Growth disorders Flashcards
Are disorders of growth developed or acquired
Both
What is agenesis
An organ does not develop at all
What is aplasia
An organs fails to develop normal stricture fromprimitive embryonic structure
What is hypoplasia
Liss tissue formed, normal structure
What is salivary gland agenesis and aplasia
Salivary gland agenesis-all salivary glands missing
Aplasia- only one gland for example the parotid glands may be missing
What are disorders of too much growth called
Hamartoma
-tumour like growth
-only grows in patient’s growth periods
Whar are examples of over growth disorders/hamartoma
Pigmenyed naevi (moles)
Haemangiona
Lymphangioma
What is a haemangioma
Vascular lesions usually red and raised
Present at birth
Vascular malformation- can develop later in life
What syndrome are haemangiomas associated with
Sturge weber syndrome
Formation of large haemangiomas
Often follows nerve pathways
(example follows course of maxillary branch of trigeminal nerve)
What are the features of lymphangioma
Mostly cavernous
Often found in oral cavity (tongue)
Cystic hygroma - on the neck large bulge
What is growth in the wrong place called
Ectopia
normal tissue in an abnormal site
What are examples of ectopia
Mickel’s diverticulum, an outpouching of the small instestine
How do aquired growth disorders occur
Adaption of cells to environmental stresses
What are the types of acquired growth disorders
Atrophy
Hypertophy
Hyperplasia
Metaplasia
Dysplasia
What is Atrophy
Reduction in size and number of cells
1-Physiological – normal growth and development; under hormonal influence
2-Pathological
How can atrophy occur
Reduction in structural components of the cell (organelles)
Imbalance of cell loss and production
May involve apoptosis (atrophy of organ)
What are the types of atrophy and the causes
Localised
ischaemic
pressure (tumours)
disuse/ denervation
autoimmune
idiopathic (no cause)
Generalised
nutritional
senile
endocrine
What is an example of atrophy
Osteoporosis
What is hyperplasia
increase in cell numbers resulting in increased tissue size and function
response to stimulus and regression once removed
cells must be capable of division
physiological and pathological
Both of these can be hormonal or compensatory
What can stimulate hyperplasia
Hormones and growth factors
What are causes of pathologic hyperplasia
- endocrine (hormonal) stimulation by hormone producing organs
Hyperplasia of target organs - benign prostatic hyperplasia
-Chronic injury and inflammation
stimulated by inflammatory cytokines; growth factors
hyperplasia of bone marrow and lymphoid tissue
HPV can induce hyperplasia of epithelium
What causes Gingival hyperplasia
Bad oral hygeine (improvement in oral hygeine is improved remodelling or surgery can reduce effects) ‘controlled hyperplasia can regress’
Medication could also stimulate gingival hyperplasia
How can hyperplasia occur
Growth factor-driven proliferation of cells
Increased output of cells from stem cells.
Liver regeneration
What is hypertrophy
increase in cell size due to increased production of cellular proteins.
often occurs with hyperplasia
What is pure hypertrophy
Cells with limited mitotic ability
-cells grow in size via production of more protein and myofibrils instead of division
In what cells do hypertrophy usually occur and why
muscle – mechanical stimulus
skeletal – exercise (physiologic)
smooth – pregnancy (physiologic)
cardiac – LVH in hypertension (pathologic)
What is goitre
Enlargement of the thyroid gland
Result of dietary iodine deficiency
decreased synthesis of thyroid hormone
compensatory increase in TSH
thyroid follicular cell hypertrophy and hyperplasia together
What is metaplasia
change from one differentiated form of a tissue to another
-adaptive response
-results from changes in environmental demand
epithelial
squamous metaplasia
mucous metaplasia
mesenchymal
osseous
What causes metaplasia
Reprogramming of stem cells or undifferentiated mesenchymal cells
What are examples of metaplasia
In smokers : ciliated columnar epithelium to squamous metaplasia
Barrett’s oesophagus :squamous to columnar
What is dysplasia
disordered growth
can occur in metaplastic tissue
mostly seen in epithelia
severity may indicate that there is the potential for malignant change
What is neoplasia
- an abnormal mass of tissue
- growth of which is excessive
- and is uncoordinated with that of normal tissues
- and persists after the provoking stimulus is removed
- includes benign and malignant tumours
