Cerebral vasculature Flashcards
What artery supplies the brain?
-Vertebral artery
-Internal carotid artery
-Common carotid artery
What is the benefit of the arrangement of the arteries of the brain?
-Arranged in a circle (“circle of willis”
-If one artery was blocked, supply on the other side of the structure can flow in & compensate
Describe the mechanism for venous drainage of the brain?
- Cerebral veins (drain into)
- venous sinuses in the dura mater (that drains into)
- The internal jugular vein
What are the different types of haemorrhage you can have?
- Extradural
* trauma, immediate clinical effects (arterial,
high pressure) - Subdural
* trauma, can be delayed clinical effects
(venous, lower pressure) - Subarachnoid
* ruptured aneurysms - Intracerebral
* spontaneous hypertensive
What is a stroke?
rapidly developing focal disturbance of brain function of presumed vascular origin and of >24 hours duration
What are the 2 types of stroke you can get?
- Thrombo-embolic (blockages)
- Haemorrhage
What is a Transient ischaemic attack (TIA):
rapidly developing focal disturbance of brain function of presumed vascular origin that resolves
completely within 24 hours”- temporary blockage
What is infarction?
Degenerative changes which occur in tissue following occlusion of an artery
What is Cerebral ischaemia?
Lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly
What is hypoxea?
Lack of a component of blood (e.g. oxygen carried)
What does thrombosis mean?
formation of a blood clot (thrombus)
What is an embolism?
plugging of small vessel by material carried from larger vessel e.g. thrombi from the heart or atherosclerotic debris from the internal carotid
Name 5 risk factors of stroke
Age
Hypertension
Cardiac disease
Smoking
Diabetes mellitus
What arteries supply the cerebral cortex?
-anterior cerebral artery
-middle cerebral artery
-Posterior cerebra artery
What would a block in the anterior cerebral artery lead to?
- Paralysis of contralateral structures= weakness
(leg > arm, face)- more likely to affect the lower limbs - Disturbance of intellect, executive function and judgement (abulia)
- Loss of appropriate social behaviour + hypersexuality
What would a block in the middle cerebral artery lead to?
“Classic stroke”
1. Contralateral hemiplegia (paralysis): arm > leg- can also cause complete hemiplegia
2. Contralateral hemisensory deficits (loss of touch sensation + muscle weakness)
3. Hemianopia (Loss of half their visual field)
4. Aphasia-difficulty with their language or speech (L sided lesion)- 2 types
What are the 2 types of aphasia
- Expressive aphasia:
-patient can’t find the right words to answer questions
-“word recall issue” - Receptive aphasia:
-Patient has issue in Wernicke’s area
-cannot understand the question
What would a block in the posterior cerebral artery lead to?
Visual deficits
* homonymous hemianopia
* visual agnosia (cannot recognise/ interpret visual information)
How can fatty deposits lead to stroke?
Yellow discolouration in the walls of vessels= build-up of atheroma, fatty deposits that cause
atherosclerosis or “hardening of the arteries”
- vessel can’t dilate or constrict
- Blood flow cannot be controlled
What is occlusion?
Complete or partial blockage of a blood vessel
What are the 5 dural venous sinuses?
- Superior sagittal
- Straight
- Confluence
- Transverse
- Sigmoid
How would you treat a subdural haematoma?
- Refer to neurosurgeons
- they would drill burr holes
- Take out a small skull flap
- Remove the blood
- Then reassemble the skull flap
How would you tell the difference between an extradural bleed and subdural on a CT scan?
Extradural: acute bleeding
(immediate clinical effects)
blood is freash
appears white on CT
Subdural: more chronic
(can have delayed clinical effects)
blood is older
appears darker on CT