Class 5 - The Brain & Its Blood Supply

Question 1

What are the three primary brain vesicles that form from the ectodermal neural tube?

Answer 1

the prosencephalon (forebrain)
mesencephalon (midbrain), and
rhombencephalon (hindbrain)

Question 2

What secondary brain vesicles will each of the primary brain vesicles develop into?

Answer 2

prosencephalon –> telencephalon and diencephalon

mesencephalon –> stays itself

rhomboencephalon –> metencephalon and myelencephalon

Question 3

What will the telencephalon eventually develop into?

Answer 3

cerebrum and lateral ventricles

Question 4

What will the diencephalon eventually develop into?

Answer 4

thalamus, hypothalamus, epithalamus, third ventricle

Question 5

What will the mesencephalon eventually develop into?

Answer 5

midbrain and cerebral aqueduct

Question 6

What will the metencephalon eventually develop into?

Answer 6

pons, cerebellum, upper part of 4th ventricle

Question 7

what will the myelencephalon eventually develop into?

Answer 7

medulla oblongata and lower part of the 4th ventricle

Question 8

What are the four major parts of the adult brain?

Answer 8

brain stem
diencephalon
cerebellum
cerebrum

Question 9

How are the cranial meninges different from the spinal meninges?

Answer 9

the cranial dura mater has two layers: periosteal and meningeal

Question 10

What forms the dural venous sinuses?

Answer 10

separations between the two layers of the cranial dura mater

Question 11

True or false: there is no epidural space around the brain

Answer 11

true

Question 12

What is the ‘falx cerebri’?

Answer 12

an extension of the dura mater that separates the left and right cerebral hemispheres

Question 13

What is the ‘falx cerebelli’?

Answer 13

an extension of the dura mater that separates the two hemispheres of the cerebellum

Question 14

What is the ‘tentorium cerebelli’?

Answer 14

an extension of the dura mater that separates the cerebrum from the cerebellum

Question 15

Brain ischemia > how many minutes causes permanent damage?

Answer 15

4 minutes

Question 16

The brain consumes what percentage of the oxygen and glucose of the body?

Answer 16

20%

Question 17

What are the two major arterial systems supplying blood to the brain?

Answer 17

internal carotid and vertebral arteries

Question 18

True or false: the dural venous sinuses are sensitive to changes in intracranial pressure.

Answer 18

false, they are unaffected by increased ICP

Question 19

Blood from the brain is ultimately drained into which two veins?

Answer 19

internal jugular and vertebral veins

Question 20

The endothelial cells of the BBB capillaries are kept tightly together by which type of glial cell?

Answer 20

astrocytes

Question 21

How do astrocytes maintain tight junctions at the BBB?

Answer 21

releasing a chemical that maintains the permeability of these tight junctions

Question 22

What substances do NOT cross the BBB?

Answer 22

proteins and most antibiotics

Question 23

What substances cross the BBB freely and easily?

Answer 23

O2, CO2, glucose, alcohol, most analgesics

Question 24

What substances cross the BBB very slowly?

Answer 24

creatinine, urea, most ions

Question 25

Where is CSF found?

Answer 25

subarachnoid space of spine and cranium central canal ventricles of the brain

Question 26

What is CSF composed of?

Answer 26

water, small amounts of oxygen, glucose, lactic acid, proteins, urea, ions, some WBCs

Question 27

Where is CSF produced?

Answer 27

the choroid plexuses in all the inter-communicating ventricles of the brain

Question 28

What are the ventricles of the brain?

Answer 28

lateral ventricles third ventricle fourth ventricle

Question 29

How do the lateral ventricles connect to the third ventricle?

Answer 29

via the interventricular foramen (foramen of Monroe)

Question 30

How does the third ventricle connect to the fourth ventricle?

Answer 30

via the cerebral aqueduct

Question 31

How does the fourth ventricle communicate with the spinal cord? (2 ways)

Answer 31

it connects with the subarachnoid space via the lateral (Luschka) and median (Magendie) apertures and via the central canal

Question 32

What is the septum pellucidum?

Answer 32

a septum separating the lateral ventricles that is connected to the corpus callosum

Question 33

Where is the CSF reabsorbed? At what rate?

Answer 33

by the arachnoid villi in the dural venous sinuses (especially the superior sagittal sinus) as rapidly as it is produced, ~20ml/hr

Question 34

Where is the main site of reabsorption of CSF?

Answer 34

the superior sagittal sinus

Question 35

What is a VP shunt?

Answer 35

a ventriculoperitoneal shunt, used in the treatment of hydrocephalus

Question 36

What glial cell type is vital to the barrier between the blood and the CSF?

Answer 36

ependymal cells