Non-Neoplastic Disturbances of Growth Flashcards
what are the 2 types of dysregulated growth?
- acquired: atrophy, hyperplasia, hypertrophy, metaplasia, dysplasia
(assumes this thing was once normal and now is abnormal due to a disturbance) - developmental: hypoplasia, aplasia, agenesis, ectopia, choristoma, hamartoma (happens in utero or shortly after)
describe cellular adaptation
how cells respond to excessive physiologic stresses or pathologic stimuli by undergoing physiologic and morphologic changes to reach a new but altered steady state to preserve the viability of the cell
describe atrophy
decrease in cell or organ SIZE
due to:
1. physiologic reasons: normal for some organs (thymic or mammary gland involution)
2. nutritional reasons: not enough nutrients (muscle wasting in starvation, serous atrophy of fat)
3. diminished blood supply: not enough oxygen or nutrients (hepatic atrophy of fat due to porto-caval shunt
4. diminished trophic stimulation: when hormones and other growth factors are absent (endocrine atrophy)
5. disuse: cells don’t get exercised (musculoskeletal atrophy when a limb is immobilized to stabilize a healing fracture)
6. denervation/neurogenic: nerves not stimulating
7. pressure: compression (hydrocephalus causes buildup of CSF and thins white matter)
8. aging: normal in some organs
in general: due to decreased trophic influences, decreased functional demands, or decreased nutrition
what are 3 types of cells in terms of cell division?
- labile cells: retain the ability to divide throughout their life; of epithelial origin; will undergo hyperplasia!
- stable (quiescent) cells: lose the ability for significant cell division and can only respond to an increase in demand via hypertrophy; muscle cells, chondrocytes, and osteocytes
- permanent cells: loss the ability for cell division all together; when damaged, they will die and not come back; cells of the central nervous system
describe hypertrophy (2)
- increase in cell size accompanied by an increase in functional capacity
- caused by: increased demand
-physiologic: normal, due to trophic hormones
-pathologic: increase in organ workload occurs secondary to a disease process
describe hyperplasia (2)
- increase in organ size due to cell division and an increase in the NUMBER of cells
- physiologic causes: increase in number of mammary epithelial cells during pregnancy or
-pathologic causes: proliferation of intestinal epithelial cells in response to cell loss during viral infections
describe metaplasia
replacement of one ADULT cell type by another, hardier ADULT cell type of the same cell line
example: pseudostratified columner epithelium can undergo metaplasia to stratified squamous epithelium as a result of chronic irritation; results in loss of function because is les specialized
describe dysplasia
an alteration in the size, shape, and organization of the cellular components of a tissue; still reversible, but has highest liklihood of crossing point of no return into neoplasia (a pre-neoplastic change);
there is increased cell proliferation but the cells look REALLY abnormal in terms of size, configuration, and orientation
if inciting cause is removed, cells will revert to normal, but is stimulus continues the cells can undergo neoplastic transformation
what do metaplasia and hyperplasia have in common?
both can precede dysplasia
describe hypoplasia
when a tissue or organ forms perfectly, but never reached full size
ex.cerebellar hypoplasia following in-utero parvovirusinfections in kittens
describe agenesis
when a tissue or organ does not form at all
describe aplasia
when a tissue or organ is formed, but into something that is unrecognizable
ex. cerebellar aplasia
what is ectopia/ectopic tissue?
finding ORGANS or TISSUES in abnormal locations
what is a choristoma?
a mass of tissue that is normal histologically, but not for the site it is found; is an example of ectopia
ex. corneal dermatoid
what is supernumerary?
additional tissue/organs
ex. presence of additional digit, additional teats, endometriosis
