Biology Report on Smoking and its health effects on the circulatory system includes reference list.

INTRODUCTION

The effects of nicotine and smoking are harmful to the physiology of the human body. The ingredients in cigarette smoke cause negative effects to the body and can eventually result in death.

EFFECTS OF NICOTINE ON BRAIN

Nicotine has direct effects on the brain, which proves that it is an addictive agent. From nicotine the brain develops a certain level at which nicotine is required so that the brain can continue receiving pleasure. This level of satisfaction for the brain becomes larger and more difficult as more nicotine is introduced. Because of this many smokers experience withdrawal symptoms. Nicotine also activates certain neurons in apart of the brain called the Mesolimbic System, this is the same pathway that creates intense cravings to indulge in certain foods or activities. When this system is stimulated, the neurons secrete dopamine, which provides the brain with a chemical reward that literally arouses it. Nicotine also increases locomotor activity and head bopping-behaviour. In long term effects there is an increased risk of brain hemorrhage (stroke).

NICOTINE ADDICTION

Nicotine has been identified as being the active pharmacological agent of tobacco that causes addictive behaviour. The physical dependence characterised by a withdrawal syndrome is undergone in the absence of nicotine. This is because of the relation between nicotine and the brain. As stated above, the brain becomes dependent on being stimulated by nicotine usage by its chemical reward. One of the major factors that makes nicotine so addictive is the tolerance that smokers develop. The novice must acquire a degree of tolerance to the local irritation and autonomic side effects of nicotine before inhaling can be enjoyed. Once established, most people continue to smoke to obtain the nicotine pleasure and are unsatisfied without it, they also unconsciously modify their puff rate to maintain a steady nicotine...