CSF, Ventricular System, Meninges: Flashcards

1
Q

-within the ____ of the brain: _____ is producing the cerebrospinal fluid

A

ventricles,

choroid plexus

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2
Q

Cerebrospinal Fluid

  • found in:
  • function (3)
A

Clear liquid
Helps to cushion
Supplies nutrients
Helps to remove waste products
Produced continuously by the choroid plexus in the ventricles
Found in your ventricles, central canal, and the subarachnoid space

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3
Q

Cerebrospinal Fluid is found in your ventricles, central canal, and the subarachnoid space

-where is it made?

A

Produced continuously by the choroid plexus in the ventricles

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4
Q

choroid plexus

-where found?
-is it vascularized?
-made of?
-function
-develops from :
probs dont have to know all of this

A

Way understudied
Found in ventricles and next to the pia mater
Highly vascularized [lots of little blood vesels]
Made of epithelial cells [not neurons]
Also contains immune cells
*Makes your CSF
Develops from the dorsal neural tube

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5
Q

Too Much CSF

-causes

A

Hydrocephaly/Hydrocephalus: too much CSF
Causes include trauma, meningitis, infection, blockage in CSF drainage pathways, and birth defects

*Why do we not want it? It puts too much pressure on your brain and within your skull. I think causing you to get headaches

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6
Q

Hydrocephaly/Hydrocephalus in an infant vs an adult

probs dont need to know

A

-this is bad in adults: the head cannot grow but in a baby the head can enlarge – getting less tissue death

In an infant: can address hydrocephaly

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7
Q

Too Little CSF

  • causation
  • result
A

Usually means you sprung a CSF leak somewhere or are severely dehydrated

  • Why do we not want it? Brain does not have enough cushion. It can also cause the brain to sag, stressing nerves and meninges
  • can get nerve damage

-the brain and spinal cord are not as protected. Cannot supply enough nutrients

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8
Q

which ventricle(s) is choroid plexus found?

A

Choroid plexus is found in each lateral ventricle and the third and fourth ventricle. It is involved in the production of cerebrospinal fluid.

(so I think all of them but the cerebral aqueduct)

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9
Q

Choroid Plexus Pathologies

(tbh confused if need to know it but i guess try to learn them)

A

Cysts- common with certain disorders
*Hemorrhages- often due to birth trauma/stress/hypoxia
Tumors and Hyperplasia- often lead to hydrocephalus
*Microorganism infiltration- seen in children who have meningitis
{Having an infection in the choroid plexus}
Deficiencies in thyroid hormone carrier protein (thus depriving brain regions of thyroid hormone)
*Perhaps involved in Alzheimer’s disease- CSF helps to clear plaques and choroid plexus appears atrophied in those with the disease

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10
Q

Ventricular Changes Due to Pathology or Trauma

A
  • Alzheimer’s and Dementia
  • Brain overall is shrinking: trying to pump the brain back out with CSF but this is a temporary fix.
  • the ventricles are changing (getting bigger?)
  • the brain is “looser”
  • hippocampus shrinking
  • schizophrenia
  • Enlargement of the lateral ventricles

*CTE: Chronic traumatic encephalopathy
-caused by hitting the head (athletes or military etc)
The primary physical manifestations of CTE include a reduction in brain weight, associated with atrophy of the frontal and temporal cortices and medial temporal lobe. The lateral ventricles and the third ventricle are often enlarged, with rare instances of dilation of the fourth ventricle.]

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11
Q

Main Functions of Meninges*

A

Provide asupportive frameworkfor the cerebral and cranial vasculature.
Acting with cerebrospinal fluid to protectthe CNS from mechanical damage.

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12
Q

The singular of meninges is

A

meninx

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13
Q

Dura Mater

  • location
  • also known as
A

The dura mater is theoutermostlayer of the meninges

  • Directly underneath the bones of the skull and vertebral column
  • Thick, tough, and inextensible
  • Fits brain like a loose bag
  • Also known as the pachymeninx
  • Continuous with the periosteum
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14
Q

two layers of Dura Mater

A

right below the skull have the

1) endosteal (periosteal)
2) meningeal

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15
Q

which is thicker: the dura around the brain or the spinal cord

A

The dura around the brain is a bit more thick than the one that protects the spinal cord.. Has to do with the number of layers

two layers in skull, one in spinal cord

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16
Q

Within the cranial cavity, the dura contains two connective tissue sheets:

A
  • Endosteal (Periosteal) layer– Lines the inner surface of the bones of the cranium; does not extend through foramen magnum
  • Meningeal layer– Lines the endosteal layer inside the cranial cavity.
  • The only layer present in the vertebral column
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17
Q

Between the two layers of the Dura, what is located?

A

Between the Endosteal (Periosteal) layer and the Meningeal layer, thedural venous sinusesare located.

Responsible for the venous vasculature of the cranium, draining into theinternal jugularveins

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18
Q

T/F

the dura layers: two layers in spinal, one in skull

A

FALSE

two layers in skull, one in spinal cord

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19
Q

The layers of the meninges

A

Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.

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20
Q

Dura Mater additional notes

  • innervation?
  • vascularization?
A

In some areas within the skull, the meningeal layer of the dura mater folds inwards asdural reflections.
They partition the brain and divide the cranial cavity into several compartments.
The dura mater receives its own vasculature; primarily from themiddle meningealartery and vein.
It is innervated by thetrigeminal nerve(V1, V2 and V3)
Can feel pain

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21
Q

Unlike cranial dura mater, spinal dura mater only has one layer, known as the ____ layer. The potential space between these two layers is known as the _____ space.

dont need to know this i think

A

Unlike cranial dura mater, spinal dura mater only has one layer, known as the meningeal layer. The potential space between these two layers is known as the epidural space.

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22
Q

The tentorium cerebelli

i dont think you need to know

A

The tentorium cerebelli is the second-largest dural reflection

-is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.

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23
Q

thedural venous sinuses

A

Responsible for the venous vasculature of the cranium, draining into theinternal jugularveins

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24
Q

Dura Mater additional notes
vasculature?
innervated?

A
  • In some areas within the skull, the meningeal layer of the dura mater folds inwards asdural reflections.
  • They partition the brain and divide the cranial cavity into several compartments.
  • The dura mater receives its own vasculature; primarily from themiddle meningealartery and vein.
  • It is innervated by thetrigeminal nerve(V1, V2 and V3) –>Can feel pain
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25
Q

hematoma vs hemorrhage

daubt need to know- I think she considered them to be the same thing

A

A hematoma can result from an injury to any type of blood vessel (artery, vein, or small capillary). A hematoma usually describes bleeding which has more or less clotted, whereas a hemorrhage signifies active, ongoing bleeding. Hematoma is a very common problem encountered by many people at some time in their lives.

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26
Q

haematoma can cause?

A

A haematoma can cause a rapid increase in intra-cranial pressure. Death will result if untreated.

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27
Q

thedural venous sinuses

A
  • Responsible for the venous vasculature of the cranium, draining into theinternal jugularveins
  • Small projections of arachnoid mater into the dura(known asarachnoid granulations)allow CSF to re-enter the circulation via the dural venous sinuses.
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28
Q

In an Extradural hemorage the ventricle….

-cause:

A

then ultimately the ventricle will be bigger

Arterial blood collects between the skull and endosteal layer of the dura. The causative vessel is usually the middle meningeal artery, tearing as a consequence of brain trauma.

(i also think that if caught this one is maybe treatable?)

29
Q

In an Subdural hemorage the ventricle….

A

Ventricles being squished over (being crossed the midline)

30
Q

which is worse- Extradural hemorage or Subdural hemorage?

A

tbh I am not sure, maybe subdural?

31
Q

Arachnoid Mater/Layer

  • surrounds:
  • lines the sulci- yes or no
  • vascularized?
  • innervation?
  • consist of ?
A

Middle layer of the meninges, lying directly underneath the dura mater
-Attached to dura mater
*Surrounds BOTH the brain and spinal cord
-Does not line the brain into the sulci, with exception of longitudinal fissure
*Avascular
*Does not receive any innervation.
Web of collagen
*It consists of layers of connective tissue
-Dorsal layer covers internal cerebral veins and fixes them to the surrounding tela choroidea
-Ventral layer of arachnoid membrane is a direct anterior extension of this arachnoid envelope that the dorsal layer forms over the pineal region
Underneath the arachnoid is a space known as thesub-arachoid space.
It contains cerebrospinal fluid, which acts to cushion the brain.
Small projections of arachnoid mater into the dura(known asarachnoid granulations)allow CSF to re-enter the circulation via the dural venous sinuses.

32
Q

is the Dura mater vascularized? innervated?

A

The dura mater receives its own vasculature; primarily from the middle meningeal artery and vein.

*It is innervated by thetrigeminal nerve(V1, V2 and V3) –>Can feel pain

33
Q

The arachnoid mater: vascularized? innervated?

A

The arachnoid mater is the middle layer of the meninges, lying directly underneath the dura mater. It consists of layers of connective tissue, is avascular, and does not receive any innervation.

*Small projections of arachnoid mater into the dura(known asarachnoid granulations)allow CSF to re-enter the circulation via the dural venous sinuses.

34
Q

-Attached to dura mater

A

arachnoid mater

35
Q

Subarachnoid Hemorrhage

A

Between arachnoid and pia
Thunderclap headache : sudden and incredible severe headache (unlike migraines)
Photophobia

36
Q

Pia Mater

  • located:
  • thickness:
  • on brain and spinal cord?
  • follows the contours of the brain?
  • vascularized?
A

Located underneath the sub-arachnoid space.
Very thin andtightly adheredto the surface of the brain and spinal cord.
It is the only covering to follow the contours of the brain (the gyri and fissures)
*Highly vascularized, with blood vessels perforating through the membrane to supply the underlying neural tissue.

37
Q

The Pia Mater: vascularized? innervated?

A

*Highly vascularized, with blood vessels perforating through the membrane to supply the underlying neural tissue.

[I think it is innervated]

38
Q

the only covering to follow the contours of the brain (the gyri and fissures)

A

Pia Mater

39
Q

Leptomeninges

A

“Thin meninges”
Arachnoid + Pia

(term used in medical setting)

40
Q

5% of cancer patients will have their cancer spread to the _____

A

5% of cancer patients will have their cancer spread to the leptomeninges
CNS symptoms are divided into the following 3 anatomic groups:
Cerebral involvement: Headache, lethargy, papilledema, behavioral changes, and gait disturbance.
Cranial-nerve involvement: Impaired vision, diplopia, hearing loss, and sensory deficits, including vertigo; cranial-nerve palsies commonly involve CN III, IV, VI, VII, and VIII
Spinal-root involvement: Nuchal rigidity and neck and back pain, or invasion of the spinal roots.

41
Q
Meningitis ***
def and causation
A

*Inflammationof the meninges.

(can lead to infection in choroid plexus and the brain swelling (edema) and cranial herniation and reduced cerebral perfusion => DEATH)

-Can be drug induced: Nonsteroidal anti-inflammatory drugs, antimicrobials, intravenous immunoglobulin, intrathecal agents, vaccines

-Usually caused by pathogens
Bacteria are the most common infective cause: The most common organisms areNeisseria meningitidisandStreptococcus pneumoniae.

42
Q

The most common organisms to cause Meningitis

A

The most common organisms areNeisseria meningitidisandStreptococcus pneumoniae.

43
Q

The immune response to the infection of meningitis causes

probs good to learn this (see slide 35)

A
  • The immune response to the infection causescerebral edema, consequently raising intra-cranial pressure. This has two main effects:
    1) Part of the brain can be forced out of the cranial cavity – this is known ascranial herniation.
    2) In combination with systemic hypotension, raised intracranial pressurereduces cerebral perfusion.

Both of these complications rapidly result in death.

44
Q

Blood-Brain Barrier

-how does it perform its function

A

An organic barrier between circulating blood and the CNS
Regulates, in part actively and in part passively, the exchange of substances between blood and the brain.
Also acts as a protective shield by preventing the penetration of harmful substances into the CSF.
Few pathogens can overcome the blood-brain-barrier

45
Q

T/F the BBB is only a passive form of protection

A

FALSE

Regulates, in part actively and in part passively, the exchange of substances between blood and the brain.

46
Q

BBB allows:

A

Allows passage/transport of small molecules (H2O, O2, CO2), lipophilic molecules (EtOH, heroin), passive transport of glucose, active transport of amino acids/NT precursors

*Prevents passage of larger molecules (dopamine), charged molecules, etc

47
Q

T/F Medications can be tailor-made in order that they can overcome the blood-brain barrier.

A

TRUE

48
Q

3 Main Functions of BBB ***

A

1) Protects the brain from “foreign substances”in the blood that may injure the brain.
2) Protects the brain from hormones and neurotransmittersin the rest of the body.
3) Maintains a constant environmentfor the brain.

49
Q

Components of the BBB ***

A
  • The filter is primarily made up of endothelial cells, which surround the blood capillaries, and from the ends of astrocytes, which have important structural and metabolic functions
  • In most parts of the body, capillaries are lined with endothelial cells. - Endothelial tissue has small spaces between each individual cell so substances can move readily between the inside and the outside of the vessel.
  • However, in the brain, the endothelial cells fit tightly together and substances cannot pass out of the bloodstream.
50
Q

T/F the BBB is mostly made up of neurons

A

FALSE

51
Q

Do the endothelial cells of the brain have small spaces between each individual cell so substances can move readily between? (like most endothelial tissue)

A

NO
In most parts of the body, capillaries are lined with endothelial cells.
-Endothelial tissue has small spaces between each individual cell so substances can move readily between the inside and the outside of the vessel.
-However, in the brain, the endothelial cells fit tightly together and substances cannot pass out of the bloodstream.

52
Q

what pathway is being reduced in its permeability by the BBB? and what causes this reduced permeability?

A

The physical barrier is caused by tight junctions that reduce the permeability of the paracellular (intercellular cleft) pathway.

53
Q

Cellular constituents of the blood–brain barrier.

A

The barrier is formed by capillary endothelial cells, surrounded by basal lamina and astrocytic perivascular endfeet.

pericytes (contractile cells) and microglia

astrocytes are a type of glial cell

54
Q

Astrocytes provide ? in the BBB

A

Astrocytes provide the cellular link to the neurons.

Astrocytes may be also be responsible for transporting ions from the brain to the blood.

[create a wall maybe?]

55
Q

helping to form the BBB

A

: glia and endothelial cells help each other to form the BBB

56
Q

things going through the BBB

A

Some things are generally allowed across, some are selected for

  • Water-soluble things going through the gaps
  • glucose uses a transport
  • insulin : can get to the brain by receptor
57
Q

What Can Open the BBB

(more permeable) ***

A
Hypertension (high blood pressure)
Hyperosmolality
Microwaves
Radiation
Infection
Trauma, Ischemia, Inflammation, Pressure
*Development: the BBB is present, but may be not fully formed at birth.
58
Q

Circumventricular Organs

A

-areas that lack a traditional BBB and are highly vascularized

Highly vascularized with fenestrated capillaries
Lack a traditional BBB
Permit polypeptide hypothalamic hormones to leave the brain without disrupting the BBB
Permit substances that do not cross the BBB to trigger changes in brain function
Mammalian examples: median eminence and adjacent neurohypophysis, organum vasculosum lamina terminalis (supraoptic crest), subfornical organ (ventral fornix), and the area postrema (vomiting center).

59
Q

which can peptides go through: BBB or circumventricular organs?

A

defs circumventricular organs, not sure about BBB tbh but i feel like the answer is no

60
Q

example of circumventricular organs ***

A

pineal body secretes melatonin hormone into blood

61
Q

dural reflections

A

In some areas within the skull, the meningeal layer of the dura mater folds inwards as dural reflections.
*They partition the brain and divide the cranial cavity into several compartments.

62
Q

what does venous vasculature of the cranium drain into?

A

draining into theinternal jugularveins.

63
Q

Hemorrhages

A

Hemorrhages- often due to birth trauma/stress/hypoxia

64
Q

cranial herniation **

A

A brain herniation, or cerebral herniation, occurs when brain tissue, blood, and cerebrospinal fluid (CSF) shifts from their normal position inside the skull.

Part of the brain can be forced out of the cranial cavity

-one of the result of cerebral edema

65
Q

cerebral edema (caused by meningitis) can lead to death. what are the two reasons why

A

cranial herniation and reduced cerebral perfusion

66
Q

can CO2 pass through the BBB

A

yes

67
Q

where is cerebrospinal fluid found?

A

Cerebrospinal Fluid is found in your ventricles, central canal, and the subarachnoid space

68
Q

Cerebral edema

A

Cerebral edema is when fluid builds up around the brain, causing an increase in pressure known as intracranial pressure.

-this happens as a result of the infection of meningitis

69
Q

when you hemorrhage, what area of the hypothalamus may kick in?

A

the SON which controls for vassopressin which is important for water (trying to increase stroke volume)