TRACHEA LEFT BRONCUS BROCHIOLES RIGHT BRONCUS

DIAPHRAGM contracts & flattens to make the chest cavity bigger. The DIAPHRAGM muscle contracts & flattens, whilst the INTERCOSTAL muscles raise the thorax and sternum out. The chest cavity is now bigger which lowers the pressure in the lungs to less than that of the environment. Air is drawn into the lungs ( as gases will always move from higher pressure to lower pressure areas ).

The DIAPHRAGM muscle relaxes and forms a dome shape, whilst the INTERCOSTAL muscles relax to lower thorax and sternum in. The chest cavity is now smaller which raises the pressure in the lungs to more than that of the environment. Air is drawn out of the lungs ( as gases will always move from higher pressure to lower pressure areas ). DIAPHRAGM relaxes to make the chest cavity smaller.

VITAL CAPACITY– the max amount of air that can be breathed out after a max inspiration. TIDAL VOLUME – the amount of air breathed in and out with each breath. INSPIRATORY RESERVE VOLUME – the max amount of air that can be breathed in on top of a normal inspiration. EXPIRATORY RESERVE VOLUME – the max amount of air that can be breathed out after a normal expiration. RESIDUAL VOLUME – the amount left in the lings after a max forced expiration. TOTAL LUNG CAPACITY – residual volume plus vital capacity.

VITAL CAPACITY– the max amount of air that can be breathed out after a max inspiration. TIDAL VOLUME – the amount of air breathed in and out with each breath. INSPIRATORY RESERVE VOLUME – the max amount of air that can be breathed in on top of a normal inspiration. EXPIRATORY RESERVE VOLUME – the max amount of air that can be breathed out after a normal expiration. RESIDUAL VOLUME – the amount left in the lings after a max forced expiration. TOTAL LUNG CAPACITY – residual volume plus vital capacity. RESIDUAL VOLUME

Gaseous exchange occurs because of differences in concentration or pressure levels. Gases will always move from an area of high concentration or pressure to an area of low concentration or pressure.

When air is breathed in and arrives at the alveoli it has a high concentration of oxygen. The capillaries surrounding the alveoli have blood with a low concentration of oxygen. Therefore oxygen will diffuse from the alveoli into the capillaries and combine with haemoglobin in the red blood cells. ALVEOLI CAPILLARIES O 2 O 2 O 2 O 2 O 2 O 2 CAPILLARY

When oxygenated blood arrives at the muscle it has a high concentration of oxygen. The working muscle has a low concentration of oxygen. Therefore oxygen will diffuse from the capillaries into the muscle cells. CAPILLARIES MUSCLE TISSUE O 2 O 2 O 2 O 2 O 2 O 2 CAPILLARY

The working muscles will produce a waste product called carbon-dioxide ( CO 2 ) The working muscle builds up a high concentration of CO 2. The capillaries arriving at the muscle will have a low concentration of CO 2. Therefore CO 2 will diffuse from the muscle into the capillaries. ( only about 20 % of CO 2 is carried by the haemoglobin – the rest is dissolved in the plasma or in the form of a bicarbonate ion ) MUSCLE TISSUE CAPILLARIES CO 2 CO 2 CO 2 CO 2 CO 2 CO 2 CO 2 CO 2 CO 2 CAPILLARY

The blood arriving back at the lungs has a high concentration of CO 2. The alveoli have a low concentration of CO 2. Therefore CO 2 will diffuse from the capillaries into the alveoli so it can be breathed out. CAPILLARIES ALVEOLI CO 2 CO 2 CO 2 CO 2 CO 2 CO 2 CAPILLARY

1.The function of the respiratory system is to : A/pump blood around the body. B/regulate hydration levels. C/extract oxygen from the air. D/all of the above. E/none of the above. 2.At rest, the average adult would breathe approximately: A/35 times per minute. B/25 times per minute. C/15 times per minute. D/5 times per minute. 3.The pathway from the environment to the lungs is as follows: A/pharynx - larynx - trachea - bronchi - bronchioles - alveoli. B/trachea - pharynx - bronchi - larynx - bronchioles - alveoli. C/alveoli - bronchioles - bronchi - trachea - pharynx - larynx. D/larynx - pharynx - trachea - bronchi - bronchioles - alveoli.

4.Ventilation is: A/the amount of air breathed in one minute. B/tidal volume multiplied by respiratory rate. C/the amount of air per breath multiplied by the number of breaths per minute. D/all of the above. E/none of the above. 5.The major muscles used in respiration are the: A/diaphragm and abdominals. B/diaphragm and intercostals. C/Abdominals and intercostals. D/trapezius and peroneus longus. 6.During expiration the diaphragm: A/contracts and flattens. B/relaxes and flattens. C/contracts and becomes dome shape. D/relaxes and becomes dome shape.

7.The volume of air remaining in the lungs after a forced max. expiration is the: A/expiratory reserve volume. B/tidal volume. C/residual volume. D/vital capacity. 8.The exchange of gas in the lungs takes place between which two structures ? A/capillaries and muscle cells B/capillaries and alveoli C/arteries and veins D/veins and alveoli 9.The exchange of gas at the muscle takes place between which two structures ? A/capillaries and muscle cells B/capillaries and alveoli C/arteries and veins D/veins and muscle cells