Commonly called breathing which is air moved into and out of the lungs. During inspiration and expiration so the gases there are continually changed and refreshed. External respiration. Oxygen diffuses from the lungs to the blood and carbon dioxide diffuses from the blood to the lungs. exchange between external environment (alveoli) & blood*. Transport of respiratory gases. oxygen is transported from the lungs to the tissue cells to the lungs. **THE cardiovascular system accomplishes this transport using blood as the transporting fluid. Internal respiration. oxygen diffuses from the blood to tissue cells, and carbon dioxide diffuses from tissue cells to blood.
While strong stimulants (such as cocaine) can cause seizures, the milder stimulant effects of nicotine and caffeine don't seem to impact on seizure frequency (except with extreme excess use).
Although you may have cravings to smoke weeks or even months after quitting, as more time goes by, these urges will diminish in strength and frequency. Nicotine withdrawal symptoms are more short-lived, and should only last a few days (or a couple weeks) at most.or most people, the first week of quitting is the most difficult time. This is a time when getting over both the psychological dependency on cigarettes and physical effects of nicotine withdrawal can feel overwhelming. You might feel anxious, depressed, impatient, tired, or even hostile.