Neurophysiology

Question 1

What are the sulci and gyrus?

Answer 1

Grooves and ridges within the brain allowing more cerebral cortex to be accommodated in a fixed brain volume

Question 2

What is contained within grey matter?

Answer 2

Cell bodies and dendrites

Question 3

What is contained within white matter?

Answer 3

Axons and oligodendrocytes

Question 4

What do oligodendrocytes do?

Answer 4

Responsible for myelin production

Question 5

Describe the three protective layers of the CNS. What is their collective name?

Answer 5

The meninges is made up of dura mater (outermost), arachnoid and pia mater

Question 6

What is the treatment of bacterial meningitis?

Answer 6

Benzylpenicillin

Cefotaxime in allergy and post benzylpenicillin

Question 7

What is the subarachnoid space?

Answer 7

Space between arachnoid and pia mater layers, containing the CSF

Question 8

How much CSF is present within the system?

Answer 8

150mL

Question 9

How does the composition of CSF differ from plasma?

Answer 9

Less protein dense

Question 10

Describe the production of CSF.

Answer 10

Produced in choroid plexus in lateral ventricles
Tuft of capillaries secrete fluid and ions into ventricles
Flows from here down through foramen and into 3rd ventricle, then into aqueduct and 4th ventricle
Then flows down central canal into spinal column or leaves via foramen of Magendie to reach subarachnoid space

Question 11

How does CSF flow around the brain?

Answer 11

Must have somewhere to go to prevent build up off pressure
Travels around the brain and upon reaching the top of the head drains into superior sagittal sinus which contains venous blood

Question 12

What is hydrocephalus?

Answer 12

Build up of CSF in the subarachnoid space

Question 13

What is the blood-cerebrospinal fluid barrier? Describe its features.

Answer 13

Found in choroid plexus
Made up of capillary leaky endothelial cells and ependymal barrier epithelial cells
Leaky capillaries allow movement of water and ins out, barrier then tightly regulates their entry into CSF
Main transporters are MRP and P-gp

Question 14

What is the blood brain barrier? Describe its features.

Answer 14

Adjacent endothelial cells locked together with tight junctions
Separates CNS from peripheral nervous system
Small, water soluble molecules can squeeze between cells

Question 15

How can larger molecules pass through the BBB?

Answer 15

Receptor-mediated transcytosis

Large neutral amino acid transporter

Question 16

What efflux transporters are present on the BBB endothelial cells?

Answer 16

P-gp
BCRP
MRP

Question 17

Give examples of anticancer drugs that are substrates for P-gp.

Answer 17

Doxorubicin
Vinblastine
Vincristine
Methotrexate

Question 18

Describe a surgical method for controlling brain tumour growth.

Answer 18

Removal of the tumour

Insertion of wafers containing anticancer drug (carmustine) which dissolve to release the drug

Question 19

Describe the administration of vincristine and methotrexate in brain tumours.

Answer 19

Methotrexate may be given intrathecally
Vncristine can be given IV but if given IT CSF must be aspirated as it is a potent neurotoxin, IT plasma given so vincristine binds to proteins for removal