Anatomy Exam 4: Functions of the brain and meninges

CSF

Arachnoid villi reabsorbed ___ back into blood stream

internal carotid arteries

Arteries carrying oxygenated blood that arrises in the neck from COMMON COROTID ARTERIES and provide anterior circulation of the brain as well as internally serving the skull. --branches inside skull to FORAMEN LASSURUM --makes up middle and anterior cerebrum (more than 80%)

vertebral arteries

Arteries carrying oxygenated blood that unite at the caudal border of the pons to form the BASILAR ARTERY that begins at the root of the neck --passes through transverse foramen to foramen magnum --ends by dividing into 2 posterior cerebral arteries --forms vestebrobasilar arterial system --posterior blood supply

CSF

Ventricles--> Central Canal of Spinal Cord--> Subarachnoid Space--> Reabsorbed in blood

non terminal branches

--posterior inferior cerebellar arteries (inner surface of cerebellum) --anterior spinal artery --anterior inferior cerebellar artery --labyrinthine (inner surface of cerebellum) --superior cerebellar arteries

tentorium cerebelli

2nd largest dural septa that separates the OCCIPITAL LOBES from the CEREBELLUM and sits in the transverse cerebral fissure between the cerebral hemispheres and cerebellum --holds weight of occipital lobes to keep weight off of cerebellum

circle of willis

A circle of arteries at the base of the brain that supply blood to the brain that contains alternate pathways to communicate --anterior communicating artery --anterior cerebral artery --internal carotid artery --posterior communicating artery --posterior cerebral artery

inferior sagital sinus

A dural venous sinus along the inferior posterior 2/3 of the flax cerebri that merges with the great cerebral vein to FORM the STRAIGHT SINUS --median plane

straight sinus

A dural venous sinus formed from the inferior sagittal sinus and great cerebral vein

superior sagital sinus

A dural venous sinus that begins at the crust gali and has little pieces of arachnoid mater coming in where CSF is reabsorbed --median plane --superior border of Falx cerebri --main reabsorbed for CSF

petrosal sinus

A dural venous sinus that superiorly and inferiorly dumps into the junction between transverse sinus and sigmoid sinus

epidural space

A meningeal space that is a potential space (don't normally find it) between the DURA MATER and SKULL bone --we can see it when theres pathology --blood can connect from a torn middle meningeal artery if skull bones crack --epidural hemorrhages or hematoma can occur

posterior cerebral artery

A terminal branch of the basilar artery --supplies inferior surface of hemisphere AND occipital

anterior cerebral artery

A terminal branch of the internal carotid artery that enters the longitudinal fissure --most of medial and superior surfaces of hemispheres --mostly frontal and parietal, NOT occipital

middle cerebral artery

A terminal branch of the internal carotid that is between the frontal and temporal to enter the lateral hemispheres --supplies lateral surface of hemispheres, NOT occipital

occipital sinus

A very small dural venous sinus that brings blood to the confluence of sinuses --runs in the junction of the falx cerebelli with the occipital bone

subarachnoid space

Actual space between ARACHNOID MATER (below) and PIA MATER (above) where CSF and the largest blood vessels are found. This could be caused from a rupture of anorisim, or head trauma --where CSF is circulated to make it back to the superior sagittal sinus

3rd ventricle

Adult structure that comes from the diencephalon

cerebral aqueduct

Adult structure that comes from the mesencephalon --connects 3rd and 4th ventricle

4th ventricle

Adult structure that comes from the metencephalon and myelencaphalon --continupus w spinal cord --3 openings (2 lateral, 1 medial) to get to subarachnoid space

paired C shaped lateral ventricles

Adult structure that comes from the telencephalon

sellar diaphragm

Smallest dural septs that connects HYPOTHALAMUS to PITUITARY GLAND allowing the opening for the passage of infundibulum

mechanically

CSF protects the brain _____ by letting it float in the skull (bouncy) so our skull is not crushed --average brain weights 3 pounds

chemically

CSF protects the brain _____ by providing the right environment for neurons

circulation

CSF protects the brain by providing _____ so oxygen and glucose can be carried to neurons and waste is carried away

choroid plexus

Creates CSF from blood plasma and hangs from the roof of the ventricles (2 lateral, 3rd, and 4th) --drained by the pia mater and epindemal cells --network of capillaries --tight junctions between epindemal cells

falx cerebelli

Dural septa that separates the CEREBRAL HEMISPHERES

falx cerebri

Largest dural septa that is shaped like a sickle (hook) and sits in the cerebral hemispheres along the sagittal plane while it anteriorly attaches to the crista gali of the ethmoid bone --keeps cerebrum from moving too far laterally or medially --lies in the longitudinal fissure

arachnoid mater

Middle layer of the brain that looks like a spider web and is connected deeper to the pia mater by web extensions --only go into large fissures, no sulci --only dips into longitudinal fissure and transverse cerebral fissure

dura mater

Most superficial (outermost) layer of the meninges that is the strongest and called "tough mother". It is opaic (not see through) and contains 2 layers: periosteal and meningeal layer

ventricles

Part of the brain that arrises from the expansion of the lumen of the neural tube

Blood-CSF barrier

Permits certain substances to enter the CSF and ventricles and excludes all harmful substances --no red blood cells in the CSF --CSF is replaced every 4 to 8 hours (20 mL per hour) --rate of production=rate of reabsorption

subdural space

Potential space that is between the DURA MATTER (below) and ARACHNOID MATER (above) that we could see from tearing a vein that could be caused by a blow to the head

CSF

The clear colorless liquid (80-150 mL) that is constantly produced and similar to blood plasma (thats what makes it) except for the different ion concentration and protects the brain --around neurons --created through choroid plexus --made from blood, dumps back into blood

meningeal layer

The deeper layer of the dura mater that continues in the vertebral column as the dural sheath of the spinal cord -contains fall cerebri and tentorium cerebelli

pia mater

The deepest layer attached to the brain that is thin and gives it a shiny appearance. --goes into large fissures and sulci

periosteal layer

The most superficial layer of the dura mater that forms the periosteum of the skull and lies next to the cranial nerves --absent in vertebral canal

epidural, subdural, subarachnoid

The spaces superficial to deep

cavernous sinus

There are 2 of these dural venous sinus that are very large and on wither side of the sella turcica

transverse sinus

There are 2 of these dural venous sinus that bring blood away from the confluence of sinuses and sits on the posterior border of the tentorium cerebelli --when it heads inferiorly, its name changes to sigmoid sinus

sigmoid sinus

There are 2 of these dural venous sinus that used to be the transverse sinus, but changed names once it turned inferiorly. It enters the jugular foramen to the internal jugular vein --C9, 10, 11

subarachnoid space

There are 2 pairs of arteries that carry oxygenated blood to the brain.. what does it travel in

adult

These structures are derived from the neural canal of the neural tube --come from telencephalon, diencephalon, mesencephalon, metencephalon, and myelencaphalon

dura mater, arachnoid mater pia mater

What are the 3 meninges? (superficial to deep) --das

superior sagital, straight, occipital

What are the 3 sinuses that make up the confluence of sinuses? --bring deoxygenated blood in --3 ways in

transverse sinus

What sinus drains blood out in 2 different ways? --2 ways out

2 lateral, 3rd, 4th

What ventricles produce CSF

dural septa

When the meningeal layer is pulling away from the external periostel layer to form partition (walls) within the cranial cavity --help limit excessive movement of the brain --help support brains weight

hydrocephalus

When water is on the brain because CSF is over producing, not flowing right, or not getting reabsorbed. Can be due to tumors, head injury, or meningitis (common to infants) --meningities: sutures still open;skull enlarges --more critical for adults because pressure increases inside skull so everything is compressed --treatment: drain CSF into vein in neck or abdominal cavity

colateral circulation

With the circle of Willis, if an artery is gradually obstructed, like a slow blockage.. what is the best alternative for communication --not for sudden blockages (stroke)

meninges

three layers of connective tissue in which the brain and spinal cord are wrapped --covers and protects brain/spinal cord --protect/support blood vessels and encloses dural venous sinuses --contains CSF --partitions of skull(creates compartments)

dural venous sinuses

where the layers of the dura mater (periosteal layer and meningeal layer) separate and deoxygenated (venous) blood collects to the internal jugular vein --blood will end up in atleast 1 sinus --no valves or smooth muscle..like viens