growth adaptations Flashcards
when is an organ places in homeostasis?
when physiologic stress is placed on it
what can occur with an increase, decrease, or change in stress on an organ?
growth adaptation
An increase in the size of an organ
hypertrophy
an increase in the number of cells
hyperplasia
Gene activation, proteins synthesis, and production of organelles is involved in:
hypertrophy
production of new cells from stem cells is involved in:
hyperplasia
true or false: hyperplasia and hypertrophy generally occur together
true
examples of permanent tissue:
cardiac muscle, skeletal muscle, and nerve
does permanent tissue undergo hyperplasia?
No. Permanent tissue undergoes hypertrophy only, because it doesn’t have stem cells.
does BPH increase the risk for prostate cancer?
no, this is an exception.
Atrophy
a decrease in stress leads to decreased organ size
a decrease in cell number occurs via which mechanism?
apoptosis
a decrease in cell size occurs via what mechanism?
ubiquitin-proteosome degradation of the cytoskeleton and autophagy of cellular components
what is the mechanism of ubiquitin proteosome degradation?
intermediate filaments of the cytoskeleton are tagged with ubiquitin and destroyed by proteosomes
what is the mechanism of autophagy?
involves generation of autophagic vacuoles
these vacuoles fuse with lysosomes with hydrolytic enzymes breakdown cellular components
what is it called when you have a change in cell type?
metaplasia
most commonly involves change of one type of surface epithelium (squamous, columnar, urothelial) to another
what is an example of metaplasia?
Barret Esophagus
What lines the esophagus?
lined by nonkeratinizing squamous epithelium
if you have acid reflux from the stomach, it will cause metaplasia to:
nonciliated, mucin producing columnar cells
What is the mechanism of metaplasia?
reprogramming of stem cells
is metaplasia reversible?
YES.
true or false: apocrine metaplasia of breast carried no increased risk for cancer
true
which vitamin is necessary for differentiation of specialized epithelial surfaces, such as the conjunctiva covering the eye?
vitamin A
the change of thin squamous lining of the conjunctiva undergoes metaplasia into stratified keratinizing squamous epithelium in vita A deficiency is called:
keratomalacia
