Cell Signalling In Human Disease Flashcards
Define pathophysiology
Altered processes leading to disease
What is vibrio cholerae?
The bacteria that causes cholera, found in infected drinking water or contaminated food.
Where does vibrio cholerae attack the body?
Enters via the mouth, colonises in the intestines, exits in many litres of fluid per day via the anal canal.
How does vibrio cholerae cause diarrhoea?
Infects cells of the intestine (mucosal cells) and prevents normal absorbing function. Excessive Cl- ion secretion occurs, causing salts and water onto be pumped out too.
What is the active agent of vibrio cholerae?
Cholera toxin
How does cholera toxin cause diarrhoea?
Targets a G protein called Gs. Cholera prevents GTP breakdown, keeping Gs in the on confirmation, so excessive Cl- secretion. This is achieved via GDP ribosylation.
What is clostridium Botulinum?
The bacteria that causes food poisoning, found in poorly preserved food and wounds.
How can C. Botulinum cause paralysis?
Secretes botulinum toxin, which is highly toxic and targets signalling at neuromuscular junction. Blocks release of acetylcholine into the neuromuscular junction, so muscle contraction cannot occur.
How is cystic fibrosis caused?
Defective ion channel function. Caused by a deletion in gene for cAMP- dependent chloride channel pump (CFTR) so epithelia of airways can no longer pump Cl- out of the cells. Increases viscosity of mucus, and causes patients to be more prone to bacterial infections.
Which signalling mechanism causes Parkinson’s disease?
G protein controlled receptors - death of neurons that release dopamine cause Parkinson’s disease, as the neurotransmitter can no longer bind to its GPCR
What is Muckle Wells syndrome?
An inflammatory condition, caused by high levels of interleukin-1 due to mutations of gene NLRP3. Causes a rash and conjunctivitis.
How can receptor tyrosine kinases cause cancer?
Due to too little signalling from tumor suppressors, too much signalling from oncogenes
What does increased EGF receptor cause?
Breast cancer.
Which drug can block over active EGF receptor tyrosine kinase?
Herceptin
