Disorders of tissue growth Flashcards
Normal cells can be classed as labile, stable or permanent. What do these mean? Give an example of each
Labile - constant division, e.g. epithelia
Stable - quiescent, low levels of replication e.g. hepatocytes
Permanent - non-dividing, cannot undergo mitosis e.g. neutrons, myocardiocytes
What is the name of stem cell replication? What is this?
Asymmetrical replication
Stem cells divide into one cell that is original to the original stem cell, and one that is differentiated
Describe the potency of embryonic stem cells and adult stem cells
Embryo - totipotent (any cell including placenta)
Adult stem cells - pluripotent (any cell excluding placenta)
What is agenesis?
Absence of organ or body part -no primordium (tissue a earliest recognisable development stage)
What is aplasia?
Failure of organ to develop (can have primordium or be rudimentary organ)
What is hypoplasia? What can cause this?
Failure of an organ to develop to full size
Genetics, hormones, deficiencies, infectious agents
What is atrophy?
shrinkage of organ/tissue after grown to full size
Reduce in cell size (qualitative) or number (quantitative)
What is the difference in aplasia and agenesis?
Agenesis - no primordium
Aplasia - primordium or rudimentary organ
What is the difference between hypoplasia and atrophy?
Hypoplasia - organ doesn’t ever reach full size
Atrophy - organ reaches full size then shrinks
What are different types of metaplasia?
Squamous - from columnar to squamous epithelium
Mesenchymal - from fibrous tissue to cartilage or bone
What is dysplasia?
Loss of uniformity and orientation of cells
Is dysplasia reversible? What can cause it?
Yes
Chronic inflammation
What happens if the injurious stimulus that causes dysplasia persists?
Becomes neoplastic
What is anaplasia?
Resemblance to embryonic form of tissue - lack of differentiation. Type of neoplasia
What is neoplasia? How does growth compare to normal tissue?
New growth - forms abnormal mass of tissue
Growth uncoordinated and faster than normal tissue
What is a tumour/oncos?
Swelling caused by neoplasia
Neoplasia can be malignant or benign. What is malignant tumour? What does it do?
Cancer
Invades and destroys adjacent tissues
Metastasises to cause death
How do benign neoplasia differ from malignant neoplasia?
Remain localised
Don’t spread
Can be surgically removed (generally)
Neoplasms are monoclonal proliferations. What does this mean?
All neoplasms are clones from one mutated cell
What are the general rules of neoplasia (3 - there are exceptions)?
Growth is not reversible
Caused by changes in DNA
Tumours are non-transmissable diseases
Epithelial tumours are of endodermal/ectodermal origin. How are they named?
Benign - end in oma
Malignant - end in carcinoma
Mesenchymal tumours are of mesodermal origin. How are they named?
Benign - end in oma
Malignant - end in sarcoma
How are leukaemia (liquid tumours named)?
Acute or chronic + cell of origin + leukaemia
Where do teratomas arise from? Where are they often found?
Arise from germ cells composed of tissues from all embryonic layers
Contain several different types of tissue
Ovaries, testes
What are hamartomas?
Abnormal mixture of tissues in a place where growth occurs (normal location)
Growth abnormality, soon after birth
What are choristomas?
Abnormal mixture of cells in an ectopic location
Growth abnormality, soon after birth
How do benign and malignant tumours vary in terms of differentiation?
Benign - well differentiated
Malignant - go between well-differentiated and anaplastic (not differentiated)
How do malignant tumours and benign tumours vary in terms of local invasion?
Benign - remain local, expansile growth
Malignant - infiltrate and destroy surrounding tissues, infiltrative growth
Stroma (connective tissue) is produced by epithelial and malignant tumours. How do they differ in stroma production?
Epithelial tumours - stroma produced by surrounding, non-neoplastic mesenchymal cells
Mesenchymal tumours - produce their own stroma
How does tumour stroma growth relate to tissue growth?
As tumour increases, stroma production increases
What do tumours do to ensure they can continue growing? What would happen if this didn’t happen?
Angiogenesis - enables blood supply
If no blood supply - necrosis
How do tumour blood vessels differ to normal blood vessels?
Tumour vessels more dilated, tortuous and permeable
Why is haemorrhage a common problem with tumours?
Tumours cause angiogenesis - blood vessels often imperfect so haemorrhage
What is metastasis? What vessels does this happen via?
Transmission of cancerous cells from one site to another on the body
Blood or lymph vessels
What is a complication of metastasis? What may this lead to?
Tumour embolism - blockage of vessel
Causes infarction and oedema
What do tumours form to evade the immune system?
Homotypic or heterotypic clusters
Describe the stages that cause a tumour to metastasise
Intravasation
Tumours evade immune system
Extravasation
Extravascular tumour creates suitable environment - e.g. neovascularisation
What is intravasation? How does this happen?
Invasion of cancer cells into vessel
Due to increased permeability or digestion of basement membrane
What is extravasation? What may tumour cells have to help this occur?
Movement of cancerous cells out of vessel and into tissue
Adhesion molecules
