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
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
- Dynamic changes during development
- 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
3
Q
What factors influence cell growth and adaptation?
A
- Cell microenvironment
- Physical / mechanical stressors on tissues and organs
- Genetic alterations of cells
4
Q
What is the cell microenvionment?
A
- Growth factors and other cytokines
- Properties of the extracellular matrix
- Abnormal or inappropriate cell stimuli
- Nutrients
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
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
7
Q
What is hyperplasia?
A
- An increase in the number of cells
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
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
10
Q
What is hypertrophy?
A
an increase in the size of the cell
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
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
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
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
- Epithelial Cells:
15
Q
What is atrophy?
A
-
Decrease in size and/or number of cells
- In most cases both size and number of cell decreases
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
- Provides a morphologic criteria for predicting biological behavior of the neoplasm
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
