Brain Metabolism

Question 1

What does the brain weigh? How much glucose does it consume?

Answer 1

1.4 kg, 2% of body weight

25% of glucose in blood stream

Question 2

How much oxygen does the brain consume? How much blood goes though the brain every minute?

Answer 2

20-25% of oxygen in blood stream. 800 ml of blood

Question 3

What does the brain do with the energy it consumes?

Answer 3

ATP turnover (consuming all of the energy the brain claims):

• Membrane depolaization & repolarization
• NT release and uptake
• NT synthesis and metabolism
• Ion pumping: eg: Na-K-ATPase, Co-ATPase
• “Housekeeping activities”

Question 4

How is energy delivered to the brain?

Answer 4

Blood flow - Blood flow delivers glucose and oxygen

Question 5

The more neurons firing. . .

Answer 5

. . . the higher blood flow to the brain.

Question 6

If energy metabolism is slow. . .

Answer 6

. . . flow is low

Question 7

Brain is constantly using energy at a ____ _____ level.

Answer 7

High basal

Question 8

What is the role of the astrocyte in the neuromuscular unit?

Answer 8

-When neuron fires, astrocyte senses what is going on (energy level used) and responds by sending signal to dilate or constrict to regulate the flow of blood and nutrients.

Question 9

What is included in the neuromuscular unit?

Answer 9

Neurons, astrocytes and blood vessels