Pathology - Cell Adaptations Flashcards
Define “Atrophy”
Decrease in size of cells. (May have a decrease in number and in metabolic activity as well)
It is a decrease in protein synthesis and an increase in protein degradation within cells.
Define “Hypertrophy”
Increase in size of cells, but no increase in numbers.
More common in cells with little to no replication; ex. cardiomyocytes, neurons, muscle cells, etc
Define “Hyperplasia”
Increase in number of cells. (May have an increase in size as well). Occurs in cells capable of replication.
Define “Metaplasia”
Change in phenotype (i.e. from cuboidal to squamous cells). The first step of changes possibly leading to dysplasia.
Define “Dysplasia”
Precursor to cells undergoing neoplastic change. Refers to abnormal development.
What is the reason or cause of cell adaptation?
It occurs when a cell’s homeostasis is disturbed by stress or a pathologic stimulus.
Describe how some cell adaptations can be reversible.
Cells can undergo morphological changes under stress, but the cell is not dead, it is morphologically different, but can go back to normal after the stress stimulus is removed.
What are a few causes of Atrophy?
- Decreased workload (arm in cast)
- Denervation
- Decreased blood supply or oxygen supply (tumor)
- Inadequate nutrition
- Loss of endocrine stimulation
- Aging (sedentary)
Describe “Serous Atrophy of Fat” and where you might expect to see this?
Serous atrophy of fat can be seen in the Bone Marrow and in the Heart. It is a lack of fat reserve in these areas, and since these are the last areas an animal will lose fat you will only see it in animals suffering/deceased from starvation.
What might cause Atrophy of the brain?
Hydrocephalus; compression due to build up of fluid.
What are a few examples of “Physiologic Hypertrophy”?
- Hypertrophic uterus during pregnancy
2. Muscle hypertrophy after weightlifting
What is the primary example of “Pathologic Hypertrophy” given in lecture?
Cardiac Hypertrophy from Hypertension or Aortic Valve disease.
Describe the difference between “Concentric Hypertrophy” and “Eccentric Hypertrophy”.
Concentric means the swelling is moving from the outside toward the center. This leads to ticker walls and smaller chambers.
Eccentric means the swelling is from the center and pushing out on the periphery. This leads to thinner walls and larger chambers.
What breed of cat is predisposed to Hypertrophic cardiomyopathy?
Main coon cats, by an inherited gene mutation.
What are a few examples of “Physiologic Hyperplasia”?
- Hormonal; Hyperplasia of the breasts during pregnancy
- Compensatory; Hyperplasia of the liver as hepatocytes can replicate to almost rebuild part of the liver that has been lost
What are a few examples of “Pathologic Hyperplasia”?
- Epidermal Hyperplasia; From repeated irritation like chemical, physical, UV light irritation, etc.
- Respiratory Mucosal Hyperplasia; From viral infections
- Fibrous Hyperplasia; Like gum overgrowth (AKA Epuli or Gingival Hypertrophy)
How can you tell the difference between Hypertrophy and Hyperplasia upon gross examination?
It can be very difficult.
You have to first decide what tissue you are looking at, i.e. do the cells replicate?
Ex. If looking at muscle it will be Hypertrophy, and when looking at Intestine it will be Hyperplasia.
Then you have to take a histological sample to confirm.
What do Atrophy, Hypertrophy, and Hyperplasia all have in common?
They are all cell adaptations.
What is the cause and effect of Metaplasia?
It is caused by chronic irritation, or stress on the cell.
It may result in decreased function and increased risk of malignant transformation (neoplasia).
It is most common in epithelial cells, and is reversible if the stimulus is removed.
What are some examples of Metaplasia?
- Chronic lung irritation
- Vitamin A deficiency
- Estrogen toxicity
- Mammary tumors
What is “Carcinoma in situ”?
It is a near synonym for severe Dysplasia, as it is the level at which the basement membrane becomes affected.
