2Learning ObjectivesTo identify and describe 5 structures of the respiratory system.To describe the process of inspirationTo describe the process of expiration
3Starter ActivityWrite a list of as many structures of the respiratory system as you can.
4Introduction The purpose of the respiratory system is to… “bring the air we breathe into close contact with the blood so that oxygen can be absorbed and carbon dioxide removed.”Basically it consists of:A pair of lungs connected to the mouth via the trachea and bronchi.The ribs and intercostal muscles of the chest which protect the lungs, trachea and bronchi.
5Respiratory SystemThe lungs are in the thoracic cavity and are also protected by 12 pairs of ribs that articulate with the vertebrae towards the back of the body. The sternum breastbone) is at the front of the rib cage.SternumThe portions of the ribs that articulate with the breastbone are made of cartilage rather than bone.Cartilage is softer and more pliable than bone and this helps the movement of the rib cage during breathing.Sets of antagonistic muscles are found between the ribs - the intercostal muscles.Cartilage
6Position of the diaphragm The Thoracic CavityThis chest X-ray shows the organs within the thoracic cavity.RibsAir-filledlungPositionofthe heartPosition of the diaphragm
7The Respiratory System Trachea(wind pipe)RibsAlveoliBronchusBronchiolesLungIntercostalmusclesDiaphragm
8The trachea or windpipe is about 10 cm long and is supported by C-shaped rings of cartilage toprevent the tube from collapsing during breathing.Air enters the body through the nasal passages and mouth, and passes via thepharynx and larynxto the trachea.The tracheasubdivides into the left and right bronchus.The bronchi arealso strengthenedby cartilage.Air is delivered tothe alveoli as thetrachea branchesinto bronchi andbronchioles.The two bronchisubdivide to forman extensive network ofBronchioles that deliver air to the gas exchangesurfaces – the alveoli.
11Worksheet – Identify and describe the different structures of the lungs
12Functions of the respiratory system Mechanism of breathing (inspiration and expiration)Gaseous exchange
13The Mechanism of Breathing They are not controlled by the central nervous systemLungs are NOT muscleLungs cannot move of the own accordSo, how do they move when we breath in and out?
14The Mechanism of Breathing The Key to Breathing is the Diaphragm and the intercostal muscles between the Ribs
15The nasal passages and lungs Air is drawn into the body via the nose or mouth. There are advantages to breathing through your nose:the air is warmed so that it is closer to body temperaturetiny hairs and mucus in the nose filter the air, preventing larger dust and pollen particles reaching the alveolimucus moistens the air, making it easier for the alveoli to absorb.Air then travels through the larynx, trachea (windpipe), bronchi (one bronchus to each lung) and bronchioles to the alveoli, where oxygen passes into the bloodstream.
16Inspiration When you breathe in: Intercostal muscles pull ribs up and outWhen you breathe in:intercostal muscles between the ribs contract, pulling the chest walls up and outthe diaphragm muscle below the lungs contracts and flattens, increasing the size of the chestthe lungs increase in size, so the pressure inside them falls. This causes air to rush in through the nose or mouth.Diaphragm contracts and moves down
18Diaphragm relaxes and bulges up ExpirationWhen you breathe out:Ribs move in and downIntercostal muscles between the ribs relax so that the chest walls move in and down.The diaphragm muscle below the lungs relaxes and bulges up, reducing the size of the chest.The lungs decrease in size, so the pressure inside increases and air is pushed up the trachea and out through the nose or mouth.Diaphragm relaxes and bulges up
20Summary of respiratory system Air passes through the nose or mouth and then on to the larynx.It carries on through the trachea.The trachea splits into tubes called bronchi (each one is a bronchus) – one each going to the lungs.The bronchi split into progressively smaller tubes called bronchioles.The bronchioles finally end at small bags called alveoli (each one is an alveolus) where the gas exchange takes place.
21Summary Task 1 bronchi bronchioles trachea larynx alveoli List the following five words in the order that breathed in air would go through themtrachealarynxalveoli
22Summary Question TimeDuring exercise why is it better to breath in through our nose rather than our mouths????When air is breathed in through the nose, it is:Filtered by the hairs at the entrance to the nose and by mucus which is a sticky substance.Warmed by blood vessels passing to the lining of the nose.Moistened by water vapour.The trachea and the bronchi also help get the air ready – they have tiny hairs and are covered in mucus helping to clean the air.