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Flashcards in Neuro Deck (133)
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1

Arnold-Chiari Type I

Adults: low-lying cerebellar tonsils below formen magnum--> vertebral canal
- Symptoms: headaches, cerebellar symptoms (ataxia), syringomyelia

2

Arnold-Chiari Type II

Babies: Cerebellar tonsil and vermian heniation through foramen magnum
- Aqueductal stenosis and hydrocephalus
- Thoraco-lumbar myelomeningocele
- paralysis below defect

Symptoms: difficulty swallowing, dysphonia, stridor, apnea

3

Dandy-Walker syndrome

Agenesis of cerebellar vermis with cystic enlargement of 4th ventricle (fills posterior fossa)
- hydrocephalus
- Spina bifida

Symptoms: postural instability, gait problems

4

Meissner's corpuscles

Large, myelinated fibers (adapt quickly)
Seen in glabrous (hairless) skin

Dynamic, fine/light touch; position sense

5

Pacinian corpuscles

Large, myelinated A-beta fibers
- Deep skin layers, ligaments, joints

Rapid vibration, pressure sense

6

Merkel's discs

Large, myelinated fibers; adapt slowly
- Hair follicles

Pressure, deep static touch (shapes, edges), position sense

7

Endoneurium

Invests single nerve fibers
- Guillain-Barre= inflammation of endoneurium

8

Perineurium

Surrounds fasicle of nerve fibers
- Permeability layer
- Rejoined in microsurgery for limb reattachment

9

Epineurium

Surrounds entire nerve (dense connective tissue)

10

Golgi Tendon Organ

Sensory receptor at muscle-tendon junction
- in SERIES with extrafusal muscle fibers
- Ib innervation--> inhibitory
GTO activated with excess contraction---> relaxation

11

Intrafusal muscle spindles

Ia and II innervation
- Sensitive to stretch (stops excess stretch force)

12

Locus Ceruleus

Site of NE formation
- SAM required to transform NE to epi

NE= tyrosine derived (like DA, epi)

13

Dopamine

Tyrosine-derived neurotransmitters
- Found in Ventral tegmentum, SNc (substantia nigra pars compacta)

14

5-HT (serotonin)

Tryptophan--> BH4 (pyridoxine= B6)--> 5-hydroxytryptamine--> serotonin
- found in Raphe nucleus (pons)

15

Basal nucleus of Meynert

ACh synthesis
- Decreased in Alzheimer's, Huntington's
- Increased in REM sleep

16

Metencephalon

Pons and cerebellum
+ Upper part of 4th ventricle

Part of Hindbrain (Rhombencephalon)

17

Myelencephalon

Medulla
+ Lower part of 4th ventricle

Part of Hindbrain (Rhombencephalon)

18

Diencephalon

Thalamus + Third ventricle

19

Mesencephalon

Midbrain + aqueduct

20

Nucleus accumbens

Site of GABA synthesis
- Glutamate converted to GABA by glutamate decarboxylase

*Decreased synthesis in anxiety, Huntington's

GABA receptor types:
- GABA(A)= Cl- influx in brain (ion channel)
- GABA(B)= K+ efflux, decreased Ca+2 influx inhibit adenylyl cyclase (G-protein)
- GABA(C)= Cl- influx in retina

*Decreased GABA(A) in long term EtOH/benzo use--> withdrawal seizures

21

Cross BBB

Glucose and AA by carrier-mediated transport (slow)

Non-polar/lipid-soluble cross rapidly

Specialized areas with fenetrated capillaries:
- Area postrema (vomiting post-chemo)
- OVLT (osmotic sensing
- Neurosecretory products (neurohypophysis--> ADH)
- Hypothalamic inputs/outputs

22

Hypothalamus areas

Lateral: regulates hunger
- Inhibited by leptin
- Destruction--> anorexia

Ventromedial: regulates satiety
- Stimulated by leptin
- Destruction (craniopharyngioma)--> hyerphagia

Anterior: cooling, parasympathetic

Posterior: Heating, sympathetic

Suprachiasmatic nucleus: circadian rhythm

**Posterior pituitary (neurohypophysis) recieves axonal projections from supraoptic nuclei (ADH) and paraventricular nuclei (oxytocin)

** Anterior pituitary (adenohypophysis) recieves stimulation from hypothalamus:
- DA--> inhibits Prolactin
- GHRH--> GH release
- LHRH--> LH release, FSH release
- CRH---> ACTH release
- TRH--> TSH release

23

Thalamus

VPL: Pain, temp, pressure, touch, vibration, proprioception

VPM: Face sensation and taste (Makeup on the face)

LGN: Vision

MGN: Hearing

VL: motor

Thalamus strok= post-stroke pain (burning/stabbing sensation)

24

Cerebellar peduncles

Input= climbing, mossy fibers
- Inferior: ipsilateral proprioceptive info
- Middle: Contralateral cortex

Output= Purkinje fibers
- Superior: Deep nuclei to contralateral cortex

* Deep nuclei (lat--> med): Dentate, Emboliform, Globose, Fastigial (Don't Eat Greasy Foods)

25

Mesolimbic pathway

Dopaminergic pathway
Midbrain VTA--> Limbic nucleus accumbens

*Stimulation--> delusions, hallucinations, pleasure (Pathway to addiction)

*D3, D4 receptors, inhibited by atypical antipsychotics

26

Mesocortical pathway

Dopaminergic pathway

Midbrain VTA--> limbic cortex (dorsolateral prefrontal)

* Cortex= cognition; defects--> negative symptoms of psychosis

*D3, D4 receptors, inhibited by atypical antipsychotics

27

Nigrostriatal pathway

Dopaminergic pathway

Substantia nigra--> basal ganglia (striatum)

*Movement pathway ("nigrostride"); damage--> Parkinson's

28

Tubuloinfunibular pathway

Dopaminergic pathway

Arcuate nucleus (hypothalamus)--> anterior pituitary

* Inhibit DA--> increased prolactin productions

29

Basal ganglia nuclei

Striatum:
- Putamen (motor) and caudate (cognitive)

Lentiform:
- Putamen and globus pallidus

30

Hemiballismus

Contralateral subthalamic nucleus
- Lacunar stroke

Sudden, wild flailing of 1 arm +/- ipsilateral leg