___________ is a decrease or lack of oxygen. There may or may not be a lack of blood circulation.
__________ is a lack of circulation and perfusion. Always leads to hypoxia.
__________ is an obstruction of blood flow, leading to death of tissue.
The most sensitive areas of the brain to ischemic neurons (red neurons) are the _________________ and _________________.
Sommer's sector of hippocampus
Purkinje cells of the cerebellum
(T/F) Laminar necrosis occurs at border-zone areas. These watershed areas are the first to lose perfusion in case of ischemia, and as such are the first to undergo necrosis.
A(n) ___________________ occurs when occlusion of an artery is incomplete and there is recirculation of blood.
Atherosclerosis and thrombosis most often result in (hemorrhagic infarction/ischemic infarction).
Emboli, vasospasms, extrinsic compression, and reperfusion most often result in (hemorrhagic infarction/ischemic infarction).
What is shown in the following cross section?
Cross section of atherosclerotic vessel.
What happens to neurons undergoing hypoxia or ischemia for less than 24 hours?
They are red neurons (ischemic neurons).
- Eosinophilic neuronal necrosis
- Acute neuronal necrosis
Tissue undergoing hypoxia or ischemia for more than 24 hours is considered _______________.
Infarcted. The tissue has most likely died.
Infiltration into dead tissue by neutrophils usually occurs in __-__ days following brain infarction.
2 - 7 days
Neutrophils that have entered infarcted tissue are gradually replaced by macrophages over the course of __-__ weeks.
_____________ remove dead tissue following a brain infarct.
(T/F) Gliosis following a brain infarction begins and finishes immediately following tissue death.
False. Gliosis occurs gradually over the course of inflammation, neutrophil invasion, and macrophage removal of dead tissue.
Macrophages subside and a cavity is formed, resulting in a cystic space. This process usually occurs around __-__ weeks following a brain infarct.
What is shown in the following picture?
Which area in the following picture is infarcted? Which is not?
Left - Infarcted
Right - Not infarcted
Epidural and subdural hemorrhages are most often caused by (trauma/vascular pathology/both).
Intracerebral and subarachnoid hemorrhages are most often caused by (trauma/vascular pathology/both).
The most common cause for an intracerebral hemorrhage is _____________.
The most common two causes for subarachnoid hemorrhages are __________________ and ___________________.
Berry aneurysms and vascular malformations
The most common two causes for cerebral hemorrhages are _________________ and ____________________.
Hypertension and vascular malformations
How does a hemorrhagic infarction compare to a hemorrhage?
- Infarction is primary.
- Hemorrhage occurs in infarcted tissue.
- No displacement of brain tissue.
- Rupture of artery causes primary hemorrhage.
- No antecedent infarction.
- Blood displaces and damages brain tissue causing hematoma.
What two vascular malformations typically cause hemorrhage?
- Arteriovenous malformation (AVM)
- Cavernous hemangioma
Abnormally thick arteries or veins with no intervening capillary channels that often cause hemorrhage are referred to as __________________.
Dilated veins with intercommunications between them, but no intervening brain tissue is characteristic of a(n) ______________________. These formations most often result in hemorrhage.
The localized abnormal dilation of a blood vessel is known as a(n) ______________.
(Saccular/Atherosclerotic/Mycotic/Dissecting) aneurysms typically involve the entire circumference of the vessel.
(Saccular/Atherosclerotic/Mycotic/Dissecting) aneurysms result from infections and septic emboli.
(Saccular/Atherosclerotic/Mycotic/Dissecting) aneurysms are spherical, often involving a portion of the vessel wall. They typically only occur in intracranial arteries and are the most common cause of non-traumatic bleeding in the subarachnoid space.
(Saccular/Atherosclerotic/Mycotic/Dissecting) aneurysms result from a tear in the vessel that forces blood between layers of the vessel wall.
What type of aneurysm is shown in the photo?
Saccular (Berry) Aneurysm
What are the two most common types of cerebral edema?
Fluid in the extracellular cerebral space caused by a disruption of the blood-brain barrier in an infarction, hemorrhage, tumor, or trauma is referred to as (cytotoxic/vasogenic) edema.
Fluid in the intracellular cerebral compartment caused by a cellular membrane injury due to hypoxia or a metabolic event such as ketoacidosis is referred to as (cytotoxic/vasogenic) edema.
Herniation of part of the cerebrum underneath the falx cerebri (such as the frontal lobe or cingulate gyrus) is referred to as a(n) (uncinate or transtentorial/subfalcine/tonsillar/fungating) hernia.
A hernia involving the tonsils of the cerebellum is referred to as a(n) (uncinate or transtentorial/subfalcine/tonsillar/fungating) hernia.
A hernia involving the uncus is referred to as a(n) (uncinate or transtentorial/subfalcine/tonsillar/fungating) hernia.
Uncinate or transtentorial
A transcalvarial hernia is referred to as a(n) (uncinate or transtenorial/subfalcine/tonsillar/fungating) hernia.
What types of herniation are shown in the following image?
Cingulate and uncal hernations.
Herniation of the ___________ is problematic because it may compress the oculomotor nerve and posterior cerebral artery. This causes ipsilateral unilateral pupillary dilation and hemorrhagic infarction in the occipital lobe.
Compression of the brainstem against the tentorium opposite a herniated uncus is referred to as __________________.
Secondary hemorrhage caused by tearing of the perforating brainstem arteries following compression of the brainstem (such as Kernohan's notch) is referred to as ______________ hemorrhage.