Pharmacology

Activation of platelets, e.g., upon contact with collagen of the extracellular matrix after injury to the vascular wall, constitutes the immediate and decisive step in initiating the process of primary hemostasis, i.e., cessation of bleeding. However, in the absence of vascular injury, platelets can be activated as a result of damage to the endothelial cell lining of blood vessels. Among the multiple functions of the endothelium, the production of NO and prostacyclin plays an important role.

Bronchodilators Narrowing of bronchioles raises airway resistance, e.g., in bronchial or bronchitic asthma. Several substances that are employed as bronchodilators are: β2-sympathomimetics (given by pulmonary, parenteral, or oral route)methylxanthine theophylline…

ACE inhibitors, such as captopril and enalaprilat, the active metabolite of enalapril, occupy the enzyme as false substrates. Affinity significantly influences efficacy and rate of elimination. Enalaprilat has a stronger and longerlasting effect than does captopril.

The term Calcium (Ca2+) antagonist is applied to drugs that inhibit the influx of Ca2+ ions without affecting inward Na+ or outward K+ currents to a significant degree. Other labels are Ca-entry blocker or Ca-channel blocker.

The distribution of blood within the circulation is a function of vascular caliber. Venous tone regulates the volume of blood returned to the heart, hence, stroke volume and cardiac output.…

Deoxyribonucleic acid (DNA) serves as a template for the synthesis of nucleic acids. Ribonucleic acid (RNA) executes protein synthesis and thus permits cell growth. Synthesis of new DNA is a…