2What you will learn about Mechanisms of breathing 2What you will learn aboutin this topic:The function of the respiratory systemThe mechanisms of breathingThe role of the lungsAlveoliComposition of air inhaled and exhaled
3Mechanisms of breathing 3 Learning objectivesBy the end of this presentation you should be able to:Understand the function of the respiratory systemDescribe the effects of exercise on breathingExplain what happens when you breathe
4The function of the respiratory system Mechanisms of breathing 4The function of therespiratory systemThe function of the respiratory system is to get oxygen into the body and carbon dioxide and waste products from metabolism out of the body.
5Mechanisms of breathing 5 This happens through the act of breathing. Breathing in (inhalation) gets the oxygen in, so it can be used by the body to release energy.Breathing out (exhalation) removes the carbon dioxide so it does not build up and poison the body.
6The following are all parts of the respiratory system: Air passages Mechanisms of breathing 6The following are all parts of the respiratory system:Air passagesLungsDiaphragm
7Composition of inspired Mechanisms of breathing 10Composition of inspiredand expired airThe air we breathe in is very different from the air we breathe out.The parts that make up inhaled and exhaled air are called its composition.
8Percentage of air inhaled: Mechanisms of breathing 11Percentage of air inhaled:KeyNitrogenOxygenCarbon dioxideOther
9Percentage of air exhaled: Mechanisms of breathing 12Percentage of air exhaled:KeyNitrogenOxygenCarbon dioxideOther
10The link between respiration Mechanisms of breathing 13The link between respirationand circulationOxygen goes from the respiratory system to the circulatory system and then back to the respiratory system.
11Mechanisms of breathing 14 Oxygen breathed in goes through the mouth or nose, down the trachea, into the lungs and into the alveoli.
12Oxygen joins with haemoglobin to make oxyhaemoglobin. Mechanisms of breathing 15Oxygen then passes through the alveoli walls into the red blood cells, via the capillaries.Oxygen joins with haemoglobin to make oxyhaemoglobin.The oxyhaemoglobin is used by the working body and is transported by the circulatory system to cells needing to release energy.
13Mechanisms of breathing 16 Carbon dioxide is produced as a waste product. This is converted into a gas and passes back through the alveoli walls, via the capillaries into the blood plasma.The carbon dioxide passes through the capillary and alveoli walls into the alveoli. It is then exhaled from the body.
14Parts of the respiratory system Mechanisms of breathing 17Parts of the respiratory system
15The mechanism of breathing Mechanisms of breathing 18The mechanism of breathingLungs are not muscle, cannot move of their own accord and are not controlled by the central nervous system.The key to breathing is the diaphragm and the intercostal muscles between the ribs.Expiration
16When we breathe in (inspiration) the following happens: Mechanisms of breathing 19When we breathe in (inspiration) the following happens:The diaphragm pulls downThe intercostal muscles contractAir pressure is reducedAir is sucked through the tubes into the lungsThe chest expands.
18When we breathe out (expiration) the opposite happens: Mechanisms of breathing 21When we breathe out (expiration) the opposite happens:The diaphragm relaxes into its dome positionThe intercostal muscles relaxThe chest becomes smallerPressure increases in the lungsAir is forced out
20Mechanisms of breathing 23 Task 1In groups of four, write 13 statements on 13 pieces of card (one on each card) about the route of oxygen and carbon dioxide around the body.Put your cards in order, starting and ending with a card marked ‘Oxygen is inhaled’.Teacher’s notesPossible answers are given on slides 24 to 27.
21Possible answers to Task 1 Mechanisms of breathing 24Possible answers to Task 1Oxygen passes through the larynx and trachea.Oxygen arrives in the lungs via the bronchi and bronchioles.Oxygen passes to the alveoli and transfers to the haemoglobin through the plural membrane
22The heart pumps the blood through the aorta to the arteries. Mechanisms of breathing 25The haemoglobin in the red blood cells binds with the oxygen to become oxyhaemoglobin.The blood travels through the pulmonary vein to the left side of the heart.The heart pumps the blood through the aorta to the arteries.The arteries carry the oxygenated blood around the body.
23The veins carry the deoxygenated blood. Mechanisms of breathing 26The haemoglobin releases the oxygen at the muscles and collects the carbon dioxide; the blood is now considered deoxygenated.The veins carry the deoxygenated blood.The deoxygenated blood arrives at the heart.
24The carbon dioxide passes through the trachea and is exhaled. Mechanisms of breathing 27The heart pumps the deoxygenated blood back to the lungs via the pulmonary artery.The carbon dioxide passes across the pleural membrane and into the alveoli.The carbon dioxide passes through the trachea and is exhaled.
25Mechanisms of breathing 28 The role of the lungsThe lungs are positioned inside the chest cavity and are protected by the ribcage.
26The pleural membrane is smooth and has a moist, slimy mucus. Mechanisms of breathing 29The action of breathing means that the lungs are constantly moving in and out. To protect them from any friction due to the movement, the pleural membrane forms a complete lining around them.The pleural membrane is smooth and has a moist, slimy mucus.
27Alveoli Alveoli are tiny air sacs at the end of the bronchioles. Mechanisms of breathing 30AlveoliAlveoli are tiny air sacs at the end of the bronchioles.
28There are millions of them that allow gases to exchange inside them. Mechanisms of breathing 31There are millions of them that allow gases to exchange inside them.Oxygen passes across the pleural membrane and into the blood. Carbon dioxide passes from blood to the alveoli.
29Here is a simplified version of what happens: Mechanisms of breathing 32Here is a simplified version of what happens:Oxygen from the air breathed in enters the circulatory system to be used by the working muscles.
30Mechanisms of breathing 33 Carbon dioxide, which is toxic to the system, transfers from the used blood, out of the circulatory system, back into the alveoli, to be breathed out along with oxygen, water and nitrogen.
31Mechanisms of breathing 34 The capillaries, covering the surface of the alveoli, link the respiratory system with the circulatory system.Regular exercise conditions the lungs to excrete more of the carbon dioxide from the body.
32Mechanisms of breathing 35 Tidal volume is the amount of air breathed in and out of the body during normal breathing.During exercise, the volume is forced to change. It is then called forced breathing.
33Mechanisms of breathing 36 Vital capacity is the largest amount or volume of air that can be exhaled after the largest possible inhalation.Residual volume is the amount of air that, even after as much air as possible has been exhaled, is left in the lungs.
34Mechanisms of breathing 37 Task 2In groups of four, describe the action of breathing using the following words to help you:NoseMouthTracheaLungsRibsIntercostal musclesDiaphragmTeacher’s notesPossible answers are given on slide 38.
35Possible answers to Task 2 Mechanisms of breathing 38Possible answers to Task 2From the nose or mouth, air enters the trachea and moves towards the lungs.The trachea divides into two branches called the bronchi. These sub-divide into smaller tubes called bronchioles.During heavy exercise the body uses the intercostal muscles between the ribs to aid the diaphragm in the exhalation of air from the lungs.At the end of the bronchioles are alveoli.Alveoli are air sacs with many tiny blood vessels called capillaries running from them.
36Explain the process of inspiration. Mechanisms of breathing 39Exam questionsExplain the process of inspiration.Explain the process of expiration.
37What you have learnt about Mechanisms of breathing 40What you have learnt aboutin this topic:The function of the respiratory systemThe mechanisms of breathingThe role of the lungsAlveoliComposition of air inhaled and exhaled
38Learning objectives You should now be able to: Mechanisms of breathing 41Learning objectivesYou should now be able to:Understand the function of the respiratory systemDescribe the effects of exercise on breathingExplain what happens when you breathe