Neuro Quiz 2

The central nervous system (brain and spinal cord) is stabilized/protected by…

tissue and fluid surrounding it

• Meninges

Meninges

3 layers of membranes that:

• protect and hold the brain and spinal cord in place

• suspend and anchor the CNS within the skull

• contain layer of Cerebrospinal fluid

• provide nourishment

Meninges run down length of…

the spinal cord

Cerebrospinal Fluid function

cushion and makes brain buoyant

3 Layers of Meninges

Dura

Arachnoid

Pia

Dura Mater

Top Layer of Meninges (thicker, strong)

Serves as mechanical support

2 layers

Divides Cranium into 3 parts (Cerebral Subdivisions)

What 2 layers make up the Dura Mater?

• Periosteal

• Meningeal

Periosteal Layer

• top layer, attached to the inside of the skull

• tougher/”steel”

Meningeal Layer

• inner layer, underneath the periosteal layer

• where other meninges are

The two dura layers separate in some places to create what?

venous sinuses

What do the Venous Sinuses do?

drain blood away from the brain

3 Dura Cerebral Subdivisions

• Falx Cerebri

• Falx Cerebelli

• Tentorium Cerebelli

Falx Cerebri

separates the two hemispheres of the brain

located in the longitudinal fissure

think: “cerebrum”

• attaches to base of skull and stabilizes

• down the middle of brain

Falx Cerebelli

lies between the left and right cerebral hemisphere

think: “cerebellum”

• attaches to base of skull and stabilizes

• down the middle of brain

Tentorium Cerebelli

think cerebellum

separates occipital lobe from cerebellum

separates the cerebellum and brainstem from the cerebrum

• tent=cover

Arachnoid Mater

Middle layer of meninges (ceran wrap/more delicate)

bridge over sulci and gyri (SPIDERY PICTURE ON QUIZ)

forms protective barrier around brain

• Arachnoid Trabeculae

• Leptomeninges

• Subarachnoid Space

What ties the Arachnoid Layer to Pia Layer?

Arachnoid Trabeculae

Arachnoid + Pia Mater = ?

Leptomeninges

• hard to separate the 2 layers, so they get that name

What is the space between the arachnoid mater and pia mater called? What does it contain?

Subarachnoid Space; Cerebrospinal Fluid (CSF)

Pia Mater

Innermost layer of meninges (thin layer)

tightly hugs brain and spinal cord

• follows brain's surface, including the sulci (grooves)

• goes deep into the grooves of the brain

Which of the following make up the leptomeninges?

arachnoid and pia mater

Label Layers “Think About It”

What is Cerebral Spinal Fluid?

clear fluid that surrounds/protects the brain and spinal cord

produced by the choroid plexus (in brain's ventricles)

What does CSF do?

acts like a cushion

• Helps control pressure inside the skull.

• nourishes nervous tissue

• removes waste from nervous tissue

Ventricular System

network of cavities (spaces) inside the brain

cavities that allow cerebrospinal fluid (CSF) to flow through the brain

4 Major Ventricles

The 4 Major Ventricles

• 2 Lateral Ventricles

• 3rd Ventricles

• 4th Ventricle

Lateral Ventricles

2 lateral ventricles → one on each side of the brain (bilateral)

C-shaped

Located in Parietal lobe, extend to frontal/temporal lobes

Lateral ventricles connect to 3rd ventricle by what?

interventricular foramen

Each lateral ventricle contains a what?

choroid plexus (projects medially into cavity)

3rd Ventricle

narrow space located between the two thalami

3rd Ventricle connects to 4th Ventricle through what?

cerebral aqueduct

Where is the choroid plexus located on on the 3rd ventricle?

above the roof

4th Ventricle

located in front of cerebellum, behind pons and upper medulla

Has 3 openings (foramina)

Three 4th Ventricle Foramina (what do they do + what are they?)

allow CSF to leave

3 Openings:

• 2 lateral foramina of Luschka

• 1 median foramen of Magendie

4th ventricle is connected to 3rd ventricle by what?

cerebral aqueduct

4th ventricle continues down where?

into central canal of spinal cord

CSF flows from the 1)______ into the 2)_______ via the 3)________.

1) lateral ventricles

2) 3rd ventricles

3) interventricular foramen

From the third ventricle, CSF flows to the ________ via the ______ in the midbrain.

1) 4th ventricles

2) cerebral aqueduct

From the fourth ventricle it can pass into the central canal of the spinal cord or into the ________ via the _______ or _________.

1) Subarachnoid Space

2) Foramen of Luschka

3) Magendie’s Foramen

Dorsal View

Anterior (Nose)

Posterior (Back of head)

“Megendies Foramen”

Think About Its Brain Label

Answers

Cerebrospinal Fluid (Origin, Structure, Circulation, Function)

Origin: Choroid Plexus

Structure: clear, colorless, suspends CNS

Circulation: from ventricles to subarachnoid space

Function: cushion between CNS and bones

after a TBI, the brain may…

swell

• causes brain to push against the meninges and skull —> damages the cerebral cortex

what is another word for stroke?

cerebrovascular accidents (CVA)

Hematoma

brain bleed → blood collects in a pocket

Types:

• Epidural

• Subdural

Epidural Hematoma

OUTSIDE Dura

blood between the skull and dura mater

“Lemon shape”

Blood can move freely btwn hemispheres bc dura isn’t holding it in place

Subdural Hematoma

UNDER Dura

blood between the dura mater and arachnoid mater

“Banana Shape”

blood is trapped bc of dura holding it in place

PATH OF CIRCULATION

made in Choroid plexus
→ Lateral ventricles
→ Interventricular foramina
→ 3rd ventricle
→ Cerebral aqueduct
→ 4th ventricle
→ Foramen of Magendie + foramina of Luschka
→ Subarachnoid space
→ Arachnoid granulations
→ Dural venous sinuses

Love in 3s Comes 4(for) Few, So Actually Don’t

Potential Space

area between periosteal and cranium

Meningitis

“inflammation of meninges”

• can be diagnosed by testing CSF

• typically occurs in dura mater

CSF Drainage

drains from the subarachnoid space into the venous (blood) sinuses/system.

depends on a pressure difference

CSF is constantly produced, circulated, and absorbed to maintain a healthy balance

What makes CSF drainage pressure-sensitive?

Higher pressure in the subarachnoid space → CSF can drain into the venous system

CSF production and absorption are what? What does that mean?

independent

• brain continues producing CSF regardless of how quickly it is being absorbed

Hydrocephalus

increased pressure in brain due to excessive CSF

Communicatig (no block) vs Non-Communicating (block)

Hydrocephalus Treatment

Lumbar Puncture/Spinal Tab - a needle is inserted between two vertebrae to collect CSF

Shunt (tube w/ catheder)

CSF analysis can help…

diagnose several diseases and conditions

What type of hematoma is indicated by the yellow arrow?

Epidural

What type of hematoma is this?

Subdural

What type of hematoma is this?

Epidural

What type of hematoma is this?

Subdural