disorders of growth Flashcards
what are the definitions of the 4 types of growth
multiplicative growth- increase in cell number - mitosis
auxetic growth increase in size of growth - e.g. fat cells get bigger
accretionary growth- refers to growth in post embryonic stage or adult stage e.g. connective tissue during adult life
combined - increase in cell growth and
what is the definition of growth
ncrease in size and applies to the whole body but also to cells, organelles in cells, organs , populations there are 4 different types accretionary , multiple;icative auxetic growth and combined
what is the definition of differentiation
cell develops a specialised function or morphology which distinguishes it from its parent cell
e.g. undifferentiated cells - differentiated into differentiated ciliated cells in the bronchus
what is the definition of morphogenesis
complex process of embryological development
formation of shape and organisation of body organs
involves growth , differentiation , and relative movement of groups of cells
programme cell death apoptosis removes
describe what normal control of systemic growth is
growth = the balance between cell division and apoptosis
growth factors can stimulate cell growth
cell check points check the integrity of Dna
withdrawing growth factors will induce apoptosis
induced stimulation of growth factors can cause
what are the endocrine factors in postnatal growth
hormones are secreted by the gland and circulate around the body
endocrine system e.g. thyroid
what are the endocrine factors in foetal growth
foetal growth= controlled by insulin through the maternal transfer of nutrients and oxygen and glucose absorbed by the fetal pancreas - regulates foetal cells - foeal pituitary develops later - things are mainly regulated by insulin- sugar comes from the placenta
- insulin effects foetal cell growth - lower foetal insulin or the ability of insulin receptors to respond to insulin
hyperinsulinaemia (maternal diabetes) too much glucose to feats results in increased growth
what are the major categories of abnormality
hyperplasia and hypertrophy are common tissue responses
can be physiological (e.g. breast enlargement) - post natal natural response
or pathological - part of disease process
(e.g. prostatic enlargement in elderly men
describe normal and abnormal growth in single tissues
can be physiological e.g. breast enlargement in pregnancy or past natal response or pathological part of disease process e.g. prostatic enlargement in elderly men
abnormal conditions - myocardial hypertrophy - enlarged heart
hypertrophy of arterial walls - leads to hypertension
what is hypertrophy
increase in cell size without cell division auxetic growth e.g. muscle cells and fat cells
what is hyperplasia
increase in cell number by mitosis
what is atrophy
atrophy = decrease in the size of an organ or cell
organ atrophy can be due to a reduction in cell size or number or both
can be mediated by apotosis
may be physiological (e.g due tp decreased function)
reduced movemenr = results in decreased function
loss of innervation - reduced blood , oxygen supply or nutritional status and hormonl deficiencies
what is physiological atrophy
occurs in foetal and postnatal ife
embryo and foetus
branchial crafts , notochord , thyroglossal duct
neonate
umbilical vessels, ductus arteriosus
foetal layer adrenal cortex
thymus
late and older age
testes , bone , uterus , gums , mandible
what is hypoplasisa
decreased growth
failure of development of an organ
process is related to atrophy
failure of morphogenesis
e.g. micropthalmia - foetus has a genetic problem - teraploid - has doubled the amount of chromosomes necessary - normal cell has 46 cells - tetraploid has 96 cells
give some examples of physiological and pathological examples of hyperplasia, hypoplasia , atrophy and hypoplasia
physiological examples of hyperplasia -physiological - breast enlargement in pregnancy
- pathological - prostate enlargement in elderly men
myocardial hypertrophy
physiological atrophy - embryo and foetus - branchial clefts , notochord , thyroglossal duct , mullein duct , wolfing duct (females)
neonate- umbilical vessels
early adult thymus
late adult - uterus , endometrium females
testes (males)
bone (particular females)
gums
mandible
hypoplasiia - pathological caused by Zika virus - mircopheley - abnormal head development - below average head size
how is differentiation controlled
embryonic differentiation of cells its controlled by gene expression - i.e. where cells are in foetus , systemic hormones , position within foetus , local growth factors and matrix proteins
maintainence of differentiated state depends upon the persistence of some of these factors - cells can become more pluripotent
what are kerogen’s and what is tetra genesis
differentiation and morphogenesis can be disrupted by environmental factors (e.g tetraogens) alter ability to foetus development
what are some acquired disorders of growth and differentiation
ancephaly - failure of head
meniogecele
cleft palate
spina bifada
what is metaplasia
metaplasia is an acquired form of altered differentiation
transformation go one mature differentiated cell type into another
reversible response to altered cellular environment
affects epithelial or mesenchymal cells
may undergo further indirect transformation to neoplasia via dysplasia e.g. squamous cell carincoma associated with squamous
Metaplasia is a type of adaptive change in which one type of differentiated cell is replaced by another type of cell that is better able to withstand the environmental stresses or stimuli. It occurs in response to chronic irritation or inflammation, and the body replaces the damaged or dead cells with a different cell type that is better able to survive under those conditions.
For example, in smokers, the ciliated columnar epithelium of the bronchi is often replaced by a non-ciliated, stratified squamous epithelium, which is better able to withstand the toxins and irritants inhaled during smoking
what are neoplasms
neoplasia(tumours)
neoplasia is characterised by abnormal , uncoordinated and excessive cell growth
persists after initiating stimulus has been withdrawn
associated with genetic alterations
neoplastic cells influence behaviour of normal cells by the production of hormones and growth factors
not usually painful
pain if nerves compressed, bone involved
what are the different classifications of neoplasms
tumours can result from genetic alterations (e.g. mutations) in cells resulting in abnormal neoplastic growth persisting in the absence of the initiating causes
malignant (invasive tumours) develop in approximately 25% of individuals
incidence increases with age
structure comprises neoplastic cells and connective tissue storm of which the vascular supply is essential for growth
what are the differences between benign and malignant neoplasms (pathology and effects)
beigin - slow growth
maliginant - relevant rapid
mitotic activity - low in being
mitotic activity - high in malignant
histological resemblance to normal tissue good in benign and variable and often poor in malignant
nuclear morphology - often normal in benign and usually hyper chromatic , irregular outline multiple nucleoli and pelmorphic in malignant
invasion in malignant not in benign
metasteses frequently in malignant not in benign
border is often circumscribed or encapsulated in benign and often poorly defined or irregular in malignant tumours
necrosis is rare in benign and common in malignant
ulceration is rare in benign and common on skin or mucosal surfaces in malignant
direction of growth is often exophytac in benign and often endophytic in malignant 1
what are the different grades of tumours
behavioural classification - benign - might grow or grow big or malignant this kills
histogenic classification - where the cell of origin comes from ie. what the cancer is
what are the different grades of tumours
behavioural classification - benign - might grow or grow big or malignant this kills
histogenic classification - where the cell of origin comes from ie. what the cancer is
