Growth Disorders Flashcards
what are the development disorders of too little growth?
agenesis, aplasia, hypoplasia
what is ageneis?
an organ does not develop at all (genetic defect/mechanical cause)
what is aplasia?
an organ fails to develop normal structure from primitive embryonic structure
what is hypoplasia?
less tissue formed, normal structure
what would salivary gland agenesis be?
all salivary glands missing
what would aplasia be?
only one gland missing e.g. parotid glands
what is a hamartoma?
tumour-like growth that only grows in patient’s growth period but excessively
give examples of hamartomas
pigmented naevi (moles), haemangioma, lymphangioma
what are the different types of haemangioma?
present at birth, vascular malformation (occurs later in life), Sturge Weber syndrome (half of face is red)
what is a lymphangioma?
mostly cavernous, tongue, cystic hygroma
what is a naevus?
mole
what is ectopia?
normal tissue in an abnormal site
give an example of a developmental disorder in the wrong place and state what it is
Mickel’s diverticulum - an outpouching of the small intestine. Can contain gastric type mucosa
give an example of an oral ectopia
an ectopic tooth - normal tooth but in the wrong position
what are the acquired growth disorders?
atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia
what is atrohy?
reduction in size and number of cells
what are the two types of atrophy?
physiological and pathological
what is physiological atrophy?
normal growth and development under hormonal influence
what are the mechanisms of atrophy?
reduction in structural components of the cell, imbalance of cell loss and production, may involve apoptosis
give examples of localised atrophy
ischaemia, pressure (tumours), disuse/denervation, autoimmune, idiopathic
give examples of generalised atrophy
nutritional, senile, endocrine
what is osteoporosis related to?
physical activity, ageing, hormones, oestrogen has inhibitory effect on osteoclasts
what is hyperplasia?
increase in cell numbers
what does hyperplasia result in?
increased tissue size and function
what stimulates hyperplasia?
hormones and growth factors
what are the causes of pathologic hyperplasia?
endocrine stimulation by hormone producing organs and chronic injury and inflammation stimulated by inflammatory cytokines
why type of hyperplasia can regress?
controlled hyperplasia
what are the mechanisms of hyperplasia?
growth factor-driven proliferation of cells, increased output of cells from stem cells, liver regeneration
what is hypertrophy?
increased cell SIZE due to increased production of cellular proteins
what does hypertrophy often occur with
hyperplasia
what is pure hypertrophy
cells with limited mitotic ability
what are the causes of hypertrophy in each muscle type?
skeletal - exercise, smooth - pregnancy, cardiac - LVH in hypertension
what is goitre?
decreased synthesis of thyroid hormone resulting in dietary iodine deficiency
what hormone increases during goitre?
thyroid stimulating hormone
what type of growth disorder is goitre?
thyroid follicular cell hypertrophy and hyperplasia together
what is metaplasia?
change from one differentiated form of a tissue to another and the reprogramming of stem cells or undifferentiated mesenchymal cells
what does metaplasia result from?
changes in environmental demand
what are the 2 types of epithelial metaplasia?
squamous metaplasia and mucous metaplasia
what is the mesenchymal metaplasia?
osseous
what is the epithelial change of metaplasia in smokers?
ciliated columnar epithelium to squamous metaplasia
what is the epithelial change of metaplasia in Barrett’s oesophagus?
squamous epithelium to columnar metaplasia
what is dysplasia?
disordered growth
where can dysplasia occur?
in metaplastic tissue
what tissue type is dysplasia mostly seen in?
epithelia
what can the severity of dysplasia mean?
it may indicate that there is the potential for malignant change
what is neoplasia?
an abnormal mass of tissue
comment on the growth characteristics of neoplasia
excessive and uncoordinated with that of normal tissues and persists after the provoking stimulus is removed
what type of tumours does metaplasia include?
benign and malignant
