What makes up the basal ganglia and associated nuclei?
-Caudate nucleus
-Putamen
-Globulus pallidus
-Subthalmic nucleus
-Substantia nigra
-Pendunculopontine nucleus
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What makes up the lenticular nucleus?
-Putamen
-Globus pallidus
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What makes up the striatum? (neostriatum) and what is it?
-Caudate nucles
-Putamen
-Input for basal ganglia
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What makes up the corpus striatum? What is it?
-Caudate nucleus
-Putamen
-Globus pallidus
-Major input of basal ganglia
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What is this?
Basal ganglia
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Cingulate gyrus
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What role does the uncus play?
Olfaction, emotions, memory
113
Olfactory tract splits into medial and lateral striae at beginning of perforated substance
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What is this and what passes behind it?
Column of fornix
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What connections can be seen from the fornix?
-Continuation of fornix to mamillary bodies
-Second fibre bundle passes from anterior mamillary body to anterior thalamus - these anterior nuclei project into cingulate gyrus cortex
-Cingulate and parahippocampal gyri connected by longitudinal association fibres
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What does this show?
Cingulum bundle, one of many association fibres
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What are association fibres?
-Axons interconnecting different areas of the cerebral cortex of one hemisphere
-All areas of the cortex receive both long and short association fibres
-Largest is superior longitudinal fasciculus
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What types of association fibres are there?
-Short - adjacent gyri
-Long - different lobes of the hemishpere
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What vertically running association bundles are found deep to the cingulum bundle?
-Corona radiata
-Carries fibres between cortical and sub-cortical structures and are continuous below with the internal capsule
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narrow cleft between the thalamus and fornix in which blood vessels covered by pia invaginate the epindyma to form choroid plexus
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-Anterior - curves downwards into frontal lobe from interventricular foramen, septum and fornix medial
-Body - roofed by corpus callosum medial walls fornix + septum
-Inferior - tail of caudate and stria terminalis follow inner curve of ventricle and continuous with anygdaloid body at tip
126
infero lateral aspect of anterior horn of lateral ventricles
127
.
slender bundle of white fibres following the curve of the caudate around temporal horn of ventricles connecting amygdala to septum and hypothalamus
Major efferent of amygdala
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-Shaped like almond
-overlies medial of tip of inferior horn deep to uncus
-continuous medially with temporal lobe and posteriorly with tail of caudate
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-Medially 5cm on floor of inferior horn of ventricle
-Anteriorly expanded into two or three shallow grooves giving paw-like appearance - pes hippocampi
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what are these?
pes hippocampi
131
What fibres run here?
efferent fibres from hippocampus leading to fornix forming flattened longitudinal bunch of white matter on medial margin of ventricular surface of hippocampus
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what can limbic system lesions cause?
-Anterograde amnesia
-Emotional responses in absence of external stimuli
-innapropriate emotional responses to stimuli
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White matter
135
-Forms part of basal ganglia being a subcortical structure derived from telencephalon
-receives from and projects into cerebral cortex in organised manner
-Has cells that respond to visual, auditory and sensory stimuli
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Seperates putamen from claustrum
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Comprised of laterally placed putamen and medially placed globus pallidus
138
what makes up the lentiform nucleus?
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What is the gray matter of the lentiform nucleus?
globus pallidus
lateral and medial sections
141
convergence and concentration of white matter projection fibres which carries all motor and sensory fibres to and from the cortex
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-Forceps major and minor
-Major - posterior curve of corpus callosum into parietal and occipital lobes forming 2/3 of a circle with opposite side
-Minor - anterior curve of corpus callosum fibres into frontal lobe forming 2/3 circle with opposite side
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144
Label papez circuit:
145
Label pathways of papez circuit:
146
What does the vertebral column consist of and in what numbers?
-7 cervical vertebrae
-12 thoracic vertebrae
-5 lumbar vertebrae
-Sacrum - 5 fused vertebrae
-Coccyx - fusion of four or more rudimentary vertebrae
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What does the vertebral column transmit and through what?
-Transmits body weight on to lower limbs through SACROILIAC JOINTS
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What is contained in the vertebral canal?
The spinal cord and its coverings and the spinal nerves are contained within the vertebral canal
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What is the upper most spinous process that is palpable and what is it called?
-7th cervical vertebra
-'Vertebra prominent'
-Long non-bifid spine
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What is the highest point in the iliac crest in line with?
-Interval between L3/L4 spines
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What is the shape of the vertebral column and when is it formed?
-Sinusoidal shape
-After birth
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Describe how the curvature of the spine forms after birth:
-In the foetus the vertebral column is C-shaped with a concavity facing anteriorly
-After birth, secondary curvatures with convexity develops in the cervical region when child holds up head
-Also in lumbar region when legs start weight bearing
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What are the four movements of the vertebral column and their angles?
-Forward flexion (40 degrees)
-Extension (15 degrees)
-Lateral flexion (30 degrees)
-Rotation (40 degrees)
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Movements and angles of vertebral column and their angles:
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What is this and what makes it up?
162
What are intervertebral discs made of and what do they withstand?
-Strong fibrocartilaginous structures
-Can withstand compression forces but are flexible enough to allow movements between the vertebrae
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What are the two components of the intervertebral discs?
-Nucleus pulposus
-Surrounded by annulus fibrosis
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What is the nucleus pulposus made of?
-Well hydrated gel
-Having proteoglycan, collagen, cartilage cells
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What is the annulus fibrosus made of and what does it connect to?
-10-12 concentric layers of collagen whose oblique arrangement alters in successive layers
-Peripherally is attached to vertebral bodies as well as to the posterior longitudinal ligament
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What are these and what connect to them?
Annulus fibrous
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Erector spinae
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Where is the epidural space?
The 'space' between the vertebrae and the dura mater of the spinal cord
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What is in the epidural space?
Small arteries that supply the spinal cord and vertebral venous plexuses
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What are some features of the veins in the plexuses of the epidural space?
-Batson's veins
-Contain no valves
-Communicate freely with the intercostal veins and pelvic veins, including veins draining the prostate
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What is a spinal cord segment?
The area of the spinal cord from which a pair of spinal nerves are given off
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How many spinal cord segments and nerves are there?
-31 pairs of spinal nerves
-31 segments:
-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal
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Where are sensory fibres carried in the spinal nerve?
-Dorsal root
-Has a dorsal root ganglion that houses the cells of origin of the dorsal root fibres
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Where are motor fibres carried in the spinal nerve?
Ventral (anterior) root
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Where do the ventral roots emerge on the spinal cord and where do they join?
-Anterolateral aspect of the cord on either side
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What happens to the anterior and posterior spinal cord roots?
-Anterior and posterior roots join together on the intervertebral foramen to form the SPINAL NERVE
-Spinal nerve emerge from foramen and divides into anterior and posterior rami
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What do anterior and posterior rami each contain?
Motor and sensory fibres
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How does length of nerve roots differ?
Increases progressively from upwards downwards
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What do lumbar and sacral spinal roots form?
Lumbar and sacral nerve roots below the termination of the cord form the cauda equina (latin for horse's tail)
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What do the spinal nerves leave the spinal cord via and what is anterior and posterior to this structure?
-Intervertebral foramen
-Anterior = bodies of adjoining vertebrae and intervening intervertebral discs
-Posterior = Synovial joints between the two superior and inferior articular processes
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Dorsal root ganglion - location of cells of origin of the dorsal root fibres
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Where does the spinal cord end?
Interval between first and second lumbar vertebrae
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Where does the spinal cord end?
Interval between first and second lumbar vertebrae
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Describe them:
-Conus medullaris - tapering end of cord
-Filum terminale - fibrous strand extending from conus medullaris to coccyx
-Cauda equina - nerves from the lower part of the cord, the lumbar and sacral cords, hanging obliquely downwards
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What are they all?
Descending motor tracts
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What are they all?
Ascending sensory tracts
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What is this?
Describe it:
-Greater petrosal nerve
-Parasympathetic branch of facial nerve (CNVII)
-Emerges from petrous temporal bone and passes anteromedially
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What is this and where does it lie?
Tegmen tympani
Lies lateral and posterior to the greater petrosal nerve
202
Describe:
-Branch of facial nerve
-Crossing tympanic membrane
Chorda tympani
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Label:
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What are in the crus cerebri?
Columns of descending fibres
e.g. corticospinal and corticobulbar
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What are in the pyramids of the medulla?
-Fibres passing from cerebral hemispheres to the cord
-Corticospinal tracts
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What happens at the decusations of the pyramids?
-Diagonally oriented bundles of fibres crossing the fissure via which 80% of the corticospinal fibres cross the midline to enter the lateral white column of the spinal cord
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What is in the olive of the medulla?
Presence of underlying inferior olivary nucleus and is concerned with the control of movement
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Label these tracts:
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What is the tectum and tegmentum made up of?
Tectum - dorsal to aqueduct and made up of colliculi
Tegmentum - ventral to aqueduct, made up of nerve fibres entering and leaving the cerebral hemispheres, nerve nuclei etc.
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What are the superior and inferior colliculi associated with?
Superior - visual system, visual reflexes
Inferior - auditory system, reflex of looking towards loud noise
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What is this and what does it do?
Pineal gland
Endocrine gland that synthesises melatonin which modulates sleep patterns in both circadian and seasonal cycles
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What are these and describe them:
Inferior brachium - conveys auditory info from medial geniculate body to inferior colliculi
Superior brachium - conveys visual info from lateral geniculate body to superior colliculus
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What does the tegmentum contain at the level of the pons?
Nuclei of:
-Abducens VI
-Facial VII
-Trigeminal V (motor of mastication)
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What does the gracile fasciculus do?
Carries fine touch, vibration, two-point discrimination and proprioception from lower limb
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What does the cuneate fasciculus do?
Carries fine touch, vibration, two-point discrimination and proprioception from the upper limb
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What does the tegmentum contain at the level of the medulla?
Nuclei of:
IX
X
XI
XII
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What are the nuclei underlying the gracile and cuneate tubercles also called and what do they contain?
-Dorsal column nuclei
-Major relay sites for the dorsal column sensory pathway (dorsal column medial lemniscus pathway)
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What is the mnemonic for the geniculate bodies?
MALES
Medial geniculate = Auditory
Lateral geniculate = Eye (visual)
Lateral = eye = superior colliculus (medial is inferior by default)
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Label the locations of the cranial nerve nuclei in the brainstem:
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What is the mnemonic to remember which cranial nerves are sensory or motor?
I Some
II Say
III Marry
IV Money
V But
VI My
VII Brother
VIII Says
IX Big
X Boobs
Xi Matter
XII More
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What is the cerebellum involved in?
Coordination of movement and balance
228
What does the cerebellum compose of?
-Two ovoid hemispheres joined by the midline by a narrow median vermis
-Outer layer of grey matter - cortex
-inner core of white matter surrounding centrally placed deep nucleu (aggregations of nerve cells)
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What are these and describe them:
-Folia are individual ridges of cerebellar cortex
-Surface is marked by closely set transverse curiving fissures which delineate the folia
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What does the cerebral aqueduct do?
Runs through the midbrain and interconnects the third and fourth ventricles
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What is the flocculo-nodular lobe primarily concerned with?
Vestibular information - balance
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What is this?
Tonsil of cerebellum
Prominent rounded swelling of cerebellar cortex anteriorly on either side of the vermis
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Describe the corticopontocerebellar tract:
-Info from the primary motor cortex of the motor plan (same info goes to the spine)
-Connects to cerebellum via middle cerebellar peduncle
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Describe the vestibulocerebellar tract:
-Vestibular impulses from labyrinths directly and via the vestibular nucleus
-Connects to cerebellum via inferior cerebellar peduncle
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Describe the spinocerebellar tracts:
-Sensory input for balance and position sense
-Ventral spinocerebellar is contraleteral and connects via superior cerebellar peduncle
-Dorsal spinocerebellar is ipsilateral and connects via inferior cerebellar peduncle
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Describe the dentate nucleus:
-Largest and most lateral of the deep cerebellar nuclei
-Major fibre bundles passing into the superior cerebellar peduncle
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What is this and describe it:
-Facial colliculus
-Rounded swelling caused by fibres of facial nerve in the substance of the pons curving around nucleus of abducens nerve at level of superior fovea
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What is this and describe it:
-Medullary striae
-Aberrant ponto-cerebellar fibres passing from pons to cerebellum
-Divide the floor of the fourth ventricle into a rostral pontine half and a caudal medullary half
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What is this and describe it:
-Area postrema
-Small tongue-shaped are immediately rostro-lateral to obex
-Commonly associated with nausea control - chemoreceptive trigger zone for the emetic response and lie outside the blood-brain barrier
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Label and describe:
Interventricular foramen - permits CSF flow from lateral ventricles to IIIrd ventricle
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Describe:
Begins a little behind the midpoint of the hemisphere
-Extends short distance onto medial surface and running forwards and downwards before reaching lateral sulcus
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Describe this:
-Paracentral lobule
-U-shaped gyrus
-Surrounds medial extensions of central sulcus
-Contains representations of lower limb within the primary motor and somatic sensory areas of the cortex
which on the lateral surface occupy the pre-central and post-central gyri respectively
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What does the cingulate sulcus do?
Separates the cingulate gyrus (on top of the corpus callosum) from the the rest of the hemisphere
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Pareto-occipital sulcus
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What lies within the walls of the bottom structure?
Primary visual cortex
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What are these?
-Striae of genari
-White band in the primary visual cortex running parallel with the pial surface in the mid-depth grey matter
-Gives the name striate cortex to the primary visual area
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Describe them:
Primary motor cortex (precentral gyrus) grey matter is over twice as thick as that of the posterior primary somatosensory cortex (postcentral gyrus)
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What is the corpus callosum?
Broad arched band of white matter and the largest of the white fibre bundles interconnecting the two halves of the brain
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Describe this:
-Fornix
-White matter bundle beneath the corpus callosum that connects the hippocampus with the diencephalon and precommissural septum
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What does the anterior commissure of the fornix do?
Thick bundle of white matter crossing the midline horizontally between lamina terminalis and fornix
Crosses to interconnect temporal lobes and olfactory structures of either side
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Label and describe:
-Dorsal part of diencephalon
-Major subcortical relay for info ascending into the cerebral cortex
-Afferent info may be modified by the substantial descending projections to the thalamus from all parts of the cortex
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What is the interthalamic adhesion?
Flattened grey disc joining the thalami of each side behind the interventricular foramen
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What is the hypothalamic sulcus?
Shallow groove on lateral wall of IIIrd ventricle extending from cerebral aqueduct to interventricular foramen
-Separates the diencephalon into dorsal and ventral parts
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What is this?
Diencephalon
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What are these and what do they do?
Medial = relays auditory info from midbrain to auditory cortex and passes some fibres via inferior brachium to inferior colliculi
Lateral = relays visual info from optic nerve to both the visual cortex via optic radiation and superior colliculi via superior brachium for pupillary reflexes
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Label and describe:
-Ventral part of diencephalon that extends from lamina terminalis to a vertical plane in front of maxillary bodies
-Important centre contributing to body homeostasis and autonomic nervous and neuroendocrine systems control
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Label and describe:
-Below thalamus
-Lateral to hypothalamus
-Closely associated with basal ganglia
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Label and describe:
Adjacent to the lamina terminalus and in front of optic chiasma
Included as part of the hypothalamus on functional grounds
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What info relates to the bringing together of seperate representations of the two halves of the body?
-Commisural fibres between areas of the cortex on wither side containing representations are concentrated almost entirely in the midline
-Upper and lower limb representations in somatic sensory cortex neither send or receive commisural fibres
-Visual areas only vertical midling of retina connected, not periphery
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What is this and what major structures does it contain?
-Primary motor cortex
-Prefrontal cortex
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What is this and what major structures does it contain?
-Primary auditory cortex
-Auditory association cortex (Wernicke's area)
-Hippocampus
-Amygdala
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What is this and what major structures does it contain?
Primary somatosensory cortex and association cortex
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What is this and what major structures does it contain?
Primary visual and visual association cortex
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What do these make up and what do they contain?
-Brainstem
-Ascending and descending tracts
-Cranial nerve nuclei and the reticular formation
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What are gyri and sulci?
Gyri - rolls of cerebral cortex
-Sulci - grooves between gyri
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What is this?
Central sulcus
-A large fissure separating the frontal from the parietal lobes
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What is this?
Lateral sulcus
-Large fissure that separates the temporal lobe from the parietal and frontal lobes
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What is this?
-Insula
-Forms the floor of the lateral sulcus
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What overlies the insula?
-Opercula
-Parts of the temporal, frontal and parietal lobes that overlie the insula
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What is this?
Corpus callosum
Large white matter bundles connecting the two sides of the brain
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What is the only part of the diencephalon viewable from outside the brain?
Hypothalamus
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What are these?
-Crus cerebri
-Two white matter tracts behind the mamillary bodies from each cerebral hemisphere
-Pass backwards and converge in the midline at the upper border of the pons
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What is inbetween the crura cerebri?
-Interpeduncular fossa
-Space between the crura roofed over by arachnoid
-CRURA ARE THE ONLY PART OF THE MIDBRAIN VISIBLE
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What is situated directly behind the point where the crura meet in the midline?
-Pons
-Forms. abridge of neural tissue between the midbrain and the medulla oblongata
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What does the parietal lobe extend from?
Central sulcus anteriorly to the imaginary parietooccipital fissure posteriorly
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Describe the general function of the parietal lobe:
-Two with the left normally the most dominant ->
-Important for:
-Perception
-Interpretation of sensory info
-Formation of the idea of a complex, meaningful motor response
-Non-dominant important for visuospatial functions
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What are the functions of two specific parts of the parietal lobe?
Supramarginal and angular gyrus of dominant lobe are concerned with language and mathematical operations
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What is the frontal lobe generally involved in?
-Motor function
-Problem solving
-Spontaneity
-Memory
-Language
-Judgement
-Personality
-Impulse control
-Social and sexual behaviour
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What is the anterior part of the frontal lobe called and what does it do?
-Prefrontal cortex
-Higher cognitive functions and determination of personality
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What does the posterior part of the frontal lobe contain and do?
-Motor and premotor areas
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What is this, describe its location and function:
-Broca's area
-Left inferior frontal gyrus and is important for language production and comprehension
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What do the temporal lobes contain?
-Primary auditory cortex
-hippocampus
-Amygdala
-Wernicke's area
300
What is this and what does it do?
-Wernicke's area
-Located in superior temporal gyrus of LEFT hemisphere
-Understanding spoken word
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Auditory cortex found around the lateral (sylvian) fissure
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What is in the occipital lobe?
Primary visual and visual association cortex
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What does the limbic lobe surround?
Medial margin of the hemisphere
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What is the limbic system involved in?
-Emotion
-Memory
-Behaviour
-Olfaction
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What are the hippocampus and amygdala involved in?
-Hippocampus - long term memory formation
-Amygdala - Motivationally significant stimuli (reward + fear)
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How does the limbic system operate?
Influencing the endocrine system and autonomic nervous system and is highly interconnected with the brain's pleasure centre (nucleus accumbens)
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What is this and what does it do?
-Nucleus accumbens
-Role in sexual arousal and high experienced with recreational drugs
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What are the two layers of the dura mater?
Outer endosteal layer - interior to skull, adhering to and sending blood vessels and fibrous processes into cranial bones
Inner meningeal layer - completely envelopes CNS, continues as tube of dura seen around spinal cord and provides tubular sheaths for cranial nerves
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How would you describe the relationship between the two layers of dura mater?
-For most part they are fused
-In places the inner layer separates from skull to form dural folds
-Supports subdivisions of brain and partially divide cranial cavity into three areas: left + right hemispheres and posterior cranial fossa
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What can dural folds form?
When dural folds attach to skull there is a system of communicating blood filled spaces called dural venous sinuses
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Label and describe it:
Arched crescent of dura lying in the longitudinal fissure between cerebral hemispheres
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Label and describe it:
Where falx cerebri attaches to cranium
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Label and describe:
At the free border of the falx cerebri
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Label and describe:
Dura forming a thick fibrous roof over the posterior cranial fossa and the cerebellum
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Label:
Within the tentorium cerebelli
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What is this?
Cavernous sinus
Lies lateral to the body of the sphenoid
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Transverse sinusesRun along the line of attachment of the tentorium cerebelli to the occipital bone
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What is this?
-Trigeminal cave
-Lies next to apex of the petrous part of the temporal bone and envelopes the roots of the trigeminal nerve
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Label and describe:
Diaphragma sellae
Small circular, horizontal fold of dura mater which forms the roof of the pituitary fossa
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Label and describe:
Small, vertical sickle-shaped reflection of dura separating the two lobes of the cerebellum
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Label the yellow:
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Label the green:
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Label the pink:
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What is this?
-Encloses the brain loosely following the contour of the meningeal layer of the dura
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What can the arachnoid mater form?
Where the arachnoid spans the gyri of the brain, spaces exist between the arachnoid and the pia mater called subarachnoid cisterns
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What are subarachnoid cisterns full of?
Cerebral spinal fluid
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What is this?
Foramen of magendie
Midline communication between the IVth ventricle and the subarachnoid space
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Foramen of luschka
Lateral communication between the IVth ventricle and the subarachnoid space
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How are subarachnoid cisterns named?
After their positions relative to the brain
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Label and describe the orange:
-Cerebromedullary cistern
-Lies in the angle formed by the dorsal surface of the medulla and the inferior surface of the cerebellum
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Label and describe the green:
-Pontine cistern
-on the ventral surface of the pons
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Label and describe the pink:
-Interpeduncular cistern
-Contains the circle of Willis
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Cistern of the lateral fissure
-Contains the middle cerebral artery and bridges the lateral sulcus on either side
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Label and describe:
-Superior cistern
-Contains great cerebral vein (of Galen) and the pinea gland
-found between the posterior (splenium) of corpus callosum and the superior surface. of cerebellum
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What do these show?
Cisterna ambiens
-Group of subarachnoid cisterns which completely encircle the midbrain
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Describe the pia mater:
-Closely adherent to the underlying nervous tissue and is indistinguishable with the naked eye
-Functionally very important as it forms part of the blood brain barrier
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Describe arteries position on the surface of the brain:
-Lie in subarachnoid space
-As vessels pass into the substance of the brain they take with them prolongations of the pia mater and some of the subarachnoid space forming a layer around the vessel
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What happens as blood vessels penetrate deeper into the brain?
How does this relate to the pia mater?
-Tunica media thins and the prolongation of the subarachnoid space narrows
-At the level of the capillary network, the basement membranes of the endothelial cell and the pia fuse
-Pia acts as a barrier between the blood vessels and the neurological tissue
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describe the blood brain barrier and its functions:
-Combination of features unique to the brain and spinal cord
-Limit the ability of molecules to pass between the blood and CNS
-Has the effect of protecting tissue from toxic substances
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What are the 4 features of the blood-brain barrier?
-Edges of adjacent endothelial cells that line blood vessels are bonded closely together by tight junctions to prevent molecule movement
-Basement membrane of CNS blood vessels lack fenestrations which are present elsewhere
-Pericytes embedded in basement membrane wrap around endothelial cells and regulate capillary blood flow, immunity and vascular permeability
-Astrocytes extend end feet to envelop CNS capillaries and restrict movement of molecules into CNS parenchyma
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What are the 3 anatomical contributory elements of the blood-brain barrier?
-Endothelial cells of capillaries
-Basement membrane between endothelial cells and astrocyte end feet - formed from true basement membrane of the pia
-The astrocytic end feet themselves
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Through what does arterial blood arrive within the brain?
-Two pairs of vessels
-Internal carotid and vertebral arteries
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What do the two inflows of arterial blood supply in the brain and in what proportions?
Vertebral (20%) - posterior cerebrum and contents of posterior cranial fossa
Internal carotid (80%) - Anterior and middle cerebrum and the diencephalon
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Draw the arterial supply to the brain:
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Describe the path of the internal carotid artery:
-Arises at common bifurcation at upper thyroid cartilage border
-Ascends to base of skull
-Enters temporal bone to lie in carotid canal
-Pierces dura forming roof of cavernous sinus to enter cranial cavity
-Reaches anterior perforated substance at medial end of lateral sulcus to divide into terminal branches
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What is referred to as the anterior circulation?
-Anterior cerebral arteries
-Middle cerebral arteries
SUPPLIED BY INTERNAL CAROTID ARTERY (internal carotid system)
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Label these arteries:
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What does the anterior cerebral arteries supply?
Corpus callosum and medial aspects of the hemispheres
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What does the middle cerebral artery supply?
-Largest of terminal branched of internal carotid
-Majority of lateral surface of the hemisphere and deep structures of the anterior part of cerebral hemispheres via ANTERIOR PERFORATING BRANCHES
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What does the middle cerebral artery supply?
-Largest of terminal branched of internal carotid
-Majority of lateral surface of the hemisphere and deep structures of the anterior part of cerebral hemispheres via ANTERIOR PERFORATING BRANCHES
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What does the anterior communicating artery supply?
Connects together the two anterior cerebral arteries and provides ANTERIOR PERFORATING BRANCHES
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What does the posterior communicating artery supply?
Connects the internal carotid and vertebro-basilar systems via the POSTERIOR CEREBRAL ARTERY
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label the green:
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label the blue:
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What do these show and what does each colour represent?
Vascular territories
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What are each of these and what vessels pass through them?
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Describe the vertebral arteries and their paths:
-Arise from first part of subclavian arteries
-Frequently of different diameter on either side
-enter skull through foramen magnum
-Lower border of pons unite to form basilar artery
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Where does the basilar artery lie?
Anterior median fissure of the pons
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What forms the posterior circulation?
-Vertebral and basilar arteries
-Branches from them
-Posterior cerebral arteries
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What connects the anterior and posterior circulations?
Circle of willis
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What pathology most commonly ocurss near the circle of willis?
Berry aneurysm
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Why do cerebral veins differ?
-First drain into the dural venous sinuses which are channels formed between the two layers of dura mater
-Then drain back to heart
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What are the types of cereberal veins?
-Internal cerebral veins - run in the substance of the brain tissue and end when they reach the surface of the brain
-External cerebral veins - run on the surface of the brain crossing the subarachnoid space to drain into dural venous sinuses (4 named groups draining into different dural sinuses)
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What is this and what does it do?
-Great cerebral vein (of Galen)
-Drains the deep structures of the brain and drains into the straight sinus
-Cut end of the vein should be identifiable just above cerebellum between the two occipital lobes
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Label the blue:
What are they?
Dural venous sinuses of the brain
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Label the green:
What do they show?
The cerebral venous system
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What do the major venous sinuses do?
-Connect the major cerebral veins to the internal jugular veins
-Major venous sinuses can be easily identified in the attached borders of the falx cerebri, tentorium cerebelli and floor of cranial cavity
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What is the course of the venous sinuses?
On skull to their termination in the basal part of the occipital bone where they join the superior bulb of the internal jugular vein in the jugular foramen
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where are the superior and inferior sagittal sinuses?
Superior - superior border of falx cerebri
Inferior - inferior margin of falx cerebri
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where is the straight sinus?
In the midline of the tentorium cerebelli
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Where is the transverse sinus?
Posterior fixed margin of the tentorium cerebelli
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Where is the sigmoid sinus?
Deep groove in the mastoid part of the temporal bone
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WHERE IS THE CAVERNOUS SINUS?
BESIDE THE BODY OF THE SPHENOID BONE (5 CRANIAL NERVES AND INTERNAL CAROTID ARTERY)
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Where are the superior and inferior petrosal sinuses?
Superior - attached to the lateral margin of tentorium cerebelli
Inferior - in the groove between the petrous temporal bone and the basal part of occipital bone
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Label the red:
What are they?
Sinuses at base of skull
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Label the green:
What are they?
Cranial nerves at base of skull
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Label the blue:
What are they?
Blood vessels at the base of the skull
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Which sinus has major clinical significance?
-Cavernous
-Houses 5 cranial nerves and the internal carotid artery
-proximity to pituitary gland
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What does this show?
What passes through cavernous sinus and what is in proximity to it
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What do intracranial venous sinuses and the veins outside the skull communicate via?
Describe them:
-Variable number of emissary veins
-Important as they represent a possible route for infection and inflammation to spread into the cranial cavity from outside the skull
-Difficult to find but 'grooves' can be found on inside of skull that demonstrate where they ran
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Label the green:
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Label the pink:
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Label the blue:
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Describe how brain development leads to development of certain structures within the brain:
-Develops from hollow neural tube
-Remains hollow
-Central spaces form the ventricles
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What are the ventricles important for?
In relation to the formation and circulation of cerebrospinal fluid
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Where is the largest aggregation of choroid plexus and what occurs here??
-In the lateral ventricles
-Majority of CSF is produced here
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Describe the movement of CSF:
-Lateral ventricles to 3rd ventricle via interventricular foramen
-3rd ventricle to fourth ventricle via cerebral aqueduct
-4th communicates with subarachnoid space via median foramen of magendie and lateral foramen of luschka
-Through these openings, CSF passes out to occupy subarachnoid space around the brain and spinal cord
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Choroid plexus
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What is this?
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Describe this and what it does:
-invagination of vessels into the ventricles produces a vascular fold of pia mater covered by an epithelium derived from ependymal lining of ventricle
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Describe the control of CSF:
-Tight junctions prevent passage of fluid from extracellular space of the choroid plexus into the ventricle
-EXCEPT via choroid cells themselves
-Enables close control over the volume and composition of the CSF
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What constitutes the CSF-brain barrier and what occurs here?
-Ependyma
-Resorption of the CSF into the venous drainage of the brain occurs via tufts of arachnoid mater called arachnoid villi
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What are these?
-Arachnoid granulations
-Villi calcify
-Tend to cause bone to be resorbed along the internal surface of the cranial vault near the midline causing small, pit-like structures
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How do you remember the position of ventricle apertures?
Magendia foramen = Medial
Luschka foramen = Lateral
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