Physiology 1 - Disease and Symptoms (Woolard) Flashcards
What are the characteristics of cancer?
A group of diseases with different etiology (and underlying cause)
Characterised by abnormal cell growth through which cells may acquire the potential to metastasise from the site of origin to a secondary tumour site.
What is tumour growth dependent on?
The development of a system capable of delivering nutrients and oxygen via increased vascular supply (angiogenesis).
What are the characteristics of benign tumours?
Encapsulated and aren’t dispersing beyond their margins. The tumour cells are well-differentiated, grow slowly and generally don’t acquire the potential to metastasise.
What are the characteristics of a malignant tumour?
Cells are poorly differentiated, the process of cell division can be observed and is frequent and rapid. They gain the ability of intravasation; can break through the capsule, push away cells in the extracellular matrix and then arrest at distant sites and metastasise into a secondary tumour. Breach their “border” and can disseminate.
What is carcinoma?
Most common form of cancer, originates from embyronic endoderm or ectoderm e.g. breast, lung, colon
What is sarcoma?
Also reasonably prevalent; arising in cells of embryonic mesoderm, the supporting tissues of the body i.e. cartilage, fat, connective tissue and muscle
What is lymphoma?
Occurs within circulatory system, arising from the lymph nodes and tissues of the body’s immune system.
What is leukaemia?
Occurs within circulatory system, arising from the immature WBCs that grow in bone marrow and accumulate in large numbers in bloodstream.
What are some of the causes of cancer?
Genetic factors
Tobacco
Body weight
Physical exercise
Diet
Hormones (reproduction factors, 1st pregnancy at a late age)
Sunlight (UV)
Occupational carcinogens (benzene, pesticides, asbestos)
Infection causes (virus, cervical, bacteria, H. pylori)
Medical Tx such as chemo or radio
Pollution (diesel exhausts)
What are some symptoms of lung cancer?
Coughing up blood, chest pain, breathlessness, tiredness
What are some symptoms of pancreatic cancer?
Jaundice, development of diabetes, weight loss, stomach or back pain
What are some symptoms of breast cancer?
Lump or thickening, change in breast size, discharge, bleeding, weight loss
What can make a cell metastatic?
Mutagenic initiation via chemical, radiation, virus etc
Point mutations: missense, nonsense, silent
Chromosomal alterations: deletion, insertions, extra numbers of chromosomes, translocation
Epigenetic alterations: acetylation or methylation
Changes to DNA positioning, doled, positioned etc
How do cells get into vasculature (intravasation)?
Local invasion into vasculature; normally endothelial cells in the vessel wall are adhesive and held together by cadherins. Loss of cadherins increases permeability of the vessel to cancer cells and they gain entrance to the vessel.
Then the cancer cells express integrins that hold them on the vessel wall and allows them to cling on.
How do cancer cells survive in the vasculature?
Expression of selectins that encourages platelets to stick to the metastatic cells and provide protection from blood flow turbulence or NK killer cells.
The cells then arrest at a different site, when flow reduces in the micro-vasculature of organ tissue. Then extravasation into the extracellular environment and set up a secondary tumour site.