2 Lung structure and function VCE Unit 1 BiologyRespirationLung structure and function
3 Structure of the respiratory system? Air enters the nose/mouthAir travels _______Air reaches major bronchiAir then gets fed through a number of smaller tubes called the _____________Air eventually reaches the _____
4 Functions of the upper airway Nose, larynx and tracheaWarms and ____________ inspired airTraps & eliminates foreign particles – involved in coughingNot involved in __________________
5 Functions of the lower airway From the ________to __________Secrete mucus to catch foreign materialCilia (hair-like structure on top of cell) can beat to push mucus back up airways where it can be coughed out
6 The alveoli are the site of gas exchange There are approximately __ _____ alveoli in our lungsThe look a bit like a bunch of grapesIf you spread out each of these alveoli, they would take up an entire ________ ________!
7 Alveoli are surrounded by capillaries Why do you think this is the case?
8 Alveoli are surrounded by capillaries Answer:Capillaries ensure that the breathed “air” is brought into close proximity to the “pulmonary” blood.This allows _________ ____ _________ _________ ___ ___ ____ ____ _______.
9 Thin tissue separates blood from alveoli ________ ___ _______ walls are thin, permitting rapid _________ of gases.Each RBC is only in lung capillary for 1 second(RBC)
10 Answer the following in your workbooks Where does gas exchange occur?What structures does air pass through to get to the site of gas exchange?What would happen if there was a thick gap between the alveoli and the capillaries?Name a disease where the gap between the alveoli and capillary is increased.What respiratory structure is affected in bronchitis and asthma?Questions to be finished for homework and handed in next class
11 Respiratory muscles allow us to inspire There are two phases in respiration (breathing): ________ ___ ________.Inspiration (breathing in) allows gas to enter the lungExpiration (breathing out) allows gas to exit the lung
12 The process of inspiration Inspiration relies on the _________ and the rib musclesThe diaphragm is _ ____ ___ _____ that separates the chest cavity from the abdomenDuring inspiration, the diaphragm and rib muscles ______. This increases the size of the chest cavity.The increase in chest cavity size _______ _______ inside the chest.As a result, the lungs are expanded and air is sucked in (just like a ______!)
13 The process of expiration _______ occurs when the _____ ____The lungs undergo a process called ______ which allows them to return to their original sizeRecoil of the lungs occurs because the lungs are very elastic – just like an elastic band!Question: what happens to an elastic band after you stretch it?
14 Muscles of Respiration ExpirationInspirationInspiratory muscles act to chest volumeDiaphragm - major inspiratory muscleRib muscles – help the diaphragm to increase chest volumeThe muscles relaxThe lungs recoil because they are elastic
15 Lung expansion relies on intrapleural pressure. How does increasing and decreasing thoracic volume alter lung volume?The lungs are only attached at the hilus!Lung expansion following increased thoracic volumes is dependent on _______ _________Lung only attached at hilus
16 What is intrapleural space? Each lung is attached to and surrounded by a thin ______ called a visceral pleural sacThe inside of the rib cage is also covered in a thin membrane called the parietal pleuraThese two membranes are separated by the a thin layer of liquid known as the ________ ______Imagine effects of drop of water between two glass sheets - easy to slide; hard to pull apartVisceral pleuraParietal pleuraIntrapleural space (-5cmH2O)
17 Why is intrapleural space important? Visceral pleuraParietal pleuraThe pressure within the intrapleural space is negative (like a vacuum). This ______ ___ _____ _____ even though they want to collapse like an elastic bandWhen the chest expands during inspiration, the intraplueral pressure becomes even more negative and sucks the lung to the chest wallThis results in the lungs ________during inspiration
18 Loss of intrapleural pressure Sheep diaphragm18
19 What is in the air we breathe? Atmospheric air contains mostly _______ gas and oxygenNitrogen makes up approximately _____ of air but is “inert”Oxygen makes up approximately ___ __ __Not much carbon dioxide is in atmospheric air – it only makes up a ____ percentage (0.0004%!)Small amounts of water vapour and other gases are also present
20 What do our cells need? The cells in our body need ______ to survive They use this oxygen in a process called __________ to create energyA by-product of metabolism is the generation of _______ ______Carbon dioxide can be _____ if it builds up in the bodyTherefore, the lungs need to supply oxygen for our cells but remove carbon dioxide
21 How do the lungs do this? Via a process called “___ ________” Gas exchange does not occur on a 1:1 basis (ie 1 molecule of oxygen is not exchanged for every molecule of carbon dioxide)Rather the entry of oxygen into the blood and the removal of carbon dioxide occurs according to differences in ________ between the alveoli and bloodThat is, it occurs via _______, down a __________ __________
22 What happens then?Once oxygen diffuses across the alveoli, it enters the blood. Which components of blood carries oxygen?Gases dissolve within the blood. They __ ___ ____ __ _______. (eg The bends in diving – what happens when bubbles of gas form in the body?)The oxygenated blood travels to the heart and then around the body to the tissues/cells.
23 Blood goes to tissues and then returns to the lung The oxygen diffuses down its concentration gradient to enter the tissuesCarbon dioxide concentrations are high in the cells. What do you think happens to the carbon dioxide here?Blood returning to the lung is deoxygenated. What does this mean?What happens to this blood at the lungs?What happens to the blood then? Think back to your circulation lessons!