Growth, cell death and neoplasia Flashcards
Granulation tissue definition
New connective tissue and microscopic blood vessels that form on the surfaces of wound during the healing process
Healing by 1st intention definition
Primary healing that occurs when a clean laceration/surgical incision is closed, usually with sutures, steri-strips, or skin adhesive
Healing by 2nd intention definition
Secondary healing of an open wound from the base upwards by laying down new tissue
Apoptosis definition
Programmed cell death
Necrosis definition
Traumatic cell death of large areas of cells
Hypertrophy definition
An increase in size of a tissue caused by an increase in size of the constituent cells
Hyperplasia definition
An increase in size of a tissue caused by an increase in number of the constituent cells
Atrophy definition
A decrease in size of a tissue caused by a decrease in number of the constituent cells or a decrease in their size
Metaplasia definition
A change in differentiation of a cell from one fully-differentiated type to a different fully-differentiated type
Dysplasia definition
An imprecise term for the morphological changes seen in cells in the progression to becoming cancer
Congenital disorder definition
A condition present at birth
Inherited disorder definition
A condition caused by an inherited genetic abnormality
Acquired disorder definition
A condition caused by non-genetic environmental factors
Acromegaly definition
A rare condition where the body produces too much growth hormone, causing body tissues and bones to grow more quickly
Progeria definition
A disease causing premature ageing in children
Telomere definition
A compound structure at the end of a chromosome which allows replication of DNA so a cell can divide
Osteoporosis definition
A decrease in the normal bone matrix where the bones become brittle and fragile
Cataracts definition
A condition where the lens of the eye becomes progressively opaque, resulting in blurred vision, caused by tissue breakdown and protein clumping
Senile dementia definition
Progressive brain atrophy occurring in old age causing deteriation in memory, thinking, behaviour and the ability to perform everyday activities
Sarcopenia definition
The loss of skeletal muscle mass and strength as a result of ageing
Deafness definition
A condition of impaired hearing or hearing loss
Adjuvant therapy definition
Treatment given in addition to the primary/initial treatment
Carcinogenesis definition
The transformation of normal cells to neoplastic cells through permanent genetic alterations or mutations
Oncogenesis definition
The formation of benign or malignant tumours
Carcinogen definition
An agent known or suspected to cause cancer
Carcinogenic definition
Cancer causing
Oncogenic definition
Tumour causing
Mutagenic definition
Acts on DNA
Tumour definition
Any abnormal swelling including neoplasia, inflammation, hypertrophy, and hyperplasia
Neoplasm definition
A lesion resulting from the autonomous or relatively autonomous abnormal growth of cells which persists after the initiating stimulus has been removed
Angiogenesis definition
The formation of new blood vessels
Benign neoplasm definition
A localised, non-invasive, non-cancerous growth
Malignant neoplasm definition
An invasive, cancerous growth which can metastasise
Metastasis definition
The development of secondary malignant growths away from the primary site of cancer
Histogenesis definition
The specific cell of origin of a tumour
Papilloma definition
A benign tumour of non-glandular, non-secretory epithelium
Adenoma definition
A benign tumour of glandular or secretory epithelium
Carcinoma definition
A malignant tumour of epithelial cells
Adenocarcinoma definition
A malignant tumour of glandular epithelium
Lipoma definition
A benign tumour of adipocytes
Chondroma definition
A benign tumour of cartilage
Osteoma definition
A benign tumour of bone
Angioma definition
A benign tumour of blood vessels
Rhabdomyoma definition
A benign tumour of striated muscle
Leiomyoma definition
A benign tumour of smooth muscle
Sarcoma definition
A malignant tumour of connective tissue
Anaplastic definition
Where the cell-type of origin of a tumour is unknown
Liposarcoma definition
A malignant tumour of adipose tissue
Rhabdomyosarcoma definition
A malignant tumour of striated muscle
Leiomyosarcoma definition
A malignant tumour of smooth muscle
Chondrosarcoma definition
A malignant tumour of cartilage
Osteosarcoma definition
A malignant tumour of bone
Angiosarcoma definition
A malignant tumour of blood vessels
Melanoma definition
A malignant tumour of melanocytes
Mesothelioma definition
A malignant tumour of mesothelial cells
Lymphoma definition
A malignant tumour of lymphoid cells
Burkitt’s lymphoma definition
A rare type of non-Hodgkin lymphoma
Ewing’s sarcoma definition
A rare type of cancer affecting the bones or tissue around the bones
Grawitz tumour definition
Renal cell carcinoma
Kaposi’s sarcoma definition
A type of angiosarcoma caused by the human herpesvirus 8 (HHV-8)
Teratoma definition
A neoplasm which contains cells from all three germ cell layers of the embryo
Blastoma definition
A neoplasm which arises from tissue that has remained embryonic
Mixed tumour definition
A neoplasm derived from multiple tissue types
APDUomas definition
Endocrine tumours arising from an APDU cell (amine content and/or precursor uptake and decarboxylation)
Carcinosarcoma definition
A malignant tumour that consists of both epithelial and connective tissue
Name some cells which are capable of regeneration
Hepatocytes, pneumocytes, all blood cells, gut epithelium, skin epithelium, osteocytes
Name some cells which are not capable of regeneration
Myocardial cells, neurones
How does apoptosis differ to necrosis?
- Apoptosis = deliberate, suppresses inflammatory response so harmful produces do not harm surrounding cells
- Necrosis = unintended, causes an inflammatory response causing traumatic cell death of a large area of cells
How does the intrinsic apoptotic pathway function?
The ratio of Bcl-2 to Bax determines the cell’s susceptibility to apoptotic stimuli since Bcl-2 inhibits caspases
How does the extrinsic apoptotic pathway function?
Binding of ligands to ‘death receptors’ (such as tumour necrosis factor receptors e.g. TNFR1, Fas) activates caspases
How does apoptosis play a role in disease?
- In cancer there is usually a lack of apoptosis
- In HIV the virus induces premature apoptosis in T helper cells
Give examples of apoptosis inhibitors
- Growth factors
- Extracellular matrix
- Sex steroids
- Some viral proteins
Give examples of apoptosis inducers
- Growth factor withdrawal
- Loss of matrix attachment
- Glucocorticoids
- Some viruses
- Free radicals
- Ionisation radiation
- DNA damage
- Ligand-binding at ‘death receptors’
How does necrosis cause inflammation?
The plasma membrane is ruptured which causes the release of the cell contents, containing immunostimulatory factors prevoking an inflammatory response and leads the way for repair.
Name and describe the 4 types of necrosis
- Coagulative necrosis - commonest form, caused by ischaemia
- Liquefactive necrosis - occurs in the brain since lack of supporting stroma causes necrotic neural issue to liquefy
- Caseous necrosis - characteristic in TB where dead tissue becomes structureless
- Gangrene - the rotting of tissues, often caused by certain bacteria where the affected tissue appears black due to the deposition of iron sulphidefromdegraded haemoglobin
What stimulates hypertropy of uterine smooth muscle and when?
Oestrogens during puberty and pregnancy
Which cells can hyperplasia not occur in and why?
Cardiac myocytes and nerve cells because they cannot replicate
How is atrophy involved in GU development?
Involution of the Wollfian duct in females and the Mullerian duct in males
Give 3 examples of metaplasia
- In smokers: ciliated respiratory epithelium of the trachea and bronchi -> squamous epithelium
- In Barrett’s Oesophagus (due to prolonged exposure to stomach acid): Squamous epithelium of the oesophagus -> columnar epithelium
- Physiological changes in the cervix during puberty
Why does shortened telomeres prevent cell replication?
DNA polymerase is unable to engage with the DNA
What causes sarcopaenia?
Ageing causing decreased growth hormone, decreased testosterone and increased catabolic cytokines
What causes age-related deafness?
Loss of hair cells in the ear
What causes senile dementia?
Brain atrophy since the nerve cells cannot replicate as well as to plaques and neurofibrillary tangles with lots of amyloid proteins
What causes age-related cataracts?
UV light damage resulting in cross-linked proteins in the eye
What causes age-related osteoporosis?
Lack of oestrogen as well as lack of vitamin D and calcium in early life
What is dermal elastosis and what causes it?
Wrinkling caused by UV light damage resulting in less collagen and less elastin in the skin so it becomes more fragile
Why can neoplasms not arise from red blood cells?
RBCs don’t have a nucleus but neoplasms can arise from RBC precursors such as erythrocytes
Why does the incidence of cancer increase with age?
The probability of neoplastic transformation increases with the number of times cells divide. Also as you age there is likely greater exposure to carcinogens
How does a carcinogen cause cancer?
They increase the probability of mutation events occuring so there is more chance that the DNA repair mechanisms will fail
Give 3 problems in identifying carcinogens
- Latent interval may be decades
- Complexity of the environment
- Ethical constraints
What are the 5 classes of carcinogens?
- Chemical
- Radiant energy e.g.UV light, ionising radiation
- Biological agents e.g. hormones, mycotoxins, parasites
- Miscellaneous carcinogens e.g. asbestos, metals
- Host factors e.g. race, age, diet etc
What are the 3 behavioural categories of tumours?
Benign, malignant and borderline
Give some key features of benign tumours
- Localised
- Slow growing
- Non-invasive
- Do not spread to other sites
- Close resemblance to normal tissue
- Rarely causes ulceration and necrosis
What are borderline tumors?
Quite rare tumours that are had to classify since they can appear benign but act malignantly e.g. ovarian lesions
Give some key features of malignant tumours
- Invade and destroy tissues
- Able to metastasise
- Rapid growth
- Irregular border
- Little resemblance to parent tissue
- Nuclei are hyperchromatic (stain darkly), pleomorphic (vary in shape and size) and have increased mitotic activity
- Necrosis and ulceration
What is histogenetic classification?
Classifying tumours according to the specific cell or origin of the tumour
What are the major subdivisions of histogenetic classification and what do they form?
- Epithelial cells – forming carcinomas
- Connective tissue – forming sarcomas
- Lymphoid (only gives malignant neoplasms) and/or haemopoietic organs (lymphomas or leukaemias)
How do benign tumours cause morbidity and mortality?
- Pressure on adjacent structures
- Obstruction to the flow of fluid
- Production of a hormone
- Transformation into a malignant neoplasm
- Anxiety & stress
How do malignant tumours cause morbidity and mortality?
- Pressure on and destruction of adjacent tissue
- Formation of secondary tumours (metastases)
- Blood loss from ulcerated surfaces
- Obstruction of flow
- Hormone production
- Paraneoplastic effects resulting in weight loss and debility
- Anxiety and pain
What are the grades of malignant tumours?
- Grade 1 - Well differentiated
- Grade 2 - Moderately differentiated
- Grade 3 - Poorly differentiated
What are anaplastic tumours?
Tumours that are so poorly differentiated that they lack recognisable histogenic features
What are the steps in the invasion process of malignant tumours?
- A cell has acquired a mutation and is now cancerous
- The cell divides faster than the normal surrounding cells/ the cell doesn’t apoptose so it starts displacing the normal cell population
- The area is filled with cancer cells which haven’t spread = carcinoma in situ
- Proteases are produced and cells have some motility to pass through the basement membrane
- After invading through the basement membrane it has entered the extracellular matrix
What are the steps in metastasis?
- Detachment of tumour cells from their neighbours
- Invasion of the surrounding connective tissue to reach conduits of metastasis i.e. blood & lymphatic vessels
- Intravasation into the lumen of vessels
- Evasion of host defence mechanisms, such as natural killer cells in the blood
- Adherence to endothelium at a remote location
- Extravasation of the cells from the vessel lumen into the surrounding tissue
What are the 3 common locations for metastasis?
Lung, liver, bone
Which 5 carcinomas frequently metastasise to bone?
Lung, breast, kidney, thyroid and prostate carcinomas
What are 4 common locations which cause liver metastases?
Colon, stomach, pancreas and small intestine cancers
What is the TNM staging system and what does each letter represent?
A classification shows the extent of a tumours spread
- T = primary tumour size, suffixed by a number that denotes tumour size (varies according to the organ of the tumour
- N = lymph node status, suffixed by a number denoting the number of lymph nodes or groups of lymph nodes containing metastases
- M = the anatomical extent of distant metastases
