10/21: CNS Part 1

Question 1

What layer does the CNS develop from?

Answer 1

Ectodermal layer
- subspecialized layer called the neuroectoderm

Question 2

When is the neural formation complete?

Answer 2

4 weeks gestation

Question 3

What does an anterior neuropore closure defect lead to?

Answer 3

Anencephaly

Question 4

What does a posterior neuropore closure defect lead to?

Answer 4

Spina bifida

Question 5

When does hemispheric division of the cerebrum occur?

Answer 5

Between 4 and 6 weeks gestation

Question 6

How does division occur?

Answer 6

Caudal to rostral
(posteiror -> anterior)

Question 7

What does lack of division lead to?

Answer 7

Various degrees of haloprosencephaly

Question 8

When does formation of the corpus callosum begin at?

Answer 8

10 weeks gestation

Question 9

When does gyral formation begin?

Answer 9

After division of the two cerebral hemispheres is complete

Question 10

What are cells of the CNS?

Answer 10

Neurons
Glial cells
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells

Question 11

What is intracranial hypertension?

Answer 11

Mean CSF pressure of more than 200mm of water

Question 12

_____________ and __________ commonly occur together but do not necessarily coexist

Answer 12

Intracranial hypertension; brain edema

Question 13

What is brain edema?

Answer 13

Increase in brain volume that is due to an increase in its water content

Question 14

What is well localized brain edema characterized as?

Answer 14

Little or no clinical evidence of brain dysfunction

Question 15

What is severe brain edema characterized as

Answer 15

Major focal or generalized signs of brain dysfunction and or medullary failure or respiration and circulation failure

Question 16

What is cytotoxic edema?

Answer 16

Cellular swelling of glial, neuronal, and endothelial cells

Question 17

What matter does cytotoxic edema involve?

Answer 17

White and grey matter

Question 18

What is interstitial edema?

Answer 18

Increased brain fluid due to block of CSF absorption

Question 19

What matter is involved in interstitial edema?

Answer 19

White matter

Question 20

What is the most common form of brain edema?

Answer 20

Vasogenic edema

Question 21

What is vasogenic edema characterized as?

Answer 21

Increased permeability of brain capillary endothelial cells

Question 22

Which matter is involved in vasogenic edema?

Answer 22

White matter is more vulnerable than grey matter

Question 23

What is hydrocephalus?

Answer 23

Increased volume of CSF within the cranial cavity

Question 24

What population does hydrocephalus occur more in?

Answer 24

Infants associated with enlarged head

Question 25

What is hydrocephalus caused by?

Answer 25

Obstruction to the CSF circulation

Question 26

What is trauma?

Answer 26

Blunt force head injury - lesions may be parenchymal and/or traumatic vascular injuries

Question 27

What is concussion?

Answer 27

Clinical syndrome of altered consciousness secondary to head injury - sudden disruption of neurologic function

Question 28

What is contusion?

Answer 28

Direct parenchymal injury of the brain (similar to bruising)

Question 29

What is an epidural hematoma?

Answer 29

Skull fracture and middle meningeal artery injury

Question 30

What is an epidural hematoma followed by?

Answer 30

Rapidly developing signs of cerebral compression

Question 31

What is a subdural hematoma?

Answer 31

Venous bleeding from bridging veins

Question 32

What is subdural hematoma follow by?

Answer 32

Gradual signs of cerebral compression-hours-days-weeks

Question 33

What is diffuse axonal injury (DAI)?

Answer 33

Widespread but often asymmetric axonal swellings that appear within hours of the injury

Question 34

What is the third major cause of death in the US after heart disease and cancer?

Answer 34

Cerebrovascular disease

Question 35

What is the most common clinical designation that applies to relatively acute cerebrovascular damage of the CNS due to different disorders?

Answer 35

Stroke

Question 36

What vascular disease are Impairment of blood supply and oxygenation?

Answer 36

Hypoxia, ischemia, and infarct of the brain

Question 37

What vascular diseases are rupture of CNS vessels?

Answer 37

Hemorrhage

Question 38

What are infarcts?

Answer 38

Tissue necrosis more frequent than hemorrhage (75-80%)

Question 39

What are hemorrhages?

Answer 39

associated with arterial hypertension, atherosclerosis, vascular malformations, berry aneurysms, trauma, coagulopathy

Question 40

What is transient ischemic attack?

Answer 40

reversible episodes of impaired neurological function

Question 41

What are transient ischemic attacks considered to be precursors of?

Answer 41

More serious occlusive events

Question 42

What is global cerebral ischemia?

Answer 42

generalized reduction of cerebral perfusion (cardiac arrest, shock, sever hypotension)

Question 43

What is focal cerebral ischemia?

Answer 43

localized reduction or cessation of blood flow to a defined portion of the brain

Question 44

What is hypoxia?

Answer 44

Low partial pressure of oxygen Impairment of bloods oxygen carrying capacity Inhibition of oxygen use in the tissue