Lesson 3: Blood Supply Flashcards
What is a watershed area?
Has irrigation from multiple arteries
What arteries branch off of the vertebral arteries before the basilar artery?
The anterior spinal artery, posterior spinal arteries, and the posterior inferior cerebellar arteries
What branches off of the basilar artery?
The posterior cerebral arteries, the superior cerebellar artery, and the anterior and posterior inferior cerebellar arteries
Where do the posterior arteries irrigate? What structure of the diencephalon?
Most of the temporal lobe, all of the occipital lobe, and the inferior surface of the brain. Also the thalamus
Where does the superior cerebellar artery irrigate?
Pons through its pontine branches
What is the role of the posterior communicating arteries?
Connect the internal carotid arteries with the vertebral arteries
Where does the MCA irrigate (one structure in particular)? Why do we care about it (2 things)?
Lateral areas of the brain, and the internal capsule. It has lenticulostriate branches deeper into the brain, and is important to communication disorders.
What are structures like the Circle of Willis called?
Anastomoses
What is the role of the anterior communicating artery?
It connects the left and right anterior cerebral arteries
What arteries are considered in the Circle of Willis?
Anterior and posterior communicating arteries, and the anterior and posterior cerebral arteries
Where does the posterior cerebral artery branch off?
From the basilar artery and part of the Circle of Willis
What irrigates the spinal cord?
The anterior spinal artery and the posterior spinal arteries, which is backed up by additional small branches from the aorta throughout the spine
What structure gives way to the venous sinuses?
The infoldings of dura mater - falx cerebri, falx cerebelli, and tentorium cerebelli
What is the process of blood back to the heart?
From the capillaries, to the cerebral veins, to the venous sinuses, to the internal jugular veins, to the heart
What is the process of the superior sagittal sinus back to the heart?
To the right transverse sinus, to the right sigmoid sinus, to the right internal jugular vein
What is the process of the inferior sagittal sinus?
To the straight sinus, to the left transverse sinus, to the left sigmoid sinus, to the left internal jugular vein
What is the process of the cavernous sinus?
Into the sigmoid vein
Why is shaken baby syndrome especially bad? What two types of injury does it consist of?
Both major trauma and axonal injury
What is a coup injury?
Injury to the area where the skull impacted the brain, causing direct damage
What is a contre-coup injury?
Backlash - the accelerating brain hits the opposite side of skull
What is an uncal herniation?
Compression of the uncus (parahippocampal gyrus) against the tentorial notch
What is a tonsillar herniation?
Compression of the brainstem and cerebellum into the foramen mangum
What is the difference between a hematoma and a hemorrhage?
A hemorrhage; higher pressure, rapid - more often arterial bleeding
A hematoma: pooling of blood that occupies space - more often venous injury
Where is an epidural hemorrhage, and what is bleeding? What is often its cause, and how urgent is it?
From the middle meningeal artery - rapid arterial bleeding between the skull and periosteal dura. It’s urgent, and associated with skull fracture. Frequently due to a fracture of the pterion.
What causes a subdural hematoma, and where does it occur? How urgent is it? What is the nature of the symptoms?
Between the dura and arachnoid mater - venous bleeding.
Symptoms are transient - hematoma may shift along the subdural space. It is less urgent, since it’s slower - but still dangerous.
What in particular often causes a subarachnoid hemorrhage, and where does it occur? What type of bleeding is it, and what is often the cause of the underlying condition? What are some early symptoms?
In the subarachnoid space, between the arachnoid mater and the pia mater. A rupture aneurysm in the Circle of Willis - arterial bleeding by a congenital defect. Warning signs include intense headaches, and oculomotor nerve damage.
What can be a consequence of a subarachnoid hemorrhage, due to its location?
It can bleed into the subarachnoid space, and mix with the cerebrospinal fluid, and thus clot and cause issues
What often causes an intracerebral hemorrhage, and what are the possible underlying causes of this condition? Where do they occur?
Ruptured arteries in the brain, often due to a TBI or hemorrhagic stroke. It occurs within the cerebrum.
What is a non-vascular head injury?
Trauma to the blood vessels that causes a space-occupying lesions
What is a vascular head injury?
Loss of circulation to the brain tissue itself
