Blood supply of the brain Flashcards
Where do the carotid arteries come from?
Aorta
How do brachiocephalic veins form?
Internal jugular vein joins with subclavian veins
How is vena cava formed?
L and R brachiocephalic veins form
What does motor homunculus do?
Represents body parts and correspondents along precentral gyrus of frontal lobe
What does sensory homunculus do?
Represents body parts along post central gyrus of parietal lobe
What is the internal capsule?
White matter structure inside inferomedial part of each cerebral hemisphere
Function of internal capsule
Carries information past basal ganglia, separating caudate nucleus and thalamus from putamen and globes pallidus
Which two are the main blood vessels to the brain?
Vertebral and internal carotid arteries from circle of Willis
Where does the internal carotid artery run?
From common carotid artery, enters the cranial cavity through the internal carotid foramen and cranial cavity with bends called carotid syphon
Where does vertebral artery come from?
Subclavian artery
Foramen transversia from level of 6th vertebrae
Enters cranial cavity through foramen magnum
Unites at medulla and pons to form basilar artery
What does basilar artery do?
Gives rise to superior cerebellar arteries and posterior cerebellar arteries
What do the internal carotid arteries do?
Gie rise to posterior communicating arteries which join the respective posterior cerebral arteries
What do middle cerebral arteries do?
Enter lateral fissure on each side
What do anterior cerebral arteries do?
Enter great longitudinal fissure
What does the anterior communicating artery do?
Joins two anterior cerebral arteries
Which part of the brain is supplied by the anterior cerebral artery?
Medial surface of front parietal lobe
Which part of the brain is supplied by the middle cerebral artery?
Lateral surface if frontal parietal temporal lobe of brain
Which part of brain is supplied by the posterior cerebral artery?
Temporal and occipital lobes
Which part of the brain is supplied by the middle artery?
Cerebral hemisphere
Which blood vessels supply the medulla and spinal cord?
Anterior and posterior spinal arteries
Which blood vessels supply the inferior cerebellum?
Posterior inferior cerebellar arteries
Which blood vessels supply the outer dura mater?
Meningeal vessels
Which blood vessel supplies the period?
Middle meningeal artery
Which condition gives the brain a characteristics biconcave shape on a CT scan?
Extradural haematoma in middle meningeal artery
Which arteries have meningeal branches?
Maxillary Phalangeal Occipital Vertebral Ethmoidal
Which bones meet at the period?
Frontal, parietal, sphenoid and temporal
Why is fracture of the pterion dangerous?
The bone is thin and could rupture the middle meningeal artery
How is the Great Cerebral Vein of Galen formed?
Deep veins drain internal forebrain (thamamostriate and choroidal veins unite to form internal cerebral veins (L and R) which unite to form Great Cerebral Vein of Galen
Venous drainage of the brain
Can drain into dural venous sinuses or into superficial veins
What are the dural venous sinuses?
Formed between two layers of dura mater
What are the major sinuses located on the floor of the cranial cavity?
Superior sagittal sinus Inferior sagittal sinus Straight sinus Confluence of sinuses Transverse sinus Sigmoid sinus
Where is the cavernous sinus?
Lateral to the sphenoid bone
How is the venous circle around the hypophysis formed?
Cavernous sinuses connected by anterior and posterior inter cavernous sinuses
Contents of venous circle
Oculomotor nerve Trochlear nerve Ophthalmic nerve Maxillary nerve Abducens nerve Internal carotid artery
Blood supply of the spinal cord
Single anterior spinal artery from two vertebral arteries, reinforced by segmental arteries
Paired posterior spinal arteries from either vertebral or posterior inferior cerebellar arteries
Function of blood-brain barrier
- Restricts paracellular permeability/diffusion of water soluble substances from blood to brain
- Maintains CNS homeostasis and limits entry of substances that could alter or harm neuronal functions
- Collectively known as neurovascular unit
What is the blood-brain barrier composed of?
- Capillary endothelium with tight junction
- Capillary endothelium basement membrane
- Astrocytes processes
- Pericytes
- Neurons
- Extracellular matrix
Where is the blood supply to the spinal cord most vulnerable and why?
Thoracic region and anterior portion
Poor segmental artery reinforcement
Symptoms of thoracic cord syndrome and when does it form?
Paraplegia and incontinence, pain and temperature modalities losy
Occlusion of anterior spinal artery
Impacts of stroke in cerebral vessels
Infarction, cerebral hemorrhage and death
What is an aneurysm?
Abnormal, balloon-like swelling of artery, rupture leads to subarachnoid/inter-cerebral hemorrhage
What is an angioma/arteriovenous malformation?
Congenital collection of swollen blood vessels, can rupture and lead to focal cerebral syndrome
