Brain Flashcards
What is the outermost layer of the meninges?
The dura mater
What is the strongest layer of the meninges?
The dura mater
What are the two layers of the dura mater?
Periosteal & meningeal
What is the outside layer of the dura mater continuous with?
-Outside layer continuous with the bone (periosteal layer)
Where are the menigneal vessel located?
Located between the dura and the cranium are the meningeal vessels
What is the epidural space?
Potential space between the dura and the cranium called the epidural space
Where is the epidural space “located”?
Potential space located between the two dural layers are the dural sinuses (provide venous drainage)
What is the purpose of the dural folds?
They separate the brain structures and provide additional cushioning and support
What does the Falx cerebri separate?
Separates the cerebral hemispheres
What does the Tentorium cerebelli form?
Forms a partition between the cerebrum and the cerebellum (another part of the dura)
What does the Tentorial notch surround?
Surrounds the midbrain
What structures does the tentorial notch connect?
Connects the cerebral hemispheres to the cerebellum
What is the Falx cerebri?
The Dura folding over itself
What is the Arachnoid membrane?
Delicate, transparent membrane
How is the arachnoid membrane Separated from the dura?
Separated by a potential space called the subdural space.
What is the inner layer of the meninges?
The Pia mater
T/F
The pia mater is not vascular
False; Highly vascular
What does the pia mater adhere to?
Adheres closely to the contours of the brain
What separates the pia mater from the arachnoid mater
The subarachnoid space
What fluid is contained within the subarachnoid space
CSF
What are Arachnoid granulations (villi)?
Small protrusions of the arachnoid mater into the dural sinuses allow for CSF to exit the subarachnoid space and enter the bloodstream.
Where does the largest granulations lie?
Lies in the superior sagittal sinus along the midline of the head
What separates the cerebral hemisphere from the cerebelli?
Tentorium cerebelli
What is the Ventricular system in the brain?
Fluid filled cavities deep within the brain
What does the Choroid plexus produce?
Produces CSF
What are the 2 superior most cavities of the ventricular system?
Right and left lateral ventricles
Where are the lateral ventricles located in the brain?
Lies within each cerebral hemisphere
What are the right and left lateral ventricles separated by?
Separated at the midline by a thin membrane called the septum pellucidum.
What does the ventricular system of the lateral ventricles of the brain consist of?
Consists of a body and 3 extensions: frontal/anterior horn, occipital/posterior horn and temporal/inferior horn
T/F
On an axial slice we will not see all three ventricles
True
How do the lateral ventricles communicate with the 3rd ventricle?
The lateral ventricles communicate inferiorly with the 3rd ventricle via the paired interventricular foramen
What is another name for the interventricular foramen
Foramen of Monro
Where is the 3rd ventricle located in relation to the lateral ventricles?
Located midline just inferior to the anterior horns of the lateral ventricles
What is the anterior wall of the 3rd ventricle formed by?
Formed by a thin membrane termed the lamina terminalis
What are the lateral walls of the 3rd ventricle formed by?
They are formed by the thalamus.
What is located within the posterior horns of the lateral ventricles?
The choroid plexus
How does the 3rd ventricle communicate with the 4th ventricle?
Communicates via a long, narrow passageway termed the cerebral aqueduct
What is another name for the cerebral aqueduct
Aqueduct of Sylvius
What part of the midbrain does the cerebral aqueduct travel through?
Travels through the posterior aspect of the midbrain.
What is the shape of the 4th ventricle?
diamond shaped
Where is the fourth ventricle located in relation to the cerebellum and the pons?
Located anterior to the cerebellum and posterior to the pons.
What separates the 4th ventricle from the cerebellum?
A thin membrane forming the superior and inferior medullary velum.
What is the last ventricle that the CSF goes through?
The fourth ventricle
After passing through the fourth ventricle, what space in the brain does it travel to?
Enters the subarachnoid space
What is the major exit route for CSF after passing through the fourth ventricle?
The median aperture
What is another name for the median aperture?
Foramen of Magendie
Where is the median aperture located?
Located on the posterior wall of the 4th ventricle.
What structure does the median aperture communicate with?
It communicates with the cisterna magna.
What are the two lateral apertures of the fourth ventricle also called?
Foramen of Luschka
What cistern do the lateral apertures of the fourth ventricle communicate with?
Communicate with the cerebellopontine angle cistern.
From the 4th ventricle, where does CSF continue within the body?
CSF continues into the spinal cord via the central canal.
What is the Midbrain?
A bundle of nervous tissue connecting the cerebrum with the cerebellum and spinal cord.
Where is the midbrain located in relation to the 3rd ventricle?
Located inferior to the third ventricle
What aqueduct does the midbrain contain?
Contains the cerebral aqueduct.
What structure is located on the anterior aspect of the midbrain?
Cerebral peduncles
What is the function of the cerebral peduncles?
Carry motor impulses from the cerebral cortex to the pons and the spinal cord.
T/F
The Pons are located in the brainstem
True
Where are the pons located in relation to the fourth ventricle?
Located anterior to the 4th ventricle.
What are the pons?
A structure where nerve fibers from the cerebellum join those from the cerebrum and spinal cord.
What structure forms the lower brain stem?
The medulla oblongata
Where is the medulla oblongata located in relation to the pons?
Directly below the pons
What structure does the medulla oblongata contain?
Contains all the ascending and descending tracts that communicate between the brain and the spinal cord.
What is the subarachnoid space?
A narrow fluid filled space surrounding the brain and spinal cord
What is the location of the widening of the subarachnoid space called?
It widens at locations called basal cisterns
T/F
Cisterns are usually named after the brain structure it borders
True
What is the largest cistern in the brain?
The Cisterna magna
Where is the cisterna magna located within the brain?
Located in the lower posterior fossa
Where is the Interpeduncular cistern located?
Located between the peduncles of the midbrain
What does the Interpeduncular cistern communicate with inferiorly?
Communicates inferiorly with the prepontine cistern
Where are the Prepontine cistern located in relation to the pons?
Located just anterior and inferior to the pons
What does the Prepontine cistern communicate with laterally?
Communicates laterally with the cerebellopontine angle (CPA) cistern.
Where is the CPA cistern located?
Located at the junction of the pons and the cerebellum.
What two structures does the ambient cistern connect?
Connects the interpeduncular cistern with the quadrigeminal cistern.
Where is the Quadrigeminal Cistern located?
The quadrigeminal cistern lies between the cerebellum and the midbrain.
Where is the Suprasellar cistern located? What does it contain?
Located above the Sella turcica and contains the optic chiasm and the Circle of Willis.
What is the largest portion of the brain?
The cerebrum
What is the cerebrum divided into?
Divided into left and right hemispheres
What are the neural tissues located within the hemispheres of the cerebrum called?
Gyri
What are gyri separated by?
Separated by shallow grooves called sulci and by deeper grooves called fissures.
What does the Central Sulcus divide?
Divides the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe.
What are the 2 main fissures of the cerebrum?
The longitudinal fissure & Sylvian/lateral fissure
What does the longitudinal fissure divide?
Divides left and right cerebral hemispheres. (deep)
What is located within the longitudinal fissure?
Falx cerebri and superior sagittal sinus
What does the lateral fissure separate?
Separates the frontal and parietal lobes from the temporal lobes. (deep)
What type of matter makes up the Cerebral cortex
Grey matter
What is located deep to the cerebral cortex?
White matter
What is the purpose of the white matter?
Contains fibers that create pathways for the transmission of nerve impulses to and from the cortex.
What is the largest and densest bundle of white matter fibers within the cerebrum
The corpus callosum.
Where is the insular cortex located?
In each hemisphere of the brain deep within the lateral fissure
Where is the Corpus callosum located?
Located midline
What does the corpus callosum form?
Forms the roof of the lateral ventricles
What two structures does the corpus callosum connect?
Connects left and right hemispheres.
What are the 4 parts of the corpus callosum?
Rostrum, Genu, Body & Splenium
What structures does the anterior commissure connect?
Connects the anterior portion of the temporal lobes.
Where is the posterior commissure located?
It crosses the midline behind the third ventricle, immediately above the cerebral aqueduct and inferior to the pineal gland.
What type of matter is the Basal Ganglia/Nuclei?
Subcortical grey matter
What does the basal ganglia/nuclei consist of?
Consists of caudate nucleus, lentiform nucleus and claustrum
Where is the Caudate nucleus located in relation to the lateral ventricle?
Parallel to the lateral ventricle
What parts does the caudate nucleus consist of?
Consists of a head, body and tail.
What causes the indentation in the frontal horns of the lateral ventricles?
The head of the caudate nucleus
Where does the tail of the caudate nucleus end?
Terminates in the amygdala in the temporal lobe.
Where is the Lentiform nucleus located in realtion to the insula, caudate, and thalamus?
Located between the insula, caudate nucleus and thalamus.
What type of matter is the lentiform nucleus?
Grey matter
What are the parts of the Lentiform nucleus?
1.Globus pallidus (medially) and
2.putamen (laterally).
What is the claustrum?
It is a thin layer of gray matter lying between the insula and the lentiform nucleus.
What are the 3 large tracts of white matter in the brain?
The internal, external and extreme capsules
What is the function of the 3 large tracts of white matter in the brain?
They separate the basal nuclei and transmit electrical impulses throughout the brain.
What are the two major components of the Diencephalon?
Thalamus and hypothalamus
What type of matter is the thalamus?
Gray masses
What makes up the walls of the third ventricle?
The thalamus
How does the thalamus connect through the middle of the third ventricle?
Through adhesions called the massa intermedia. (hole in the 3rd ventricle)
Where is the Hypothalamus located in relation to the thalamus?
Below thalamus
What is the Hypothalamus made of?
Consists of a cluster of small but critical nuclei
What forms the floor of the third ventricle?
The Hypothalamus
What does the Hypothalamus consist of?
Consists of the optic chiasm, mammillary bodies and the infundibulum
Which way does the optic nerve extend through the orbit? What canal does it exit through?
Extends posteriorly through the orbit and leaves the orbit via the optic canal.
T/F
The optic nerve enters the anterior cranial fossa.
True
What do the optic nerves join to form?
Form the optic chiasm
Where is the optic chiasm located?
The suprasellar cistern.
What makes up the optic tracts?
The fibers of each optic nerve cross the midline (decussate) at the chiasm, forming the optic tracts.
What structure Occupies the posterior cranial fossa?
The cerebellum
What is the function of the cerebellum?
Coordination of motor functions
How many cerebellar hemispheres are there?
2
What is the Midline structure of the cerebellum?
The vermis which connects the two hemispheres
T/F
The walls of the arteries of the brain are thin and weak
True; causing them to be susceptible to aneurysms and strokes.
T/F
The veins of the brain contain valves.
False; They do not contain valves
Why is it beneficial that the veins of the brain do not have valves?
This lack of valves allows blood to flow in either direction.
What is the function of the blood brain barrier?
To prevent movement of certain molecules from their vascular compartment into the brain tissues.
T/F
Some structure within the brain do not have a BBB
True
How do structures that do not a have a BBB appear when contrast media is used?
They will enhance when contrast media is used.
Read over the following structures that do not have a BBB:
pituitary gland, infundibulum, pineal gland, choroid plexus, mucosal lining of the sinuses, venous structures and meninges
Where are dural venous sinuses located in relation to the layers of the brain?
Located between the periosteal and meningeal layers of dura mater in the brain.
Where do the dural venous sinuses recieve blood from? Where do they recieve CSF from?
-Receive blood from internal and external veins of the brain
-Receive CSF from the subarachnoid space via arachnoid granulations
What vein do the dural venous sinuses generally drain into?
Mainly empty into the internal jugular vein.
Where is the superior sagittal sinus located in relation to the falx cerebri?
Located within the upper margins of the falx cerebri
What do the layers of the dura form?
Form a sinus for venous blood draining from the upper cerebral hemisphere.
Where is the superior sagittal sinus located in relation to the calvarium?
Located near the inner surface of the calvarium.
What structure does the superior sagittal sinus start and end at?
Begins at the crista galli and ends at the internal occipital protuberance.
Where is the inferior sagittal sinus located in relation to to the falx cerebri?
Located within the lower margin of the falx cerebri.
In the coronal section where is the inferior sagittal sinus located in relation to the hemispheres and the corpus callosum?
It is located between the hemispheres just above the corpus callosum.
What sinus is this describing?
A space for venous blood between the layers of the dura at the juncture of the falx cerebri, the falx cerebelli and the tentorium cerebelli.
Straight sinus
What is the straight sinus formed by?
Formed by the union of ISS and the great cerebral vein (of Galen)
What does the straight sinus empty into?
Empties into the confluence of sinuses.
T/F
The internal cerebral veins are paired.
True
Where are the internal cerebral veins located in relation to the 3rd ventricle and where do they drain into?
Located on the roof of the 3rd ventricle and drain into the vein of Galen.
Where are the internal cerebral veins located in relation to the corpus colosseum?
They are located just inferior to the splenium of the CC. (corpus collosum)
What vein is this describing?
Unpaired, short, and runs between the splenium of the CC and the pineal gland.
Great cerebral vein (of Galen)
What is the opening of the COS formed by?
Formed by the layers of the dura where the SSS, SS and transverse sinus meet
Where is the Transverse sinus located in relation to the tentorium cerebelli?
Located within the posterior margin of the tentorium cerebelli.
What sinus drains blood from the COS?
The transverse sinus
What sinus does the transverse sinus join with?
Joins the sigmoid sinus.
Where are the Cavernous Sinuses located in relation to the body of the sphenoid and the pituitary gland?
Located on either side of the body of the sphenoid and pituitary gland.
What does the Cavernous Sinuses drain blood into?
Drains blood into the petrosal sinuses, which drain into the sigmoid sinuses
Where does the sigmoid sinus drain blood from?
The petrosal sinuses
Where does the petrosal sinus drain blood into?
Into the internal jugular veins.
What two main pairs of vessels does the brain receive arterial blood from?
The internal carotid artery and the vertebral arteries.
Once the ICA exits the carotid canal, what two structures does it run through after?
Runs superior to the foramen lacerum and then forward to enter the cavernous sinus.
What vessel forms the carotid siphon before it exits the cavernous sinus?
The ICA
What vessel does the ophthalmic artery branch off of?
The ICA (just inferior to the anterior clinoid process.)
Within the circle of willis, what does the ICA branch into?
Branches into anterior and middle cerebral arteries
What is the Superior border of the cavernous sinus?
The optic chiasm, internal carotid artery
What is the Inferior border of the cavernous sinus?
The greater wing of sphenoid bone
What is the Medial border of the cavernous sinus?
Sella turcica and sphenoidal sinus
What is the Lateral border of the cavernous sinus?
The temporal lobes
What arteries does the vertebral artery branch off of?
The subclavian arteries.
Where do the vertebral arteries enter the skull through?
Enters the cranium through the foramen magnum.
What structure do the 2 vertebral arteries run along prior to their union?
Run along the medulla oblongata
What do the vertebral arteries unite to form?
Form the basilar artery.
What does the basilar artery give rise to?
Gives rise to the posterior cerebral arteries.
What is the circle of willis?
The Anastomosis of 4 major arteries: 2 vertebrals and 2 internal carotids.
What is this describing?
Located in the suprasellar cistern
The circle of willis
