Flashcards in Head Full Of Blood Deck (70)
What are the meninges?
Connective tissue covering that encloses and protects the brain and spinal cord.
What are the 3 parts of the meninges?
Dura mater, arachnoid mater, and pia mater
Which meninge creates the dural folds and venous sinus system of the brain?
Which is the middle layer of the meninges?
Where does CSF flow?
Under the arachnoid mater, in the subarachnoid space
What forms the arachnoid villi?
What is the arachnoid villi responsible for?
Reabsorbing CSF and returning it to the blood stream.
Which layer is adherent to the brain and spinal cord?
Which layer is impermeable to fluid?
Where is the falx cerebri located?
In the longitudinal fissure
What are the names of the dural folds?
Falx cerebri, tentorium cerebelli, falx cerebelli, sellar diaphragm
Where is the tentorium cerebelli located?
Separates the cerebellum from the occipital lobe
Where is the falx cerebelli located?
Separates the cerebellar hemispheres in the posterior cranial fossa
Where is the sellar diaphragm?
Covers the pituitary in its fossa
What are denticulate ligaments?
Specialized structures of the pia mater.
What do the denticulate ligaments do?
Attach to the dura mater. Thought to stabilize the motion of the spinal cord.
Where is the filum terminali?
Extends from the lowest tip of the spinal cord. Continuous with the pia mater.
What is the function of the filum terminali?
Anchors the spinal cord at the level of the sacrum and coccyx.
What is the cauda equina?
Area for lumbar punctures, insert needle below L3
How is CSF propelled cranially?
By brain movements and pulsations of surface arteries.
What structure keeps the brain in place?
What are ventricles?
Intracerebral spaces that CSF move through.
What are the ventricles lined with?
What are ependymal cells?
Epithelial-like neuron list cells that can create and transport CSF and create the blood-CSF barrier.
Which cells are responsible for creating CSF?
Ependymal cells in the lining of the ventricles.
Where are the lateral ventricles?
Spaces curve from the medial part of the hemispheres around into the temporal lobes.
How does CSF flow from the lateral ventricle into third ventricle?
Via interventricular foramen (of Monro)
Where is the third ventricle?
Lies between halves of thalamus and hypothalamus
How does CSF flow from the third to the fourth ventricle?
Via the cerebral aqueduct
What structure does the cerebral aqueduct pass through?
Where is the fourth ventricle?
Between the medulla and cerebellum.
Where does CSF flow after the fourth ventricle?
Down into the spinal canal or into the subarachnoid space.
What does CSF pass through to get to the subarachnoid space?
Foramina of Luschka and Magendie
Where is CSF reabsorbed?
Superior sagittal sinus
How is CSF reabsorbed in the superior sagittal sinus?
By the arachnoid granulations.
What is the choroid plexus?
Modifies ependymal cells that surround capillaries
How does the choroid plexus generate CSF?
By filtering blood from capillaries that run through it.
What is the blood-CSF barrier?
Tight junctions between choroidal epithelial cells that prevent passage of large molecules.
What is the brain-CSF barrier?
Minimal restriction between ventricles and brain interstitium
Where does the common carotid artery originate?
Branches from the brachiocephalic artery
Where does the internal carotid split from the external carotid?
At the carotid sinus.
What does the internal carotid artery spit into?
Anterior and middle cerebral arteries
Where does the vertebral artery ascend from?
What does the vertebral artery pass through?
Transverse foramina of C1-C6
What are the basivertebral branches?
Anterior/posterior spinal arteries, posterior inferior cerebellar artery (PICA), anterior inferior cerebellar artery (AICA), superior cerebellar artery, pontine arteries, labyrinthins artery
What are symptoms of occlusion of an anterior/posterior spinal artery?
Loss of spinal cord function at the level of occlusion
What are symptoms of occlusion of a posterior inferior cerebellar artery?
Wallenberg Syndrome. Loss of pain and temp. sensation on contra lateral side of the body and ipsilatetal side of the face
What are symptoms of occlusion of an anterior inferior cerebellar artery?
Lateral Pontine syndrome. Sudden onset of vomiting, vertigo. Ipsilatetal loss of sensation to face and facial paralysis
What are symptoms of occlusion of a superior cerebellar artery?
Ipsilateral limb dysmetria, contra lateral loss of sensation
What are symptoms of occlusion of a pontine artery?
Contralateral paralysis and loss of sensation. Often results in death. Several outcomes possible depending on size of infart
What are symptoms of occlusion of a labyrinthin artery?
Ipsilateral hearing loss and vertigo
Where is the anterior communicating artery?
Between the anterior cerebral arteries
Where is the posterior communicating artery?
Connects the middle to posterior cerebral arteries
Where is the middle cerebral artery?
Along the lateral fissure and lateral surface of the cerebral cortex
Where is the anterior cerebral artery?
Along the medial surface of cerebral cortex, including the cingulate gyrus
What are the symptoms of an occlusion of the anterior cerebral artery?
Paralysis and sensory loss in contralateral leg and foot. Abulia
Where is the posterior cerebral artery?
Projects to the occipital and temporal lobes.
What are the symptoms of an occlusion of a posterior cerebral artery?
Visual field defects, face blindness (prosopagnosia), contralateral deficits of the facial, vagus, and hypoglossal nerve and ipsilateral deficits of the oculomotor nerve.
Where do cerebral veins drain venous blood?
Into the dural sinuses
What are dural sinuses?
Venous compartments within the dura mater.
What are the spinal veins?
Valveless veins around the dura.
What does the basivertebral vein do?
Drains the vertebral body
What are emissary veins?
During hypothermia, cooler blood from the surface travels internally through the emissary veins to cool the brain.
What does the blood brain barrier consist of?
Endothelium, pericytes, atrocyte feet, and basal lamina
What are the BBB tight junctions maintain by?
Where is there no BBB?
Hypothalamus, area postrema, other peri ventricular regions
Why is there no BBB in the hypothalamus?
So hormones can contact hypothalamic cell receptors
Why is there no BBB in the area postrema?
Digested poisons stimulate area postrema's pathway to vomiting center
What is the BBB permeable to?
Water and small molecules