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Respiration. What is “ respiration ”? NOT “breathing”! This is the action of your lungs inhaling and exhaling air; “ ventilation .” Respiration = the process of breaking down glucose to use for ENERGY If glucose were gasoline, then respiration would be the engine running in your car.
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What is “respiration”? • NOT “breathing”! • This is the action of your lungs inhaling and exhaling air; “ventilation.” • Respiration = the process of breaking down glucose to use for ENERGY • If glucose were gasoline, then respiration would be the engine running in your car. • (you can’t go anywhere if the engine’s not running!)
Aerobic Respiration Anaerobic Respiration Using O2 to break down glucose “with air” ~ “with oxygen” NOT using O2 “without air”
Aerobic Respiration • Using O2 to break down Glucose to release Energy for cells. • Glucose + Oxygen Carbon Dioxide + Water + Energy • C6H12O6 + 6O2 6CO2 + 6H20 + Energy
But where did the Glucose come from? • You ate it! • Food breaks down into glucose molecules in the stomach (Digestion). • These glucose molecules enter your blood in the small intestine (Absorption). • Blood carries the glucose molecules to individual cells (Circulation).
But where did the Oxygen come from? • You inhaled it (breathing). • In your lungs, your blood takes in O2 and lets out CO2. • This is called Gas Exchange. • (you’re exchanging one gas for another) • You need LOTS of surface area to exchange gasses quickly enough. • Lungs have about 70 square meters of S.A. • (about the size of a tennis court!)
How do you get so much Surface Area in the Lungs? • Alveoli: very tiny sacs about 0.25 mm across • Alveoli are where Gas Exchange occurs • Gas can only exchange through a small distance • Blood capillary is right next to alveolus • Gas moves through capillary wall and alveolus wall • Distance of 0.001 mm
Pathway of Inhaled Air • Mouth/nose • Trachea • R + L Bronchi • Bronchioles • Alveoli
Pathway of Oxygen • Alveoli • Pulmonary (Lung) Capillaries • Pulmonary Vein • The blood in this Vein is Oxygenated (!!) • It is moving AWAY from the Lungs, but TOWARD the Heart. • Heart Aorta Arteries Arterioles Capillaries Body Cells • Respiration (conversion to Energy) happens in the Cell • Now the Cell has plenty of Energy!
Question Time! • Where does the blood in Pulmonary Vein come from? (Hint: it is Oxygenated) • The Lungs • Where is it going? • The Heart • Where does the blood in the Pulmonary Artery come from? (Hint: it is Deoxygenated) • The Heart • Where is it going? • The Lung
How do we Breathe? • Ventilation: • Moving fresh air into lungs • Moving “used” air out of lungs • Ventilation happens because of changes in pressure that our body creates by contracting and relaxing muscles: • Diaphragm • Intercostals (“between ribs”) • Pleural membranes keep everything airtight.
Inhalation • Diaphragm contracts • It moves DOWN because of its unique shape • Intercostal muscles contract • Making the ribs move UP • Volume increases inside pleural cavity. • Pressure decreases; creates a vacuum! • Air from outside flows into the Lungs.
Exhalation • Diaphragm relaxes • Now it moves back UP • Intercostals also relax • Ribs can move back DOWN • Volume DECREASES • Pressure INCREASES – like a full balloon! • Air moves back out of the Lungs.
How do Other Animals Breathe? • Diffusion: • Small animals with no ventilation structure • Gills: • Fish • Lungs: • Mammals • Birds • Herpetiles (Reptiles + Amphibians) • Skin: • Amphibians • Tracheae: • Insects
Diffusion • O2 and CO2 diffuse in and out of the organism without a specialized organ • Small size • Large surface area
Gills • Structures on fish that allow gas exchange with water. • Fish “pump” water over and through gills.
Lungs • Allow gas exchange with air. • Bird lungs are structured to allow maximum gas exchange • Air moves through the lungs, not in-and-out like in mammals
Tracheae • Network of branching tubes in insects. • Gas exchange occurs directly between tracheae and respiring cells. • No blood involved! • Insects breathe in and out through spiracles.
Respiration WITHOUT Oxygen • “Anaerobic Respiration” • Many organisms respire anaerobically. • Even humans! (sometimes) • But Aerobic Respiration is more efficient • It yields about 19 times as much energy from one glucose molecule as Anaer. Resp.
Anaerobic Respiration in Yeast • Yeast is a single-celled fungus. • Breaks down Glucose into Ethanol and CO2 • Can be used to make alcoholic drinks and bread • Ethanol = alcohol • CO2 bubbles = bread rises
Anaerobic Respiration in Humans • Only when our muscles run out of O2 • During strenuous exercise • We break down glucose into lactic acid to release useable energy. • Lactic acid is toxic! • So, we can’t do this very long.
How do your Lungs stay Clean? • The air we inhale contains dust and bacteria. • Lung passages are lined with goblet cells and cilia, which keep unwanted particles from getting to the alveoli.
Goblet Cells + Cilia • Goblet cells secrete mucus that traps dust and bacteria. • Cilia are tiny hairs that sweep the mucus up toward the back of your throat. • Then you swallow the mucus, along with everything else! • Bacteria die in your stomach’s acid and enzymes.
Cigarette Smoke: Tar • Damages DNA in lung cells • This can result in lung cancer • Lung cells divide uncontrollably into a mass called a tumor. • If Tar (or other harmful chemicals) get into the blood, they can be carried to other parts of the body and cause other types of cancer.
Cigarette Smoke: Tar • Tar can paralyze or destroy Cilia • Now they can’t sweep mucus out of the bronchial tubes! • Tar makes Goblet Cells excrete more mucus • Mucus slides down into lungs, creating a breeding ground for bacteria • Excessive coughing damages lining of tubes • Bronchitis: inflammation of bronchi • Damage to alveolar walls hinders gas exchange • Emphysema: difficulty getting enough O2