WEEK 5: 5.6 Blood supply of the Brain and Spinal Cord Flashcards
What is a drawback in terms of the brain’s energy dependence?
The brain cannot use fats or amino acids for energy
It requires a constant supply of glucose to function properly
When oxygen is absent (anaerobic conditions), what happens to pyruvate?
It undergoes fermentation, producing lactic acid or ethanol, which is inefficient and provides minimal energy
When oxygen is present, what happens to pyruvate?
It enters oxidative decarboxylation, followed by krebs cycle and the electron transport chain, yielding up to 36 ATP and making it more efficient
If oxygen is unavailable to the brain, what happens?
The brain solely relies on inefficient anaerobic metabolism, which can quickly impair brain function
After 5 minutes of lack of oxygen to brain, what can occur?
Irreversible brain damage
What is ischaemia?
reduced/lack of blood supply
What is infarction?
region of cell death due to ischaemia
What is penumbra?
region of cells which are functionally compromised and injured but not dead & can be salvaged if blood flow is restored in time
What 3 branches arise from the aorta?
1) brachiocephalic artery
2) left common carotid artery
3) left subclavian artery
What are the two parts that branch off from the brachiocephalic artery?
- Right subclavian artery
- Right common carotid artery
What do the brachiocephalic, left common carotid and left subclavian arteries form?
Both anterior circulation and posterior circulation
What % of blood supply is anterior and posterior circulation respectively ?
80 & 20 %
Anterior circulation is supplied by ?
Internal carotid arteries
Posterior circulation is supplied by?
vertebral arteries
What is anterior and posterior circulation linked together by?
the circle of Willis
What is the circle of Willis comprised of?
- posterior cerebral arteries
- posterior communicating arteries
- internal carotid arteries
- anterior cerebral arteries
- anterior communicating artery
What is the importance of arterial blood flow
It allows a continuous supply of oxygen and glucose, without it, neurological impairment and brain infarction (tissue death) can occur
What is an ischameic stroke , and what are its causes?
when blood flow is blocked to the brain, leading to cell death. it is caused by atherosclerosis and embolism
What is a hemorrhagic stroke? What is its cause?
When a blood vessel in the brain ruptures, leading to bleeding
caused by aneurysms
What are some characteristics of MCA stroke?
paralysis weakness of the contralateral face and arm, sensory loss of the contralateral face and arm
