1.What do you understand by the term “endothelium-dependent” vasodilation?  Explain?

The concept that the endothelium controls vascular tone in a paracrine fashion (i.e. by secreting diffusible soluble mediators able to act on physically contiguous cells, in this case smooth muscle) was extremely innovative and relevant to vascular physiology

2. When we talk about the NOS enzyme, what is meant by “constitutive” and “inducible” enzymes and what are the pathological and physiological implications thereof?

iNOS are expressed through transcriptional induction (inducible) when exposed to inflammatory mediators and this expression, and thus NO synthesis, is not regulated by calcium. eNOS and nNOS are expressed constituvely (=continuously produced regardless of cells' needs) and NO synthesis is dependent on calcium regulation. Cytosolic calcium forms complexes with calmodulin which then binds and activates eNOS and nNOS.

3.Explain how NO contributes to fatal pathology of septic shock

It is a systemic inflammatory response which is caused by an infection. Some components which are present in bacteria (endotoxins, cytokines and tumor necrosis) cause the formation of iNOS in macrophages, smooth muscle cells etc. formation of NO in a large area therefore leads to severe hypertension, shock and may also lead to death. 

4.Which autacoids mechanism of action depends on effects on the guanylyl cyclase-cGMP system

Nitric oxide (NO)

5.NO may be toxic to the cell.  Which mechanisms are available to the body to counter this detrimental effect of NO?

the body makes sure that there is not an excess of NO present, for example through homeostasis.

6.Name a way in which NO can act pro-inflammatory. Give examples where it will have advantages or disadvantages.
NO is pro-inflammatory because it induces inflammation when there is an overproduction in abnormal conditions.
Benefits- Accelerates the healing of injured tissue, as the inflammation increases blood flow to the affected area.
Adverse- in a swollen joint, where it can cause pain when the joint is used.

7. In what possible neurological and mental illnesses is NO involved?
Parkinsonism, Alzheimer's, Huntington's disease, stroke