BMB 1 - Cranial Foramina, Meninges, the Ventricular System, CSF, & the Blood-Brain Barrier Flashcards
The cervicomedullary junction (where the medulla oblongata meets the spinal cord) is located where?
The foramen magnum
The cranial vault is divided into how many fossae?
Three
(anterior, middle, posterior)
Identify the major structures withiin each of the following fossa of the cranial vault:
Anterior -
Middle -
Posterior -
Identify the major structures withiin each of the following fossa of the cranial vault:
Anterior - frontal lobe
Middle - temporal lobe
Posterior - cerebellum; brainstem
Name the skull foramina through which each of the following exits the cranial vault:
CN I
CN II
CN III
Cribriform plate
Optic canal
Superior orbital fissure
Name the skull foramina through which each of the following exits the cranial vault:
CN IV
CN V1
CN V2
Superior orbital fissure
Superior orbital fissure
Foramen rotundum
Name the skull foramina through which each of the following exits the cranial vault:
CN V3
CN VI
CN VII
Foramen ovale
Superior orbital fissure
Internal auditory meatus
Name the skull foramina through which each of the following exits the cranial vault:
CN VIII
CN IX
CN X
Internal auditory meatus
Jugular foramen
Jugular foramen
Name the skull foramina through which each of the following exits the cranial vault:
CN XI
CN XII
Jugular foramen (Note: the accessory n. entered the skull via the foramen magnum)
Hypoglossal canal
Identify the major structure(s) passing through the foramen magnum (nervous, vasculature, etc.).
Medulla oblongata
Vertebral arteries
CN XI roots
Identify the major structure(s) passing through the hypoglossal canal (nervous, vasculature, etc.).
CN XII
Identify the major structure(s) passing through the jugular foramen (nervous, vasculature, etc.)
CN IX, X, and XI
The internal jugular vein
The inferior petrosal and sigmoid sinuses
Identify the major structure(s) passing through the internal acoustic meatus (nervous, vasculature, etc.).
CN VII and VIII
Identify the major structure(s) passing through the carotid canal (nervous, vasculature, etc.).
The internal carotid artery
The internal carotid nerve plexus
Identify the major structure(s) passing through the foramen spinosum (nervous, vasculature, etc.).
The middle meningeal artery
The meningeal branch of the mandibular nerve
Identify the major structure(s) passing through the foramen ovale (nervous, vasculature, etc.).
CN V3
The lesser petrosal nerve
Identify the major structure(s) passing over the foramen lacerum (nervous, vasculature, etc.).
The greater petrosal nerve
Identify the major structure(s) passing through the foramen rotundum (nervous, vasculature, etc.).
CN V2
Identify the major structure(s) passing through the superior orbital fissure (nervous, vasculature, etc.).
CN III, IV, V1, VI
The superior ophthalmic vein
Identify the major structure(s) passing through the optic canal (nervous, vasculature, etc.).
CN II
the ophthalmic artery
Identify the major structure(s) passing through the cribriform foramina (nervous, vasculature, etc.).
CN I
Via what foramina do the lesser and greater palantine neurovasculature exit the cranial vault?
The lesser and greater palantine foramina
(respectively)
From external to internal, name the three layers of meninges (and also the two layers of the external layer).
Dura (periosteal and inner meningeal)
Arachnoid
Pia
What is the name of the sheet of dura mater that separates the two hemispheres of the brain?
The falx cerebri
(frontally attaches at the crista galli)
What is the name of the sheet of dura mater that separates the occipital lobe and the cerebellum?
The tentorium cerebelli
What structure separates the supratentorial from the infratentorial brain structures?
The tentorium cerebelli
The midbrain must pass through an opening in the tentorium cerebelli. What is the opening called?
The tentorial notch
True/False.
The dura mater is the tough outer layer.
The arachnoid mater is a spider layer beneath which contains the CSF.
The pia mater is the imperceptibly thin layer closely covering the brain.
True.
The pia mater surrounds the initial portion of each blood vessel as it penetrates the brain surface, forming a space called the __________ space.
The pia mater surrounds the initial portion of each blood vessel as it penetrates the brain surface, forming a space called the perivascular space (a.k.a. the Virchow-Robin space)**.
What is the only significant difference between the cranial meninges and the spinal meninges?
A layer of epidural fat in the spinal cord
(between the dura and periosteum)
The middle meningeal artery runs in what potential space?
The epidural space
(a pseudospace between dura mater and closely adhered cranium)
Name the main blood vessels found in the following meningeal spaces:
Epidural -
Subdural -
Subarachnoid -
Name the main blood vessels found in the following meningeal spaces:
Epidural - middle meningeal artery (along the pterion)
Subdural - bridging veins
Subarachnoid - major brain arteries
Name the location for the following blood vessels within the meningeal spaces:
Middle meningeal artery (along the pterion) -
Bridging veins -
Major brain arteries -
Name the location for the following blood vessels within the meningeal spaces:
Middle meningeal artery (along the pterion) - epidural space
Bridging veins - subdural space
Major brain arteries - subarachnoid space
Dural venous sinuses are large venous channels that are enclosed within what space?
Between the two layers of dura
What is the purple labeled portion of the lateral ventricle called?
And the yellow portion?
Frontal (or anterior) horn
Body
What is the green labeled portion of the lateral ventricle called?
And the red portion?
And the blue?
Atrium
Occipital (posterior) horn
Temporal (inferior) horn
The lateral and third ventricles are connected via the foramina of ________.
The third ventricle is connected to the fourth ventricle via the ________.
The lateral and third ventricles are connected via the foramina of Monro.
The third ventricle is connected to the fourth ventricle via the cerebral aquaduct.
The fourth ventricle is drained medially via the foramina of ________ and laterally via the foramina of ________.
.
The fourth ventricle is drained medially via the foramina of Magendie and laterally via the foramina of Luschka.
.
Where is the third ventricle of the brain located?
Between the left and right thalami
The cerebral aquaduct is a small passageway that mainly passes through which general structure?
The midbrain
The fourth ventricle is a flaring of the cerebral aqueduct found at the location of the _______ and ______________.
The fourth ventricle is a flaring of the cerebral aqueduct found at the location of the pons and rostral medulla oblongata.
Does CSF enter or exit the brain via the subarachnoid space?
Exit
The reabsorption of CSF occurs in the subarachoid space via arachnoid __________ that absorb the CSF into _____ _____ _____ (which drain to the bloodstream).
The reabsorption of CSF occurs in the subarachoid space via arachnoid granulations that absorb the CSF into dural venous sinuses (which drain to the bloodstream).
Adults typically have ~_____ mL of CSF at any given time.
Adults typically produce ~_____ mL of CSF per day.
Adults typically have ~150 mL of CSF at any given time.
Adults typically produce ~500 mL of CSF per day.
What are the cranial cisterns?
Enclosed spaces serving as CSF reservoirs
Where is the cisterna magna (the largest of the cisterns)?
Inferior to the cerebellum
Where are the paramesencephalic cisterns?
Where is the quadrigeminal cistern?
(PC - lateral to the midbrain)
(QC - posterior to the midbrain, surrounding the colliculi)
Where is the interpeduncular cistern?
Where is the prepontine cistern?
(IPC - anterior to the midbrain)
(PPC - anterior to the pons)
Which cranial nerve or vasculature can be found in the interpeduncular cistern?
CN III
Which cranial nerve or vasculature can be found in the prepontine cistern?
CN VI
Basilar artery
True/False.
Cerebral endothelial cells express an extremely high level of leukocyte adhesion molecules greatly facilitating immune cell entry into the CNS.
False.
Cerebral endothelial cells express an extremely low level of leukocyte adhesion molecules greatly limiting the amount of immune cells that enter the CNS
What cell type is abundant along the CNS blood vessels and contains contractile proteins to aid in regulating the dilation and constriction of those blood vessels?
Pericytes
(they also play an important role in angiogenesis, wound healing, and immune cell regulation)
True/False.
Pericytes can serve as multipotent stem cells for the CNS.
True.
Astrocytes contain a discrete array of proteins such as ___________, ___________, and ___________.
Astrocytes contain a discrete array of proteins such as dystroglycan, dystrophin, and aquaporin 4.
The astrocyte dysroglycan–dystrophin complex is important to link the end feet cytoskeleton to the basement membrane by binding ______.
The astrocyte dysroglycan–dystrophin complex is important to link the end feet cytoskeleton to the basement membrane by binding agrin.
Why do astrocytes contain a large amount of aquaporin4?
CNS water regulation
True/False.
Pericytes are involved in relaying signals to blood vessels and astrocytes to regulate constriction and dilation.
False.
Astrocytes are involved in relaying signals to blood vessels and pericytes to regulate constriction and dilation.
The capillaries of the choroid plexus are freely permeable, but the _________ _________ cells form a barrier between the capillaries and the CSF.
The capillaries of the choroid plexus are freely permeable, but the choroid epithelial cells form a barrier between the capillaries and the CSF.
Areas where the blood-brain barrier is interrupted are known as ____________ organs.
Areas where the blood-brain barrier is interrupted are known as circumventricular organs.
Name a few circumventricular organs (areas where the blood-brain barrier is interrupted).
Median eminence, neurohypophysis;
area postrema;
organum vasculosum;
pineal gland;
subcomissural organ
Where is the area postrema located?
The caudal wall of the fourth ventricle
(in the medulla)
How much can a normal human increase their absorption of CSF before there is an increase in intracranial pressure?
a. None b. 2 times c. 3 times d. 6 times e. 10 times
a. None b. 2 times c. 3 times d. 6 times e. 10 times
A defect in which of the following would affect the permeability of the blood-brain barrier the most?
a. Keratin b. Collagen c. Cadherin d. Occludin e. Myelin
d. Occludin
Which of the following can modify the composition of CSF? Select all that apply.
a. The dura mater b. The arachnoid mater c. The choroid plexus d. A state of dehydration e. Chronic hypertension
a. The dura mater b. The arachnoid mater c. The choroid plexus d. A state of dehydration e. Chronic hypertension
Where would you expect find the choroid plexus? Select all that apply.
a. In the lateral ventricles b. In the diencephalon c. In the dural sinuses d. In the fourth ventricle
a. In the lateral ventricles b. In the diencephalon c. In the dural sinuses d. In the fourth ventricle
Which barrier would you expect to allow the most freedom of substrate passage?
a. Across capillaries into brain parenchyma
b. Across capillaries and choroid epithelial cells into CSF
c. Across ependymal cells into brain parenchyma
a. Across capillaries into brain parenchyma
b. Across capillaries and choroid epithelial cells into CSF
c. Across ependymal cells into brain parenchyma
The fourth ventricle lies between what structures?
The pons and cerebellum
In what location(s) is CSF made?
The superior and inferior choroid plexi in the lateral and third ventricles
CSF cushions the brain (and spinal cord) mainly through its presence in what space?
The subarachnoid space
Where is the main location in which arachnoid granulations are found?
The superior sagittal sinus
The arachnoid granulations are ______-way valves driven by __________.
The arachnoid granulations are one-way valves driven by pressure.
Describe the general make-up of CSF as a hyperfiltrate (in terms of electrolytes, protein levels, cellular presence, glucose levels, etc.).
High chloride;
low protein,
almost no cells,
low glucose (60% of serum levels)
What are the two most sensitive tests (in order) for a subarachnoid hemorrhage?
(1) LP
(2) Head CT
Name the purpose of the four tubes taken in a lumbar puncture.
Tube 1 - Cell count + differential
Tube 2 - Protein + glucose
Tube 3 - Infectious studies (Gram studies, PCRs, cultures, inflammatory markers, etc.)
Tube 4 - Cell count + differential again (involved in screening for subarachnoid hemorrhage)
Cell count and differential is seen in which tube(s) in a lumbar puncture?
Tubes 1 and 4
Protein and glucose is seen in which tube in a lumbar puncture?
Tube 2
Infectious studies are performed on which tube in a lumbar puncture?
Tube 3
What two conditions, if suspected, warrant an especially urgent lumbar puncture?
CNS infection (especially in the immunocompromised)
Subarachnoid hemorrhage (with negative CT scan)
Name two general contraindications to lumbar puncture.
Risk for cerebral herniation (due to the increased ICP)
Bleeding issues (thrombocytopenia, anticoagulant use, etc.)
What is an archaic term for idiopathic intracranial hypertension?
Pseudotumor cerebri
Name two general methods (procedural and pharmacological) for treating intracranial hypertension.
Lumbar puncture
Carbonic anhydrase inhibitors
Intracranial hypotension is typically seen following what?
Some procedure (e.g. LP)
You see neutrophils in a patient’s CSF.
What does this indicate?
Bacterial meningitis
You see lymphocytes in a patient’s CSF.
What does this indicate?
Viral meningitis
Bacterial meningitis is indicated by _________ in the CSF.
Viral meningitis is indicated by _________ in the CSF.
Bacterial meningitis is indicated by neutrophils in the CSF.
Viral meningitis is indicated by lymphocytes in the CSF.
Lumbar puncture shows a high number of RBCs in tube 1 only.
What does this indicate?
Traumatic tap
(high count in 1; low in 4)
Lumbar puncture shows a high number of RBCs in tube 1 and tube 4.
What does this indicate?
Subarachnoid hemorrhage
(can also be seen in HSV encephalitis)
Most CNS infections show _________ CSF protein.
Most CNS infections show elevated CSF protein.
Besides infectious etiologies, what two immune disorders are associated with elevated CSF protein?
Guillain-Barré syndrome
Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)
(NOTE: CSF WBCs are low in these demyelinating disorders.)
Guillain-Barré syndrome and acute inflammatory demyelinating polyradiculoneuropathy (AIDP) are associated with __________ CSF protein and __________ CSF WBCs.
Guillain-Barré syndrome and acute inflammatory demyelinating polyradiculoneuropathy (AIDP) are associated with elevated CSF protein and low CSF WBCs.
A low-glucose tap (in an infectious meningitis setting) is likely _______ meningitis.
A low-glucose tap is likely TB meningitis (due to reactivation).
True/False.
Immunoglobulin is not produced within the CSF but must be transported over from the serum.
False.
Immunoglobulin is produced within the CSF.
Immunoglobulin produced in the CSF will lead to an increased quotient relative to what?
Albumin
What causes the oligoclonal bands sometimes seen on protein gel electrophoresis?
IgG found in CSF but not serum
Name three major causes of oligoclonal bands.
Multiple sclerosis,
neurosarcoidosis,
CNS lupus
