Lect 17 - Abnormalities of growth, differentiation & morphogenesis Flashcards
give examples of cells that adapt easily
Epithelial cells:
Labile cell population
Active stem cell compartment
Highly adaptive in number and function
give examples of cells which dont need to adapt
Fibroblasts:
Survive severe metabolic stress without harm
eg absence of O2
give examples of cells that can’t adapt
Cerebral neurons:
Terminally differentiated
Permanent cell population
Highly specialised function
Easily damaged by environmental change
what is physiological change?
Responding to normal changes in physiology or demand
What is pathological change?
Responding to disease related changes
what is an increase in cell size called?
HYPERTROPHY
what is an increase in the number of cells called?
HYPERPLASIA
what factors contribute ti INCREASED CELL MASS
HYPERTROPHY and HYPERPLASIA
why to tissues undergo hypertrophy?
for the Increase in functional capacity
give examples of three tissues which undergo hypertrophy particularly extensively?
Particularly seen in permanent cell populations esp cardiac and skeletal muscle.
uterine bulk also massively increases in pregnancy
what conditions can be caused by excessive hypertrophy?
hearts compensating for systemic hypertension. this leads to less efficient pumping (because of the actin and myosin not overlapping as well).
prostate enlargement.
Gynaecomastia
what do patients with left ventricle hypertrophy show on ecg?
Patients with LVH have increased ectopic beats
which can predispose to sudden degeneration of rhythm to:
ventricular tachycardia / ventricular fibrillation and sudden cardiac death.
what important consideration must me made about subcellular hypertropy/plasia?
Increase in size and number of subcellular organelles could lead to Increased metabolism of drugs
what pathological endocrine effects can be seen as a side effect of Hyperplasia
Excess hormones such as
Growth factors
what is Gynaecomastia?
Enlargement of the male breast (gynaecomastia) due to hyperplasia of the glandular and stromal tissue in the breast.
when would you expect to see Hypertrophy of one kidney?
in the case of hypoplasia of the other.
what causes Graves disease?
an autoantibody binds to and switches on the TSH receptor in the thyroid, leading to prolonged, uncontrolled hyperplasia of the thyroid and hyperthyroidism
what is the classic clinical sign for grave’s?
The eye signs - bulging.(exophthalmos)
what is Atrophy?
Reduction in size of organ or tissue by decrease in cell size and number
give examples of Physiological Atrophy
Embryogenesis, uterus after pregnancy or menopause. thymus with aging. (In an adult the thymus is barely recognisable macroscopically.)
what causes Pathological atrophy (6)
Decreased workload (disuse atrophy) Loss of innervation (denervation atrophy) Diminished blood supply Inadequate nutrition (eg cachexia) Loss of endocrine stimulation Pressure
atrophy of brain tissue is commonly seen in what conditions?
cerebrovascular disease/dementia
give two conditions which can lead to kidney Atrophy
Renal artery stenosis
Hydronephrosis (back pressure due to ureteric obstruction.)
what are the 2 Mechanisms of atrophy?
Reduction in volume of individual cells or Death of individual cells.
not all reduced cell mass is due to atrophy. what is agenesis?
failure to form embryonic cell mass
what is aplasia?
failure of embryonic cell mass to differentiate into organ-specific tissues
what is dysgenesis?
the failure of tissues to develop the structure of organs successfully in development
what is metaplasia?
Transformation of one differentiated cell type into another with Better adaptation to new environment
what tissue undergoes metaplasia pysiologically?
cervix at pregnancy
columnar -> squamous
give some examples of pathological metaplasia
oesophagus turning into columnar in reflux
bronchial pseudostratisfied ciliated turning into squamous in smoking.
bladder turning into squamous in longstanding catheter, bladder calculus or schistomosiasis
what is the risk of pathological metaplasia?
neoplasia
what is the process by which a metaplastic tissue becomes a neoplastic one?
dysplasia:
“Earliest morphological manifestation of multistage process of neoplasia (hence irreversible)”
Shows cytological features of malignancy, but no invasion
