(2.2) Blood Supplies, Venous Drainages and CSF

Question 1

Label:

• Pia mater
• Arachnoid mater
• Dura mater
• Superior sagittal sinus
• Calvaria (skull)
• Falx cerebri
• Subarachnoid space containing CSF

Answer 1

https://www.google.co.uk/search?q=csf+system&espv=2&biw=1039&bih=717&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIy93c6IG4yAIVC3IUCh31eQ9v#imgrc=j0puLl7mclHM0M%3A

Question 2

Briefly describe the arterial supplies to the brain, e.g. the origins and the courses

Answer 2

All from Circulus Arteriosus (Circle of Willis) that is made up from:

• Internal Carotid A: run in Carotid Canal in Pterous Temperoal Bone -> Cavernous Sinus -> Middle Cranial Fossa
• Vertebral A: ascend through Transverse Foramen -> becomes Basilar A

https://www.google.co.uk/search?q=Circle+of+Willis&es_sm=119&source=lnms&tbm=isch&sa=X&ved=0CAgQ_AUoAWoVChMIiv6svYC4yAIVQWoaCh0o3wL0&biw=1039&bih=717#imgrc=6g4zrynYX_uugM%3A

Question 3

Label the parts of brain that is supplied by:

• Anterior Cerebral A
• Middle Cerebral A
• Posterior Cerebral A

Answer 3

https://www.google.co.uk/search?q=cerebral+blood+supply&espv=2&biw=1039&bih=717&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIhaqSyoC4yAIVxn8aCh0j6wJC#imgrc=WiEQZW1mww7lLM%3A

Question 4

Which arteries supply the spinal cord?

Answer 4

• 1 Anterior Spinal A
• Paired Posterior Spinal A
• These arteries are derived from vertebral, intercostal and lumbar arteries depending upon
  vertebral level

Question 5

Define

• Vascular
• Haemorrhagic stroke

Answer 5

• A vascular stroke arises when a large artery is suddenly occluded by an embolism or by a
  thrombosis
• An hemorrhagic stroke follows the rupture of an artery or an aneurysm

Question 6

What type of blood (arterial, venous, mixed) characterises an

• Epidural (Extradural) haemorrhage,
• Subdural haemorrhage and
• Subarachnoid haemorrhage?

Answer 6

• Arterial blood: The epidural space is a potential space between the cranial bones and the dura
  mater. It becomes a real space if blood from torn meningeal arteries accumulates in the space
• Venous blood: Although the dura and the arachnoid mater are closely apposed to each other,
  blood, from a torn cerebral vein may force them apart to give a subdural haematoma
• Arterial blood: Following rupture of an aneurysm of one of the cerebral arteries it may fill with blood

Question 7

Which imaging procedure would be most useful in diagnosing an aneurysm in a cerebral artery?

Answer 7

Angiography

Question 8

What are the three layers of meninges?

Answer 8

• Pia mater (innermost)
• Arachnoid mater
• Dural mater (outermost)

Question 9

What two layers make up the Dura mater in the head? How is it different to the spine?

Answer 9

• Meningeal layer
• Epiosteal layer
• Spine only has one layer

Question 10

What structure separate the brain into compartments? What do they separate?

Answer 10

The meningeal and epiosteal layers of Dura mater strongly adhered each other, except at:

• 1 Falx Cerebri - separates the 2 hemispheres
• 2 Tentorium Cerebelli - separate occipital lobe & cerebellum

Question 11

What structures lie between the two layers of Dura mater?

Answer 11

Dural venous sinuses.

Question 12

What is the innervation to the Dura mater?

Answer 12

Trigeminal nerve

Question 13

Describe the structures of the leptomeninges.

Answer 13

• Pia mater: thinnest, delicate meshwork of vasculatures

- Arachnoid mater: thin, avascular with no innervation

Question 14

Which structure is commonly damages to results in an Extradural haematoma?

Answer 14

Middle Meningeal Artery at Pterion -> bleeds between skull and dura mater

Question 15

Which structure is commonly damages to result in an subdural haematoma?

Answer 15

Cerebral veins as they enter into a Dural venous sinus

Question 16

Suggest two possible organisms that may cause bacterial meningitis.

Answer 16

• Nesserira meningitidis

- Streptococcus pneumonia

Question 17

Which space of the meninges is an actual space as opposed to one of those shitty potential spaces? What is in it?

Answer 17

• Subarachnoid space

- CSF & lots blood vessels

Question 18

Suggest 4 possible functions of CSF

Answer 18

• Lightening the brain
• Cushing the brain for protection, buoyancy
• Removes metabolies
• Stable ionic environment e.g. low K+

Question 19

Where is the CSF produced?

Answer 19

Choroid Plexus cells

Question 20

Describe the drainage of CSF.

Answer 20

From 2 lateral ventricles -> 3rd ventricle -> Cerebral Aqueduct -> 4th ventricle -> Subarachnoid space -> reabsorbed by Arachnoid Grannulations -> Superior Sagittal venous sinus

Question 21

Distinguish the two types of Hydrocephalus.

Answer 21

• Non-communicating: obstruction of the CSF outflow e.g. between ventricles, commonly at Cerebral Aqueduct