disorders of growth Flashcards
What are the two types of controlled non neoplastic disorders of growth? Briefly describe.
1- Congenital.
Present at birth and includes, Aplasia, Agenesis, Hypoplasia and Dysplasia
2- Acquired
Adaptive change and involves Hypertrophy, Hyperplasia, Dysplasia and Metaplasia
What is Metaplasia? Is it anon neoplastic of neoplastic characteristic?
Non neoplastic characteristic
Uncommon change which involves involves the replacement of one cell type with another. It may be reversible.
What is hyperplasia?. Is it anon neoplastic of neoplastic characteristic?
Non-neoplastic characteristic
Refers to an increase in cell number rather than cell size.
Define Hypoplasia and hyperplasia. Is it anon neoplastic of neoplastic characteristic?
Non neoplastic characteristic
Hypoplasia: Failure of an organ or tissue to achieve its full size or development
Hyperplasia: Increase in cell number
Define Aplasia. Is it anon neoplastic of neoplastic characteristic?
Non neoplastic characteristic
Complete failure of development. Agenesis is the same but you can not see a rudimentary remain
Define Atrophy? Is it anon neoplastic of neoplastic characteristic?
Non- neo
Decrease in organ/cell size and number
Define hypertrophy, Is it anon neoplastic of neoplastic characteristic?
Non- neo
Increase in cell size
Define dysplasia. Is it anon neoplastic of neoplastic characteristic?
Non-neo
Proliferation and disorganisation in tissue that may be a precursor stage leading to neoplasia eg epithelial dysplasia of the skin
What gene groups are altered as a result of neoplasia? And what are their usual significance?
Proto-oncogenes and tumour supressor cells. They are normally involved in •Production of growth factors •Growth factor receptors •Signal transduction •DNA replication •Apoptosis
Differ between the behaviour and appearance of benign and malignant disorders
Benign growths are slow growing, dont metastasise and are well differentiated. Malignant is opposite
How are proto-oncogenes altered by neoplasms?
Proto-oncogenes are essential for controlling normal cell devision. They are mutated into oncogenes which constantly signal cells to divide.
Define anaplasia. Is is a non neo or neo characteristic?
Neo
Loss of differentiation of cells
How do malignant neoplasms invade?
Many tumour cells produce proteolytic enzymes or induce neighbours to produce these so that they can dissolve proteins and move through tissues easier
There is also the selection for more malignant forms
What is the mechanism/multi step process of metastasis?
They travel via body cavities, lymphatics or through blood.
1. Cells must separate from each other (loss of cadherin function)
2. Cells must attach to ECM components and increase in integrin expression
3. Secrete proteases or induce cells around them to secrete proteases→enzyme that breaks down proteins
4. Migration requires coordinated cytoskeletal alterations. Stimulated by autocrine growth factors and cleavage products of ECM
5. Tumour embolisation. Cells need to break away from each other
6. Site of extravasation determined by
o vascular anatomy
o tumour surface adhesion molecules
What is a carcinogen and what are the 4 stages?
A carcinogen is a physical or chemical cancer causing agent. The 4 stages are as follows: 1- Initiation 2. Promotion 3. Progression (benign stage) 4. Malignant conversion
