module 9

Question 1

The blood brain barrier restricts?

Answer 1

the entry of pathogens into the brain and meninges

Question 2

Hematogenous spread of organisms requires
spread through?

Answer 2

at least 2 layers to infect the brain

Question 3

Hematogenous Spread (Bloodborne Invasion) into the CNS

Answer 3

Growing across:
● Microbes can grow in the endothelial cells and then into the
astrocytes or choroid plexus
– Passive:
● Transported across in intracellular vacuoles
– Carried in infected cells:
● Infected inflammatory cells can migrate into the brain and
meninges, lyse and release
the organism or the organisms may pass
from cell to cell

Question 4

Rabies and other Lyssaviruses may invade Muscle Cells @
The Bite Site > Move up the Nerves to the Dorsal Root
Ganglia > Spinal Cord > Brain
- Herpesviruses may migrate up the nerves using normal
retrograde transport mechanisms

Answer 4

Invasion Via Peripheral Nerves