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MC - Neurologia, Neurocirurgia e Neurociência > HISTOLOGY > Flashcards

HISTOLOGY Flashcards

1
Q

NEURONS

classification

A

FORM + NUMBER OF THEIR PROCESSES

bipolar

unipolar

multipolar

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2
Q

NEURONS

Nissl substance

A

Clumps or rough ER (endoplasmatic reticulum) with bound polysomes

sites of protein synthesis

(also are free polusomes in cytoplasm)

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3
Q

NEURONS

Cytoplasmic Inclusions in CNS disease

(2)

A

LEWY BODIES

  • in degenerating neurons
  • Parkinson’s - pars compact of the substantia nigra
  • Dementia - cortical and brain-stem neurons

NEGRI BODIES

  • eosinophilic in degenerating neurons
  • Rabies - hippocampus and cerebellar cortex
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4
Q

NEURONS

Cytoskeleton

A

NEUROFILAMENTS

+

MICROFILAMENTS

+
MICROTUBULES

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5
Q

NEURONS

Neurofilaments

(where and why)

A

Most numerous in the axon and dendrites (proximal part)

+
structural support

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6
Q

NEURONS

Microfilaments

(where and why)

A

form matrix near the periphery of neuron

+

growth cones (add motility)

and

dendrites (specializations at synaptic membranes)

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7
Q

NEURONS

Microtubules

(where and why)

A

In ALL parts of the neuron

+
axonal transport

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8
Q

NEURONS

NEUROFIBRILLARY TANGLES

(Cytoskeleton)

A

DEGENERATIVE NEURONAL DISEASES

(Alzheimer’s, Amyotrophic Lateral Sclerosis, Down Syndrome)

tau protein becomes more phosphorylated and microtubules form helical filaments

(also senile plaques are formed in dendrites e in the cell body)

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9
Q

NEURONS

Dendrites

A

may contain spines

+

provide major surface for synaptic contacts

\+
highly branched (the pattern is used to define cell type)
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10
Q

NEURONS

Axon

(diameter, collateralls and proximal part)

A

uniform diameter

+

may branch at right angles into collaterals (90º)

+

proximal part is marked by axon hilllock

(lacks of Nissl substance)

+

trigger zone

(sodium ion channels)

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11
Q

NEURONS

Axon

(myelin sheath)

A

CNS

Oligodendrocyte can myelinate individual segments of many axons

PNS

Schwann cells (each one can myelinate only single internodal segment of a single axon) - also phagocyte debris after PNS injury

(node of Ranvier - saltatory conduction)

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12
Q

NEURONS

Axon

(cytoplasm)

A

Entire axon lacks

polysomes

+

Nissl substance

+

Golgi apparatus

(only contains mitochondria and smooth ER)

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13
Q

NEURONS

Anterograde axonal transport

(fast and slow)

A

cell body → synaptic terminal

  1. fast (100-400 mm/day) transport is dependent on kinesin (motor molecule) - deliver precursors of peptide NT
  2. slow transport (1-2 mm/day) is the movement of soluble cytoplasmic components (isn’t dependent of ATP or microtubules) - cytoskelon proteins, enzymes and precursos of small NT
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14
Q

NEURONS

Retrograde axonal transport

A

synaptic terminal → cell body

(material returns to recycle or be digested)

(trophic factors go to cell body)

  • microtubules
  • slower than anterograde (60-100 mm/day)
  • dynein (ATPase) - dependent
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15
Q

NEUROPATHIES AND AXONAL TRANSPORT

DIABETES

A

hyperglicemia → alterations in proteins of microtubules → disrupt axonal transport

long axons

glove-and-stocking pattern

(altered sensation and pain)

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16
Q

NEUROPATHIES AND AXONAL TRANSPORT

Other causes

A
  • Anoxia (mitochondria) and anticancer agents (depolymerize microtubules) - disrupt fast anterograde transport
  • Polio, herpes, rabies and tetanus (only the toxins) - disrupt retrograde transporte of SKELETAL MUSCLE
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17
Q

GLIAL CELLS

general statements

(synapses, proliferation and process)

A

do not form chemical synapses

+

readily divide and proliferate

(glioma is the most commom type of primary tumor of the CNS)

+

have only one kind of process

18
Q

GLIAL CELLS

ASTROCYTES

(most numerous glial cells)

4 functions

A

SRBS

  • structural support - intermediate filaments (GFAP - glial fibrillary acidic protein)
  • remove the NT glutamate and K+ from extracellular space
  • foot processes form glial-limiting membrane- blood-brain barrier
  • hypertrophy and proliferate after injury - astroglial scar
19
Q

GLIAL CELLS

RADIAL GLIA

(function)

A

precursors of astrocytes

+

guide neuroblast migration during CNS development

20
Q

GLIAL CELLS

MICROGLIA

(smallest glial cells)

link between cells of CNS and immune system

A
  • derived from bone marrow monocytes (enter the CNS after birth)
  • phagocytose neuronal debris (during CNS injury) - secrate toxic free radicals (eg. superoxide)
  • diferenciated in pericytes - blood-brain barrier
  • determine the chances of survival of a CNS tissue graft

(also are the cells targeted by HIV-1 virus)

21
Q

GLIAL CELLS

EPENDYMAL CELLS

A

line the ventricles in the adult brain

(some cells differentiate into choroid epithelial cells)

+

produce cerebrospinal fluid (CSF)

+

ciliary action helps circulate CSF

22
Q

GLIAL CELLS

TANYCYTES

A

specialized ependymal cells

+
basal cytoplasmic processes in contact with blood vessels

+
transport substances

(blood - ventricle)

23
Q

DISORDERS OF MYELINATION

(leukodystrophies)

MULTIPLE SCLEROSIS (MS)

(SCRIPTS)

A
  • S: vision loss (optic neuritis) + internuclear ophthalmoplegia (MLF) + motor and sensory deficits + vertigo + neuropsychiatric
  • C: symptoms separated in space and time + relapsing-remitting course
  • R: 2:1 woman + 30-40 aged + temperate zones (high prevalence)
  • I: demyelinated plaques (often in periventricular areas), IgG (oligoclonal bands) in CSF, chronic inflamatory-axons initially preserved
  • T: high-dose steroids, interferon-beta, glatiramer
24
Q

DISORDERS OF MYELINATION

(leukodystrophies)

METACHROMATIC LEUKODYSTROPHY

(MLD)

SCRIPT

A
  • S: motor and cognitive issues with seizures - four types
  • I: arylsulfatase A deficiency in lisosomes

(both CNS and PNS)

25
Q

DISORDERS OF MYELINATION

(leukodystrophies)

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY

(PML)

SCRIPTS

A
  • S: limb weakness, speech problems
  • R: JC virus (John Cunningham), affect immunocompromised (AIDS)
  • I: cortical myelin affected - demyelination, astrogliosis, lymphohistiocytosis
26
Q

DISORDERS OF MYELINATION

(leukodystrophies)

CENTRAL PONTINE MYELINOLYSIS

(CPM)

SCRIPTS

A
  • S: pseudobulbar palsy + spastic quadriparesis + mental changes + locked-in syndrome
  • R: severely malnourished + alcoholics + liver disease
  • I: focal demyelination of central area of basis pontis (corticospinal and corticobulbar tracts) + probably caused by overly aggresive correction of hyponatremia
27
Q

DISORDERS OF MYELINATION

(leukodystrophies)

GUILLAIN-BARRÉ

SCRIPTS

A
  • S: weakness first in lower limbs and ascends, respiratory failure can occur, autonomic dysfunction, cranial nerve involviment and decrease reflexes

(sensory loss, pain and paresthesias rarely occur)

  • C: 2/3 of patients have history of respirtatory or GI illness 1-3 weaks prior
  • I: CSF protein elevate + normal cell count
28
Q

BLOOD-BRAIN BARRIER

functions

A

restricts access of

  1. micro-organisms
  2. proteins
  3. cell
  4. drugs
29
Q

BLOOD-BRAIN BARRIER

structures

A
  • capillary endothelial cells (intercellular tight junctions)
  • underlying basal lamina
  • astrocytes - “end feet” cover > 95% of the basal lamina
  • pericytes
30
Q

BLOOD-BRAIN BARRIER

transport

A

diffusion (O2, CO2, heroin, ethanol and nicotine)

seletive transport (glucose, aminoacids, vit K and vit D)

ion channels (Na+ and K+)

31
Q

LESIONS

response of axons to a destructive or irritative lesions

A
32
Q

TUMORS

half of brain and spinal cord tumors are metastatic

TRUE or FALSE?

A

TRUE

33
Q

TUMORS

GLIOBLASTOMA MULTIFORME

(astrocytoma grade IV)

features + pathology

A
34
Q

TUMORS

ASTROCYTOMA

(pilocytic)

features + pathology

A
35
Q

TUMORS

OLIGODENDROGLIOMA

features + pathology

A
36
Q

TUMORS

EPENDYMOMA

features + pathology

A
37
Q

TUMORS

MEDULLOBLASTOMA

features + pathology

A
38
Q

TUMORS

MENINGIOMA

features + pathology

A
39
Q

TUMORS

SCHWANNOMA

features + pathology

A
40
Q

TUMORS

RETINOBLASTOMA

features + pathology

A
41
Q

TUMORS

CRANIOPHARYNGIOMA

features + pathology

A

MC - Neurologia, Neurocirurgia e Neurociência (13 decks)

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