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Histology > Nucleus > Flashcards

Nucleus Flashcards

Understand structure of nucleus and its role in cell cycle/death

1
Q

What is the arrangement of centrioles?

A

9 sets of MTs arranged in triplets

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2
Q

How many centrioles in a centrosome?

A

2 centrioles

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3
Q

Function and clinical significance of primary cilia

A

act as receptors

ciliopathies stem from defects

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4
Q

What proteins cross-links actin filaments in the cytoplasm?

A

Filamen & also spectrin acid

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5
Q

What proteins cross-link actin filaments w/i microvilli?

A

Fimbrin & fascin

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6
Q

What sites are IM filaments anchored to on PM?

A

Desmosomes & hemidesmosomes

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7
Q

What tissue types are IM filaments abundant in & what are their functions there?

A

epithelial cells of skin (form tough outer layer thru packing together) & neurons (anchor membrane ion channel proteins via the link protein ankyrin)

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8
Q

Describe aggresomal response

A

in damaged cells, IM filament network collapses around abnromal/damaged cell proteins to facilitate proteolysis/autophagy; will then re-expand

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9
Q

Give clinical examples of aggresomal response

A
  1. Liver cells: xs alc –> accumulation of collapsed cytokeratin IM bundles (Mallory’s hyaline)
  2. Parkinson’s: accumulation of Lewy bodies in neurons of brain
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10
Q

Match specific IM to its localization:

  1. cytokeratins
  2. vimentin
  3. desmin
  4. glial fibrillary acidic proteins
  5. neurofilaments
  6. nuclear lamin
A
  1. epithelial cells
  2. mesenchymal, lymphocyte, & phagocyte cells
  3. muscle (both types)
  4. asctrocytic glial cells
  5. neurons
  6. nucleus of all cells
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11
Q
  1. defects in org of MT & dynein
  2. immobilization of cilia in resp epithelium
  3. resp dysfunction
  4. defects in sperm motility & male sterility
  5. female sterility due to impaired ovum transport from overy to uterine cavity
  6. autosomal recessive
  7. caused by mutations in DYNEIN gene
A

Kartagener’s syndrome (aka immotile cilia syndrome)

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12
Q

Name this drug:

  1. binds tubulin & prevents polymerization
  2. treats gout attacks
  3. prevents neutrophil migration so they can’t respond to urate crystal deposits in tissues
  4. inhibits mitosis
A

Colchicine

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13
Q

Which cytoskeletal filament plays a crucial role in endo/exocytosis?

A

Microtubules

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14
Q

Name these 2 drugs:

  1. bind MTs and inhibit formation of mitotic spindle
  2. antiproliferative agents in cancer therapy
A

Vinblastine & vincristine

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15
Q

Name that drug:

  1. chemotherapy for breast cancer
  2. prevents depolymerization of MTs by stabilizing them
  3. arrests cancer cells during cell division
A

Paclitaxel

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16
Q

Function of cytochalasin B & D?

A

prevent actin polymerization by binding to + end of actin filament –> inhibition of lymphocyte migration, phagocytosis, & cell division –> apoptosis

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17
Q

Function of phalloidin toxin?

A

stabilize & prevent depolymerization of actin filaments –> disruption of dynamic equilibrium

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18
Q

Which filament is assoc w/ Alzheimer’s?

A

IM filaments; production of neurofibrillary tangles of neurofilaments

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19
Q
  1. Mutations of GFAP gene
  2. presence of Rosenthal fibers in astrocytes
  3. inhibit astrocyte mitosis & division
  4. leukoencephalopathy (brain infection)
  5. macrocephaly (large head)
  6. seizures
  7. psychomotor impairment
  8. death in 1st decade of life
A

Alexander disease

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20
Q

T/F, the nuclear envelope is permeable to most proteins & ions

A

False, impermeable to ions/proteins of all sizes; pathways provided by nuclear pores

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21
Q

Which is more electron-dense: euchromatin or heterochromatin?

A

Heterochromatin

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22
Q

Describe appearance of heterochromatin & euchromatin in EM & LM

A

Heterochromatin: electron-dense, coarse clumps in EM; basophilic clumps in LM
Euchromatin: seen as finely dispersed granular material b/c it is a site of active transcription

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23
Q

Where in the nucleus are rRNA & protein in abundance?

A

Nucleolus

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24
Q

3 components of nucleolus seen by EM?

A
  1. Nucleolar organizer DNA
  2. Pars fibrosa
  3. Pars granulosa
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25
Q

What is Nucleolar organizer DNA?

A

(base seq’s coding for rRNA)

26
Q

What is Pars fibrosa?

A

(densely packed ribonucleoprotein fibers, primary transcripts of rRNA genes)

27
Q

What is Pars granulosa?

A

(15-20nm granules rep’ing maturing ribosomes)

28
Q

What stain is used for visualizing heterochromatin under LM & where is it predominantly found?

A

Feulgen stains; periphery of nucleus

29
Q

T/F, euchromatin is visible w/ LM?

A

False

30
Q

What happens in G1?

A

Cells accumulate enzymes & nucleotides req’d for DNA replication

31
Q

What happens in S?

A

DNA replication

32
Q

What happens in G2?

A

Short prep pd for mitosis

33
Q

What are the 3 major checkpoints of the cell cycle?

A
  1. start/restriction checkpoint just before start of S
  2. G2/M checkpoint to ensure completion of DNA replication
  3. metaphase spindle checkpoint ensures all chromo’s are segregated
34
Q

What category of cells are CNS, skeletal, & cardiac cells?

A

static cells

35
Q

What category of cells are periosteal/perichondrial, smooth mm, blood vessel endothelial, & connective tissue fibroblast cells?

A

Stable cells, divide rarely & slowly

36
Q

What category of cells are smooth mm of hollow organ, fibroblast of uterine wall, & lens epithelial cells?

A

Slowly renewing cells

37
Q

Category of blood, epithelial, dermal fibroblast, & epithelial/subepithelial cells of alimentary tract musocal lining?

A

Rapidly renewing cells

38
Q

Type of cell death w/o rupture of PM or immune activation?

A

Apoptosis

39
Q

Type of cell death that is accidental & caused by pathologic mechanism?

A

Necrosis

40
Q

Similarities/differences in histo presentation of apoptosis vs. necrosis

A

Apoptosis: caspase-induced; compact (pyknotic nuclei) –> nuclear fragmentation (karyorrhexis); blebs @ cell periphery; cytoplasm –> condensed & stains darker; cell fragmentation
Necrosis: swollen cells; bleb formation; cell contents free in extracell space; pyknotic nuceli –> lysis (karyolysis); phagocytosis of remnants
Similarities:
pyknotic nuclei; bleb formation

41
Q

Regulated cell process that uses autophagosome to induce self-degradation & lysis?

A

Autophagy

42
Q

Cell death mediated by mitogen-activated protein kinases (MAPKs), recognized by formation of multiple large vacuoles & swollen mitochond

A

Paraptosis

43
Q

Cell death dep on caspase-1 & inflammatory cytokines (IL-1/18)

A

Pyroptosis

44
Q

Characteristics of nucleoli in malignant cells?

A
  1. nucleoli more prominent
  2. larger than normal
  3. mutliple
  4. perinuclear cap – distinct area around nuceolus
45
Q

Diseases characterized by presence of nuclear inclusions (abnormal proteins in nucleus)

A

Huntington’s disease

Frontotemporal dementia

46
Q

Method used to detect changes in chromo # & chromo abnormalities?

A

Cytogenetic testing

47
Q

Key gene mutations in cell cycle regulation & roles (4)

A

BRCA-1 & BRCA-2 (tumor suppressors); RAD-51 (homologous recombo/DNA repair); p53 (triggers apoptosis)

48
Q

Where are + and - ends of MTs located?

A

+ end = periphery

- end = MTOC (nucleus)

49
Q

Whet tissue contains the IM filament desmin?

A

Cardiac mm

50
Q

What tubule are dynein arms always attached to?

A

Tubule A

51
Q

Is the Nissl substance (neuronal RER) located w/i or outside nucleus?

A

Outside, in cytoplasm

52
Q

What end of microfilament does F-actin bind to along w/ ATP?

A

+ end

53
Q

What is a major symptom of phalloidin poisoning?

A

Acute hunger due to destruction of liver cells (necrosis)

54
Q

Name this disease:

1) a genetically determined hemolytic anemia chracterized by spherical shaped RBCs
2) deficiency of spectrin, ankyrin, or band 3 protein

A

Hereditary spherocytosis

55
Q

What Cyclin-CDK pair allows G1 –> S?

A

Cyclin E-Cdk2

56
Q

What Cyclin-CDK pair allows G2 –> M?

A

Cyclin A-Cdk1

57
Q

Role & location of progenitor cells?

A
  • similar to stem cells except pushed to differentiate into their designated target cells
  • located in tissue lining of small intestine
58
Q

What organelle is well-dvp’d in large neurons active in protein synth?

A

Nucleolus

59
Q

What is a Nissl body?

A
  • granules of RER w/ rosettes of free ribosomes

- site of protein synht

60
Q

What is a Barr body?

A

Inactive X chromosome

61
Q

Major feature of Aprt syndrome?

A

Webbing/fusion of digits

62
Q

Cause of Apert syndrome?

A

Failure of DNA degradation by endonucleases

Histology (7 decks)

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