IGCSE Biology - Health & Disease

Smoking affects the respiratory system by paralyzing cilia in the trachea, preventing mucus from being wafted away.  This buildup causes coughing and the subsequent damage of the bronchiole lining and alveoli, making smokers more susceptible to disease and with less efficient gas exchange surfaces (because the surface area has gone down).  The carbon monoxide in smoke makes the smoker breathless because haemoglobin has a higher affinity with carbon monoxide than with Oxygen, so bonds with that instead.

Some symptons of gonorhhoea include a burning sensation when urinating and the dishcharge of a greenish-yellow fluid by the reproductive organ.  In anal infection, the anus becomes itchy, sore and bleeds.  These symptons sre…