Lecture 11 - Linking Neuronal Activity To Blood Flow

Question 1

What are some examples of metabolism in brain?

Answer 1

Neurons

Other cells: glia, microglia, fibroblasts, endothelial cells

Question 2

What does metabolism in brain require?

Answer 2

15-20% of cardiac output

2% of body mass

Question 3

What are the energy usage in the brain?

Answer 3

Restoration of ionic gradients
Maintaining the resting potential
Tissue maintenance

Question 4

What are examples of tissue maintenance?

Answer 4

Cell division
Growth and repair I.e. protein synthesis, mRNA synthesis, protein and organelle transportation, neurotransmitter production and packaging

Question 5

What are the primary and obligatory fuels for the brain?

Answer 5

Glucose

Oxygen

Question 6

When does long-lasting ischaemia occur?

Answer 6

Following infarction

Question 7

What does loss of blood supply to brain cause?

Answer 7

Loss of consciousness in seconds

Question 8

What do muscles have the ability to do?

Answer 8

Function anaerobically

Question 9

Muscles have a store of oxygen bound to what?

Answer 9

Myoglobin

Question 10

What form do muscles have energy store in?

Answer 10

Glycogen

Question 11

What do muscles produce when they are metabolising?

Answer 11

Vasoactive metabolites

Question 12

What happens following the release of vasoactive metabolites?

Answer 12

Vasodilation

Increase in blood flow

Question 13

What are the ways to make ATP?

Answer 13

Glycolysis
Cytoplasm ATP production
Generates pyruvate/lactate

Question 14

What does kerbs cycle utilise?

Answer 14

Pyruvate/lactate

Question 15

Where do most ATP come from!

Answer 15

Oxidation of 3 NADH via electron transport chain in mitochondria

Question 16

What makes the largest portion of ATP?

Answer 16

Mitochondrial respiration

Question 17

What is present inside axons?

Answer 17

Dyed stained mitochondria

Question 18

What is an example of dye?

Answer 18

tetramethylrhodamine methyl ester (TMRM)

Question 19

What happens When TMRM is placed inside axons?

Answer 19

Penetrates the membrane

Question 20

Where can mitochondria be concentrated?

Answer 20

at or near node of Rancher

Synpases

Question 21

What moves mitochondria on Dunedin and kinesin?

Answer 21

Molecular motors

Question 22

Dynein and kinesin move mitochondria in 2 different directions by interacting with what?

Answer 22

Microtubules

Question 23

What is mitochondria?

Answer 23

Major energy making structures within neuron/axon

Question 24

Kinesin can generate movement toward what?

Answer 24

Ending of nerve fibre

Step along microtubule which is involved in retrograde movement of mitochondria and other organelles

Question 25

What requires glucose and express glucose transporters?

Answer 25

Both glia and neurons

Question 26

What are special feature of glucose?

Answer 26

Acts as energy substrate | Precursor for neurotransmitters

Question 27

What is lactate shuttle?

Answer 27

Glia can provide lactate as a fuel for neurons and ensheathed axons

Question 28

What is dependent upon perfusion pressure?

Answer 28

Flow of blood | Delivery of oxygen

Question 29

When the perfusion pressure drops when does the flow drop also?

Answer 29

Flow is driven by pressure

Question 30

What happens when flow falls?

Answer 30

Vascular bed in tissue reacts | Increase the flow to compensate for the drop in pressure

Question 31

How is drop in pressure compensated

Answer 31

Change the resistance of capillary/vascular bed

Question 32

What happens when resistance is decreased?

Answer 32

Increase auto regulation

Question 33

define auto regulation

Answer 33

I stein six ability of organ to maintain constant blood flow despite changes in perfusion pressure

Question 34

What does auto regulation attempt to keep?

Answer 34

Perfusion constant over a range of boood pressures

Question 35

How is autoregulation achieved?

Answer 35

Changing vascular resistance across a tissue or organ

Question 36

What are examples of blood flow regulation?

Answer 36

Myotonic Neurogenic Metabolic

Question 37

What is myogenic regulation?

Answer 37

The diameters of arterioles are adjusted to keep blood flow constant Through mechanical action of flow on the vessel walls and local hormonal effects

Question 38

What does myogenic regulation not explain?

Answer 38

Functional increases in blood flow seen in the brain

Question 39

What is neurogenic regulation?

Answer 39

Nerve fibres innervating the vasculature changing the tone of resistance vessels

Question 40

What is metabolic regulation?

Answer 40

Seeks to balance cerebra blood flow to its demands

Question 41

What is the hallmark of blood flow control in brain?

Answer 41

Localised nature of response

Question 42

What was Eric Newman study?

Answer 42

Used retina as a model (neutrophil) to understand how nerve cells talk to the circulation and did it using microscope imagining techniques

Question 43

what is retina?

Answer 43

Flat surface at the back of eye

Question 44

What does retina have?

Answer 44

Substantial blood supply to provide glucose and nutrients and oxygen to metabolising nerve cells and photoreceptors

Question 45

What is retinal surface composed of?

Answer 45

Nerve fibre layer

Question 46

Where does the nerve fibre layer come from?

Answer 46

Retinal Ganglia that will form the optic nerve

Question 47

What are present on the back of retina?

Answer 47

Ghostly grey size (moligolia)

Question 48

Why are molioglia important?

Answer 48

Form structural scaffold for the formation of the structure of retina

Question 49

What is active hyperaemia?

Answer 49

Increase in organ blood flow that is associated with an increased metabolic activity of an organ or tissue

Question 50

What is a way to activate the neurons in the retina?

Answer 50

Shining a light - activate the photoreceptors and get information from the retina

Question 51

What is an example of way of activating neurons in reruns

Answer 51

Flicker light stimulation

Question 52

What does flicker light stimulation do?

Answer 52

Changes the BF

Question 53

What are arterioles response measured in?

Answer 53

Confocal microscopy

Question 54

What is the link you observed in flicker light stimulation?

Answer 54

Link between what neuron is doing and the blood flow

Question 55

What are Muller Glia?

Answer 55

Large glial cells within the retina

Question 56

What is one key player in the retina?

Answer 56

ATP

Question 57

What is Apyrase?

Answer 57

An enzyme that gobble up any ATP that gets released within neurophil of retina

Question 58

What happens when TTX is applied onto retina?

Answer 58

Reduces the response to light Block sodium channels Prevent any neuronal contribution that requires sodium channel

Question 59

Why use Reina as a model system?

Answer 59

Study link between neuronal activity and blood flow

Question 60

What does application of NMDA to brain tissue increase?

Answer 60

CBF by 20%

Question 61

What is a NMDA receptor antagonist?

Answer 61

MK-801

Question 62

What increases neuronal activity?

Answer 62

NMDA/kainite | More transmitters released