Which permanent tissues only undergo hypertrophy and not hyperplasia?
-Cardiac muscle, skeletal muscle, and nerve
How does hyperplasia lead to cancer? Is there an exception to this rule?
Name of process that results in a decrease in cell #
apoptosis
Name of processes that results in decrease cell size
Ubiquitin-proteosome degradation of the cytoskeleton and autophagy of cellular components
What is Metaplasia?
A change in stress on an organ leads to a change in cell type.
Barret esophagus is a classic example of what type of growth adaptation?
Metaplasia
What type of tissue changes occur most commonly in metaplasia?
Change of one type of surface epithelium (squamous, columnar, urothelial) to another
What type of metaplasia do we see with Barret esophagus?
Non-keratinizing squamous epthelium –> nonciliated, mucin-producing columnar cells
Metaplasia is (reversible or irrreversible)?
reversible - in theory, with removal of the driving stressor
Can metaplasia progress to cancer?
Yes - under persistent stress:
-metaplasia –> dysplasia –> cancer
ex) Barret’s –> adenocarcinoma of the esophagus
EXCEPTION:apocrine metaplasia of breast - no increased risk for cancer
What vitamin deficiency can result in metaplasia?
Vitamin A.
-is necessary for differentiation of specialized epithelial surfaces such as the conjunctiva covering the eye
How will a Vitamin A deficiency manifest?
Night blindness
Thin squamous lining of the conjunctiva undergoes metaplasia into stratified keratinizing squamous epithelium. Change = KERATOMALACIA
MYOSITIS OSSIFICANS is an example of what?
- muscle tissue changes to bone during healing after trauma (inflammation)
Define Dysplasia in 3 words
Disordered cellular growth
Cervical intraepithelial neoplasia (CIN) is an example of what growth adaptation?
Dysplasia
How does dysplasia arise?
-often from longstanding pathologic hyperplasia (endometrial hyperplasia) or metaplasia (Barrett)
IS DYSPLASIA REVERSIBLE?
Yes, in theory, with alleviation of inciting stress
-if the stress persists and it progresses to carcinoma –> that is irreversible
Define Aplasia:
Failure of cell production during embryogenesis
Define Hypoplasia
Decrease in cell production during embryogenesis resulting in a relatively small organ (ex streak ovary in turner syndrome)
What type of cells are highly susceptible to ischemic injury?
NEURONS (occurs after 3-5 minutes)
What does slowly developing ischemia result in?
Results in atrophy
In contrast to acute ischemia - which results in cellular injury
Define Hypoxia
Low oxygen delivery to tissue
What are the 3 causes of hypoxia?
What are 3 causes of ischemia?