Lecture 12- CNS development and protection

Question 1

what does the brain look like at the 3rd week of development?

Answer 1

human brain starts as a hollow tube

Question 2

what does the brain develop at the 4th week of development?

Answer 2

specializes in the anterior end

Question 3

what does the forebrain develop into in late development?

Answer 3

cerebrum
diencephalon

Question 4

what does the cerebrum develop into in adult brain?
what does the diencephalon develop into in adult brain?

Answer 4

cerebrum: cerebral hemispheres, basal ganglia, lateral and 3rd ventricles
diencephalon: thalamus, hypothalamus

Question 5

what does the midbrain develop in to in late development?

Answer 5

midbrain

Question 6

what does the midbrain develop into in adult brain?

Answer 6

superior colliculi
inferior colliculi
substantia nigra

Question 7

what does the hindbrain turn into in late development?

Answer 7

pons/ cerebellum
medulla

Question 8

what does the pons/ cerebellum and medulla turn into in adult brain?

Answer 8

pons/ cerebellum: pons and cerebellum
medulla: medulla

Question 9

what are ventricles? what are they lined with? how many do we have?

Answer 9

fluid filled cavities within the brain lined with ependymal cells we have 4

Question 10

what is a central canal? what re they lined with?

Answer 10

hollow tube in the spinal cord that is continuous with the ventricles lined by ependymal

Question 11

what does grey matter consist of?

Answer 11

unmyelinated cell bodies/ neuronal cell bodies
axon terminals
dendrites

Question 12

what does white matter consist of?

Answer 12

myelinated axons

Question 13

where is the grey matter normally?

Answer 13

outer surface of the brain
clustered together in groups in the middle of brain

Question 14

why does the brain and spinal cord (CNS) need protection?

Answer 14

because they are delicate

Question 15

what are different types of protection used to protect the CNS? (4)

Answer 15

bony skull and vertebral column
wrapped by meninges
cerebrospinal fluid
blood brain barrier

Question 16

what are meninges?

Answer 16

3 layers of protective membranes

Question 17

what are the 3 meningeal layers?

Answer 17

dura matter
pia matter
arachnoid membrane

Question 18

what is the dura matter?

Answer 18

thick most obvious meningeal layer
outer layer, closest to your skull
dura= mother (mothers protect you the most)

Question 19

what is the pia matter?

Answer 19

delicate meningeal layer that rests against the surface of the brain
inner layer closest to your brain tissue
pia= soft

Question 20

what is the arachnoid membrane?

Answer 20

meningeal layer attached to pia layer by webs
arachnoid= spider

Question 21

what happens if you get a deep cut in the scalp?

Answer 21

can be dangerous because some veins pass through the skull, if you get an infection in the cut, your brain will be infected

Question 22

what is meningitis?

Answer 22

contagious bacterial, viral or fungal infection of the meninges that causes swelling and pressure on the brain. neurons don’t like this pressure so they won’t function together/ properly

Question 23

what are the 3 types of bleeding that traumatic head injury can cause?

Answer 23

epidural bleeding
subdural bleeding
subarachnoid bleeding

Question 24

where do epidural bleeds occur?
where do subdural bleeds occur?
where do subarachnoid bleeds occur?

Answer 24

skull and dura
dura and arachnoid membrane
arachnoid membrane and pia matter

Question 25

what produces cerebrospinal fluid?

Answer 25

choroid plexus in the 3rd and 4th ventricles

Question 26

where is the cerebrospinal fluid found?

Answer 26

in ventricles

Question 27

where does cerebrospinal fluid circulate?

Answer 27

throughout the subarachnoid space because it keeps the cerebrospinal fluid moving. some circulates around the spinal cord

Question 28

where does cerebrospinal fluid exit the brain?

Answer 28

through the foramen of Lushka laterally, or the foramen of Magendie medially to the subarachnoid space

Question 29

what makes CSF so important?

Answer 29

helps maintain proper solute concentrations in the interstitial fluid surrounding neurons
helps remove waste
provides a cushion for the brain

Question 30

what is the blood- brain- barrier? where is it located?

Answer 30

barrier between the interstitial fluid of the brain and the plasma

Question 31

what is the function of the blood brain barrier?

Answer 31

keeps unwanted materials out
keeps wanted materials in

Question 32

what is the difference between blood circulation in the body and blood circulation in the CNS (blood brain barrier)?

Answer 32

body: endothelial cells are not connected and have pores (very leaky)
CNS: endothelial cells joined by tight junctions, surrounded by astrocyte endfeet (very tight)

Question 33

what molecules can diffuse across the blood brain barrier?

Answer 33

lipophilic (fat soluble) molecules
ex. steroids, ethanol, nicotine, benadryl

Question 34

how do polar, hydrophilic molecules cross the blood brain barrier?

Answer 34

transporters
ex. insulin, glucose, Na+