Lecture 37 - Ischemia and Reperfusion Flashcards
(47 cards)
Metabolic rates are higher in the (white/gray) matter.
gray - these are neurons that require energy for signal transduction/resetting of membrane potential
The Blood Brain Barrier (BBB) has transporters specifically for what molecules that are used by the brain?
glucose
monocarboxylic acids
This is a measurement of the carbohydrate metabolism in the brain.
Respiratory quotient
CO2 produced/O2 consume
[Oxygen] is lower in the cerebral (venous blood/arterial blood).
venous blood
The brain contains small stores of _____, which may be utilized instances of anoxia when the brain cannot undergo anaerobic metabolism.
A. glycogen
B. G-6-P
C. ATP
D. lactate
A. glycogen
Cerebral neurons are known to be ____ and use ____ for their neurotransmitter.
A. inhibitory; glutamate
B. excitatory; glutamate
C. Inhibitory; GABA
D. excitatory; GABA
B. Excitatory; glutamate
Cortical neurons are known to be _____ and use ____ as their neurotransmitter.
A. inhibitory; glutamate
B. excitatory; glutamate
C. Inhibitory; GABA
D. excitatory; GABA
C. Inhibitory; GABA
Brain imaging is capable of detecting gross changes to the brain’s anatomical structure, true or false?
True
A patient is brought in for evaluation of a potential stroke. He is given a glucose analog, which allows for monitoring of the activity of hexokinase. Decreased hexokinase activity is an indicator of damage to the brain parenchyma. What imaging study was performed?
A. PET scan
B. MRI
C. MRS
D. CT scan
A. PET scan
A patient is suspected of having had a stroke. They are given a radioactive form of glucose, and is the resulting image is used to determine the metabolic activity of the neurons and glial cells in the brain. Wha imaging study was performed?
A. PET scan
B. MRI
C. MRS
D. CT scan
C. MRS (Magnetic Resonance Spectroscopy)
Disruption of blood flow to a small region of the brain is known as ______.
Focal cerebral ischemia; usually results from blockage to a small blood vessel
In focal ischemia, the total area of infarction is often less than the area of tissue supplied by the occluded vessel. Why is that so?
Collateral circulation
The ischemic core, or _________, is the a region caused by the ischemia that results in electrophysiology changes, metabolic and perfusion disturbances.
umbra
Impaired protein synthesis is characteristic of the _____ of focal ischemia.
A. ischemic core
B. umbra
C. periumbra
D. thrombolytic zone
C. periumbra
If reperfusion is not successful in _____ hours, necrosis extends to the penumbra.
3
These cells are responsible for many signalling actions in the CNS. As a result, they require many pumps and gradients, and are therefore more sensitive to ischemia. What are they?
neurons
Absence of oxygen due to ischemia causes reduced levels of _____. This produces disf(x) in ____.
ATP;
ATPases necessary for maintaining ion gradients
When ion pumps are disrupted due to ischemia, the membrane becomes depolarized. This results in _____.
voltage gated Na pump opening
Describe the “Pasteur effect.”
A. A decrease in PO2 causes lactate production
B. Changes to ion channels from decreased pH causes depolarization
C. Necrosis of brain tissue occurs from low arterial [oxygen]
D. K+ efflux from opening of K+ channels
A. A decrease in PO2 causes lactate production
Anaerobic metabolism from ischemia produces lactate, reducing the brain pH to _____ from 7.3.
6.2-6.8
Membrane proteins change shape through denaturation after acidosis secondary to ischemia. What major ion begins to efflux when this occurs?
K+
K+ efflux from acidosis results in a collapse of Na+ and Ca2+ gradients. What is the ultimate result?
Release of neurotransmitters
Ion gradient loss results in an increase of extracellular _______. This elevates intracellular Ca2+, which causes NT release.
glutamate
Glutamic activated Ca2+ and Zn2+ influx activates ______.
A. caspase
B. complement
C. cytotoxic intracellular pathways
C. cytotoxic intracellular pathways
