1. Growth Adaptations, Injury, Cell Death Flashcards
what are the main types of Growth Adaptations?
hyperplasia, hypertrophy, atrophy, metaplasia, dysplasia
what is hyperplasia?
ex?
increase in number of cells, due to increase in stress to organ
Congenital Adrenal Hyperplasia
Benign Prostatic Hyperplasia
Cushing’s Dz
Endometrial Hyperplasia
what is hypertrophy?
ex?
increase in size of cells, due to increase in stress to organ
ex = cardiac hypertrophy
what processes are involved in hyperplasia?
new cells made from stem cells
what tissues cannot perform hyperplasia? why?
cardiac, skeletal muscle, nerve. these are permanent tissues and have no stem cells
in response to systemic hypertension, what will the cardiac myocytes do?
hypertrophy, NOT hyperplasia
pathologic hyperplasia can lead to what?
dysplasia –> cancer
what is an exception to pathologic hyperplasia leading to dysplasia and cancer?
benign prostatic hyperplasia (does not increase the risk for prostate cancer). technically a pathologic hyperplasia still.
what are the mechanisms of hypertrophy?
gene activation, protein synthesis, production of organelles.
what are the 2 mechanisms of atrophy?
decrease in size of cells decrease in number of cells
atrophy: how do the TWO mechs work for decreasing the size of cells?
- via ubiquitin-proteosome degradation of cytoskeleton: intermediate filaments of cytoskel are tagged with ubiquitin and destroyed by proteosomes 2. autophagy of cellular components: autophagic vacuoles fuse with lysosomes and hydrolytic enzymes break down cellular components.
atrophy: how does the mech work for decreasing the number of cells?
apoptosis
example of physiologic hyperplasia?
pregnancy
def of metaplasia?
change in stress on an organ leads to a change in cell type
classic example of metaplasia?
Barrett esophagus
what is usually involved in metaplasia?
one type of surface epithelium changes to another
why would metaplasia occur?
metaplastic (new) cells are better able to handle the new stress.
three main types of surface epithelium?
squamous, columnar, urothelial/transitional
explain Barrett esophagus
esophagus epithelium is typically squamous. if acid is in contact with esophag for a prolonged time, squamous tissue will change to columnar, which can better cope with the acid
stomach: normal epithelium?
columnar: non-ciliated, mucinous (goblet cells). suited to handle acid
esophagus: normal epithelium?
nonkeratinizing squamous (suited to handle friction)
how does metaplasia occur?
reprogramming of stem cells
metaplasia, dysplasia, carcinoma: which are reversible?
in theory, metaplasia and dysplasia are reversible with removal of stressor
Barrett esophagus can progress to what?
metaplasia of Barrett esophagus can progress to adenocarcinoma (dysplasia)
what is a risk factor for adenocarcinoma?
Barrett esophag
metaplasia can progress to what?
dysplasia
metaplasia progressing to dysplasia: exception?
apocrine metaplasia of breast. no increased risk of cancer
metaplasia can result from stress and what else?
Vit A deficiency
what is the key distinction between dysplasia and cancer?
dysplasia is reversible
how does Vit A def result in immunodeficiency?
it is required for maturation of immune cells
specific situation in which Vit A def results in metaplasia?
Vit A = required for differentiation of specialized epithelium of conjunctiva. with def, squamous lining of conjunctiva –> metaplasia into stratified keratinizing squamous epithelium. Keratomalacia Cause of night blindness
a classic example of metaplasia involving skel muscle?
myositis ossificans. after trauma, muscle cells in process of healing converts to bone
how can you tell the difference between myositis ossificans and osteosarcoma?
MO: nearby bone is NORMAL Osteosarcoma: bone and abnormal growth in muscle are connected.
definition of dysplasia
disordered cell growth
dysplasia generally refers to what?
proliferation of precancerous cells
what type of dysplasia is a precursor to cervical cancer?
CIN: cervical intraepithelial neoplasia
dysplasia may arise from what?
metaplasia (ex: Barretts), or pathologic hyperplasia (ex: endometrial hyperplasia)
aplasia: definition
failure of cell production during embryogenesis
aplasia: example
unilateral renal agenesis
hypoplasia: definition
decr in cell production during embryogenesis resulting in relatively small organ
hypoplasia: example
streak ovary in Turner syndrome
