Gross Brain, Brain Stem, And Spinal Cord Flashcards
What are the cranial meninges?
What do they do?
3 dense regular CT layers
Separate soft tissue of brain from bones of cranium
Functions of Cranial Meninges (3)?
‣ Enclose and protect blood vessels that supply the brain
‣ contain and circulate cerebrospinal fluid
‣ Form some of the veins that drain blood from the brain
What are the layers of the cranial meninges from superficial to deep?
‣ Dura Mater
‣ Arachnoid Mater
‣ Pia Mater
What is the composition of
Dura mater?
‣ Tough membrane composed of 2 fibrous layers
‣ Strongest
What are the layers of the dura mater?
- Periosteal layer: more superficial layer, attaches to the periosteum of the cranial bones
- Meningeal layer: deep to the periosteal layer
‣ meningeal layer fuses to periosteal
What can the 2 layers of Dura Mater form?
dural venous sinuses
When meningeal and periosteal layer become separated
What is an epidural hematoma from?
How will it appear on a CT?
Ruptured middle meningeal a.
Will look like a “lens” on a CT
What is the composition of the arachnoid layer?
‣ Composed of web of collagen and elastic fibers = arachnoid trabeculae
What is between the arachnoid and dura mater layers?
When is this formed?
Potential space - Subdural space
Only occurs when an accel/deacell. Event has happened and caused a bleeding from a bridging v.
How does a Subdural hematoma appear on a CT?
Crescent shaped
What space is found deep to the arachnoid layer of meninges?
What is found in here?
Subarachnoid space
CSF
How does a subarachnoid hemorrhage occur?
How does it appear on a CT?
Hemorrhage from cerebral artery; berry aneurysm
Spiderweb
What is the pia mater?
Innermost meninges
Adheres to brain and follow contour of brain
What are the 12 CNs?
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Spinal accessory n.
- Hypoglossal
What brainstem nuclei give rise to the modalities in
CN 3?
GSE - nucleus f oculomotor n. In mesencephalon
GVE - edinger-westphal nucleus (paras.)
What brainstem nuclei give rise to the modalities in
CN 4?
GSE - Nucleus of Trochlear N. In Mesencephalon
What brainstem nuclei give rise to the modalities in
CN 5?
GSE: motor nucleus of trigeminal n.
SVE: Principal sensory nucleus of CN 5;
Mesencephalic Nucleus of Trigeminal n.; Spinal Nucl. Of Trigeminal N.
What brainstem nuclei give rise to the modalities in
CN 6?
GSE: Nucleus of Abducens N.
What brainstem nuclei give rise to the modalities in
CN 7?
GSA: Rostral Nucleus, cadual nucleus?
GVE: Superior salivatory nucleus
SVA: solitary tract nucleus
SVE: Nucleus of Facial N. (In lower part of pontine tegmentum)
What is the floor of the fourth ventricle divided into?
What divides them?
Medial part = basal lamina
Lateral part = alar lamina
Sulcus limitans
What nuclei lie in the basal lamina?
Motor nuclei (efferent)
What nuclei lie in the alar lamina?
Sensory nuclei (afferent nuclei)
Where does visceral nuclei lie in the alar and basal lamina?
In both:
Visceral nuclei (SVE, GVE, SVA, GVA) lie closer to sulcus limitans than somatic nuclei
What is the sequence of the nuclear column from midline to lateral?
What lamina of the floor of the 4th ventricle are they in?
From median sulcus of 4th entirely to lateral aspect
GSE —> SVE—> GVE
(GSE closest to median sulcus)
(GVE is farther from median sulcus but next to sulcus limitans)
Basal lamina (medial pat)
What is the sequence of nuclei on the alar lamina?
On other side of sulcus limitans..
GVA—> SVA—> GSA—> SSA
(SSA is farthest from sulcus limitans laterally)
Where does the CN 1 originate from?
Olfactory bulb
Where is the olfactory bulb? What does it control?
Forebrain
Controls olfaction
Where does CN 2 originate from?
Where does it transmit to?
Retina
Transmits visual impulses to visual cortex (occipital lobe)
What nuclei make up the GSE column?
3, 4, 6, 11, 12
Oculomotor nucleus
Trochlear nucleus
Abducens nucleus
Hypoglossal nucleus
What nuclei make up the SVE column?
5, 7, 9, 10
Motor nucleus of Trigeminal N. (Pons)
Nucleus of facial N.
(Pontine tegmentum)
Nucleus ambiguus
(Medulla)
(9, 10, and 11 receive fibers from this)
What nuclei make up the GVE column?
What do they give origin to?
Give origin to preganglionic fibers
3, 7, 9, 10
Edinger-westphal nucleus (midbrain)
Superior and inferior Salivatory Nuclei (dorsal part of pons)
Dorsal vagal nucleus (Vertical in medulla)
What nuclei make up the GVA and SVA columns?
GVA: 9, 10
SVA: 1, 7, 9, 10
Nucleus of solitary tract (medulla) (9 and 10)
Commissural nucleus of vagus (10)
Gustatory nucleus (in upper part of solitary tract, for SVA [taste] for 7, 9, 10)
How does the commissural nucleus of the vagus nerve form?
Fibers from solitary tract end here and fuse together
What nuclei make up the GSA column?
GSA: 5, 7, 9, 10
Principle sensory nucleus of the trigeminal n. (Pons)
-for proprioceptive impulses, touch and pressure
Spinal nucleus of Trigeminal N.
(Extends from main nucleus in pons down to medulla, continuous with substantia of spinal cord)
-receives GSA from 7, 9, 10; mediates pain and thermal sensibility
Mesencephalic Nucleus of Trigeminal N.
(Main nucleus in pons to midbrain)
-center for jaw jerk, proprioceptive impulses from Ms. of mastication
What nuclei make up the SSA column?
2, 8
2 cochlear nuclei
- dorsal and ventral nucleus
(At level of pontine medullary junction)
Vestibular nucleus
(Partly in medulla partly in pons)
What are the 3 sub-nuclei of the spinal nucleus?
Oralis
Interpolaris
Caudalis
What are the 4 nuclei of the vestibular nucleus?
Medial
Lateral (aka Deiter’s nucleus)
Inferior
Superior vestibular nuclei
Where does the nucelus of the solitary tract mainly send fibers to?
Where does it receive fibers from?
From: 7, 9, 10
Send to: hypothalamus, thalamus, cerebral cortex
What does the PNS consist of?
Collection of spinal and cranial Ns. Whose branches convey messages to and from the CNS
What does the CNS consist of?
Brain and spinal cord?
What is the brain composed of?
Forebrain
Cerebellum
Brain stem
What composes the forebrain?
Cerebral hemispheres
Diencephalon
Where is the brainstem?
Between forebrain and spinal cord
What is “Grey matter”?
Areas w/ neuronal/glial cell bodies and dendrites
What is “White matter” ?
Areas where there is a collection of axons, many myelinated
What is a nuclei?
Collections of cell bodies w/ common function
What is a “cortex”?
What are examples?
Layers of grey matter over other parts of CNS
Cerebral and cerebellum vortices
What are other terms for white matter?
Fascicles, funiculars, lemniscus, peduncle, tract
What are the 2 parts to the name of a tract?
1st: location of neuronal cell bodies from which axons originate
2nd: site of axon termination
What does central white matter consist of?
Arcuate fibers Longitudinal/Association fasciculi Projection tracts Corpus callosum Anterior commissure
What do arcuate fibers do?
Connect cortical areas within
SAME sulci/gyri
What do longitudinal/association fasciculi do?
Connect cortical areas within
SAME Hemisphere
What do projection tracts do?
Connect cortical areas within
OTHER Body Regions
What does the corpus callosum do?
How many axons does it contain?
Interconnects 2 cerebral hemispheres
~250 million axons
What does the anterior commissure do?
Commissural fibers to and from temporal lobe
Esp. Inferior parts
What is a gyrus?
Ridge of cortical tissue
What is a sulcus? Fissure?
Groove located b/w gyri
Fissure = deep sulci
What does the folding seen in brain do?
Increase total cortical area and total number of cortical neurons
What are the 4 prominent sulci?
Central sulcus
Lateral sulcus
Parietooccipital sulcus
Cingulate sulcus
What is the limbic lobe?
Strip of cortex that encircles telencephalon-diencephalon junction
(Between corpus callosum, and F, P, and O lobes)
What does the frontal lobe contain generally?
Motor areas
What are the gyri in the
Frontal lobe?
Precentral
Superior/middle/inferior frontal gyri
On lateral surface
What does the precentral gyrus house?
Primary motor cortex
What are the function of the primary motor cortex?
Where do you find this cortex?
In precentral gyrus
Planning and initiating voluntary movements
What lobe is broca’s area in?
What does it do?
Left Frontal lobe
Motor aspects (Production) of written and spoken language
What gyrus is Broca’s area in?
Opercular and triangular parts of inferior frontal gyrus
Where is the prefrontal cortex?
Function?
Frontal lobe
Executive functions - personality,d excision making, insight and foresight
What does the parietal lobe contain generally?
What gyri doe it have?
Somatosensory areas
Post-central gyrus
Superior/inferior parietal lobules
What is the function of the post central gyrus?
What lobe do you find it in?
Primary somatosensory cortex to process tactile and proprioceptive info and sensory localization
Parietal lobe
What does the inferior parietal lobule do?
Where do you find this?
Language comprehension
Usually left hemisphere
What other functions does the parietal lobe assist in that is not tactile, propioceptive, sensory, or language comprehension?
Not assoc. w/ any structure
Remain does spatial orientation and directing attention