Neurovascular coupling and blood brain barrier Flashcards

1
Q

What can brain scans reveal?

A

How brain function changes in response to a task, challenge or disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does fMRI stand for?

A

Functional Magnetic Resonance Imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does fMRI detect?

A

Does not measure brain activity directly

This imaging detects signals associated with changes in cerebral blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does fMRI rely on?

A

The coupling between neuronal activation and cerebral blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does fMRI indirectly measure neural activity?

A

When neural activity in a region increases, blood flow to that region also increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How active is the brain?

A

Most metabolically active of all organs in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How much does the brain weigh?

A

Roughly 2% of total body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How much cardiac output does the brain receive?

A

15%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How much body energy does the brain consume at rest?

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the brain not have?

A

Glycogen stores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the brain require because of the lack of glycogen stores?

A

Constant supply of glucose and O2 for ATP metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why does the brain use so much energy?

A

Communication of neurons requires a lot of energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the main site of energy consumption?

A

Synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is energy in the synapses for?

A

Energy is used to reverse the movement of ions at synapses during neuronal communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do synapses rely heavily on?

A

Local ATP synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is within each synapse which suggests the synapse needs a lot of energy?

A

Mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the ATP used to do in the synapse?

A

Resetting the synapse to its normal state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is required to maintain synaptic activity?

A

Constant supply of glucose and oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are glucose and oxygen delivered to the brain?

A

Via its blood supply in cerebral circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 2 sources the brain receive its blood supply from?

A

Arising from the dorsal aorta
o Common carotid→ internal carotid arteries
o Subclavian artery→ vertebral arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do the right and left vertebral arteries join to form?

A

Single basilar artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the basilar artery and two internal carotid arteries form?

A

Circle of Willis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where is the Circle of Willis located?

A

Base of brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What part is the Circle of Willis?

A

Arterial ring formed from basilar artery and internal carotid arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does the Circle of Willis give rise to?

A

The major cerebral arteries

26
Q

Where do pairs of left and right cerebral arteries arise from?

A

Circle of Willis

27
Q

What do pairs of left and right cerebral arteries supply?

A

All parts of the brain

28
Q

What happens if one of the main carotid or vertebral arteries are blocked?

A

The cerebral arteries can receive through blood through Circle of Willis

29
Q

What is each cerebral hemisphere supplied by?

A

Three major arteries

30
Q

What are the three major arteries that supply each cerebral hemisphere?

A

Anterior Cerebral Artery
Left Middle Cerebral artery
Posterior cerebral artery

31
Q

Where does stroke usually form?

A

In the middle cerebral artery

32
Q

What are symptoms of stroke related to?

A

Affected area

33
Q

Where do cerebral arteries branch?

A

Over the brain structures

Arteries on brain surface–> Penetrating arterioles –> capillary bed

34
Q

What do cerebral arteries give rise to?

A

Penetrating arterioles then capillaries

35
Q

How vascularised is brain tissue?

A

Highly vascularised

36
Q

What does functional activation by sensory stimulation lead to?

A

Regional increase in the glucose metabolism in corresponding cerebral structures

37
Q

What is the relationship between glucose use in a brain region to the blood flow in that region?

A

Proportional

38
Q

What is neurovascular coupling?

A

Changes in neural activity cause changes in local blood flow

39
Q

What happens with neuronal activation

A

Neurotransmitter release
Increase ATP consumption
Increase O2 and glucose consumption

40
Q

What happens with neurotrasmitter release and increase in O2 and glucose consumption?

A

Vasoactive chemical agents cause vasodilation

Increased cerebral blood flow

41
Q

What is neurovascular coupling the basis for?

A

BOLD signal detected by fMRI

42
Q

What does fMRI measure?

A

Scanner measures function-related changes in blood flow

43
Q

What does fMRI indirectly measure?

A

Neuronal activity

44
Q

What cells are responsible for dilation and constriction of arterioles?

A

Vascular smooth muscle

45
Q

What are responsible for dilation and constriction of capillaries?

A

Pericytes

46
Q

What does the blood brain barrier (BBB) restrict?

A

Movement of substances into and out of the brain

47
Q

What does the term BBB refer to?

A

A complex of cells that separate the brain parenchyma from the luminal contents of the cerebral vasculature

48
Q

What are the functions of the BBB?

A

Protects the brain from “foreign substances” in the blood that may injure the brain
Protects the brain from hormones and neurotransmitters released in the rest of the body
Maintains a constant environment for the brain to enable normal neuronal function

49
Q

What lines the lumen of cerebral vessels?

A

Endothelial cells

50
Q

what do cerebral endothelial cells have?

A

Tight junctions

51
Q

What do tight junctions in endothelial cells restrict?

A

Free passage of substances from the blood to the brain

52
Q

How does glucose enter the brain?

A

Transport carriers for glucose facilitate its entry into the brain

53
Q

How does O2 enter the brain?

A

Diffuses freely from blood to brain

54
Q

What is the first pathway across the blood-brain barrier?

A

Transcellular lipophillic pathway

Lipid-soluble agents

55
Q

What is the second way across the blood brain barrier?

A

Transport proteins

Glucose, amino acids, nucleosides

56
Q

What is the third way across the blood brain barrier?

A

Receptor mediated endocytosis

Insulin and transferrin

57
Q

What is the last way across the blood brain barrier?

A

Absorptive endocytosis

Albumin, other plasma proteins

58
Q

Do all areas if the brain have a BBB?

A

No

59
Q

Where is there no BBB?

A

Structures in the midline of the ventricular system collectively referred to as circumventricular organs (CVOs)

60
Q

What are some examples of CVOs?

A
Pituitary gland
Median eminence 
Area postrema
Preoptic recess
Paraphysis
Pineal gland
Endothelium choroid plexus