Presentation on theme: "6.4 Gas Exchange ★Distinguish between ventilation, gas exchange and cell respiration. ★Explain the need for a ventilation system. ★Describe the features."— Presentation transcript:
1 6.4 Gas Exchange★Distinguish between ventilation, gas exchange and cell respiration.★Explain the need for a ventilation system.★Describe the features of alveoli that adapt them to gas exchange★Draw and label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli★Explain the mechanism of ventilation of the lungs in terms of volume and pressure changes caused by the internal and external intercostal muscles, the diaphragm and abdominal muscles.
2 Respiration = chemical reaction to obtain ATP 6.4 Gas ExchangeOur lungs must act together with our transport system (heart/blood vessels) to make sure our body is well supplied with O2 and is able to get rid of CO2Cell Respiration: the process that requires O2 (and gives off CO2) - this is aerobicRemember: pathway where chemical bonds in a glucose molecule are broken and that energy is stored as ATP.Respiration = chemical reaction to obtain ATPVentilation: continuously repeat filling our lings with air and breathing the air out.
3 Gas Exchange: the movement/diffusion of gases, happens in 2 places. 1. In the lungs where O2 moves from the air of the lungs into the bloodstream (CO2 moves in opposite direction)2. In a capillary bed elsewhere in the body where the opposite gas exchange happens - O2 diffuses out of bloodstream and into a body cell (CO2 diffuses out of body cell and into capillary bed to take back to lungs)6.4 Gas Exchange
5 The Human Ventilation System 6.4 Gas ExchangeThe Human Ventilation SystemOur bodies are so thick that oxygen cannot diffuse directly into our body - O2 would have to make it through millions of cells to reach our blood stream.We need lungs for diffusion, but thin skinned organisms like worms do not need a ventilation system (O2 diffuses directly through their skin).Our ventilation (respiratory) system and circulatory system function together to pick up O2 molecules in the inner lungs and transport that O2 to body cells deep in our tissues.
6 6.4 Gas ExchangeRemember: for diffusion to occur, there must always be a concentration gradient with a higher level of the diffusing substance in one area than in another.Air inside alveoli contain a higher concentration of O2 than the blood, so O2 diffuses into the blood.Blood contains a higher level of CO2 than inhaled air, so CO2 diffuses into alveoli for us to later exhale and rid of the waste.A ventilation system is needed to maintain high concentration gradients in the alveoli!
8 Alveoli Efficiency 6.4 Gas Exchange Adaptation Advantage Spherical shape of alveoliProvides a large surface area for respiratory gases to diffuse throughSingle layer of flattened cellsPrevents respiratory gases from having to diffuse through more cell layersMoist inner lining of alveolusAllows for efficient diffusionDense network of capillariesRich blood supply maintaing concentration gradient and carries absorbed gases away rapidly
9 Anatomy of the Ventilation System 6.4 Gas Exchange
10 Pharynx: both air and food share this pathway 6.4 Gas ExchangePharynx: both air and food share this pathwayEpiglottis: flap of skin that separates the trachea and esophagus (air and food)Larynx: voice-box, first place for just airTrachea: single ridged air tubeBronchi: trachea forks into 2 main branchesBronchioles: bronchi continue to branch out into smaller tubesAlveoli: last stop for air, tiny air sacs for gas exchange
11 Mechanism of Ventilation: 6.4 Gas ExchangeMechanism of Ventilation:Lungs are not muscles and cannot move by themselves.Breathing happens by 2 sets of muscles:Intercostal muscles: muscles between ribsDiaphragm: sheet of muscle separating the thorax from the abdomenAir is inhaled into the lungs through the trachea, bronchi and bronchioles (exhaled opposite route)Muscles are used to lower and raise the pressure inside the lungs to cause the movements of air
12 6.4 Gas Exchange Inhalation Exhalation External intercostal muscles contract, moving the ribcage up and outInternal intercostal muscles contract, moving the ribcage down and inDiaphragm contracts, becoming flatter and moving downThe abdominal muscles contract, pushing the diaphragm up into a dome shape, diaphragm relaxesThoracic cavity has increased its volume, so pressure inside the cavity decreases - leads to less pressure 'pushing on' the lung tissueThese muscle movements decrease the volume of the thoraxA decrease in pressure inside the lungs, also known as a partial vacuumThe pressure inside the thorax rises aboveAir comes in through your open mouth or nose to counter the partial vacuum within the lungs (and fills alveoli with air)Air flows out from the lungs to outside the body until the pressure inside the lungs falls to decrease partial vacuum
15 6.2 Transport System/Circulatory 1. Which of the following is correct about the blood found in these structures?Answer: CAortaLeft VentriclePulmonary ArteryAoxygenateddeoxygenatedBCD
16 2. Which vessel directly supplies the heart muscle with blood? 6.2 Transport System/Circulatory2. Which vessel directly supplies the heart muscle with blood?A. The aortaB. The pulmonary arteryC. The pulmonary veinD. The coronary arteryAnswer: D
17 3. Which of the following is transported by the blood? A. Heat 6.2 Transport System/Circulatory3. Which of the following is transported by the blood?A. HeatB. StarchC. GlycogenD. GametesAnswer: A
18 4. What is a role of the pacemaker or sinoatrial node (SAN)? 6.2 Transport System/Circulatory4. What is a role of the pacemaker or sinoatrial node (SAN)?A. To initiate contraction of the ventricleB. To pass the excitation through the Purkinje fibersC. To originate excitation in myogenic muscleD. To cause the relaxation of the atriaAnswer: C
19 5. Which chamber of the heart has the thickest walls? A. Left atrium 6.2 Transport System/Circulatory5. Which chamber of the heart has the thickest walls?A. Left atriumB. Left ventricleC. Right atriumD. Right ventricleAnswer: B
20 6. Which of the following describes arteries? 6.2 Transport System/Circulatory6. Which of the following describes arteries?A. They carry blood from the lungsB. They carry blood towards the heartC. They usually contain valvesD. They have thick muscular wallsAnswer: D
21 7. Which vessel carried deoxygenated blood? A. The coronary artery 6.2 Transport System/Circulatory7. Which vessel carried deoxygenated blood?A. The coronary arteryB. The pulmonary arteryC. The aortaD. The pulmonary veinAnswer: B
22 B. Changes in the volume of the thoracic cavity 6.4 Gas Exchange8. Which of the following is part of the process of cellular respiration?A. GlycolysisB. Changes in the volume of the thoracic cavityC. Exchange of gases across the surface of the alveoliD. Exchange of gases across the surface of capillariesAnswer: A
23 9. What is the function of the structure labelled X? A. Inspiration 6.4 Gas Exchange9. What is the function of the structure labelled X?A. InspirationB. Gas ExchangeC. RespirationD. VentilationAnswer: B
24 10. What causes air to be breathed out by the lungs? 6.4 Gas Exchange10. What causes air to be breathed out by the lungs?A. The internal intercostal muscles contract and the ribs riseB. The diaphragm contracts and internal intercostal muscles contractC. The ribs rise and the external intercostal muscles relaxD. The diaphragm relaxes and the ribs fallAnswer: D
25 A. Internal intercostal muscles and abdomen wall muscles 6.4 Gas Exchange11. What normally prevents the membranes of the alveoli from sticking together during expiration?A. Internal intercostal muscles and abdomen wall musclesB. Internal intercostal muscles and diaphragmC. External intercostal muscles and diaphragmD. External intercostal muscles and abdomen wall musclesAnswer: C
26 A. The pressure within the thoracic cavity 6.4 Gas Exchange12. What muscles contract to cause air to pass into the lungs through the trachea?A. The pressure within the thoracic cavityB. The dense net of fluids in the inner surface of the alveoliC. The secretion of fluids in the inner surface of the alveoliD. The thickness of the single-cell layer of alveoli membranesAnswer: D
27 6.4 Gas Exchange13. Capillaries surround the alveoli in the lungs. Which pair of statements correctly describes the concentrations of oxygen and carbon dioxide in the lungs?Answer: BOxygenCarbon DioxideALower in the capillariesHigher in the alveoliBHigher in the capillariesCLower in the alveoliDHIgher in the capillaries
28 14. What feature of alveoli adapts them to efficient gas exchange A. A dense network of capillaries surrounds themB. They have muscles which pump air in and out regularlyC. A constant blood supply flows through themD. Their membranes are more permeable to gases than waterAnswer: A
29 A. Blood flowing in the capillaries B. A moist lining of the alveoli 6.4 Gas Exchange15. Which feature maintains a high concentration gradient of gases in the ventilation system?A. Blood flowing in the capillariesB. A moist lining of the alveoliC. Thin-walled alveoliD. Thin-walled capillariesAnswer: A
30 A. Both pressure and volume increase 6.4 Gas Exchange16. What change occurs to the pressure and volume of the lungs when the external intercostal muscles contract?A. Both pressure and volume increaseB. Pressure decreases and volume increasesC. Both pressure and volume decreaseD. Pressure increases and volume decreasesAnswer: B
31 A. The external intercostal muscles relax 6.4 Gas Exchange17. What muscle action is associated with an increase in the volume of the thoracic cavity during inspiration?A. The external intercostal muscles relaxB. The internal intercostal muscles contractC. The diaphragm contractsD. The abdominal muscles contractAnswer: C