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Neuroinfectious Diseases > Neuroinfectious Diseases Exam 1 > Flashcards

Neuroinfectious Diseases Exam 1 Flashcards

1
Q

What are 3 reasons that neuroanatomy is important?

A
  1. remains incredibly clinically relevant portion of anatomy
  2. necessary to interpret the neurologic and mental status of patients
  3. important for fundamental understanding of the brain’s functions
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2
Q

what are the 2 main divisions of the nervous system

A
  1. CNS
  2. PNS
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3
Q

what makes up the CNS?

A
  • encased in bone: brain and spinal cord
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4
Q

what is the brain

A

the central processing organ

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5
Q

what is the spinal cord

A

the major conduit of information

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6
Q

what is the PNS? How is it divided

A

everything outside of the CNS
- divided into the somatic and visceral PNS

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7
Q

Somatic PNS

A

voluntary control

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8
Q

Visceral PNS

A

involuntary or autonomous

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9
Q

What are both the CNS and PNS made up of?

A

neural cells

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10
Q

What are the 3 main regions that the brain can be divided into?

A
  1. cerebrum
  2. cerebellum
  3. brainstem
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11
Q

Cerebrum

A

largest, and newest part of brain

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12
Q

Cerebellum

A
  • Involved in all voluntary functions
  • smaller than cerebrum, but contains more than half of the total neurons in brain
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13
Q

Brainstem

A
  • Involved in all involuntary functions
  • smallest, and oldest part of brain
  • base where the cerebellum and cerebrum rest on
  • connects the brain and spinal cord
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14
Q

What are the 2 divisions of the cerebrum

A

left and right hemispheres

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15
Q

what connects the 2 hemispheres

A

corpus callosum

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16
Q

Cerebrum lateralization

A

idea that the 2 hemispheres of the brain are distinct in what they process with each side having specific specialties

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17
Q

The sulci

A

the deep folds in the brain

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18
Q

the gyri

A

the mountains in the brain

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19
Q

what are the 4 main lobes of the cerebrum

A
  1. frontal lobe
  2. parietal lobe
  3. occipital lobe
  4. temporal lobe
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20
Q

Frontal lobe function

A

responsible for attention, planning, and decision making (behavior)

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21
Q

parietal lobe function

A

integrates information from the senses (orientation and cognition)

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22
Q

occipital lobe function

A

responsible for vision (and perception based on visual cues)

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23
Q

temporal lobe function

A

associated with language, memory, and emotion (specially based on sound cues)

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24
Q

The 5 main segments of the spinal cord

A
  1. cervical cord
  2. thoracic cord
  3. lumbar cord
  4. sacral cord
  5. coccygeal cord
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25
Q

what grows faster, the vertebral column or the spinal cord?

A

the vertebral column

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26
Q

each segment of the spinal cord contains various pairs of..?

A

spinal nerves

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27
Q

what are the layers of protection of the CNS

A
  1. skull and vertebral column
  2. meninges
  3. Cerebrospinal fluid (CSF)
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28
Q

how does the meninges protect CNS

A
  • it encompasses both the brain and spinal cord
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29
Q

what are the layers of the meninges?

A

Dura mater (outermost)
arachnoid mater (middle)
pia mater (innermost)
- there is also the SLYM which is bw the arachnoid and pia mater

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30
Q

what divides the subarachnoid space into 2 functional spaces?

A

the SLYM

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31
Q

Function of SLYM

A
  • forms a new anatomical barrier
  • plays an active role in immune surveillance
  • necessary for correct function of the glymphatic system
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32
Q

after a traumatic injury to the cerebellum, which of the following activities will most likely be affected?
a: establish a conversation over the phone
b) run a marathon
c) sing on a concert
D) playing chess
E) solving math equations

A

B. running a marathon because the cerebellum is in charge of voluntary movement which is really active when moving the body to make it run

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33
Q

Ventricles

A

Canals that connect CSF filled spaces

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34
Q

who first discovered ventricles

A

Hippocrates

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35
Q

who described morphology of ventricles

A

Leonardo Da Vinci

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36
Q

what are the 4 main ventricles

A
  1. left lateral
  2. right lateral
  3. third ventricle
  4. fourth ventricle
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37
Q

what connects the ventricles

A

connected by interventricular foramen (connect lateral ventricles to third ventricle) and cerebral aqueduct (connect third and fourth ventricles)

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38
Q

What is the spinal tap

A

a clinically important process used to diagnose neural disorders
- it takes a needle and injects it into the CSF to take a sample which is then used to diagnose

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39
Q

What is CSF

A

it is mostly water with some sugar and salts, it is an electrolyte, almost 100% p and cell free
- aka has no RBC

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40
Q

How does spinal tap help diagnose neural disorders?

A

the presence of p or cellular infiltrates is indicative of dysfunction

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41
Q

Hydrocephalus (from greek words “hydro” meaning water and “cephalus” meaning head) is a condition where there is excessive accumulation of fluid in brain. What would be a direct consequence of it?
a) the infant skull will expand to accommodate the buildup of water bc the sutures have not yet closed, resulting in a large head
b) excess water will flush out all the toxins from the brain, resulting in better functioning of neurons
c) can result in development of other mental diseases/disorders, such as Alzheimer’s disease or Parkinson’s
d) the meninges will withstand the intracranial pressure, redirecting the force towards the soft brain tissue, compensating for it and keeping its function.

A

a) the infant skull will expand to accommodate the buildup of water because the sutures have not yet closed, resulting in a large head

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42
Q

Grey vs white matter in CNS

A

in the brain, the grey matter is on the outside while the white is on the inside but the inverse is true on the spinal cord

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43
Q

post mortem brains are useful for

A

visual or manual inspection aka anatomical description

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44
Q

what are some functional brain imaging techniques

A

CT, MRI, and PET scans

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45
Q

CT scan

A

it distinguishes air, liquid, and bone filled areas
- skull appears white while parenchyma is grey and sinuses are black

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46
Q

MRI scan

A

distinguishes soft tissue
- white from grey matter
air and bone give no signal
- both appear black

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47
Q

PET scan

A

highlights areas of metabolic activity
bc it uses radioactive tracers, it is very quantitative w/ large dynamic range

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48
Q

Who injected melted wax into a brain to reveal the exact nature of the brain’s ventricles?

A

Leonardo Da Vinci

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49
Q

The brain is involved in processing or directing all of the following except:
a) taste, vision, touch, smell and hearing
b) movement and response to stimuli
c) food degradation and absorption
d) learning, talking, emotions

A

C

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50
Q

The high degree of folding of the cerebral cortex creates more space for neurons, which is postulated to allow what of the following?
a) move and coordinate our limbs
b) coordinate and reasoning
c) to have at least nine senses
d) to multitask (like walk and talk at the same time)

A

B

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51
Q

Evolutionary speaking, what three parts of the brain can be put in order of appearance during evolution, starting with the ancient part first?

A

C. the brainstem -> the cerebellum -> the cerebrum

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52
Q

The brain is a __________ ball, with empty space inside filled with liquid

A

hollow

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53
Q

Many nerves come together to form nerve fibers, which can also come together to form thick bundles called nerve tracks. The largest of these is called the ____________________, which forms a bridge between the brain’s_________________

A

corpus callosum; hemispheres

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54
Q

The spinal tap is a procedure possible because the _____________ grows faster than the ___________

A

vertebral column; spinal cord

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55
Q

What are the two functional units of the nervous system

A
  1. nerve cells (neurons)
  2. glia cells (neuroglia)
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56
Q

what are neurons, what is the function

A

basic units of nervous system
involved in acquisition, integration, and transmission of electrical signals

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57
Q

what are neuroglia and what is their function?

A

homeostasis-maintaining cells that support neurons and allow them to function optimally by performing a variety of functions

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58
Q

What is the basic structure of a neuron

A
  1. dendrites
  2. soma
  3. axon
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59
Q

dendrites

A

branching extensions that collect information from other neurons

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60
Q

soma

A

the cell body, the core region of a neuron

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61
Q

axon

A

one root that transmits messages to other neurons

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62
Q

direction of flow of information in a neuron?

A

unidirectional
goes from dendrite to soma to axon to synapse to dendrite

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63
Q

what is the gap between neurons called

A

synapse

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64
Q

what carries signals between neurons

A

ions and molecules

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65
Q

what are the 4 types of axon connections to transmit info

A
  1. axon-dendrite
  2. axon-spine
  3. axon-soma
  4. axon-axon
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66
Q

what transmits signals across synaptic cleft

A

neurotransmitters

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67
Q

what triggers secretion in a neuron

A

action potential

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68
Q

what are the 2 main types of receptors that receive information from an axon?

A

ionotropic or metabotropic

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69
Q

what are the 4 types of morphology for the soma in a neuron?

A
  1. unipolar
  2. bipolar
  3. multipolar
  4. psuedounipolar
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70
Q

what are the 3 main types of information that neurons process

A
  1. sensory
  2. motor
  3. interneuron
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71
Q

sensory neuron function

A

bring info to the CNS

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72
Q

motor neuron function

A

send signals from brain and spinal cord to muscle

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73
Q

interneuron function

A

associate sensory and motor activity in the central nervous system

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74
Q

what are the 3 zones of the macroanatomy of a neuron?

A

the input zone
conducting zone
output zone

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75
Q

what brain matter holds the conducting zone of the neuron

A

white matter

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76
Q

what are the 4 main types of neuroglia

A
  1. astrocytes
  2. oligodendrocytes
  3. microglia
  4. ependymal cells
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77
Q

what are the other specialized or ill-defined glia?

A
  1. NG2 cells
  2. radial glia
  3. muller glia
  4. bergmann glia
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78
Q

Based on your knowledge of the relationship bw micro and macro anatomy of the nervous system, which of the following is FALSE:
a) because the thick fibers in the brain (like corpus callosum) are myelinated, they appear as “white matter”
b) the grey matter and white matter localization (relative to each other) are the same between the brain and the spinal cord
c) the neurons in the brain cortex are specialized on integrating multiple signals, hence they have extensive branching and can process complex action potentials
d) the neuron’s function will determine its structure (ex: number or length of processes)

A

B

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79
Q

Main 5 functions of Astrocytes

A
  1. regulate neuronal communication (Synaptogenesis)
  2. regulate blood brain barrier (BBB)
  3. nutrients support to neurons
  4. regulate signal transmission by interacting with nodes of Ranvier (space bw myelin sheets)
  5. repair metabolic damage (caused by ROS; osmotic; pH)
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80
Q

what is the most abundant glia cell

A

astrocytes

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81
Q

what is the function of oligodendrocytes

A

these cells are in charge of myelination in CNS (like Schwann cells are in PNS)
they surround axons and produce myelin

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82
Q

what if function of NG2 cells

A

they act as multipotent precursors to other glia, but in particular to oligodendrocytes

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83
Q

what is the most proliferative (grow and increase in size most rapidly) cell in the CNS

A

oligodendrocytes

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84
Q

What causes myelinated axons to be faster than unmyelinated ones?

A

saltatory conduction produced due to nodes of Ranvier on myelinated sheaths

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85
Q

which cells are the immune cells of the CNS

A

microglia

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86
Q

where does microglia come from

A

originates in blood
- enter CNS during embryonic development
- are very long lived (varies depending on brain region)

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87
Q

What are the 3 ways that microglia are immune cells of CNS

A

travel through brain and spinal cord keeping it clean via:
- synaptic pruning
- removal of death cells
- remodel neuronal networks

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88
Q

location of ependymal cells

A

found in the walls of ventricles

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89
Q

function of Ependymal cells

A
  • make and secrete CSF
  • ciliated side creates flow of CSF
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90
Q

Which of the following would result in attenuation of the action potential?
a) a disease that cause all axons to enlarge (but keep concentration of cell components)
b) a disease that destroys myelin sheaths
c) a disorder that prevents production of neurotransmitters
d) a condition that restricts ion exchange to nodes of Ranvier

A

B

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91
Q

Which of the following statements is the most accurate description of neuroglia?
a) they all originate from the blood and then migrate to the brain
b) they are electrically non-excitable cells that support the function of the brain
c) they are the homeostasis- maintaining cells of the nervous system
d) is the collective name for all the cell types present in the brain and spinal cord

A

c

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92
Q

which of the following cells could be described as a stem cell?
a) oligodendrocytes
b) astroglia
c) NG2 cells
d) ependymal cells

A

C

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93
Q

What are the two broad types of receptors in a synapse?

A

ionotropic and metabotropic

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94
Q

How does a signal flow through the nervous system?
a) Dendrite > axon > soma > synapse > dendrite
b) Synapse > dendrite > soma > axon > synapse
c) Axon > soma > dendrite > synapse > axon
d) Soma > axon > synapse > axon > soma

A

B

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95
Q

What are examples of synapses?
a) Axon with dendrite
b) Axon with spine
c) Axon with axon
d) All of the above.
e) Only (a) and (b)

A

D

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96
Q

T or F: Microglia are the resident immune cells of the brain.

A

True

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97
Q

T or F: In the brain you can find these three types of cells: neurons, endothelial cells, and epithelial
cells.

A

True

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98
Q

T or F: Myelin is a fatty substance produced by oligodendrocytes in the central nervous system and by
Schwann cells in the peripheral nervous system.

A

True

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99
Q

T or F: The ‘all-or-nothing law’ of cellular excitation establishes that neurons can regulate the action
potentials.

A

False, neurons cannot control whether they fire or not

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100
Q

T or F: The special neurons of the cerebral cortex can process complex signals because they harbor
multiple axons.

A

False, all neurons only have 1 axon

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101
Q

A neuroglia with a characteristic star-like morphology?

A

astrocyte

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102
Q

Cells in charge of myelination in CNS are _____________ (similar to _________ cells in PNS)?

A

oligodendrocytes; Schwann

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103
Q

Pluripotent cells that give rise to other glia, in particular oligodendrocytes

A

NG2 cells

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104
Q

Epithelial cells that form the walls of the ventricles

A

ependymal cells

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105
Q

Based on morphology (physical form), neurons can be classified as __________,_________,__________, or __________

A

unipolar, bipolar, multipolar, or pseudounipolar

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106
Q

The ____________ are very long lived glia also involved in synaptic pruning and healing

A

microglia

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107
Q

What is unique about the blood in the brain ( 3 things)?

A
  1. one of the highest metabolic demands in the body
  2. unique blood makeup
  3. require a tight control of water and ion concentrations
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108
Q

What metabolic demands does brain blood have? (3 things)

A
  1. need lots of oxygen
  2. need a constant carbon source
  3. generate a lot of waste
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109
Q

what is the makeup of brain blood

A
  • 55% water
  • has lots of ions and molecs
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110
Q

what causes tight control of water and ion concentrations in brain blood?

A
  • little spaces for liquid inside the head
  • ionic strength of extracellular and intracellular milieu critical for action potentials
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111
Q

Functions of cerebral circulation (5 things)

A
  • has to provide large volumes of blood
  • has to provide a constant supply
  • has to be insensitive to fluctuations in blood pressure
  • work together with choroid plexus to generate CSF
  • essential part of glymphatic system
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111
Q

functions of the BBB (5 things)

A
  • allow uptake of glucose
  • allow removal of waste
  • allow gas exchange
  • control cellular migration
  • formidable barrier for pathogens
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112
Q

3 main types of vessels

A
  1. arteries
  2. veins
  3. capillaries
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113
Q

flow of arteries vs veins

A

arteries come from heart and go to rest of body (in this case brain) while veins are on their way to the brain

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114
Q

What is the vasculature

A

the system of vessels that carry blood and lymph throughout the body

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115
Q

what is the vasculature made up of ?

A

endothelial cells that line the inside of all the vessels

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116
Q

what are the 3 types of endothelium

A
  1. continuous
  2. fenestrated
  3. sinusoid (or discontinuous)
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117
Q

What type of vessels are seen in the CNS

A

continuous

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118
Q

what are the 4 large arteries that come directly from the aorta

A
  1. left internal carotid
  2. right internal carotid
  3. left vertebral artery
  4. right vertebral artery
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119
Q

how much of the brain blood supply comes from the carotids?

A

80%, the other 20% comes from the vertebral arteries

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120
Q

where does the spinal cord blood supply come from

A

all from vertebral arteries

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121
Q

Carotids mostly flow to what region of the brain?

A

mostly the cerebrum

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122
Q

the vertebral arteries mainly flow to what areas of the brain?

A

mostly to the cerebellum and brain stem

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123
Q

where does all the blood flow to the brain meet?

A

the circle of willis

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124
Q

what is the circle of willis

A

where the 3 next main arteries that supply blood to the rest of the brain are located

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125
Q

what are the 3 main arteries in the circle of willis

A

anterior, middle, and posterior cerebral arteries

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126
Q

what are the functions of the circle of willis

A
  1. main collateral ensuring blood flow to brain
  2. allow redistribution of blood if one or more of the arteries are occluded
  3. low resistance (pressure), allows blood flow to go either way in the ring
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127
Q

what forms the second collateral system that ensures blood flow to the brain?

A

the pial network of vessels in the meninges

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128
Q

make up of the main arteries

A
  • extracellular matric and nerve cells
  • smooth muscle layers (up to 20)
  • endothelial layer (contains dozens of ECs)
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129
Q

make up of pial arteries

A

same as main but has 3 smooth muscle layers

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130
Q

make up of intracerebral arteriole

A
  • pericytes and astrocytic endfeet
  • 1 layer of smooth muscle
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131
Q

make up of microcapillaries

A
  • specialized ECs that DO NOT have smooth muscles
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132
Q

example of a microcapillary

A

the blood brain barrier

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133
Q

what are the 3 barriers of the CNS

A
  1. BBB
  2. Blood CSF
  3. Blood meningeal
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134
Q

where is the BBB located

A

at the level of the microcapillaries

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135
Q

where is the Blood-CSF located

A

at the choroid plexus

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136
Q

where is the blood-meningeal located?

A

in the arachnoid space

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137
Q

where are there fenestrated endothelium in the brain?

A
  • at the surface intracranial vessels (in the dura)
  • at the choroid plexus vessels
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138
Q

how does blood drain from the blood

A

draining occurs from inside towards the surface and involves all major sinuses

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139
Q

where do all the sinuses join

A

join at the jugular

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140
Q

why is venous drainage important (3 reasons)

A
  1. removes spent blood from brain, parenchyma, meninges, and eyes
  2. removes CSF
  3. removes waste
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141
Q

Where is the BBB present

A

in the capillary beds of the brain (microcapillaries)

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142
Q

The BBB is formed by: (5 things)

A
  1. special endothelial cells known as BMECs
  2. pericytes (type of mural cell)
  3. astrocytes (their endfeet)
  4. Basal (or basement) membrane
  5. microglia (constantly surveying the microvessels for “insults”)
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143
Q

what is the main component of the BBB

A

BMECs

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144
Q

what are the 4 functions of the BBB

A
  1. control molecular traffic: CO2 and O2 permeable; lipid soluble permeable; small peptide permeable
  2. ion homeostasis: anything ionic impermeable
  3. high affinities for nutrients: active transport by protein transporters
  4. control cellular traversal: immune surveillance w/ minimal inflammation
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145
Q

BMEC structure

A
  • flatter and larger than systemic ECs
  • vessel diameter is span by a single BMEC
  • have tight junctions
  • high number of mitochondria
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146
Q

function of BMECs

A
  • restrict paracellular passage using TJ
  • very low rates of transcytosis
  • restrict transcellular passage
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147
Q

what regulates transcellular passage across BMECs

A

regulated by cellular transports, localized at specialized domains, apical or basal

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148
Q

Efflux transporters in BMECs, location and function

A
  • on apical side
  • bind lipophilic (lipid soluble) molecs inside the cells and transport them back into the blood
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149
Q

Influx transporters of BMECs, location and function

A
  • on both sides (apical and basal)
  • highly specific nutrient channels
150
Q

what is required to power transporters of BMECs

A

lots of mitochondria

151
Q

4 main types of cellular junctions

A
  1. tight junctions (TJ)
  2. Adherens junctions (AJ)
  3. Desmosomes
  4. Gap junctions
152
Q

TJ are ______________________ barrier to ions, molecs, and cells

A

paracellular

153
Q

what type of interactions can occur at TJ

A

homotypic or heterotypic interactions

154
Q

examples of TJs

A
  1. claudins
  2. occludins
  3. junctional adhesion molecs (JAMs)
155
Q

describe TJs

A

interactions are so tight, that cellular traversal in the CNS occurs mainly by transcellular pores (imagine a donut)

156
Q

Diff bw AJs and TJs in location

A

AJs are further away from the apical side compared to TJs

157
Q

examples of AJs

A

Cadherins, in BMECs it is VE-cadherin

158
Q

how are AJs regulated

A

Ca regulated

159
Q

what are the major regulators of permeability

A

AJs

160
Q

AJs link to the_______ _________ of the cell?

A

link to the actin cytoskeleton

161
Q

What is the main type of endothelial cellular junction in the brain outside of the BBB

A

AJs

162
Q

what are LAMs

A

low levels of leukocyte adhesion molecs

163
Q

Where is velocity of blood flow greater? in systemic capillaries or microcapillaries

A

velocity is greater in microcapillaries than in system capillaries

164
Q

What occurs when LAMs are upregulated during certain diseases?

A

TJs are disassembled and JAMs are exposed leading to cellular infiltration

165
Q

Key properties of the BBB are due to features provided by?

A

BMECs (TJ, transporters, etc)

166
Q

BMECs stands for

A

brain microvascular endothelial cells

167
Q

where are pericytes located?

A

embedded in basal membrane of vasculature

168
Q

general functions of pericytes

A
  1. elasticity and rigidity (vessel diameter regulation)
  2. angiogenesis, extracellular matrix production
169
Q

what is angiogenesis

A

production of new blood vessels

170
Q

functions of Pericytes in CNS

A
  1. regulate immune cell infiltration
  2. regulate permeability of BBB
  3. inhibit features normal in the peripheral vasculature
171
Q

function of Astrocytic endfeet in CNS? (4 things)

A
  • astrocytes produce many factors that regulate BBB permeability
  • increase TEER = decrease permeability
  • regulate blood flow through secreted molecs that act on pericytes
  • provide second layer of support (secrete extracellular matrix)
172
Q

TEER

A

transendothelial electrical resistance

173
Q

2 layers of basal membrane

A
  1. vascular layer
  2. parenchymal layers
174
Q

function of basal membrane

A
  • support function
  • barrier function
175
Q

what is needed to traverse the basal mem

A

enzymatic degradation

176
Q

what surveys the basal membrane

A

microglia

177
Q

what are the different permeabilities of the 3 barriers in the brain

A
  1. BBB is impermeable
  2. BCSFB is selectively impermeable
  3. BMB is less impermeable
178
Q

what other areas have permeable vessels and what barrier do they have

A
  1. choroid plexus, pituitary gland, etc
  2. each one has its own barrier
  3. there is a need and mech to regulate it
179
Q

what Diseases are associated with the BBB

A
  1. stroke
  2. multiple sclerosis
  3. parkinson’s disease
  4. alzheimer’s disease
  5. epilepsy
  6. TBIs
  7. infectious diseases
180
Q

what 4 pathologies are seen when diseases affect the BBB?

A
  1. increased permeability
  2. increased cellular infiltration
  3. disruption of ion/pH homeostasis
  4. disruption of neural function
181
Q

Which of the following are functions carried out by the BBB?
a) Regulates the composition of the cerebrospinal fluid (CSF).
b) Controls the passage of bone-marrow stem cells into the brain.
c) Protects the brain from “foreign” substances in the blood by restricting their passage.
d) Provides the brain with a source of energy in the form of lipids.

A

C

182
Q

The properties of the BBB are mostly due to the microvascular endothelial cells, but are
augmented and maintained by the action of which types of cells?
a) Astrocytes, microglia, and pericytes.
b) Microglia, muscle cells, and perivascular macrophages.
c) Astrocytes, pericytes, and perivascular macrophages.
d) Ependymal cells, microglia, and pericytes.

A

A

183
Q

A scientist has discovered a drug to treat a specific type of brain infection. The drug is
ionized at the pH of human blood, which means that _____.
a) It will be actively absorbed by the BBB.
b) It will passively diffuse through the BBB.
c) It will not be pass through the BBB.
d) It will pass into the endothelial cells and remain trapped there.

A

C

184
Q

There are 3 cellular barriers in the CNS:
a) The blood-CSF barrier, the meningeal barrier, and the BBB.
b) The choroid plexus, the dura mater, and the skull.
c) The dura mater, the meningeal barrier, and the BBB.
d) The blood-CSF barrier, the choroid plexus, and the arachnoid.

A

A

185
Q

Which of the following are specialized features of the endothelial cells of the BBB?
a) Cellular junctions similar to that found in epithelial barriers.
b) Are highly ciliated.
c) A high concentration of plasma membrane transporters for lipids.
d) Fenestrations and ion-permeable pores.

A

A

186
Q

The neurovascular unit includes: ____________, ____________, ____________, and
____________.

A

BMECs, pericyte, astrocyte endfeet, basal membrane, and microglia.

187
Q

In the cerebral vasculature, there are two collaterals that ensure blood supply. These are
____________________ and ____________________.

A

circle of willis and pial network of vessels in meninges

188
Q

The BMECs have many ________________ to be able to power all the transporters on their
surfaces.

A

mitochondria

189
Q

____ side of the cell facing the basal membrane
(the solid extracellular matrix).

A

Basal side

190
Q

____ can regulate the opening/closing of
cellular junctions.

A

Adherens junctions

191
Q

____ protein plaques that link intermediate
filaments in the cell with the extracellular matrix.

A

Desmosomes

192
Q

____ tunnels that traverses neighboring cells
allowing sharing of their cytoplasm.

A

Gap junctions

193
Q

____ side of the cell facing the lumenal space
(i.e. ventricular space).

A

Apical Side

194
Q

____ glue cells together to prevent leakage of
molecules between them.

A

Tight Junctions

195
Q

what is the choroid plexus?

A

a highly vascularized structure that is the main gateway of immune cell entry into CNS, it contains the B-CSF barrier and is the main source of CSF

196
Q

where is the choroid plexus located?

A

one in each ventricle (4 total)

197
Q

how many stages in the structure of the choroid plexus

A

4 stages

198
Q

Stage 1 of choroid plexi

A
  • pseudostratified
  • central nuclei
  • microvilli (brush border)
  • no villi
199
Q

stage 2 of choroid plexi

A
  • columnar epithelium
  • apical nuclei
  • microvilli (brush border)
  • sparse primary villi (tissue folds)
200
Q

stage 3 of choroid plexi structure

A
  • cuboidal epithelium
  • central or apical nuclei
  • microvilli (brush border)
  • more abundant primary villi (tissue folds)
201
Q

Stage 4 of choroid plexi structure

A
  • cuboidal epithelium
  • basal nuclei
  • microvilli (brush border)
  • complex villi (multiple tissue folds)
202
Q

flow of molecules in choroid plexi

A

travel through fenestrated capillary (exit through gaps there) and travel into interstitial space, from there, they must have an APC or be allowed in to cross into the choroidal epithelium

203
Q

what is the flow of CSF in ventricular system

A
  • unidirectional flow in ventricular system:
    from lateral to interventricular foramina to third ventricle to cerebral aqueduct to fourth ventricle to central canal (into spinal cord) and median/lateral apertures (into subarachnoid spaces)
  • multidirectional flow in the subarachnoid spaces
204
Q

another name for subarachnoid spaces

A

perivascular spaces

205
Q

Possible reasons that generate the CSF flow

A
  1. beating cilia
  2. pulsations on vessels from heartbeat
  3. constant generation from one side and absorption on another
  4. a combo of any of the above
206
Q

what occurs if csf flow is interrupted?

A

brain will be damaged which has many causative reasons, most congenital
ex: infections or tumors

207
Q

why can congenital problems in CSF flow can go unnoticed for years

A

because baby skulls are flexible and will not be immediately obvious, in these cases, it is treatable with a drainage tube

208
Q

If CSF flow is interrupted as an adult, how can you treat this?

A
  • it is very serious because by this time the skull is formed (no longer flexible) meaning that there is no room for expansion
  • this interruption must be treated with surgery focusing on the cause not the consequence
209
Q

How does CSF reabsorption occur?

A
  1. travels from choroid plexus to the interventricular foramen
  2. goes through the cerebral aqueduct, lateral aperture, fourth ventricle and its choroid plexus and exits through the median aperture
  3. flow will then cross central canal of spinal cord and up the subarachnoid space
  4. it then exits through the arachnoid villus into the superior sagittal sinus
210
Q

what changes the valve opening in CSF reabsorption

A

the valve is the arachnoid villus that is controlled based on pressure
- low pressure causes valve to close and less CSF is absorbed
- high pressure causes valve to open and more CSF absorbed

211
Q

The Choroid plexus can be involved in various pathologies, all of which can be grouped into 2 main categories: high volume and low volume of CSF. What causes each of these conditions?

A
  1. conditions with high CSF volumes: BTI that damages valves, cancer of choroid plexi causing too much CSF, stroke, inflammation infection by fungi
  2. conditions with low CSF volumes: death of ependymal cells, not enough water, autoimmune disease that attacks choroid plexus, CSF leak either due to trauma or medical intervention
212
Q

2 main functions of Choroid plexus

A
  1. CSF
  2. immunosurveillance
213
Q

what cells does the parenchyma not contain under normal conditions?

A

no t cells or b cells in parenchyma only microglia

214
Q

how does choroid plexus immune surveillance in brain

A

they patrol the surfaces of the brain (yet low numbers)

215
Q

most surveillance cells are …?

A

resident effector cells such as perivascular macrophages

216
Q

How do immune cells get into the CSF filled ventricle?

A
  1. migrate across fenestrated endothelium into the stromal space
    - this is where APCs and T cells are
  2. they move along basal surface of ependymal cells
  3. they cross into the CSF filled ventricle (either paracellularly or transcellularly)
217
Q

what is the glymphatic system?

A

it is formed by the flow of the CSF and ISF through channels inside the brain and the channels are formed by astrocytes which actively pump water into parenchyma

218
Q

function of glymphatic system

A

to remove waste and distribute nutrients

219
Q

what drives the glymphatic system

A

driven by glia (astrocytes)

220
Q

glymphatic system is similar to?

A

lymphatics

221
Q

mice that are aquaporin deficient are similar to what disease?

A

develop a pathology similar to Alzheimer

222
Q

When is the glymphatic system most active

A

when asleep

223
Q

potential applications for glymphatic system

A
  • gene therapy delivery
  • drug targeting
  • treatment for diseases related to molecule aggregates
224
Q

what happens if you inject a dye into the blood?

A

the dye would stay in the blood
- does NOT travel into brain or CSF

225
Q

what happens if you inject a dye into the CSF?

A

dye would travel into the brain and CSF area

226
Q

The CSF flows in what direction?
a) Lateral ventricles > third ventricle > fourth ventricle > central canal
b) Interventricular foramina > third ventricle > fourth ventricle > cerebral aqueduct
c) Lateral ventricles > Interventricular foramina > cerebral aqueduct > third ventricle
d) Meninges > fourth ventricle > cerebral aqueduct > third ventricle

A

A

227
Q

Which of the following is NOT a function of the CSF?
a) Decreases the effective weight of the brain by ~90%.
b) Cushions the brain and spinal cord from physical trauma, reducing the impact on the tissue.
c) Allows blood into the brain parenchyma to ensure good oxygenation.
d) Removes waste products from the CNS.

A

C

228
Q

What would be an explanation for the Choroid plexus highly vascularized tissue?
a) It needs access to the blood to carry out its functions.
b) It generates more waste than normal epithelium, hence requires more blood flow.
c) Like the kidneys, it acts as a filter of the brain’s blood supply.
d) Like the liver, it secretes important molecules that need to be disseminated throughout the
body.

A

A

229
Q

The Choroid plexus plays an important role in the brain’s immune system because
_____.
a) Is the primary site for red blood cell entry into the brain.
b) Is the entryway of immune cells into the perivascular spaces (and sub-arachnoid space).
c) Is thought to be the source of microglia as they differentiate from ependymal cells.
d) Ependymal cells are the resident immune cells of the brain.

A

B

230
Q

Which of the following is NOT a feature of the glymphatic system?
a) Is driven by aquaporin channels on astrocytes
b) It distributes nutrients in the parenchyma of the brain
c) It is most active while awake
d) It removes wastes such as amyloid plaques.

A

C

231
Q

T or F: The Choroid plexus is located within the ventricles and contains the B-CSFB.

A

True

232
Q

T or F: The 4 Choroid plexi (one per ventricle) develop differently and carry out different functions
depending on location.

A

False, choroid plexi develop the same on each of the four ventricles and carry out same functions

233
Q

T or F: Unlike the BBB, the vasculature in the choroid plexus contains sinusoid vessels.

A

False, vasculature of choroid plexus has fenestrated vessels and BBB has continuous

234
Q

T or F: The glymphatic system is involved in both nutrient distribution and waste removal.

A

True

235
Q

T or F: A defect in the function of the Choroid plexus will lead to disease, regardless of the magnitude of the defect as the brain will not be able to compensate

A

False, brain is able to compensate for these defects by making changes through reabsorption

236
Q

what is the 2nd circulatory system that is essential for life?

A

the lymphatic system

237
Q

function of lymphatic system is to support what 3 other systems in the body?

A
  1. cardiovascular
  2. immune
  3. digestive
238
Q

how does lymphatic system support the cardiovascular system

A

it unilaterally returns interstitial fluid (ISF) to the vascular system

239
Q

how does the lymphatic system support the immune system?

A

it provides the environment that allows for initiation of an adaptive immune response

240
Q

how does the lymphatic system support the digestive system

A

through the absorption of fat soluble vitamins and fatty substance from the GI tract

241
Q

where is the lymphatic system found

A

throughout the body, it is parallel to blood vessels

242
Q

which system is closed

A

blood circulation

243
Q

what type of system is the lymphatics system

A

it is an open system

244
Q

every blood capillary is interconnected with the lymphatics system except?

A

except the capillaries in the BBB

245
Q

what is the fluid collected by the lymphatic vessels called?

A

lymph

246
Q

what is lymph made up of?

A
  • mostly derived from blood
  • immune cells
  • cholesterol, FA, and other fat and large products
  • there is NO RBC in lymph
247
Q

what is lymph from the GI tract called?

A

chyle

248
Q

what is not present in lymph?

A

antibodies are too large

249
Q

how are lymphatic vessels shaped?

A

they are blind ended, not fenestrated, just have endothelial flaps that interstitial fluid can enter through

250
Q

Will the components of the lymph be the same regardless of the position in the body?

A

not all lymph is the same and the composition depends on where it comes from

251
Q

what is constantly moving bw the blood and lymph

A

lymphocytes (t and b cells)

252
Q

what constantly surveys tissues in lymphatic system

A

innate immune cells including macrophages and neutrophils

253
Q

what does lymph collect from the blood and tissues

A

lymph collects all sorts of molecs including PAMPs and DAMPs

254
Q

what are PAMPs

A

pathogen associated molecular patterns

255
Q

what are DAMPs

A

danger associated molecular patterns

256
Q

all the lymph, innate immune cells and molecules come together at what region

A

come together at lymph nodes

257
Q

How does lymphocytes and lymph return to blood

A

via thoracic duct

258
Q

where do naive lymphocytes enter the lymph nodes through?

A

enter lymph nodes from blood

259
Q

how do antigens from sites of infection reach lymph nodes

A

via lymphatics

260
Q

where does adaptive response start

A

at lymph nodes

261
Q

why do activated lymphocytes return to blood

A

to target infection

262
Q

why does lymphatic vessel enter through the opposite side of the blood circulation

A

the aorta has a lot of pressure and lymph does not have any, so if lymph valve is placed there, blood from aorta would invade into the lymph valve

263
Q

why was immune privileged organ idea applied to the CNS

A

bc the CNS was traditionally thought to be devoid of lymphatics

264
Q

location of CNS lymphatics

A

located in dura, next to major sinuses

265
Q

make up of CNS lymphatics

A

intradural vessels that are leaky (fenestrated)

266
Q

what type of molecules move through CNS lymphatics

A

cells and large molecs move bw layers

267
Q

how is CSF transported within the large cavity of the subarachnoid space?

A

visualize CSF and immune cell movement within SAS

268
Q

SLYM

A

sub-arachnoid lymphatic like membrane

269
Q

SLYM features

A

divides SAS
phenotypically distinct from the dura, arachnoid and pia maters
acts as barrier for molecules that are 3kDA and bigger

270
Q

what is the glymphatic lymphatic connection

A

it is an anatomically continuous and functionally related system that goes from glymphatic to lymphatic

271
Q

glymphatic lymphatic connection function

A

glymphatic removes waste into veins and lymphatic removes fluid into lymph nodes

272
Q

how does the CNS lymphatics survey immunology

A
  • immune cells go in and out of brain through vasculature and lymphatics
  • CSF/ISF constantly absorbed by lymphatics and monitored at cervical lymph nodes
  • if antigens are found by immune cells, or antigens find their way into cervical lymph nodes, an immune response can be mounted
273
Q

how does SLYM support role of dural lymphatics in CNS immunity

A
  • it is closer to brain surfaces
  • larger number of resident immune cells
  • can regulate influx of immune cells from dura/skull bone marrow
274
Q

SLYM can act like?

A

immune hubs

275
Q

what role does CNS lymphatic system have in autoimmune disease

A

if they control immune responses in the brain, then controlling that gate could hold promise to treat autoimmune diseases

276
Q

Which of the following is NOT a function of the lymphatic system?
a) Support the immune system by providing space for activation of lymphocytes.
b) Return excess protein and interstitial fluid (ISF) in the tissues back to the blood.
c) Allows absorption of nutrients passing through your intestines.
d) Removes CSF and ISF directly from the parenchyma of the brain and drains it into the gut
for disposal.

A

D

277
Q

During a routine visit to your primary doctor, the physician finds enlarged lymph nodes
in your neck. What could be the cause of this enlargement?
a) You have an infection and immune cells in the node closest to the infection (your neck) are
actively dividing and specializing in killing the invader.
b) You have drink too much water causing the lymph node to inundate.
c) You have a defect in your skin.
d) The node is actively absorbing nutrients and lipids and have become swollen due to lack of
space.

A

A

278
Q

Disorders like Alzheimer’s and Parkinson’s are thought to be a consequence of the accumulation of misfolded proteins in the brain. Which of the following statements could
be correct?
a) The glymphatic system is not working correctly, resulting in accumulation of these proteins.
b) The lymphatic system is not working correctly, resulting in accumulation of these proteins.
c) The vasculature in the brain is not working correctly, resulting in accumulation of these
proteins.
d) The meninges are not working correctly, resulting in accumulation of these proteins.

A

A

279
Q

Which of the following is thought to be correct about the SLYM?
a) Is similar in structure and composition to the other meningeal layers.
b) Can organize the CSF in the SAS.
c) Is not a barrier (i.e. molecules can freely pass through it).
d) Is made up entirely of immune cells.

A

B

280
Q

Which of the following statements best describes the neurolymphatic system?
a) Is a unique blind-ended unidirectional, absorptive and transport system that penetrates deep
into the brain tissues.
b) It consists of a multitude of lymphatic vessels all over the brain that drain directly into the
thymus.
c) It is present throughout the meninges and constantly scan the CSF and ISF for foreign
compounds.
d) It only scans, and survey, the CSF for foreign particles and does not have access to the
parenchyma of the brain, hence this area cannot be monitored.

A

C

281
Q

T or F: Lymph from anywhere in your body will at least be filtered by one lymph node prior to return to the
blood.

A

True

282
Q

T or F: The CSF/ISF flow is the common link between the glymphatic and lymphatic systems.

A

True

283
Q

T or F: Lymph contains water, proteins, immune cells, and red blood cells.

A

false, lymph does not have RBC

284
Q

T or F: The location of the CNS lymphatics vessels (i.e. in the dura mater rather than in the brain parenchyma) may explain the evidence previously used to state the immune-privileged organ hypothesis.

A

True

285
Q

T or F: The lymphatic vessels are blind ended and as such, can allow easy flow of large molecules and cells.

A

True

286
Q

why are cancers so hard to treat

A
  • side effect of the brain barriers
  • cancers are not inflammatory
  • steal nutrients and blood away from normal cells
287
Q

what does increased lymphatics result in

A

increased number of t cells and surveillance

288
Q

what promotes lymphogenesis

A

VEGF-C

289
Q

what results in destruction of a tumor

A

combinatorial therapy

290
Q

how long is BBB

A

thousands of miles of blood vessels

291
Q

what does the BBB allow to cross

A

glucose, oxygen and other nutrients
- prevents most toxins and infectious agents from coming in

292
Q

2 main types of immune system responses

A

innate or adaptive

293
Q

what is the time, effector cells and mechanism used during an innate immune response

A

innate is immediate bc it is the 1st/2nd line of defense, it uses physical (and chem) barriers; phagocytes (macrophages, etc) as effector cells and has a nonspecific mechanism against all invaders

294
Q

what is the time, effector cells and mechanism used during an adaptive immune response

A

an adaptive immune response takes time bc it is reinforcements, the last line of defense (>48 hrs to 1 to 2 wks), uses humoral (antibodies) and cellular (cytotoxic lymphocytes) effector cells, and uses a specific mechanism against each antigen, provides memory (immunity)

295
Q

what is another way that immune system response can be classified

A

afferent and efferent branches of immune system

296
Q

what is an immune response

A

the body’s response to antigens
- sneezing, coughing, inflammation, etc

297
Q

what is inflammation

A

movement of immune cells into an area
- field of battle, needs to be balanced

298
Q

what is the damage response framework

A
  • outcome depends on host response
  • outcomes can move along the parabola
  • host and pathogen factors can affect parabola
299
Q

what is unique about the CNS (4 things)

A
  1. rigid layers covering CNS
  2. immune responses have to be controlled
  3. historically thought to be “immune privileged” (IP)
  4. like other organs, must have a way to defend itself from infections
300
Q

what does immune privileged mean

A

the absence or a greatly diminished immune system

301
Q

how can IP be a double edge sword

A

it prevents complete clearance of pathogens and provides protection to tumors

302
Q

5 pieces of evidence FOR immune privilege

A
  1. tissues implanted on brain parenchyma are not rejected
  2. bacterial/viral antigens injected on brain parenchyma failed to evoke an adaptive response
  3. at steady state, very low levels of lymphocytes seen on perivascular spaces (none in parenchyma)
  4. absence of lymphatic vessels
  5. presence of BBB
303
Q

5 pieces of evidence AGAINST immune privilege

A
  1. tissue are rejected if transplanted into ventricles
  2. PAMPs on CSF filled compartments elicit rapid infiltration of immune cells (inflammation-meningitis)
  3. large number of phagocytes (antigen presenting cells APCs) are constantly present on CSF filled compartments (and the parenchyma has microglia)
  4. discovery of meningeal lymphatic vessels
  5. Lymphocytes can be forced to cross BBB (artificial solution, but biologically possible)
304
Q

what does each CNS barrier establish

A

compartments with diff relationships with the immune system

305
Q

what are the 3 CNS barriers established compartments

A
  1. meninges
  2. ventricles
  3. parenchyma
306
Q

Meninges connections

A

incoming and outgoing connections through the vasculature and lymphatics

307
Q

ventricles connections

A

incoming and outgoing connections through choroid plexus

308
Q

parenchyma connection

A

no connection, only resident cells, microglia

309
Q

what removes antigens from parenchyma into CSF spaces

A

glymphatics

310
Q

what kind of molecules does glymphatics remove

A

small/soluble antigens

311
Q

The meninges is bathed by?

A

both CNS fluids, CSF and ISF

312
Q

what does the meninges contain?

A

lymphatic vessels which allow for sampling of fluids and potential immune hub

313
Q

what is the meninges connected to

A

cervical lymph nodes

314
Q

function of the meninges

A

exhibit rapid inflammatory responses

315
Q

where do activated T cells come from and where do they enter

A

activated T cells can enter SAS from arachnoid or dural veins

316
Q

what does choroid plexi generate

A

the CSF

317
Q

what kind of vessels are located in the ventricles

A

fenestrated vessels which allow easy access for immune cells to choroid plexus stromal space

318
Q

what is the imp of a large number of resident APCs present in the ventricles

A

helps sample CSF (and ISF that drains there)

319
Q

function of ventricle connections

A

exhibit rapid inflammatory responses

320
Q

where do t cells cross into after activation in choroid plexi

A

cross into ventricles

321
Q

what is the brain parenchyma protected by

A

by bbb, no direct entry

322
Q

what does ISF do in parenchyma

A

ISF washes parenchyma and drains into veins and SAS (limited to small, soluble antigens)

323
Q

T or F: there is direct access to lymph nodes from the brain parenchyma

A

false

324
Q

what are epiplexus cells

A

intraventricular macrophages

325
Q

at steady state in the parenchyma, there are no _________?

A

no lymphocytes

326
Q

presence of APCs in perivascular spaces flanking BBB?

A

low number of APCs present

327
Q

what is cut off from adaptive immune response

A

the brain parenchyma

328
Q

why is the brain parenchyma being cut off from adaptive immune response significant?

A

because it means it cannot get waste out/bring nutrients in, which is where the glymphatic system comes in

329
Q

what can cross the BBB into brain parenchyma

A

monocytes and other innate immune cells (APCs) can cross
- perivascular macrophages or dendritic cells
lymphocytes can cross into perivascular space of venules during surveillance (which is infrequent) and when signaled by endothelia

330
Q

what is needed in order to cross into brain parenchyma

A

need to be reactivated by APCs

331
Q

Over the last decade, a lot has become clear about the CNS’s immunology, and explains some of the observations leading to the IP hypothesis. How would you explain these observations?
1. transplantation of a tumor, or foreign tissue, into the brain parenchyma is not ejected
2. transplantation of the same foreign tissue peripherally or into the ventricles elicited immediate rejection
3. soluble components from the parenchyma and the CSF were found in the cervical nodes
4. there are no professional antigen presenting cells in the brain parenchyma (microglia have low MHC expression) to activate T cells

A

…

332
Q

4 ways of immune surveillance of the CNS

A
  1. blood derived APCs patrol CNS covering tissues (but dont enter brain parenchyma
    - meninges, ventricles
  2. in homeostasis, soluble CNS antigens are shed into CSF via the glymphatics
  3. Antigens can be picked up by APCs or by lymphatics (then traffic to the cervical lymph nodes for activation)
  4. non activated/activated lymphocytes return back to bloodstream and back to CNS
333
Q

steps (10 total) walking through an immune response example

A
  1. virus gain access to parenchyma
  2. virus recognized by microglia
  3. microglia is activated
  4. cytokines released
  5. endothelia activated
  6. cytokines released and JAMs/LAMs are upregulated
  7. circulating lymphocytes enter the brain
  8. infected cells are killed (and viruses with them)
  9. lymphocytes become anti-inflammatory
  10. signaling ends
334
Q

what are regulatory T cells

A

cells that suppress and regulate the function of other immune cells

335
Q

what are the two classes of Regulatory T cells

A
  1. natural
  2. adaptive
336
Q

natural regulatory T cells

A

created in the thymus

337
Q

adaptive regulatory T cells

A

formed by differentiation in the affected tissue

338
Q

what cells are not present in the brain

A

no T cells in the brain, so these are adaptive regulatory t cells

339
Q

what happens to t cells after virus/infection is defeated in the brain

A

they undergo apoptosis

340
Q

8 steps of an immune response when dealing with an autoimmune disease

A
  1. the own proteins cause microglia to activate
  2. cytokines are released
  3. incoming lymphocytes are activated against the same antigen
  4. activated APCs go to lymph node which activate more lymphocytes
  5. more lymphocytes are recruited
  6. constant presence of antigens inhibits anti-inflammatory response
  7. BBB collapses causing more infiltration
  8. neurodegeneration ensues
341
Q

Which of the following ideas was consistent with the “immune privilege” hypothesis?
a. The BBB prevented entry of immune cells into the parenchyma of the brain.
b. The lack of conventional lymphatic organs in the brain.
c. The lack of an immune response towards the injection of antigens directly into the ventricles.
d. All of the above.
e. (a) and (b).
f. (a) and (c).

A

E

342
Q

Which of the following observations questioned the “immune privileged” status of the brain?
a. The constant presence of lymphocytes (albeit at low levels) in the CSF-filled compartments.
b. That nonself-tissue transplanted into ventricles is rejected.
c. That a substantial amount of the CSF drains into cervical lymph nodes.
d. All of the above.
e. (a) and (b).
f. (a) and (c).

A

D

343
Q

Under healthy conditions, T cells rarely cross into the brain parenchyma. When they do, they cross-
downstream BBB, in the postcapillary venules. Which of the following is the correct sequence of events?
a. Cross the vascular endothelia, reactivation in perivascular space, cross the glia limitans.
b. Cross the vascular endothelia, cross the glia limitans, reactivation in the brain parenchyma.
c. Cross the glia limitans, reactivation in the blood, cross the vascular endothelia.
d. Cross the fenestrated vascular endothelia, reactivation in the perivascular space, cross the
ependymal cell monolayer.

A

A

344
Q

Various features that explain the uniqueness of the neuroimmune system are?
a. Rigid layers preventing swelling.
b. Presence of BBB controlling migration of immune cells.
c. Absence of traditional lymphatics directly innervating the brain parenchyma.
d. All of the above.
e. (a) and (b) only.

A

D

345
Q

Because the brain’s lymphatics are restricted to its surface, how do they still sample the parenchyma for
the presence of antigens?
a. Through T cells that constantly go inside and scan the brain parenchyma.
b. Through microglia, which when activated (by antigens) migrate out of the parenchyma and into the
lymphatics.
c. Through the glymphatic system, which removes waste (and antigens) from the parenchyma into the
SAS, where is now available to be sampled by the lymphatics.
d. Through arteries and veins that run parallel to the lymphatics and interexchange solutes (and
antigens).

A

C

346
Q

Inflammation plays various important roles in an organism. These are?
a. Killing of pathogens.
b. Healing of tissues.
c. Removal of wastes and foreign bodies.
d. All of the above.
e. (a) and (b) only.

A

D

347
Q

What will happen if T cells cross into perivascular spaces and fail to be activated by Antigen-presenting
cells there?
a. Nothing, they will just scan the area and if nothing is found, head back into the circulation or are
removed via CSF-drainage pathways.
b. They turn into Tregs and then undergo apoptosis.
c. They will immediately cross the glia limitans into the brain.
d. They will destroy the astrocyte’s endfoot, generating a hole in the glia limitans.

A

A

348
Q

Which of the following are instances that highlight drawbacks of the neuroimmune system?
a. The parenchyma of the brain can serve as a safe haven for tumors and encapsulated (large
enclosures) pathogens.
b. The CSF-filled spaces do not have access to lymphatics.
c. The ventricles are surrounded by BBB, preventing easy access of immune cells.
d. The neuroanatomy of the CNS both prevent foreign particles entry but also CNS-specific antigens
from exiting into the peripheral circulation.

A

A

349
Q

Which of the following BEST describe the brain’s immune defenses?
a. The three cellular barriers (BBB, BCSFB, and BMB).
b. The BBB, microglia, and all the perivascular antigen-presenting cells (such as epiplexus cells).
c. The meninges, the CSF, and the skull.
d. The lymphatic and glymphatic systems.

A

B

350
Q

The importance of Treg cells in the brain’s immune system is best depicted by which statement?
a. They promote infection clearance by expressing highly inflammatory markers that aid on pathogen
killing.

b. They regulate the immune response and coordinate the shift from inflammatory to anti-
inflammatory (healing).

c. Whenever cytotoxic T cells enter the brain they are turned into Tregs by the CNS environment,
ensuring that there are never inflammatory cells inside the brain.
d. They can respond to neurotransmitters like serotonin, which allow them to respond and follow
brain’s signals.

A

B

351
Q

T or F: The different brain barriers define compartments in the CNS that differ functionally in their communication
with the immune system.

A

true

352
Q

T or F: The CNS parenchyma is completely cut-off from the immune system, while the perivascular compartments
(including ventricles) have active immune systems.

A

False, the parenchyma is indirectly connected to immune system via the glymphatic system, also it has microglia

353
Q

T or F: The brain’s ventricular and subarachnoid spaces exhibit the same immune privilege as the brain parenchyma.

A

False, CSF filled spaces have more access to the immune system compared to the parenchyma

354
Q

T or F: Antigen-presenting cells in the SAS access the lymph nodes through dural lymphatics and come back to the brain through the same lymphatic vessels.

A

False, Lymphatic system is unidirectional so the APCs have to circulate back through the blood

355
Q

T or F: An innate immune response will take between 1 and 2 weeks to develop - a clear example of that is the
COVID19 vaccine that takes 14 days to show protection.

A

false, an innate immune response is immediate while an adaptive takes time up to 1 to 2 wks

356
Q

what is disease of the NS caused by

A

infectious agents, not necessarily living organisms

357
Q

meninges nomenclature

A

meningitis

358
Q

brain parenchyma nomenclature

A

encephalitis

359
Q

spinal cord nomenclature

A

myelitis

360
Q

focal contained infections

A

abscess or cysts

361
Q

3 entry routes of virus into CNS

A
  1. through a cellular monolayer (endothelium or epithelium)
  2. through contiguous tissue
  3. through nerve endings
362
Q

how does a virus enter through a cellular monolayer into CNS (3 ways)

A

entry occurs at brain’s capillaries and venules or at choroid plexi
1. transcellular route
2. trojan horse (infected leukocyte)
3. paracellular route (TJ broken)

363
Q

what kind of invader enters CNS through contiguous tissue

A

mostly parasites and large pathogens (certain bacteria as well)

364
Q

what invader enter through nerve endings

A

common for viruses, who can hijack secreted vesicles in synapses

365
Q

6 symptoms associated with meningeal involvement

A
  1. headache
  2. fever
  3. nausea
  4. vomiting
  5. neck pain (stiff neck)
  6. reflex impairment
366
Q

what are all the meningeal involvement symptoms related to

A

all related to increased intracranial pressure

367
Q

how does CSF analysis differ if there is meningeal involvement

A
  • high number of leukocytes, mainly polymorphonucleated cells
  • high protein
  • very low glucose
  • high lactate
    all related to pathogen’s metabolism on the CSF
368
Q

what are the 6 parenchymal involvement symptoms

A
  1. headache
  2. fever
  3. impairment of senses (go blind, deaf)
  4. impairment of consciousness
  5. psychological changes
  6. focal neurologic deficits
    symptoms related to area of brain affected
369
Q

how does the csf analysis differ with parenchymal involvement

A
  • high number of leukocytes, mainly mononucleated cells
  • high protein
  • normal glucose
  • normal to high lactate
    presence of pathogen can usually be seen in brain scans
370
Q

5 spinal cord involvement symptoms

A
  1. back pain
  2. muscle pain
  3. partial paralysis
  4. lower limbs paralysis
  5. motor movement impairment
    all related to interruption of comms bw CNS and PNS
371
Q

how does CSF analysis differ with spinal cord involvement

A
  • inflammatory markers
  • immune cell pop depends on pathogen
  • normal glu
  • normal protein
    aka not useful for determining pathogen
372
Q

what study is conducted to determine pathogen is involved in spinal cord

A

neuroimaging must be performed, almost always in conjunction with meningitis or encephalitis

Neuroinfectious Diseases (8 decks)

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