Cell Growth and Adaptation Flashcards

1
Q

What are the classifications of cell growth and adaptation?

A
  • Congenital
    • Aplasia
    • Hypoplasia
  • Acquired
    • Hyperplasia
    • Hypertrophy
    • Atrophy
    • Metaplasia
  • Abnormal
    • Anaplasia
    • Dysplasia
    • Neoplasia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do cells grow and adapt?

A
  • Cells confront changes throughout lifespan
    • Dynamic changes during development
      • embryogenesis and postnatally
    • Increased need for function
      • high metabolic activity
    • Decreased need for function
      • aging
  • Often occurs in the best interest of the animal
    • maintain homeostasis based on current need/demands
  • Sometimes detrimental
    • responding to abnormal or adverse stimuli
    • Cells don’t grow or develop sufficiently
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What factors influence cell growth and adaptation?

A
  • Cell microenvironment
  • Physical / mechanical stressors on tissues and organs
  • Genetic alterations of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the cell microenvionment?

A
  • Growth factors and other cytokines
  • Properties of the extracellular matrix
  • Abnormal or inappropriate cell stimuli
  • Nutrients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Aplasia?

A
  • Cells do NOT grow
  • Characterized by absence or partial absence of a tissue / organ
  • Results in congenital morphologic abnormalities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is hypoplasia?

A
  • Decreased cell growth
  • A developmental problem leading to incomplete or partial formation of a tissue/organ
  • Results in congenital morphologic abnormalities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is hyperplasia?

A
  • An increase in the number of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Physiological hyperplasia?

A
  • Cells increase in number to fulfill their functional responsibilities
  • Ex:
    • Endometrial hyperplasia during pregnancy
    • Fibroblast hyperplasia during healing
    • Mammary glandular hyperplasia during lactation
    • Gastrointestinal epithelial hyperplasia to replace excessive mucosal loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Pathological Hyperplasia?

A
  • Increased cell numbers and activity are detrimental to the animal
  • Ex:
    • Excessive fibroblast proliferation during healing (exuberant granulation tissue)
    • Bone loss secondary to parathyroid hyperplasia (see picture)
    • Thyroid hyperplasia causing tracheal compression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is hypertrophy?

A

an increase in the size of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is physiological hypertrophy?

A
  • Cells increase in size to fulfill their functional responsibilities
  • Ex:
    • Uterine smooth muscle during pregnancy
    • Cardiac myocytes during training
    • Skeletal muscle due to increased demands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is pathological hypertrophy?

A
  • Many of the same stimuli that cause physiological hypertrophy become pathologic if they are excessive or inappropriate
  • Ex:
    • Cardiac myocyte hypertrophy in a failing heart
    • Small intestinal muscular hypertrophy causing intestinal stenosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is primary hypertrophy?

A
  • Hypertrophy as a primary change is restricted to muscle cells
    • Myocytes respond to increased demand by increasing in size, not number
    • Myocytes are post-mitotic cells that do NOT undergo replication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Can Hyperplasia and Hypertrophy occur concurrently?

A
  • Yes
  • Increased demand for function by most cell types is met by both increased size and increased number of cells
    • Epithelial Cells:
      • Endocrine - parathyroid
      • Mucosa - Intestinal crypts
      • Parenchyma - Prostate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is atrophy?

A
  • Decrease in size and/or number of cells
    • In most cases both size and number of cell decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is physiological atrophy

A
  • Occurs in response to a decreased demand for function of the cell
  • Ex:
    • Endometrial and myometrial atrophy following parturition
    • Mammary glandular atrophy at the end of lactation
    • Myocyte atrophy due to decreased activity or training
17
Q

What is pathological atrophy?

A
  • Inappropriate loss of stimuli or inhibitory stimuli result in atrophy
  • Ex:
    • Skeletal muscle atrophy following denervation
    • Bone loss due to mineral imbalance, such as occurs with renal failure
    • Loss of stimulation of endocrine tissues
18
Q

What is metaplasia?

A
  • Cell adaptation
  • Replacement of one mature cell type with another mature cell type
19
Q

What is physiological metaplasia?

A
  • Often a response to irritation or an adverse environment
  • Cells often return to previous type if the cause is removed
  • Ex:
    • Squamous metaplasia of airway mucosa due to poor air quality/Chronic irritation
    • Squamous metaplasia of salivary and esophageal ducts/glands due to Vit A deficiency
20
Q

What is Pathological Metaplasia?

A
  • Metaplasia often contributes to pathologic change
    • Decreased pulmonary defense
    • Decreased glandular secretions
    • Osseous changes in various tissues (See picture)
21
Q

What is cellular dysplasia?

A
  • Abnormal cell morphology and growth
    • Size, shape, and appearance of cells is different than normal cells
    • Also typically increased in number
    • Larger nuclei, more organelles, more rapid mitosis
  • Causes include chronic irritation or infection
  • May represent a pre-neoplastic change
22
Q

What is tissue/organ dysplasia?

A
  • Term sometimes used as a reference to congenital or acquired gross abnormalities characterized by abnormal tissue or organ morphology
  • Ex:
    • Chondrodysplasia
    • Retinal dysplasia
    • Hip dysplasia
23
Q

What is anaplasia?

A
  • Cells are poorly differentiated
    • Lack morphologic features of the cell they were derived from
    • Nuclei and other cell structures often have abnormal morphology
  • Common morphologic feature of neoplastic cells
    • Provides a morphologic criteria for predicting biological behavior of the neoplasm
      • High degrees of anaplasia are usually associated with poorer prognosis
24
Q

What is neoplasia?

A
  • “New growth” of genetically abnormal cells
  • Cell morphology can range from normal, to dysplasia, to anaplasia
  • Histologic, gross, and biological properties of neoplasms (“tumors”) vary widely