The pathophysiology of an ischemic stroke involves the ischemic cascade, which includes the following steps:

Question

1. Change in pH
2. Blood flow decreases
3. A switch to anaerobic respiration
4. Membrane pumps fail
5. Cells cease to function
6. Lactic acid is generated

Put these steps in order in which they occur.

A) 635241
B) 352416
C) 236145
D) 162534

Answer 1

Ans: C
Feedback:
The ischemic cascade begins when cerebral blood flow decreases to less than 25 mL per 100 g of blood per minute. At this point, neurons are no longer able to maintain aerobic respiration. The mitochondria must then switch to anaerobic respiration, which generates large amounts of lactic acid, causing a change in the pH. This switch to the less efficient anaerobic respiration also renders the neuron incapable of producing sufficient quantities of adenosine triphosphate (ATP) to fuel the depolarization processes. The membrane pumps that maintain electrolyte balances begin to fail, and the cells cease to function.