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Genetics > Nervous System > Flashcards

Flashcards in Nervous System Deck (40):
1

Anencephaly

Cephalic end of neural tube fails to close, resulting in absence of large part of brain and skull

2

Spina bifida

Myelomeningocele- protrusion of meninges and a portion of the spinal cord through open vertebral column and spinal cord
Rarest and most severe
Meningocele- protrusion of meninges
Spina bifida occulta- small gap in spine, no opening in back

3

Example of developmental disorders due to genetics

Phenylketonuria
Tay-Sach disease

4

Example of developmental disorders due to chromosomal abnormalities

Down's syndrome

5

Example of developmental disorders due to intrauterine infections

TORCH syndrome

6

Example of developmental disorders due to dysraphic disorders

Neural tube defects

7

Vasogenic edema

Disruption of blood-brain barrier or cerebral capillaries (trauma, tumors, inflammation, late stages of cerebral ischemia)

8

Cytotoxic edema

Inadequate fxn of Na and K pump in glial cells (various toxins)

9

Osmotic edema

Plasma gets diluted (water intoxication, hemodialysis)

10

Hydrocephalus

Accumulation of excessive CSF within the ventricular system
Impaired CSF flow or resorption
Before suture closure- enlargement of head
After suture closure- expansion of ventricles

11

Herniation

Increased pressure (CSF volume, edema, hemorrhage) can displace tissue across dural barriers in skull or through openings in the skull

12

Causes of CVA

Atherosclerosis
HTN
Vasculitides
Angiopathy
Aneurysm
Malformation

13

CVA

Any abnormality of the brain caused by a pathologic process involving blood vessels
-Thrombotic occlusion of vessels
-Embolic occlusion of vessels
-Vascular rupture

14

Epidural hemorrhage

Rupture of middle meningeal artery

15

Subdural hemorrhage

Rupture of bridging veins

16

Subarachnoid hemorrhage

Ruptured berry aneurysm

17

Types of brain injuries- caused by trauma

Brain concussion
-Microscopic and widespread lesions
Brain contusion
-Localized and macroscopic lesions
Laceration

18

Types of neck and spinal cord injuries

Hyperextension injury
Hyperflexion injury

19

Cause of bacterial CNS infections

N. meningitidis
S. pneumoniae
E. coli
H. influenzae
T. pallidum

20

Types of meningitis

Acute pyogenic (bacterial)
Chronic (TB, syphilis, fungi)
Viral

21

Cause of acute pyogenic (bacterial) meningitis

E. coli, group B streptococci, N. meningitidis, H. influenzae, S. pneumoniae

22

Cause of chronic (TB, syphilis, fungi) meningitis

M. tuberculosis
T. pallidum
Fungi (Cryptococcus)

23

Cause of viral meningitis

Acute lymphocytic

24

Clinical approach to meningitis

Spinal tap and examination of CNS are impt for disease

25

Types of parenchymal infections

Brain abscess
Localized infections
Viral encephalitis

26

Cause of brain abscess

Various pyogenic bacteria that reach the brain from infections elsewhere in the body

27

Cause of localized infections in the parenchymal

TB, fungi, toxoplasma

28

Cause of viral encephalitis

Arbovirus, herpes simplex, rabies, HIV

29

Clinical approach to parenchymal infections

Brain abscess- Imaging: CT, MRI
Localized infections and viral encephalitis: CSF

30

Cause of opportunistic infections

Toxoplasmosis
CMV
JC virus

31

Clinical approach to opportunistic infections

CT, MRI

32

Spongiform encephalopathy

Creutzfeldt-Jacob disease, Kuru in humans and scrapie, bovine spongiform encephalopathy ("mad cow") disease in animals

33

Cause of spongiform encephalopathy

Unconventional agents called prions, which are proteins folded into an infectious conformation

34

Clinical approach to spongiform encephalopathy

CSF EEG

35

MS

Most common autoimmune disease involving the nervous system
Usually between 20-40 yo
Demyelinating disorder of the CNS
Decreased nerve function from initial inflammation of the myelin sheath covering nerves of the brain and spinal cord, with eventual scarring

36

Sx of MS

Sx and severity vary widely and may progress into episodes of crisis alternating with episodes of remission
Sx of MS may mimic those of many other nervous system disorders
Dxed by ruling out other conditions
Multifactorial
15-fold higher when 1st degree relative has MS

37

Alzheimer etiology and incidence

Panethnic, genetically heterogenous disease
Sporadic- 75%
-Almost all cases are late-onset (>65 yo) and multifactorial
Familial- 25%
-95% have late-onset, and most exhibit multifactorial inheritance
-5% have early-onset, some as early as in their 20s or 30s, and most of these pts have autosomal dominant mutations in single genes

38

Principles of Azlheimer

Variable expressivity
Genetic heterogeneity
Gene dosage
Toxic gain of function
Risk modifier

39

Pathology of Alzheimer

Central neurodegenerative disorder, esp of cholinergic neurons of the hippocampus, neocortical association area, and other limbic structures
Neuropathological changes include cortical atrophy, extracellular neuritic plaques, intraneuronal neuro-fibrillary tangles, and amyloid deposits in the walls of cerebral arteries
The neuritic plaques contain many different proteins includes Ab42 and apolipoprotein E

40

Amyloid beta precursor protein (APP)- Alzheimer

A transmembrane protein subject to endoproteolytic cleavage to produce peptides with neurotrophic and neuroprotective fxns
When APP is cleaved abnormally, it makes Ab42, a neurotoxic form of amyloid found in AD pts