Disorders of growth Flashcards
Examples of disorders of growth
Moles
Too many BVs?
Hyperplasia
> in cell numbers
Response to stimulus
Regression once stimulus removed
size and function
Endocrine growth control stimulus to hyperplasia
Physiological -normal growth and development -puberty and pregnancy Pathological -parathyroids and thyroid
Other growth control stimulus to hyperplasia
Chronic irritation/ inflammation
Bone marrow, lymphoid tissue
Thyroid hyperplasia
Places in low % of iodine
Pituitary produces more and more thyroid hormone but little iodine so can’t do it
Nifedipine
> effect of inflammation on gingival tissue
in fibrous CT underlying epithelium of gingiva
Gingival hyperplasia (teeth sometimes almost not able to be seen)
Hyperplasia of tonsil
Lymphocytes divide and expand
Hypertophy
> in cell size
Often occurs with hyperplasia
Pure hypertophy
Muscle: mechanical stimulus
- skeletal: exercise
- smooth: pregnancy
- cardiac: LVH in hypertension
Hypertrophy in relation to heart
Hypertension –> resistance to pumping blood around body
> size of cardiac muscle fibres in left ventricle
Can lead to heart failure
Neoplasia
Growth which is uncontrolled & does not
stop and which persists after stimulus is removed
Too little tissue
Developmental
- Agenesis (does not develop at all) e.g. wisdom teeth
- Aplasia (fails to develop normal structure so some deficit in function)
- Hypoplasia (less tissue formed)
Achondroplasia
Cartilagenous structures in body do not develop properly
Inherited disorder
Hypoplasia
Enamel hypoplasia
Can be inherited (every tooth affected)
An effect on single tooth e.g. after knocking front teeth
Hypoplastic mandible and malocclusion
Atrophy
< in size after growth
- size and number of cells
- can be physiological - in embryology
Mechanisms of atrophy
Imbalance of cell loss and production
- apoptosis
- not necrosis (mostly)
- < in structural components of cell, esp. proteins
Generalised atrophy
Nutritional e..g in starvation
Senile e.g. as we grow older we get shorter
Endocrine e.g. maintenance of bone mass by oestrogen
Bone - osteoporosis (reduction in structural density of bone)
Nutritional deficiency
Tongue e.g. without papillae - iron deficient. Lacking full development of epithelium
Localised atrophy
- Ischaemic
- Pressure e.g. bed-ridden pxs
- DIsuse e.g. if you stop gyming
- Neuropathic/ denervation e.g. damage to nerve supplying muscle
- Immune mediated (autoimmune)
- Idiopathic
Ischaemic atrophy in kidney
Partially occluded renal artery –> smaller kidney to cope with reduced amount of oxygen & nutrients
Atrophic mandible
In edentulous pxs
Affects retention of denture
Alzheimer’s brain
Atrophic
< of white matter
Romberg’s disease
Hemifacial atrophy
Not developmental
Affects soft tissue and muscular structures
Not well understoof
Metaplasia
Abnormal differentiation
- change from one differentiated tissue to another (within same germinal layer)
- result from changes in environmental demands
- epithelium (mucous or squamous)
- mesenchymal
Examples of metaplasia
Bronchi of smokers
- columnar pseudostratified squamous cells with goblet cells –> stratifiied epithelium because better barrier, worse at expelling ‘rubbish’
- Can be first step on route to cancer
Gastric metaplasia
In pxs with acid reflex
Barrett’s esophagus
Squamous –> columnar with goblet cells
Dysplasia
Abnormal growth & differentiation in a tissue, with abnormal cells & tissue architecture
-may be premalignant
Ectopia
Developmental abnormality
Normal tissue
Abnormal site
e.g. offset kidney or in orthodontics!
Cell stress –> cell death
Cell stress + (dose intensity and cell vulnerability) –> adaptation or injury
Structural or metabolic adaptation
Structural adaptation –> injury
Injury –> reversible –> irreversible (past point of no return) –> cell death
Normal cell adaptations
Atrophy
Hypertrophy
Hyperplasia
Hamartoma
Tumour-like overgrowth
- grows in px’s growth period
- stops growing
- tissues are normal for site, but excessive
- e.g. pigemented naevi (moles), haemangioma
