Ch3:Tissue Renewal, Regeneration, and Repair Flashcards Preview

Pathology > Ch3:Tissue Renewal, Regeneration, and Repair > Flashcards

Flashcards in Ch3:Tissue Renewal, Regeneration, and Repair Deck (102)
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1
Q

Two parts of tissue renewal?

A
  1. Regeneration

2. Repair

2
Q

What is regeneration?

A

Complete restitution of lost or damage tissue through proliferation of cells and tissues

3
Q

What is the requirement for regeneration to occur?

A

Stem cells of tissues are not destroyed

4
Q

What is repair?

A

Restoration of original structures but can be structurally deranged.

5
Q

What does repair consist of?

A

Combination of regeneration and scar formation by the deposition of collagen

6
Q

What is the predominant healing process that occurs when the extracellular matrix framework is damaged?

A

Scar formation

7
Q

What is fibrosis?

A

Extensive deposition of collagen

8
Q

Damage to the matrix (parenchymal stem cell matrix) results in what? 2

A
  1. Fibrosis

2. Scar formation

9
Q

The size of cell population is determined by what? (3)

A

Rates of:

  1. Cell proliferation
  2. Cell differentiation
  3. Death by apoptosis
10
Q

Cells incapable of replication are known as what?

A

Terminally differentiated cells

11
Q

Proliferation of cells can be stimulated by what two types of conditions?

A
  1. Physiologic

2. Pathogenic

12
Q

What is epithelium?

A

A covering

13
Q

What is mucosa?

A

Epithelium that absorbs and is moist

14
Q

What are continuously dividing tissues called?

A

Labile

15
Q

Examples of continuously dividing cells? 3

A
  1. Epithelium/Mucosa
  2. Hematopoietic cells
  3. Mature cells derived from adult stem cells
16
Q

What are quiescent tissues called?

A

Stable tissues

17
Q

Level of replication in quiescent?

When can it speed up?

A

Low

In response to stimuli

18
Q

Examples of quiescent cells? 3

A
  1. Parenchymal cells of liver, kidney, pancreas
  2. Mesenchymal cells
  3. Vascular endothelium
19
Q

Nondividing tissues are known as what?

A

Permanent tissues

20
Q

Examples of permanent tissue? (3)

A
  1. Neural tissue
  2. Skeletal muscle
  3. cardiac muscle
21
Q

What is regenerative medicine?

A

Repairing damaged human tissues through stem cells

22
Q

What makes stem cells so intriguing for repair? 2

A
  1. Self-renewal properties

2. Capacity to generate differentiated cell lineages.

23
Q

How is the replication of stem cells described?

A

Obligatory asymmetric replication

24
Q

What is obligatory asymmetric replication?

A

Each stem cell division, one of the daughter cells retains its self-renewing capacity while the other enters differentiation pathway

25
Q

How is the ratio of stem cells/differentiated cells described?

A

Stochastic differentiation

26
Q

What is stochastic differentiation?

A

Population if maintained by the balance between stem cells divisions that generate either two self-renewing stem cells or two cell that will differentiate

27
Q

Stem cells that can generate all tissues of the body are known as what?

A

Pluripotent

28
Q

Examples of pluripotent cells? 2

A

Embryonic cells

Induced pluripotent stem cells (iPS)

29
Q

Where do adult stem cells reside?

A

Niches

30
Q

What makes up a niche?

A

Mesenchymal, endothelial, and other cell types

31
Q

Niche cells do what?

A

Generate or transmit stimuli that regulate stem cell self-renewal and generationi of progeny cells

32
Q

Embryonic stem cells are found where?

A

Inner cell mass of blastocysts in early embryonic development

33
Q

Research applications of embryonic stem cells? 3

A
  1. Study specific signals and differentiation steps required for a tissue
  2. Production of knockout or knockin mice
  3. Repopulate damaged organs
34
Q

Result of reprogramming differentiated cells?

A

Induced pluripotent stem cells

35
Q

What is reproductive cloning?

A

Transfer of nuclear material into oocyte

36
Q

How effective is therapeutic and reproductive cloning?

Why?

A

Inefficient

Deficiency in histone methylation results in improper gene expression

37
Q

What does the pluripotency of cells in a clone depend on?

A

Expression of four transcription factors known as oncogenes

38
Q

What are transit amplifyin cells?

A

Rapidly dividing cells generated from somatic stem cells

39
Q

What is transdifferentiation?

A

Change in the differentiation of a cell from one type to another

40
Q

What is special about hemopoietic stem cells?

A

Can differentiate into hepatocytes and neurons upon fusion with already differentiated cells of target tissue

41
Q

What is developmental plasticity?

A

Ability of cell to transdifferentiate into diverse lineages

42
Q

How might HSC’s be involved in repair/immune?

A

Migrate to site of inflammation and generate innate immune cells, release GF’s and cyotkines for promoting repair

43
Q

Stem cells in bone marrow include? (2)

A
  1. HSC’s

2. MSC’s

44
Q

What do HSC’s generate in bone marrow?

A

All blood cell lineages

45
Q

What do MSC’s generate in bone marrow?

A

Chondrocytes, osteoblasts, adipocytes, myoblasts, and endothelial cell precursors

46
Q

Stem cells in liver are found where?

Differentiate into what

A

Canals of Hering (oval cells)

Hepatocytes and biliary cells

47
Q

Stem cells in the brain are called what?

A

Neural stem cells

48
Q

Where are stem cells in the skin? 3

A

Hair follicle bulge, interfollicular layers of epidermis, and sebaceous glands

49
Q

Replication of cells in cell cycle is stimulated by what? 92)

A
  1. Growth factors

2. Signaling from ECM components through integrins

50
Q

Components of cell cycle? 4

A
  1. G1 (presynthetic)
  2. S (DNA synthesis)
  3. G2 (premitotic)
  4. M (mitotic phases)
51
Q

When do most controls of cell cycle act?

A

Between G1 and S phase at restriction point

52
Q

Progression in cell cycle regulated by what?

A
  1. Cyclins

2. Cyclin-dependent kinases

53
Q

What do CDK’s do?

A

Bind and form complexes with cyclins

Phosphorylate cell cycle inhibition proteins such as RB

54
Q

How does RB inhibit cell cycle?

A

Forms tight inactive complex with TF E2F

55
Q

What will inhibit CDKs? And when?

A

CDK inhibitors at checkpoints

56
Q

What regulates the CDK inhibitors?

A

Growth factors

57
Q

Senescence or apoptosis is triggered via what?

A

p53-dependent mechanisms

58
Q

Proliferation of cells is driven mainly by what?

A

Growth factors

59
Q

What effects can growth factors have? 4

A
  1. Promote survival
  2. Affect locomotion, contractility
  3. Affect cellular differentiation
  4. Promote angiogenesis
60
Q

How do growth factors act?

A

Ligands that stimulate transcription of genes

61
Q

Epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha) share what?

A

Common receptor (EGFR) family of four membrane receptors with intrinsic tyrosine kinase activity

62
Q

EGFR1 mutations/amplification result in what?

A

Cancers of lung, head, neck, breast, glioblastomas, and others

63
Q

ERB B2 receptor is overexpressed in what?

A

Breast cancer

64
Q

Hepatocyte growth factor (HGF) has what receptor?

A

c-MET

65
Q

c-MET is highly expressed or mutated in what

A

Tumors of renal and thyroid papillae

66
Q

HGF is identical to what?

A

Scatter factor for fibroblast

67
Q

Is HGF important?

A

Required for survival during embryonic development

68
Q

Platelet derived growth factor binds to what?

A

PDGFR alpha and Beta

69
Q

Where is PDGF stored?

When is it released?

A

Platelet granules

Upon platelet activation

70
Q

Effect of PDGF?

A

Migration and proliferation of fibroblasts, smooth muscle cells, and monocytes to areas of inflammation and healing of skin wounds

71
Q

How many forms of VEGF are there?

A

5

72
Q

Effect of VEGF? 2

A

Vasculogenesis and angiogenesis in chronic inflammation, healing of wounds, and in tumors

73
Q

Fibroblast growth factor includes how many members?

A

20

74
Q

What is FGF-7 known as?

A

Keratinocyte growth factor?

75
Q

What FGF works in wound repair? (2)

A

FGF-2 and KGF re-epithelialize skin wounds

76
Q

What FGF works in angiogenesis?

A

FGF-2

77
Q

What are four main functions of FGF?

A

Wound repair
angiogenesis
Hematopoiesis
Development of muscle and lung

78
Q

What is a growth inhibitor for most epithelial cells?

A

TGF-Beta

79
Q

TGF-Beta is what type of agent?

Pathologically involved in what?

A

Potent fibrogenic agent

Fibrosis in chronic inflammatory conditions and hypertrophic scars

80
Q

Is TGF-beta involved in immune response?

A

Strong anti-inflammatory BUT might enhance some immune functions

81
Q

What is autocrine signaling?

A

Cells respond to molecule that they themselves secrete

82
Q

Examples of autocrine signaling? 2

A

Liver generation

Tumors

83
Q

What is paracrine signaling?

A

One cell type produces the ligand which in turn acts on adjacent cells

84
Q

Example of paracrine signaling?

A

CT repair and wound healing

85
Q

What is endocrine signaling?

A

Hormones synthesized by cells of endocrine organs act on target cells distant from site of synthesis

86
Q

Main receptor types? (4)

A
  1. Tyrosine kinase activity receptors
  2. Receptors that recruit kinases
  3. G-protein-coupled receptors
  4. Steroid hormone receptors
87
Q

Example of receptors with intrinsic tyrosine kinase?

A
  1. Growth factors
88
Q

Ligand binding in tyrosine kinase receptors causes what? (3)

A
  1. Dimerization of receptor
  2. Tyrosine phosphorylation
  3. Activation of receptor tyrosine kinase
89
Q

Example of receptors that recruit kinases?

A

Cytokine

90
Q

Cytokine receptors transmit signals to nucleus by what?

A

JAK/STAT pathway

91
Q

G-coupled protein receptors are used by what?

A

Endocrine ligands

92
Q

How do g-coupled protein receptors transmit signals?

A

Trimeric GTP-binding proteins

93
Q

What is the largest family of plasma membrane receptors?

A

G-protein coupled receptors

94
Q

Defects in G-coupled receptors result in what?

A

Retinitis pigmentosa, corticotropin deficiencies, and hyperparathyroidism

95
Q

Steroid hormone receptors are found where?

A

Nucleus

96
Q

Ligands that bind to steroid hormone receptors include what? (3)

A
  1. Thyroid hormone
  2. Vitamin D
  3. Retinoids
97
Q

What is one special branch of steroid hormone receptors?

And they are involved in what?

A

Peroxisome proliferator-activated receptors

Adipogenesis, inflammation, and atherosclerosis

98
Q

Transcription factors do what mainly?

A

Modulate gene activity

99
Q

Growth promoting genes include? (2)

A

c-MYC

c-JUN

100
Q

Cell cycle-inhibiting gene?

A

p53

101
Q

Why can’t mammals regenerate limbs or organs?

A

Absence of blastema formation

102
Q

What is similar to regeneration that mammals can do?

A

Compensatory hyperplasia