Pathoma Chapter 1 Flashcards
T or F. An increase in stress leads to an increase in organ size
T. Atrophy is the opposite
How can an increase in organ size occur?
Hypertrophy or Hyperplasia
How does hypertrophy result in increased cell size?
increased production of proteins, increased gene activation, and increased production of organelles
not an increase in cytoplasm
What organs can only undergo hypertrophy?
Heart, brain, nerve, skeletal muscle. These are termed permanent tissue and are terminally differentiated
caused by increased pressure and need to work harder
Pathologic hyperplasia can lead to what?
Exception?
dysplasia, and eventually cancer
exception: benign prostatic hyperplasia (BPH) does not increase the risk of prostate cancer
How does atrophy occur?
Decrease in cell size occurs via ubiquitin-proteasome degradation of the cytoskeleton and autophagy of cellular components.
Intermediate filaments of the cytoskeleton are tagged with ubiquitin and destroyed by proteosomes
How does autophagy occur?
Involves generation of autophagic vacuoles that fuse with lysosomes who’s hydrolytic enzymes break down cellular components
Barrett’s esophagus.
Metaplasia of the nonkeratinizing squamous epithelium of the esophagus for nonaffiliated, mucin-producing columnar cells
How does metaplasia occur?
re-prgramming of stem cells, which then produce the new cell type
Is metaplasia reversible?
YES, with removal of the driving stressor.
However, under persistent stress, metaplasia can progress to dysplasia and eventually cancer
Ex. barrett’s esophagus can lead to adenocarcinoma of the esophagus
Under persistent stress, metaplasia can progress to dysplasia and eventually cancer. Exception?
apocrine metaplasia of the breast
Deficiency of what can lead to metaplasia?
Vitamin A
What does Vitamin A do?
necessary for differentiation of specialized epithelial surfaces such as the conductive of the eye
In vitamin A deficiency, the goblet cell/columnar epithelium of conductive undergoes metaplasia into keratinizing squamous epithelium
T or F. Mesenchymal tissues can undergo metaplasia
T. A classic example is myositis ossificans in which connective tissue within muscle changes to bone during healing after trauma
Dysplasia
Proliferation of precancerous cells
Example of Dysplasia?
Cervical intraepithelial neoplasia (CIN) represents dysplasia and is a precursor to cervical cancer
Dysplasia often arise from what?
longstanding pathologic hyperplasia (endometrial hyperplasia) or metaplasia (eg. Barrett’s esophagus)
T or F. Dysplasia is reversible.
T. If stress persists, dysplasia can lead to carcinoma (irreversible)
What is aplasia?
failure of cell production during embryogenesis
What is hypoplasia? Example?
decrease in cell production during embryogenesis, resulting in a small organ (streak ovary in Turner’s syndrome)
What is cellular injury?
Occurs when stress exceeds the cell’s ability to adapt
The likelihood of injury depends on what?
the type of stress, its severity, and the type of cell affected.
Nerve cells are more susceptible to ischemic injury than skeletal muscle
Slowly developing ischemia (i.e. renal artery atherosclerosis) results in ____, while acute ischemia (e.g renal artery embolus) results in ____.
atrophy; injury
Common causes of cellular injury include:
inflammation, nutritional deficiency or excess, hypoxia, trauma, and genetic mutations
How does hypoxia lead to cell injury?
lack of O2= lack of ATP produced
What are some common causes of hypoxia?
ischemia, decreased O2 carrying ability of blood, hypoxemia
What is ischemia?
decreased blood flow to an organ