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USMLE/ Step ONE > Neuro > Flashcards

Neuro Flashcards

0
Q

When does neural plate form?

A

Day 18

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1
Q

Origin of the neural plate?

A

From ectoderm. Notochord induces ectoderm -» neuroectoderm-» Neural plate

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2
Q

Adult derivative of notochord?

A

Nucleus pulposus & Intervertebral disc

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3
Q

What is the basal plate?

A

In the developing nervous system, the basal plate is the region of the neural tube ventral to the sulcus limitans. It extends from the mesencephalon to the end of the spinal cord and contains primarily motor neurons, whereas neurons found in the alar plate are primarily associated with sensory functions. The cell types of the basal plate include lower motor neurons and four types of interneuron.

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4
Q

What are the neural tube plates and where are they located?

A

Alar plate- dorsal

Basal plate- ventral

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5
Q

Function of alar plate?

A

Sensory

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6
Q

What are the 3 primary vesicles of brain? When do they form?

A

Forebrain- prosencephalon
Midbrain- mesencephalon
Hindbrain- rhombencephalon

Week 4

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7
Q

Vesicle derivatives of prosencephalon?

A

Telencephalon and Diencephalon

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8
Q

Vesicles that derived from hindbrain?

A

metencephalon & myelencephalon

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9
Q

Adult derivatives of midbrain?

A

Wall: Midbrain

Cavity: aqueduct

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10
Q

What are adult derivatives of telencephalon?

A

Hippocampus
Amygdala
Cerebral hemispheres
Basal ganglia

Cavity: lateral ventricles

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11
Q

Adult derivatives of Diencephalon?

A

Thalamus
Optic nerve and tracts
Hypothalamus

Cavity: 3rd ventricle

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12
Q

What are the adult derivatives of metencephalon?

A

Pon
Cerebellum

Cavity: upper part of 4th ventricle

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13
Q

Adult derivative of myelcephalon?

A

Medulla
“I love MY medulla”

Cavity: lower part of 4th ventricle

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14
Q

List all 5 secondary vesicles, cranial to caudal?

A 
Telencephalon
Diencephalon
Mesencephalon
Metencephalon 
Myelencephalon

Spinal cord below

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15
Q

Failure of neuropores closure cause?

A

Insufficient intake of folic acid before conception or during pregnancy (0.8 to 1mg)

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16
Q

Abnormal levels of what indicative failure of neuropores to fuse?

A

Elevated in amniotic fluid:
α-fetoprotein
Maternal serum
Fetal AchE

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17
Q

Meningocele vs. meningomyelocele

A

Meningocele: meninges go outside of spinal canal, trough vertebra (but not spinal cord)

Meningomyelocele: meninges and spinal cord move out of spinal canal.

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18
Q

What is condition where spinal canal bone fails to close, no structures herniates, and tuft of hair or skin dimple at level of bony defect?

A

Spina bifida occultation

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19
Q

Elevated AFP indicates?

A

Neural tube defect

Omphalocele

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20
Q

Increased AFP, polyhydramnios, and open calvarium

A

Anencephaly

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21
Q

Anencephaly presentation and associations

A

Association: mom has diabetes type 1

Baby has no forebrain, open calvarium, polyhydramnios (no swallowing center in brain)

“Frog like appearance”

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22
Q

Increased risk of anencephaly?

A

Mom with diabetes type 1

And low folic acid intake by mom

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23
Q

Defect in telencephalon leading to hemispheres not separating ?

Sx?

A

Holoprosencephaly

Sx: cleft lip(moderate) or cyclopia (severe form)

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24
Q

What genetic condition can show holoprosenceohaly

A

Patau syndrome, trisomy 13

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25
Q

What causes holoprosenceohaly?

A

Multifactorial etiology, w/ mutations in sonic hedgehog signaling

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27
Q

Non genetic cause of holoprosenceohaly?

A

Fetal alcohol syndrome

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28
Q

Free nerve endings, location? What senses?

A

All skin. Epidermis, some viscera

Pain & temperature

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29
Q

What are types of free nerve endings (w/ descriptions)?

A

C- slow, unmyelinated fibers
Aδ- fast, myelinated

“Cooked slow, but Ate dessert fast”

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30
Q
  • Describe Mesissner’s corpuscles
  • Location
  • sense
A
  • Large myelinated fibers which adapt quickly
  • Glabrous (hairless) skin
  • Dynamic fine/light touch; position sense
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31
Q

Which receptors for sensation are unmyelinated?

A

C fibers!

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32
Q

Which sensory fibers adapt slowly and have myelin?

A

Merkel’s discs

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33
Q

location of Pacinian and sense?

A

Deep skin, ligaments, & joints

vibration & pressure

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34
Q

What are the pressure sensory corpuscles?

A

Pacinian & Merkel’s discs

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35
Q

Which sensory fibers located @ hair follicles? What are affiliated sense?

A

Merkel’s discs

Pressure, DEEP static touch (shapes, edges), position

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36
Q

Describe oligodendroglia on Nissl stain & H&E stain?

A

Nissl: small nuclei, dark chromatin, little cytoplasm

H&E: fried-egg look

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37
Q

MC glial cell in white matter?

A

Oligodendrocyte

38
Q

What are the myelinating cells of CNS & PNS? Embryo origins?

A

CNS: Oligodendrocyte; from neuroectoderm
PNS: Schwann cells; from NC cells

39
Q

What disease destroys Schwann cells?

A

Guillain-Barre syndrome

40
Q

How do Schwann cells increase conduction?

A

Increase conduction velocity via saltatory conduction between nodes of Ranvier, which have high Na-channel #

41
Q

Schwannoma located in internal acoustic meatus?

A

Acoustic neuroma

42
Q

MS affects which glial cell?

A

Oligodendrocytes are destroyed

43
Q

What are structures that lack a BBB called?

A

circumventricular organs

44
Q

List circumventricular organs

A

OVLT
Subfornical organ (SFO)
Area postrema

45
Q

Structures part of Basal ganglia?

A

Caudate nucleus, putamen, globus pallidus, Substantia nigra

Striatum = caudate + putamen
Lentiform = globus pallidus + putamen

(globus pallidus internus + externus)

46
Q

What conditions associated w/ a Berry-Aneurysm?

A

AD-PKD
Ehlers-Danlos syndrome
Marfan’s syndrome
HTN

47
Q

What is Kinesin?

A
  • Microtubule
  • Fx: anterograde transport of intracellular vesicles & organelles towards the “+” (growing) end of MT.
  • NT vescles down axon to synaptic terminal
48
Q

What triggers Ach release from presynaptic terminal vesicles @ NMJ?

A

Influx of extracellular Ca into presynaptic terminal

49
Q

Describe NMJ AP duration, all steps!

A

1) AP depolarizes Presyn terminal membrane
2) Voltage-gated Ca channels open
3) Ca influx
4) Presyn vesicle fuses w/ Presyn membrane, then exocytosis
5) Ach binds to nicotinic R’s, Postsyna membrane, Na/K channels
6) Na/K channels–> AP conduct. Postsyn memb
7) Ach degraded by Ach-esterase

50
Q

What type of diagnosis is Alzheimer’s?

Therapy?

A

diagnosis of EXCLUSION

Therapy:
Cholinesterase (-), like Donepezil
Antioxidant (Vit E)
NMDA receptor antagonists (i.e. Memantine)

51
Q

Why cant Mycoplasma bugs (including Ureaplasma) not be killed by Penicillins, caphalosporins, carbapenems, vancomycin?

How to Tx then?

A

This drugs target Peptidoglycan cell wall, which Mycoplasma doesn’t have!!!!!!!!!!!!

Tx: Ant-ribosomal agents like Tetracyline & erythromycin

52
Q

Tx of h. pylori?

A

PPIs (omeprazole, etc)

combined w/ Clarithromycin & amoxicillin w/ or w/o bismuth

53
Q

Describe how PCP is used and it’s effects

A

Sprinkled on marijuana and smoked

Clonic jerking of extremities (psychomotor agitation)

Belligerence behavior

(naked dude that punched fence)

54
Q

Active ingredient in marijuana? Effects?

A

Tetrahydrocannabinol (THC), acts on CB1 & CB2 receptors–> mood, memory, perception changes

Euphoria, slowed time feel, laughing, STM loss.

Tachycardia & Conjunctival injection

55
Q

What is conjunctival injection?

A

The forcing of a fluid into the conjuctiva, the mucous membrane that lines the eyelids.

56
Q

What is Dysarthria?

A

Dysarthria is when you have difficulty saying words because of problems with the muscles that help you talk.

57
Q

Presentation of Vit E deficiency?

A

Degeneration of spinocerebellar tracts, dorsal column, & peripheral nerves

looks like Friedreich ataxia- ataxia, dysarthria, loss of position and vibration senses

58
Q

MOA of Morphine?

A

Binds Mu-receptors, which are G-protein linked

-> activates Potassium efflux -> Hyperpolarization of Postsynaptic neurons & termination of pain transmission

59
Q

If body temp increases, what nucleus works to oppose this and how?

A

Anterior hypothalamic nuclei

MOA: stimulates PANS-> vasodilation & sweating

60
Q

Damage to what nuclei reduces hunger? Affect in adults & infants

A

Lateral nucleus.
Adults: starvation
Infats: failure to thrive

61
Q

Sx of AIP?

Acute Intermittent Porphyria

A 
The 5 P's
Painful abdomen
Port-wine colored pee (darkens w/ light exposure; upon standing)
Polyneuropathy
Psychological disturbance
Preciptated by drugs

Also, elevated ALA & PBG in pee

62
Q

Review synthesis pathway, draw it!

A

FA, 358

63
Q

Tx of AIP?

A

Tx of acute attacks of porphria approach: reduce pain & activity of ALA synthetase

Give IV GLUCOSE & HEME-> reduce tummy pain & neuropsychiatric pain

64
Q

Presentation of Neurofibroma?

A

Pigmented spots; “cafe-au-lait spots
Optic gliomas
Lisch nodules (pigmented iris hamartomas)
skin-colored, rubbery texture tumor, w/ “buttonholing” (vacant space under the skin that may remain for some time )

65
Q

Cause of neurofibromas?

A

AD disroder, defect of NF-1 on chromosome 17

tumors of Schwann cells (neural crest origin)

66
Q

Draw circle of willis, ID on radiograph:

ACA (left and right)
Anterior communicating artery
Internal carotid artery (left and right)
PCA (left and right)
Posterior communicating artery (left and right)
A

FA 422 (for Fx)

67
Q

How does hydrocephalus present in infants?

A

Poor feeding
Irritable
Large head circumference

Due to UMN damage: Hyperreflexia & muscle hypertonicity, due to stretching of periventricular pyramidal tracts

68
Q

MCC of bacterial meningitis?

Lab presentation?

A

Strep pneumonia

CSF: high pressure, elevated Neutrophils, less glucose, elevated protein

lancet shaped GPC in pairs

69
Q

Uses of Diazepam?

A

1) anxiolytic- axiety, panic attacks
2) sedative-hypotic effects- insomnia
3) Anticonvulsant (like in alcohol withdrawal)
4) Muscle relaxant- can stops spasms by UMN (MS, strokes) & tetanus

70
Q

MC S/E of diazepam?

What drugs enhance this?

A

Sedation!

First gen antihistamines cause this, like, Chlorpheniramine & Diphenhydramine

71
Q

Toxicity of Benzodiazepines?

Tx of this?

A

Dependence (increases w/ alcohol)

Tx toxicity w/ Flumazenil

72
Q

What binds to 3’ end of tRNA?

A

Amino acid, to 3’ OH

73
Q

Where do anticodons bind on tRNA?

A

side of molecule opposite 3’ & 5’

74
Q

What enzyme is the “matchmaker” for AA & tRNA?

A

Aminoacyl-tRNA synthetase

Scrutinizes AA before & after it binds to tRNA

75
Q

What is malignant hyperthermia and when does it occur?

A

Fever and muscle rigidity in some people after admin of inhalation anesthetics and/or succinylcholine

Defect in ryanodine R’s in Sarcoplasmic reticculum–> excess Ca release, and extra ATP used up (more body heat!!!)

76
Q

Tx of malignant hyperthermia?

A

Dantrolene- blocks ryanodine receptors

77
Q

Cause of subdural hematoma When does this happen?

A

rupture of bridging veins-> slow venous bleeding

cause: motor vehicle accident, shaken baby, blunt trauma, eldelry fall

78
Q

Presentation of subdural hematoma

A

Cresent shapped hemorrhage (between dura matter and arachnoid), midline shift

cannot cross falx tentorium

slow onset of Sx of confusion, headache (slow bleeding)

79
Q

Which S/E of opoids remain, even though patients develop tolerance for it for pain management ( need to increase dose to have same reduction in pain)

A

Constipation and Miosis

As long as patient on opoids, normal GI Fx doesn’t resume

drug binds to M-Rs in GI-> decreased secretions. Give laxatives to help

80
Q

Epilglottitis, caused mostly by?

A

H. influenza type b, due to Abs against capsule PRP

81
Q

What causes Serotonin Syndrome?

A

acy drug that increases Serotonin: MAOs (-), SNRIs, RCAs

82
Q

Sx of Serotonin syndrome?

A

Hyperthermia
myoClonus
Heart failure
Altered mental status (confused, pissed off)

83
Q

Tx of Serotonin syndrome?

A

Cyproheptadine- antihistamine w/ anti-serotonergic effects.

receptor antagonist

84
Q

Effect of entacapone? What is it anways

A

a COMT blocker (i.e. TOLCAPONE)

Increased levodopa bioavailability in brain; also done by DOPA decarboxylase

85
Q

Timeframe to have Schizophreniform disorder?

A

1-6 months of Sx

86
Q

Clozapine S/E?

A

-Agranulocytosis
FDA requires regular CBCs

-Seizures

87
Q

When is Clozapine used? What receptors does it act on?

A

Tx of Positive and Negative Sx in schizophrenic patients

Acts on D4 receptors

88
Q

Alzhimer’s microscopic presentation

A

Neurofibrillary tangles
Senile plaques
Amyloid Angiopathy

89
Q

Biochemical changes in Alzhiemer disease?

A
  • Decrease Ach leveles (due to defieienct choline acetyltransferase)
  • Ach levels low in Basal Nucleus of Meynert & Hipposampus
90
Q

Phenytoin S/E, long term therapy? Explain

A

Gingivial hyperplasia

drug increases PDGF-> gingivial machages cause proliferation of gingival cells and alveolar bone

91
Q

All phenytoin S/E

A
  • Gingivial hyperplasia
  • CNS: nystagmus, ataxia
  • Folic acid levels -> Megaloblastic anemia
  • Pregnancy, Fetal hydantoin syndrome

“Big fall, big teeth, big anemia”

USMLE/ Step ONE (20 decks)

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