B6 Respiration

6.2 Gas ExchangeB6 RespirationIdentify and label the parts of the respiratory system

Identify and label the parts of the respiratory system

pharynxlarynxtrachearibbronchiolediaphragmbronchusmouthnoseplural membraneintercostal musclelungalveolusGas exchangeOccurs at alveoliOxygen diffuses into capillariesCarbon dioxide diffuses out of capillariesOccurs at cellsOxygen diffuses into cellsCarbon dioxide diffuses into capillaries

Copy into your books the diagram on p121 Red blood cells in an alvelousAlveolar circulation5Features of gas exchange surfacesGas exchange surfaces in animals have features that make them more efficient:Large surface areaMoist surface so gases will dissolveWalls that are only 1 cell thick to reduce diffusion distanceA good blood supply to maintain concentration gradient.

Click on the Passage of air buttonsThe mechanics of breathingInhalationExhalationIntercostal musclescontractrelaxDiaphragmcontractsrelaxesVolume of thoraxincreasesdecreasesPressure in thoraxdecreasesincreasesEffectair is pulled inair is pushed outRespiratory systemWhat are the differences between inhaled and exhaled air? inhaled airnitrogen (78%)oxygen (21%)carbon dioxide (0.04%)other

Comparing inhaled and exhaled airCopy in the table on p120 to show the different compositions.exhaled airnitrogen (78%)oxygen (17%)carbon dioxide (4%)other

10The cells lining the nose and trachea are designed to trap dust and bacteria.

ciliated epithelial cellsMucous and ciliatracheaThe cells that line the wall of the trachea show two special adaptations. We say the cells show specialisation. These specialised cells have a particular job to do. produce a sticky liquid - mucous tiny hairs called cilia

Ciliated epithelial cells ciliated cellsmucus being made by the ciliated cellsmicrobes travelling down the trachea within inhaled airmicrobes become stuck within the mucusThe presence of mucus and cilia on the lining of the trachea ensures that the air we breathe is clean and free from disease. Mucus cells and ciliaTobaccoTobacco comes from the Americas and was introduced to the rest of the world by traders. Can be taken in the form of cigarettes, cigars, pipes and chewing tobacco.The tobacco plant is called Nicotiana tobacca

TobaccoThe plant makes an insecticide called nicotineNicotine acts as an addictive drug in our bodyin the blood stream, nicotine acts as a stimulant to make the heart beat faster and the small arteries narrow thus increasing blood pressure.nicotine increases the stickiness of blood plateletsUse p164-165 to describe the effects of the other components of smoke on our bodies:TarCarbon monoxideSmoke particles

Effects of smokingThe chemicals in tobacco smoke have effects on the heart, circulatory system and the respiratory system.Hot tobacco smoke can irritate the mucus-producing cells and cause cilia to stop beating:Chronic bronchitis is caused when bacteria-filled phlegm (mucus) blocks the bronchi, making it harder to breathe. smokers cough to help move the phlegm outEmphysema is when the walls of the alveoli break down, reducing the surface area for gas exchange making people gasp for breathNicotine causes platelets to become stickier, trapping fatty deposits in blood vessels. This narrows the vessel walls and can cause heart disease.Tar in tobacco smoke is carcinogenic, causing cancer. The most common cancer in smokers is lung cancer. Cancer is when body cells begin to grow out of control.

Effects of smokingSecond hand smoke