lecture 2 - ventricles, meninges, csf

Question 1

broadly speaking, what are the ventricles?

Answer 1

four cavities and connecting channels

Question 2

how do the ventricles develop?

Answer 2

from expansions of the lumen of the embryonic neural tube

Question 3

are the ventricles continuous with one another? explain.

Answer 3

yes - and the central canal of the spinal cord, because of how they develop

Question 4

describe the shape of the lateral ventricles

Answer 4

backwards ‘c’ shaped chambers (paired)

Question 5

describe the component parts of the lateral ventricles

Answer 5

• anterior horn
• posterior horn
• inferior horn
• body

Question 6

do the posterior or anterior horns lie closer together?

Answer 6

anterior horns lie closer to eachother, while the posterior horns are more separated

Question 7

each component part of the lateral ventricles lies in a different lobe of the brain, list these.

Answer 7

ant horn: frontal lobe
post horn: occipital lobe
inf horn: temporal lobe
body: parietal lobe

Question 8

where does the body of the lateral ventricles join the posterior and anterior horns?

Answer 8

at the atria

Question 9

what is the choroid plexus?

Answer 9

• tissue that lines all of the lateral ventricles, but specifically the body and the inferior horns
• responsible for the production of CSF

Question 10

what is the foramina of Monro?

Answer 10

• aka interventricular foramen

- passageway via which the lateral ventricles drain into the third ventricle

Question 11

the head of the caudate nucleus forms which border?

Answer 11

lateral wall of the anterior horn

Question 12

the body of the caudate nucleus forms which border?

Answer 12

most of the lateral wall of the body

Question 13

the caudate tail forms which border?

Answer 13

lies in roof of the inferior horn

Question 14

the thalamus forms which border?

Answer 14

floor of body

Question 15

the genu of the corpus callosum forms which border?

Answer 15

anterior wall of anterior horn

Question 16

the body of the corpus callosum forms which border?

Answer 16

roof of the anterior horn and the body

Question 17

the septum pellucidum forms which border?

Answer 17

medial wall of the anterior horn and the body

Question 18

the hippocampus forms which border?

Answer 18

most of the floor and medial wall of the inferior horn

Question 19

where is the 3rd ventricle?

Answer 19

btwn the two thalami

Question 20

describe the shape of the 3rd ventricle

Answer 20

narrow, slit like cavity

Question 21

which secondary vesicle does the 3rd venticle form from?

Answer 21

diencephalon

Question 22

what is the cerebral aquaduct?

Answer 22

passageway that connects the 3rd and 4th ventricles

Question 23

where does the cerebral aqueduct pass through?

Answer 23

midbrain

Question 24

what secondary vesicle does the cerebral aquaduct form from?

Answer 24

mesencephalon

Question 25

what forms the walls of the 3rd ventricle?

Answer 25

medial surface of thalamus and hypothalamus

Question 26

what forms the floor of the 3rd ventricle?

Answer 26

hypothalamus

Question 27

what are the borders of the 4th ventricle?

Answer 27

- posterior to the pons and the rostral medulla | - anterior to the cerbellum

Question 28

what is the 4th ventricle continuous with?

Answer 28

- cranial: 3rd ventricle (via cerebral aquaduct) | - caudal: central canal

Question 29

what secondary vesicle foes the fourth ventricle form from

Answer 29

rhombencephalon

Question 30

what secondary vesicle does the central canal form from

Answer 30

neural tube

Question 31

what does the central canal pass through?

Answer 31

medulla, then sc

Question 32

describe how CSF leaves the 4th ventricle

Answer 32

-most drains into the subarachnoid space via either: ( 1) foramen of Magendie (medial) (2) foramen of Luschka (lateral) -some leaks into the central canal of the sc

Question 33

outline the cycle of CSF

Answer 33

- choroid plexus creates CSF in lateral ventricles - drains via foramen of Monro to 3rd ventricle - choroid plexus creates CSF in 3rd ventricle - accumulates - drains via cerebral aquaduct to 4th ventricle - choroid plexus creates CSF in 4th ventricle - accumulates - drains via foramen of Magendie or Laschuka to subarachnoid space or drains into central canal - flows around CNS - eventually reabsorbed into bloodstream

Question 34

what is the main take away from the cyle of CSF?

Answer 34

it is accumulating in each ventricle

Question 35

what are the 3 meningeal layers?

Answer 35

dura matter, arachnoid matter, pia matter

Question 36

what is the outermost layer? (superficial)

Answer 36

dura matter

Question 37

what is the middle layer?

Answer 37

arachnoid matter

Question 38

what is the innermost layer? (deep)

Answer 38

pia matter

Question 39

which one of the cranial meninges is a double membrane?

Answer 39

dura

Question 40

what are the two layers of the double membrane?

Answer 40

periosteal layer | meningeal layer

Question 41

which dural layer is closer to the skull and which dural layer is closer to the brain?

Answer 41

skull - periosteal | brain - meningeal

Question 42

are the dural layers relatively easy of hard to separate?

Answer 42

hard

Question 43

during development, what happens to the dura matter?

Answer 43

it is reflected inwards, forming folds called the dural septa

Question 44

what are the dural septa?

Answer 44

falx cerebri and tentorium cerebelli

Question 45

what is the function of the dural septa?

Answer 45

function as scaffolding to help minimize excessive brain movement within the skull

Question 46

where is the falx cerebri?

Answer 46

dural invagination into saggittal fissure

Question 47

where is the tentorium cerebelli?

Answer 47

dural invagination into horizontal fissure

Question 48

what is the subdural space

Answer 48

potential space between dura matter and arachnoid matter

Question 49

what is the epidural space?

Answer 49

potential space between dura matter and bone (skull or vertebral collumn)

Question 50

what is the subarachnoid space?

Answer 50

real space between the arachnoid matter and pia matter that is filled with csf and bvs (surrounds entire brain)

Question 51

explain how the arachnoid matter is connected to the pia matter

Answer 51

denticulate ligaments: web-like threads of collagen and elastin fibres extend from the arachnoid matter down to the pia matter to secure it

Question 52

describe the pia matter

Answer 52

thinnest, vascualarized protective layer attached firmly to the surface of the brain and the sc (even dips into fissures and sulci of the brain)

Question 53

do all three meningeal layers cover both the brain and sc?

Answer 53

yes, except pia only reaches L1/L2

Question 54

describe the composition of CSF

Answer 54

similar to blood plasma ('watery broth')

Question 55

how is CSF formed?

Answer 55

as a filtrate from blood plasma by the choroid plexus

Question 56

where is CSF reabsorbed back into circulation?

Answer 56

dural venous sinus (mainly superior saggittal sinus)

Question 57

how is CSF reabsorbed back into circulation?

Answer 57

via arachnoid vili in the sinus

Question 58

what is hydrocephalus?

Answer 58

the buildup of fluid in the ventricles of the brain - very deadly

Question 59

what meningeal layer are the cisterns located in?

Answer 59

subarachnoid space

Question 60

what are the spinal cisterns?

Answer 60

lumbar cistern

Question 61

describe the lumbar cistern (3 facts)

Answer 61

- largest - occurs because pia only reaches L1/L2 - where do spinal tap

Question 62

what are the cranial cisterns?

Answer 62

pontine, cisterna magna, quadrigeminal, ambient, interpeduncular

Question 63

what is the function of cisterns?

Answer 63

areas where CSF can accumulate to allow for lots of good stuff

Question 64

where is the pontine cistern?

Answer 64

anterior and inferior to the pons, superior to the medulla

Question 65

where is the cisterna magna?

Answer 65

inferior to the cerebellum, posterior to the medulla

Question 66

where is the quadrigeminal cistern?

Answer 66

posterior to the midbrain

Question 67

where is the ambient cistern?

Answer 67

lateral to the midbrain

Question 68

where is the interpeduncular cistern?

Answer 68

anterior to the midbrain

Question 69

where is CSF reabsorbed back into circulation?

Answer 69

internal jugular vein

Question 70

are the dural venous sinuses connected?

Answer 70

yes