Blood supply to the CNS, meninges and CSF Flashcards
1
Q
how is CSF formed
A
by dialysis of blood in the choroid plexus within the lateral, third and fourth ventricles
- ultrafiltration of plasma and active transport across ependymal cells/tight junctions
2
Q
what is the pathway of CSF flow
A
- arterial blood
- choroid plexus (blood-> CSF)
- lateral ventricles (1st and 2nd)
- 3rd ventricle
- 4th ventricle
- subarachnoid space
- arachnoid villi (CSF -> blood)
- venous blood
3
Q
what are the 2 physiological sections of the nervous system
A
- somatic (voluntary actions)
- visceral (no concious control)
4
Q
what are the functions of cerebral spinal fluid
A
- prtoection
- support
- nutrition
5
Q
what ar the 3 layers of the meninges (list moving medially from the cranium
A
- dura mater
- arachnoid mater
- pia mater
6
Q
what are 3 qualities of the dura mater
A
- intracranially adherent to the periosteum of the skull
- spinal - separated from the periosteum by the epidural space which is filled with fat
- tough layer composed mainly of dense connective tissue
7
Q
what are 2 qualities of pia mater
A
- thin layer which is adherent to the underlying brain/spinal cord
- blends with the fibres of the arachnoid layer
8
Q
what is th arachnoud mater
A
fine layer pressed up against the dura mater with fine whispy filamnts which extend to and blend with th pia mater
- contains CSF
9
Q
what is the function of th meninges
A
- protection
- containment of CSF
- maintenance of the blood, brain barrier
- support
10
Q
what is the blood brain barrier
A
- a selective barrier between the circulating blood and parenchyma of the nervous system
- selective block to large molecules
- mainly uses active transport
11
Q
capillaries in the brain are surrounded by:
A
- closed overlaping endotherlium
- dense basement membrane
- processes of astrocytes
- selective barrier for exchang of substances
