Blood Vessels
Smoking is dangerous for our body. It can cause some life threatening diseases such as stroke and heart attack. The heart attack and stroke are basically the result of high blood pressure caused by the smoking. Due to the smoking, nicotine and tar enter the body through lungs it affects the blood circulatory system. It constricts the blood vessels due to the accumulation of tar, nicotine and other harmful substances on the inner lining of blood vessels, especially arteries. This induces the heart to pump more blood to maintain the flow of blood, which results in an increase of blood pressure.

Oxygen Deficit
Smoking causes accumulation of tar and mucus in the lung around the alveoli, which reduces the oxygen retention capacity of the lungs. Therefore, respiratory system of lungs gets affected, which results in oxygen deficit in the body. The respiratory system of the body oxidizes the blood and provides it to the organs and cell for their function. In lack of the adequate oxygen cardiovascular system is induced to pump more blood starts pumping more blood to maintain the oxygen level in the body. This whole process to maintain the oxygen level in the blood results in the rise of blood pressure.

Cardiac Output
The cardiovascular system is responsible for the blood circulation in the body. Heart is a vital organ that pumps the impure blood to the lungs and pure oxidized blood to the various parts of organs. When a person smokes, the nicotine, carbon monoxide and other harmful substances accumulate in the lung that reduces the oxygen retention capacity. That results in lack of an adequate amount of oxygen in the body. When the brain detects the low oxygen level it induces heart to pump blood faster so that oxygen level can be maintained in the body. The increase in cardiac output of pumping blood increases the blood pressure in the body.   

Stimulation of Adrenal Glands
The adrenal glands are responsible for secretion of many hormones, which regulates body health. During smoking, the nicotine level increases in blood which stimulates adrenal glands to release excessive hormones such as epinephrine, norepinephrine and aldosterone. Epinephrine acts as a neurotransmitter, which increases the heart rate that results in the increase in blood pressure. Similarly, norepinephrine tightens the blood vessels and affects the blood pressure. The secretion of aldosterone increases the sodium retention that increases the water retention, which results in the higher blood pressure. Basically, the presence of nicotine in the blood causes hormonal imbalance, which results in an increase in blood pressure.

Cough
Usually, the cough is considered as the sign of any respiratory infection. The accumulation of tar and other harmful substances in the lungs causes secretion of mucus. The presence of mucus irritates the defensive mechanism of lungs and to clear the lungs the mechanism induces coughing. The cilia that present in the lining of lungs are sensitive to the toxins such as arsenic, methane and carbon monoxide. When a person smokes these toxins enter the lung and stimulate cilia, which results in coughing. The coughing causes stress on the lungs to remove the irritant from the lungs. The chronic cough increases the blood pressure to get rid of the foreign body present in the lungs.