Exam 1 (Lecture 5) - Cellular Adaptations Flashcards
What causes a cell to utilize adaptations?
Being under chronic stress for prolonged periods of time.
What are the types of cellular adaptations?
1) Hypertrophy (increase in size of cells)
2) Hyperplasia (increase in number of cells)
3) Atrophy (decrease in size of cells)
4) Metaplasia (replace one cell type with another of the same germ line)
5) Dysplasia (abnormal cells/cell growth)
6) Autophagy (self-degradation of cells)
What is hyperplasia and what are the physiologic types of hyperplasia?
Increase in the number of cells.
Hormones (in pregnant animals), compensatory, repair (callus), and regenerative
Describe pathologic hyperplasia.
1) Nodular or cystic form
2) Hormones –> inappropriate/excessive –> ACTH –> Adrenal Cortex
Irritation
Unknown/idiopathic
Examples: Liver, spleen, pancreas, lymph nodes, cystic endometrial hyperplasia
In which cell types do we not see hyperplasia?
Neurons and myocardiocytes
Why does the cell type matter in hyperplasia?
Because in some cells (skin, GI, respiratory, hematopoietic) hyperplasia is changing/can change.
In other cell types (glandular, liver, kidney, and endocrine) it is stable.
What is the significance of hyperplasia?
It is caused by chronic or hormonal stimulus.
Potentially preneoplastic (MUST differentiate from neoplasia)
Controlled growth (normal process), reversible, and causes are known. (Compare to neoplasia)
What is hypertrophy?
Increase in the size of cells/organs (increase in volume of organelles = increase in cell size is how you differentiate from cell swelling)
Caused by increased workload/demand
May cause harm; may be reversible
What is metaplasia?
One adult cell type is replaced by another adult cell type of the same germ line.
Irritation: Exposure to smoke can cause a change from ciliated columnar epithelium to stratified squamous epithelium
Induced: caused by estrogen or vitamin A deficiency
Positive: It’s a protective mechanism
Negatives: Loss of cilia = loss of mucous/pathogen clearance; can be preneoplastic
What is the significance of metaplasia?
It’s reversible, may be protective or harmful, may be preneoplastic (carcinoma in situ)
What is dysplasia?
Abnormal pattern of tissue growth, disorderly arrangement of cells within the epithelium
What is atrophy and what are the types?
Decrease in mass of tissue/organ due to decreased size or number of cells.
1) Simple atrophy (gets smaller over time; due to aging)
2) Pressure atrophy (mass/fluid causing pressure on something, there will be atrophy of tissues)
3) Serous atrophy of fat (serious cases of starvation; there will be atrophy of fat)
What are the causes of atrophy?
1) Disuse
2) Denervation
3) Pressure (decreased blood flow)
4) Reduced workload
5) Decreased hormones (ex: mammary tissue)
6) Any reduction in nutrition/O2
7) Aging/senility
What are the fates of atrophy?
1) Reversible = resolve
2) Persist as is
3) Progress
What is involution?
Reduction in cell number without degeneration (involves apoptosis)
Is physiologic (Ex: uterus after parturition)
