Support Systems

Question 1

between the arachnoid and dura mater

Answer 1

Subdural space

- virtual space, not an actual space in healthy brains - can fill up with things like hematomas that make a space

Question 2

between arachnoid and Pia mater; Space filled with CSF and blood vessels

Answer 2

subarachnoid space

Question 3

between dura mater and skull

Answer 3

epidural space

- virtual space, not an actual space in healthy brains

Question 4

what are the two layers of the dura mater?

Answer 4

1. Periosteal layer- attaches to skill

2. meningeal layer - attaches to arachnoid

Question 5

The two layers of dura matter are attached except at ________.

Answer 5

Dural venous sinuses

Question 6

Projection of meningeal layer of dura matter that separates L and R cerebral hemisphere

Answer 6

Falx cerebri

Question 7

Projection of meningeal layer of dura matter that separates cerebellum and posterior cerebellum

Answer 7

Tentorium cerebelli

Question 8

What is the order of mater from superficial to deep

Answer 8

1. Dura
2. Arachnoid
3. Pia

Question 9

bars of tissue deep to arachnoid membrane

Answer 9

Trabeculae

Question 10

Thin layer

Firmly attached to brain and spinal cord

Answer 10

Pia mater

Question 11

Where are the lateral ventricles?

Answer 11

Telencephalon

Question 12

Where is the 3rd ventricle?

Answer 12

Diencephalon

Question 13

Where is the 4th ventricle?

Answer 13

Pons/medulla/ cerebellum

- opens to subarachnoid space

Question 14

Where is the cerebral aqueduct?

Answer 14

Midbrain

Question 15

What is CSF made by? how does it travel?

Answer 15

Choroid plexus
Made in lateral vent –> 3rd –> cerebral aqueduct –> 4th –> subarachnoid space (surrounds outside brain and spinal cord)

Question 16

Where does CSF go after the subarachnoid space?

Answer 16

Arachnoid villi into dural venous sinuses and enters general circulation

Question 17

How many seconds of O2 deprivation does it take to lose conscious ness? how long until electrical activity stops? low long until irreversible injury occurs?

Answer 17

10s
20s
few minutes

Question 18

Arteries supply Superior spinal cord brainstem, cerebellum, posterior occipital and temporal lobes of the cerebrum; most of telencephalon and diencephalon

Answer 18

vertebral arteries

- travels along medulla, branches in medulla to supply the spinal cord (Post/ ant spinal arteries)

Question 19

What are the branches of the vertebral arteries?

Answer 19

1. Posterior spinal arteries – posterolateral cord; Posterior 1/3rd of cord
2. Anterior spinal artery – just one; anterior median cord; Anterior 2/3rd of cord
3. Posterior inferior cerebellar artery (PICA); Inferior cerebellum

Question 20

Supplement vascular supply (not enough blood supply by A and P spinal arteries); Most are small, only a few are significant; Blockage can damage the spinal cord at that level, but also axons passing through that region

Answer 20

Radicular arteries

- enter the SC with the nerve roots

Question 21

The 2 vertebral arteries join at the pons is called the ____. what are the branches of this artery? What do they supply?

Answer 21

Basilar
1. Anterior inferior cerebellar artery (AICA)
2. Superior cerebellar artery
Supply: pons and most of cerebellum

Question 22

At the rostral pons the basilar artery forks to form the ______ arteries. What do they supply?

Answer 22

2 posterior cerebral;
supply:
1. Midbrain
2. Occipital lobe
3. Medial and inferior temporal lobes

Question 23

Around the optic chasm, the Internal carotid artery (ICA) splits into?

Answer 23

Anterior cerebral artery (ACA) - travels in longitudinal fissure
Middle cerebral artery (MCA) - passes through lateral sulcus

Question 24

What is supplied by the ACA? by the MCA?

Answer 24

ACA = Primary motor and somatosensory cortex for LE
MCA = Supplies most of lateral cerebral hemispheres

Question 25

What does the circle of Willis connect (3 communicating arteries)?

Answer 25

Anterior communicating artery - L and R anterior cerebral artery Posterior communicating arteries - PCA and ICA on each side

Question 26

Regions where small anastomoses link the ends of the cerebral arteries; regions are relatively spared with strokes; when blood supply in two adjacent arteries is affected, these regions are most affected

Answer 26

Watershed regions

Question 27

Where are common sites for aneurysms?

Answer 27

circle of willis (branches points are weak)

Question 28

Why isn't there a lot of blood flow in the circle of willis? What's the point of the circle of willis if it doesn't allow a lot of blood flow?

Answer 28

- blood vessels are small; similar pressure on each end of the artery - arteries can expand to adapt to slowly developing occlusions in one of the MCA (long term adaptation)

Question 29

What events can affect blood flow in two (or more) adjacent arteries, affecting watershed regions?

Answer 29

1. Severe drop in systolic blood pressure | 2. Blockage or restriction in internal carotid artery (Supplies both ACA and MCA)

Question 30

Where are impairments when there is damage to watershed regions?

Answer 30

1. For ACA and MCA - Often includes the trunk and proximal limbs (Man in a barrel syndrome); Transcortical aphasia syndromes 2. Between MCA and PCA -Difficulties in higher order visual processing

Question 31

Supplies choroid plexus in lateral ventricles; Parts of optic tract, putamen, thalamus, internal capsule and hippocampus

Answer 31

Anterior choroidal artery

Question 32

Supplies choroid plexus in third ventricle; Parts of hippocampus and thalamus

Answer 32

Posterior choroidal artery

Question 33

What are the deep cerebral blood supply structures?

Answer 33

1. Branches of cerebral arteries 2. Anterior choroidal artery 3. Posterior choroidal artery

Question 34

What are the unique features of veins of the brain?

Answer 34

1. Not paired with arteries 2. Valvless - can carry infections into brain 3. frequent anastomoses 4. Superficial and deep veins

Question 35

Superficial veins are on the surface of cerebral hemispheres. Bridging veins that connect to dural sinuses can be damaged with shearing forces. What is the result?

Answer 35

blood moving into subdural space (subdural hematoma)

Question 36

Where do most superficial veins drain into?

Answer 36

Superior sagittal sinus | - Some connect to other sinuses located between the two layers of the dura

Question 37

Where are the deep veins?

Answer 37

Drain deeper regions of telencephalon and diencephalon

Question 38

What causes blood vessels to dilate?

Answer 38

- Low BP, Oxygen or pH | - High CO2 or lactate

Question 39

What causes blood vessels to constrict?

Answer 39

- High pH, Oxygen or BP | - Low CO2 or lactate

Question 40

Autoregulation important to ensure adequate blood flow and prevent ____.

Answer 40

edema

Question 41

The amount of blood flow to the brain depends on how much activity is going on in that area. The brain requires glucose and oxygen but can't store either. Is the CC or brainstem more sensitive to hypoxia?

Answer 41

CC | - results in persistent vegetative state