Neuro Week 3 - Specialized Support Systems of the Brain

what are the three meninges?

• dura mater

• arachnoid mater

• pia mater

what are the three fossa’s of the brain and what parts do they hold?

• anterior fossa: ventral aspects of the frontal lobe

• middle fossa: much of the temporal lobe

• posterior fossa: brainstem and cerebellum

falx cerebri

the fold of the dura matter than descends vertically in the longitudinal fissure separating the two hemispheres

surrounds the corpus collosum

what is the tunnel that connects the lateral ventricles to the third ventricle?

the interventricular foramens

describe where the third ventricle is

in between the two thalami

what connects the two thalami together?

axonal tract

where is the fourth ventricle?

between the dorsal brainstem and cerebellum

what connects the third and fourth ventricle?

the cerebral aqueduct

what does the choroid plexus do?

modifies vascular structure lining the ventricles that produces CSF by filtering blood

create a flow chart of the circulation of the CSF

lateral ventricles → interventricle foramen → 3rd ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space → arachnoid granulations

Foramen of Magendie

a small midline opening that drains CSF from 4th vent. to the subarachnoid space

Foramina of Luschka

two lateral openings that drains CSF from the 4th vent. to subarachnoid space

arachnoid granulations

specialized portions of the arachnoid that protrude

through the inner layer of dura matter and into the superior sagittal sinus

what region of the ventricular system would be prone to blockage

cerebral aqueduct

what is hydrocephalus?

occurs when there is an abnormal buildup of CSF in the ventricles due to an obstruction

• common in children

• caused by congenital or aquired due to cerebral disease (ex. meningitis, hemorrhage, traumatic brain injury, brain injury, brain tumors)

what happens with patients Alzheimer’s (brain size and ventricles)

brain can shrink up to 1/3 of normal size

ventricles become larger

• provides more space for the ventricles to expand

how long does it take to loose consciousness when you have no oxygen going to the brain?

10 sec

what is a stroke?

the sudden loss of brain function caused by a

sudden blockage or rupture of a blood brain vessel

symptoms of a stroke

• loss of balance

• blurred vision

• one side face drooping

• one side arm or leg weakness

• speech difficulty

difference between a ischemic stroke vs. a hemorrhagic stroke

blocked blood vessel vs. ruptured blood vessel

two types of ischemic strokes

thrombotic stroke: fatty plaque blockage on cerebral vessels

embolic stroke: blood clot somewhere else that then travels the brain

the entire blood supply of the brain and spinal cord depends on which 2 sets of branches of the aorta?

1. internal carotid arteries

2. vertebral arteries

what arteries are part of the circle of willis

• Posterior Cerebral Artery

• Posterior Communicating Artery

• Internal Carotid Artery

• Anterior Cerebral Artery

• Anterior communicating artery

Lenticulostriate arteries

the deep-penetrating branches of the MCA that supplies most of the basal ganglia

aka the end arteries

prone to blockage and rupture (stroke)

what part of the brain layers is called real space

subaracnoid space

what are the 4 areas that cause localized bleeding (hemorrage/hematomas)

1. epidural hematoma

a collection of blood between the skull and dura mater
- Usually happens due to injury (e.g., skull fracture causes tear to underlying
blood vessels)

2. subdural

a collection of blood between the dura mater and
arachnoid mater
• Symptoms can occur suddenly or take days to weeks to develop

3. subarachnoid

a collection of blood within the subarachnoid space
surrounding the brain (the area between the arachnoid and pia mater)
• Usually happens due to brain aneurysm

4. intracerebral

• bleeding within the brain tissue itself

Medullary arteries

a collection of 6-10 arteries that arise from various branches of the aorta and supply the anterior and posterior spinal arteries along the spinal column

what is the purpose of the BBB

makes the movement of substances from blood vessels into brain cells difficult

what/ how can cross the blood brain barrier

• soluble in lipids

• special transporters

glymphatic system

a lymphatic system in the brain to remove wastes and aid movement of nutrients

when is the glyphatic flow the fastest

during sleep

what does the dura matter consist of?

the outer layer and the inner layer

tentorium cerebelli

U-shaped infolding of dura matter that runs under the occipital lobe dividing the occipital lobe and the cerebellum

what does the tentorial notch provide space for?

the brainstem

falx cerebelli vs. falx cerebri

falx cerebelli is the dura matter that divides the cerebellum (smaller one)

falx cerebri is the dura matter that divides the cerebrum (larger one)

follow the same orientation

tentorium cerebelli

U-shaped fold that runs between the occipital lobe and the cerebellum

tentorial notch

space created by the tentorium cerebelli providing a space for the brainstem to pass

Falx cerebelli

small midline fold that runs in the space between the two cerebellar hemispheres

subarachnoid space

space under the arachnoid layer filled with cerebral fluid

falx cerebri

a crescent shape fold that descends vertically in the longitudinal fissure, separating the two hemispheres

meningiomas

are typically benign tumors arising from the dura mater

meningitis

is an infection and inflammation (swelling) of the two inner meningeal layers

what is the common cause of meningitis?

viral or bacterial infection

meningitis can result in stroke, brain damage, or death

what are the major functions of the ventricular system

1. protects brain (shock absorber for brain)

2. provides buoyancy (reduces weight of brain from 1400gm to only 50gm)

3. provides a medium for the exchange of materials between blood vessels and brain

label the diagram

left side top to bottom:

1. interventricular foraman

2. frontal horn of lateral ventricle

3. third ventricle

4. temporal horn of lateral ventricle

right side top to bottom:

1. occipital horn of lateral ventricle

2. fourth ventricle

3. cerebral aqueduct

what is the cauliflower-like fronds in the lateral and fourth ventricle that produce the CSF by filtering blood

choroid plexus