Blood supply to the brain Flashcards
What is the impact of 20 seconds and >5 minutes without oxygen respectively?
20 seconds = unconsciousness
>5 minutes = permanent unconsciousness
If cerebral perfusion pressure of the brain is 60-100mmHg then what should the cerebral blood flow be?
~50 ml per 100g of brain tissue
What areas/structures do the lenticulostriate arteries supply?
internal capsule and white matter tracts
if there is a blockage in one of these arteries then this will impact sensations such as pain and vibration
What parts of the cerebral cortex doe the ant., middle and post. cerebral arteries supply?
ACA = medial + superior cerebral cortex MCA = lateral + inferior cerebral cortex PCA = posterior + inferior cerebral cortex
What part of the CNS do the vertebral arteries supply?
Posterior and anterior spinal arteries supply the spinal cord
PICA = dorsal medulla of the brainstem
What part of the CNS does the basilar artery supply?
Pons and cerebellum
What part/s of the CNS does the posterior cerebral artery supply?
inferior and medial aspects of the temporal and occipital cortex
thalamus and posterior internal capsule
midbrain
What will be the result of an MCA stroke in the dominant hemisphere?
Global aphasia
Sensorimotor loss on contralateral face, upper limb and trunk
What will be the result of an MCA stroke in the non-dominant hemisphere?
Neglect syndrome
What will be the result of an ACA stroke?
Contralateral sensorimotor loss below the waist
Urinary incontinence
Personality defects
Split-brain syndrome
What will be the result of an PCA stroke?
Contralateral homonymous hemianopia
Reading and writing deficits
Impaired memory
What are the symptoms of a TIA in the anterior circulation?
Motor weakness
Hemisensory loss
Dysarthria
Transient monocular blindness
What are the symptoms of a TIA in the posterior circulation?
Vertigo
Diplopia
Ataxia
Amnesia
Where does an epidural haematoma occur? What is the mortality rate? What are the symptoms?
Between the dura mater and skull
Arterial bleed therefore rapid bleeding
Mortality is 10%
Symptoms:
- compress CNIII
- weakness of extremities on opposite side of lesion
- loss of visual field opposite to lesion (compress PCA)
What does an epidural haematoma look like on CT/MRI?
Convex lens
expansion stops at sutures and then pressure pushes inwards
Where does a subdural haematoma occur? What is the mortality rate? what are the symptoms?
Between dura and arachnoid mater Rupture to bridging veins and therefore a slower bleed Mortality is 40-60% Symptoms: - irritability - seizures - headache - numbness - disorientation
What does a subdural haematoma look like on CT/MRI?
crescent shape with concave surface
will cross suture lines
Where does a subarachnoid haematoma occur? What are the symptoms?
Spontaneous Between arachnoid + pia mater arterial bleed Symptoms: - vomiting - THUNDERCLAP HEADACHE - confusion - reduced levels of consciousness
What does a subarachnoid haematoma look like on CT/MRI?
CT = white signal diffuse over sulci on both sides
List the 3 types of cerebral aneurysm
Saccular
Fusiform
Berry
What is the importance of arachnoid granulations?
- Allow CSF to flow into venous blood of sinuses
- prevent backflow of blood into subarachnoid space
