ventricles and blood supply to the brain

Question 1

Three meninges

Answer 1

• Dura
  
  • Thick parchment like tissue
  • Protection to underlying brain
• Arachnoid
  
  • Thinner fibrous layer
  • Not as strong
• Pia
  
  • Thin membrane
  • Permeable to CSF

Question 2

draw diagram and label outer layers of the brain and meninges

Answer 2

Question 3

role of arachnoid trabeculae

Answer 3

• connective tissue strands which
  
  • provides structure
  • keeps pia and arachnoid layers apart

Question 4

what is arachnoid granulation and role?

Answer 4

• Projects through dural layer
• Forms vesicles
  
  • One way valves into venous sinuses
  • Allow flow of CSF through superior sagittal venous sinus

Question 5

what is falx cerebri

Answer 5

= vertical sheet of dura separating the two cerebral hemispheres

Question 6

what is tentorium cerebelli

Answer 6

= horizontal sheet of dura separating the occipital cortex and cerebellum

Question 7

draw and label spinal cord meninges

Answer 7

Question 8

what are role of denticulate ligaments?

Answer 8

• connect the pia to the arachnoid/dura
• provide stability to the spinal cord

Question 9

draw and label ventricular system

Answer 9

Question 10

how does CSF enter the subarachnoid space?

Answer 10

at the median and lateral apertures of the fourth ventricle

Question 11

how is excess CSF removed?

Answer 11

drained into venous system via the arachnoid granulations

Question 12

draw the flow CSF

Answer 12

Question 13

what is CSF synthesised and secreted by?

Answer 13

by choroid plexus which is found in the roof of each of the four ventricles

Question 14

what is CSF drived from

Answer 14

blood plasma

Question 15

role of CSF

Answer 15

• flow into venous sinuses
  
  • removes toxic metabolic by-products from the brain
• protects brain from injury
  
  • brain floats in CSF - reduces its weight

Question 16

Why is lumbar puncture used?

Answer 16

to sample CSF

• for signs of infection or metabolic disturbances within the brain

Question 17

how is lumbar puncture used to sample CSF?

Answer 17

• Spinal cord ends at L1/L2 vertebra
  
  • Cauda equina below
  • Has enlarged subarachnoid space as theres no spinal cord
• Introduce needle at L4/L5

Question 18

draw and label the blood supply to the brain

Answer 18

vertebral artery

common carotid artery

Question 19

blood supply to the base of the brain draw and label

which are circle of willis?

Answer 19

Question 20

role and importance of the circle of willis

Answer 20

When there is a blockage still able to have blood supply to the brain

No damage to the brain

Can go other way of circle of willis

Question 21

which artery supplies blood to most of the primary sensory and motor cortex?

Answer 21

middle cerebral artery

Question 22

draw which cortical areas are supplied by which arteries

cortical blood supply:

Answer 22

Question 23

draw and describe venous drainage of the brain

Answer 23

most sinuses drain into the transverse and sigmoid sinuses

in turn these drain into the internal jugular vein

cavernous sinus drains into the facial vein

Question 24

clinical importance of facial vein

Answer 24

blood flow is very slow

therefore infection can often occur in cavernous sinus