Chapter 3 Healthy Lungs Air and the lungs

Chapter 3 Healthy Lungs

Air and the lungs n n n n n Lungs are the site of gas exchange Inhaled air passes - the voicebox - the windpipe - the bronchioles Ends up at the air sacs (alveoli) Each air sac is surrounded by a capillary - oxygen goes into the blood from the air sac - CO 2 goes the opposite way

Breathing rate n n n n n Number of breaths per minute - inhalation and exhalation Rate depends on level of activity - will increase with more exercise - to allow more oxygen into the blood - rate will eventually return to normal (recovery time) Breathing rate depends on - age - gender - level of fitness or health

Lung measurements n n n All depend upon: - body size, age, gender, fitness Vital capacity: - max. volume of air breathed out Tidal volume: - volume of air breathed in or out in a normal breath Both can be measured using a spirometer Peak Flow - maximum rate air can be forced out of the lungs - measured with a peak flow meter - can check the condition of the airways (e. g. asthma sufferers)

Smoking & health n n n Cigarette smoke contains: Carbon Monoxide - combines with haemoglobin in red blood cells - oxygen cannot be picked up by red blood cells - heart has to work harder (leads to heart failure) Nicotine - stimulates the nervous system - increases pulse rate & blood pressure - very addictive Tar - clogs up the hairs in the airways - contains many carcinogens (lead to cancer)

Smoking & Disease n n n Cancer - uncontrolled growth of cells - starts with lumps of cells (tumour) - tumours grow in size if undetected - 90% of lung cancer is caused by smoking Smoking & pregnancy - slows down growth of the child - baby gets less oxygen - (carbon monoxide replaces oxygen) - reduced amount of glucose to the baby - (nicotine blocks glucose) - babies often small and less intelligent