Neurovascular unit and function

Question 1

How much of the cardiac output does the brain app. receive during rest?

Answer 1

20-30%

Question 2

How does the energy use change during heavy thinking compared to rest in the brain?

Answer 2

Overall energy consumption is app. the same, but local bloodflow and energy use change with activity

Question 3

How are the energy budget in the brain?

Answer 3

Neural resting potential: app. 10 %
Glial resting potential: app. 3 %
APs: app. 47 %
Synaptic transmission: app. 40 %

Question 4

Describe the autoreglation of arteries in the brain.

Answer 4

Contracts with increased BP

Question 5

Which cells converts glycogen to glucose in the brain?

Answer 5

Astrocytes/glia cells

Question 6

What takes up app. 90 % of the energy consumption in the brain?

Answer 6

Na/K pump

Question 7

What can alter the coupling between brain activity and blood flow?

Answer 7

Alzheimers, aging and hypertension

Question 8

How does the coupling between brain activity and blood flow work?

Answer 8

Nerve cell activity dialates blood vessels –> increase BF

Question 9

How are the distribution of arterioles and capillaries in the brain?

Answer 9

Arterioles: 20 %
Capillaries: 80 %

Question 10

What is the neurovascular unit?

Answer 10

The cells surrounding the capillaries adn regulating the transport to/from blood: Astrocytes (endfoot), endothelial cells, preicyte, smooth muscle cells and microglia

Question 11

What are the potential feedforward and feedback mechanisms driving the local vascular response evoked by synaptic activity?

Answer 11

Feedforward: GluR –> Ca2+ influx –> NO + prostanoids –> local vascular response

Feedback: pO2 drops –> adenosine + lactate + CO2 –> local vascular response

Question 12

How are pericytes involved in capillarie dilation/constriction?

Answer 12

Dilation: dilators released by active neurons and astrocytes dialated the pericytes surrounding the capillaries –> capillaries dialate

Constriction: low [ATP] raises pericyte [Ca2]i –> pericyte contricts –> capillary are blocked

Question 13

How are the correlation between CBF and PO2 dynamics?

Answer 13

Linear

Question 14

What is cerebral metabolic rate (deltaCMRO2) dependent on?

Answer 14

Activation of AMPA-Rs.

Question 15

What regulate capillary BF on a precapillary level?

Answer 15

Precapillary sphincters (segments of smooth muscle cells)