CNS Path Flashcards
(57 cards)
1
Q
Type II fibers
A
- white
- fast glycolytic
- quick actions
- when high pH these are dark
- more type II in muscles than type I
2
Q
Type I fibers
A
- red
- slow oxidative (mitochondria)
- when low pH these are dark
3
Q
perimecium
A
- connective tissue around vesicles of muscle fibers
4
Q
group atrophy
A
- when many skeletal fibers atrophy at once
- adipose and fibrous tissue replaces
5
Q
Myopathies: Muscular Dystrophy
A
- genetic loss or abnormality of the contractile proteins in the muscle
6
Q
Progressive (Duchenne) Muscular Dystrophy
A
- x-linked, recessive
- affects boys
- loss of dystrophin which anchors actin to the cell membrane
- muscle weakness results
- fatal around age 20
- distinctive sign is small clusters of muscle fibers undergoing necrosis at the same time or are in same stage of regeneration
7
Q
what are most disorders of peripheral nerves a cause of? (Besides trauma)
A
- metabolic (acquired) & toxic 50%
- inflammation/infection (10-20%)
- idiopathic (10-20%)
8
Q
epineurium
A
- connective tissue that combines all the vesicles of nerve fibers together
9
Q
perineurium
A
- connective tissue that surrounds a vessicle
10
Q
endoneurium
A
- in between individ fibers
11
Q
Axonal Degeneration cause
A
- from mechanical insults (compression or transection)
12
Q
Wallerian degeneration
A
- axon distal to point of insult will undergo degeneration and fragmentation
- myelin breaks down but schwann cells remain
- macrophages clean up debris
- proximal axon produces new sprouts which can reconnect with severed pathway
- schwann cells often larger # but remyelinate the axon
- slower transmission b/c more cells
13
Q
traumatic neuroma
A
- open injuries (penetrating wounds) result in aberrant regenerative sprouting
- scar tissue buildup
- painful whenever compressed
14
Q
arterial circle (circle of wills)
A
- composed of internal carotids, veterbral arteries and a circle that includes anterior, middle, and posterior cerebral arteries
15
Q
anterior cerebral artery supplies blood to
A
- medial surface of the brain
- frontal and parietal lobes on medial surface
- little of lateral surface also
16
Q
posterior cerebral artery supplies blood to
A
- temporal lobe, occipital lobe on medial surface
- little of lateral surface also
17
Q
middle cerebral artery supplies
A
most of the lateral surfaces of the brain of all lobes
18
Q
border zones (water shed)
A
- region of brain on later surface receiving blood from two different vessels
- still right amt of blood
19
Q
Cerebrovascular Accident (CVA)
A
- stroke
- sudden onset of focal neurological deficit w/o etiology
- 40-80 yrs with equal prevalence in each decade
- more common in males
- 3rd leading cause of death
- 42% of stroke victims have reoccurrence
20
Q
arteriosclerosis
A
- generic hardening of arteries
21
Q
atherosclerosis
A
- large and medium arteries
- hyperlipidemia
- cause large infarcts
22
Q
arteriolosclerosis
A
- small arteries and arterioles
- CAUSES hypertension
- cause mostly hemorrhages in the brain
- microaneursyms
23
Q
pattern of injury of CVA
A
- 73% infarcts (thromboembolism causing hypoxia/ischemia)
- 19% intraparenchymal hemorrhages secondary to hypertension
- 7% subarachnoid hemorrhages, most common cause rupture of berry aneurysms (that isn’t trauma)
24
Q
Hypoxia
A
- decreased amount of oxygen in perfused tissue regardless of bp
- can lead to ischemia
25
Ischemia
decrease in blood supply
26
Infarct
- necrosis of tissue secondary to ischemia/hypoxia
| - some strokes do not result in this b/c they are reversible
27
Cerebral emboli
- commonly result of carotid or cerebral vessel thrombi
| - sudden and most common cause of cerebral infarction
28
Thrombosis
- occlusion of a vessel in situ (it's original place)
| - usually somewhere with atherosclerosis
29
Hemorrhage
- association with hypertension
| - common sites cerebellum, pons, basal nuclei
30
Blood Brain Barrier
- has tight junctions
| - protects brain from large particles that would bring in fluid and result in swelling
31
Infarcts-
- vascular occlusions (thrombosis, embolism), hypotension, or hypoxia
- cerebral emboli most common cause of strokes
32
transient ischemic attacks
- loss of speech days or weeks before a stroke or hemiparesis (weakness of one side of body)
33
Intraparenchymal hemorrhage
- can be all sizes and caused by variety of things
| - hemorrhage in the parenchymal parts of brain
34
Hypertensive hemorrhage
- most common cause of non-traumatic intraparenchymal hemorrhage
- immediate threat to life
- results in loss of smooth muscle, thinning of vessel wall, and rupture under pressure
- if rupture into ventricles, death results rapidly
35
Subarchanoid hemorrhage
- most commonly due to rupture of saccular or berry aneurysm ( if not by trauma)
36
Saccular or berry aneurysm
- disease of adults though the aneurysm is thought to be genetic defect in the vesicle elastica
- more common in women
- 90% of all aneurysms found in anterior portion of the arterial circle
- 30% of patients die
37
Aneurysms present in 3 ways
- subarachnoid hemorrhage (most common)
- intracranial hemorrhage into brain parenchyma (associated with rapid death)
- expanding intracranial masses that compress the hypo mimicking pituitary tumors
38
Brain Herniation: parahippocampal/uncal
- entire or part of parahippocampal gyrus herniates through the opening of the tentorum (incisura) causing compression of brain stem
39
Brain herniation: cerebellar tonsilar herniation
- cerebellar tonsils herniate though the foramen magnum causing compression of the medulla
- can lead to cardiac and respiratory interference and death
40
what else can happen with a brain herniation?
- when brain is pulled down, arteries stretch and can tear
41
Epidural Hemorrhage
- one of the most acute medical emergencies
- usually occurs with temporal bone fracture
- laceration of middle meningeal artery
- blood accumulates very rapidly, lethal within a few hours
- lucid interval where brief loss of consciousness and then fine
- rapidly deteriorates, losing consciousness, fixed pupil on ipsilateral side; hemiparesis
42
Subdural Hemorrhage
- hematoma
- present in 50% of fatal cases of head injury
- may be nontraumatic
- very young and very old patients
- ruture of cortical veins
- frontal parietal
43
Acute, subacute, and chronic subdural hemorrhage
- acute: lethal within hours if sufficient blood accumulates
- subacute: occur within a few days of injury
- chronic: may be discovered years after in autopsy
44
Meningitis
- inflammation of the pia and arachnoid (leptomeningies)
45
three types of meningitis
- pyogenic - bacterial
- granulomatous - fungal or TB
- lymphocytic - viral
46
Bacterial Meningitis
- sudden onset with fever, headaches, stiff neck, coma
- thick yellow, fibrino-purulent exudate over the convexity or base of brain
- congestion of meningeal vessels and brain edema
- exudate accumulates in compartments where CSF circulates
47
Perinatal period meningitis
- E. coli
| - B streptococcus
48
Infants and children meningitis
- haemophilus influenzae
49
adolescents and young adults meninigitis
- neisseria meningitidis (meningococcus)
50
adults meningitis
- streptococcus pneumonia
51
Granulomatous meningitis
- from fungus (cryptococcus neoformans) or TB
- subacute, slowly progressive with headaches and cranial nerve deficits
- location at base of brain, whitish thickening of meningies
- granulmatous tissue
- hydocephalus due to partial outflow blockage of CSF
- gets to brain by blood
52
Viral Meningitis
- - ECHO and Cowsackie
- via the bloodstream
- do not require treatment
- headaches, anorexia, apathy
- PCR for diagnosis
53
Viral encephalitis
- no pus
- can be RNA or DNA
- target is nerve cells (polio; rabies) or nerve and glia cells (herpies, CMV)
- glial nodules: microscopic accumulation of lymphocytes
54
Poliomyelitis
- enteric virus
- attacks and kills motor neurons
- respiratory paralysis is immediate cause of death
55
Rabies-
- transmitted through saliva of infected animal
- reaches CNS through peripheral nerves
- incubation 4-6 wks
- confusion, hyperirritability, pharyngela spasms
- hydrophobia, flaccid paralyses, coma
- death 1-2 wks b/c of respiratory failure
- negri bodies in cerebellum, brainstem, hippo neurons
56
Arthropod-borne viruses
- mosquito or tick vectors
- california virus in midwest
- attacks nerve cells of the cerebral cortex, basal nuclei, brainstem
- irritability, confusion
57
HIV
- 30% develop subacute dementia
- brain atrophy
- perivasculated multinucleated giant macrophages
