Download B 1.5, 1.6, 1.7 – Breathing, lungs, inhaled and exhaled air

THE WESTMINSTER SCHOOL, DUBAI
B 1.5 – BREATHING
http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/1_anatomy_respiratorysys_rev1.s
html
The act of breathing is part of the respiratory system, a complex process where air travels into
and out of the lungs.
Respiration is slightly different, where exercise causes muscles to release energy in the form of
glucose. Both systems are co-dependent, especially when you’re playing sport and inhaling
greater quantities of oxygen.
Breathing:http://www.youtube.com/watch?v=o2OcGgJbiUk
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Air is warmed, moistened and filtered as it travels through the mouth and nasal passages.
It then passes through the trachea and one of the two bronchi into one of the lungs.
After passing into the many bronchioles, it finally arrives into some of the millions of tiny sacs
called alveoli.
This is where gas exchange takes place - oxygen passes out of the air into the blood, and carbon
dioxide passes out of the blood into the air in the alveoli.
When you inhale:http://www.youtube.com/watch?v=Mf8xTqfspp4
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the intercostal muscles contract, expanding the ribcage.
the diaphragm contracts, pulling downwards to increase the volume of the chest.
pressure inside the chest is lowered and air is sucked into the lungs.
When you exhale:
the intercostal muscles relax, the ribcage drops inwards and downwards
the diaphragm relaxes, moving back upwards, decreasing the volume of the chest.
pressure inside the chest increases and air is forced out.
B 1.6 – LUNGS
The right lung is a little bigger than the left lung. This is because the left lung has to fit around
the heart making it slightly smaller.
The lungs are split into lobes. The left lung is split into 2 lobes while the right lung is split into 3
lobes. Lungs have a very spongy texture and have a large surface area.
Capillary
The alveoli are adapted to make gas exchange in lungs happen easily and efficiently. They have
moist, thin walls (just one cell thick). They give the lungs a really big surface area. They have a
lot of tiny blood vessels called capillaries.
Diffusion is the process by where gases move from a high concentration to a low concentration:
Oxygen diffuses from the air in the alveoli into the blood.Carbon dioxide diffuses from the blood
into the air in the alveoli.
Emphysema is a chronic lung disease caused by damage to the alveoli, the tiny air sacs in the
lung where exchange of oxygen and carbon dioxide takes place. With emphysema, damage to the
alveoli results in air becoming trapped, causing them to expand and rupture.The most common
symptom is shortness of breath. The most common cause is smoking.People with emphysema
are also at increased risk of developing lung cancer. Quitting smoking is very important for
individuals living with this condition, and can help to slow the progression of the disease.
Keeping the lungs clean: The goblet cells in the bronchioles produce mucus which traps foreign
substances in the airway such as pollen, pathogens and dust particles. The cilia of the ciliated
cells will then waft the mucus and the trapped particles up to the larynx where it can be
swallowed and the pathogens can be destroyed by the stomach acid.
B 1.7 - INHALED AND EXHALED AIR
Inhaled air contains:
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more oxygen used to create energy
less carbon dioxide than…
Exhaled air which contains:
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more carbon dioxide produced as a waste product of energy production
less oxygen as it has been used in respiration
Gas exchange takes place by diffusion in the alveoli within the lungs. As a result the
composition of inhaled and exhaled air is different.
Aerobic respiration is the form of respiration which uses oxygen. It can be summarised by this
equation: glucose + oxygen → carbon dioxide + water (+ energy)
C6H12O6 + 6O2 → 6CO2 + 6H2O
Energy is shown in brackets because it is not a substance. Notice that:
 Glucose and oxygen are used up
 Carbon dioxide and water are produced as waste products.