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Bio 20 C7.2 & 7.3 Breathing, Respiration, Disorders Two Muscles and Changes in Air Pressure are Responsible for the Mechanics of Breathing p. 249 Check out this clip https://www.youtube.com/watch?v=lr5dDmTASos The first half shows how air pressure changes during breathing. • Two muscles, the diaphragm and the intercostals (rib muscles), work simultaneously to move air in and out of the lungs, by controlling the air pressure inside the lungs. • The diaphragm is a dome-shaped layer of muscle that separates the lung region (the thoracic cavity) from the abdominal cavity. • The intercostals (rib muscles) are between the ribs and along the ventral (front) inside surface of the ribs. • The air in your lungs moves passively from areas of high pressure to low pressure during inhalation and exhalation. Inhalation results from muscle contraction intercostals and diaphragm contract the rib cage moves up and out and floor of chest cavity (the diaphragm) moves downward volume of thoracic cavity increases (the thoracic cavity is air tight) air pressure in thoracic cavity decreases so air pressure in the lungs decreases (because the air in the lungs now fills a larger space) air moves into the lungs because pressure in lungs is less than in the environment (remember air moves from high pressure to low pressure). Exhalation results from muscle relaxation (just the reverse of inhalation) diaphragm and intercostals relax, decreasing the volume of thoracic cavity this decreases the lung volume so air pressure in the lungs increases air moves from high pressure in the lungs to the lower pressure of air in the environment outside of the body NB: the air pressure in the environment is NOT changing, just in the lungs and thoracic cavity. Learning check! 1. What are the 2 main muscles used for breathing? Where are they located? 2. Put HIGH and LOW Pressure on figures above. Check out Figure 7.5 pg. 249: Inhalation and Exhalation Make lung model (See #3, pg. 254). Go through the inhalation and exhalation steps listed above with your model. Use the information below to answer the following questions Fig. 1. Pressure in the Thoracic Cavity during a Normal Breath. Y axis is atmospheric pressure (kPa). X axis is time in seconds (A-E is 3 seconds). 101.3 KPa is standard atmospheric pressure as noted. a) Describe what is happening in each interval (A-B, B-C, C-D, D-E). Include breathing movements, muscle movements, etc. that would result from the pressure changes shown. Connections between Respiratory and Circulatory System Deoxygenated blood carrying waste CO2 from our tissues from cellular respiration (remember? Glucose + O2 CO2 + H2O + ATP (energy)) is returned to the heart through the veins, enters the Right Atrium and enters the right ventricle which pumps it through the pulmonary artery to the lungs. There the blood and alveoli exchange waste CO2 and O 2. Now the oxygenated blood returns to the heart through the pulmonary vein to the Left Atrium then enters the Left Ventricle which is a massive muscle that pumps the oxygenated blood to the rest of the body through the aorta. The waste CO2 that was picked up by the alveoli is now exhaled. Answer questions #8, 9, 10 pg. 254 Respiratory Volumes and Spirographs p. 250 Normally your regular breathing does not use the full capacity of your lungs, so when you need more O2 you can increase the volume of air you take into your lungs. Using a spirometer, an instrument that measures your respiratory volumes, a spirograph can be made demonstrating the amount of air moving in and out of your lungs with each breath. Using p. 250 define the following and locate each volume on the spirograph above Tidal volume: Inspiratory reserve volume: Expiratory reserve volume: Vital capacity: Vital capacity = _________________________ + _____________________________________ + ________________________ Residual volume: Using the above information determine the following volumes: A normal breath mL. The inspiratory reserve volume The inspiratory capacity mL. The expiratory reserve volume Vital capacity + + + = mL Residual volume mL mL Learning Check: Label 1, 2, 3, 4, 5 using residual volume, tidal volume, vital capacity, inspiratory capacity, expiratory reserve volume. Answer #10 pg. 264 Exchange of O2 and CO2 in External and Internal Respiration p. 250 Check out these clips: https://www.youtube.com/watch?v=AJpur6XUiq4 - reviews how O2 gets to alveoli and gas exchange https://www.youtube.com/watch?v=B-X4_hx6j0w - This clip also explains the links of the respiratory system with the circulatory system. • External respiration is the exchange of gases between the alveoli of the lungs and the blood in the capillaries. Internal Respiration is the exchange of gases between the blood and the body tissues. External Respiration Internal Respiration • Because the walls of the alveoli and the capillaries are only one cell thick, O2 and CO2 can be exchanged passively by diffusion and facilitated diffusion, along the concentration gradient (high concentration low concentration which is the same as high pressure (mm Hg) low pressure in the diagram above) • 30% of the O2 transferred is through facilitated diffusion - diffusion with the help of protein carriers. This speeds up the rate of oxygen diffusion. Diffusion alone does not always carry enough O2 fast enough to meet our needs. Check out this clip https://www.youtube.com/watch?v=AyUtdqiOgCA which discusses how O2 binds to hemoglobin, and is dissociated and why hemoglobin is so suited for O2 transfer, even in low O2 conditions. Hemoglobin: Oxygen is carried in the blood bound to haemoglobin in red blood cells. Bicarbonate ion: Most carbon dioxide is carried as bicarbonate ion (HCO3 -) dissolved in the blood plasma. When the blood reaches the lungs the bicarbonate forms CO2 and H2O and the CO2 diffuses into the alveoli and is exhaled. Bicarbonate also maintains the pH of our blood by acting as a buffer and minimizing the change in pH in our plasma by binding CO2 (homeostasis). CO2 Concentrations in the Blood Initiate the Control of Rate of Respiration Check out this clip on the mechanics and brain control of breathing https://www.youtube.com/watch?v=lr5dDmTASos • As CO2 levels in the blood rise, the repiratory center in the medulla oblongata and the carotid arteries detect this rise. The medulla oblongata in the brain stem then stimulates the diaphragm and intercostal muscles to contract faster, increasing the rate of breathing to get rid of the toxic CO2. Do Investigation 7.b pg. 253 “Carbon Dioxide and the Rate of Respiration.” Complete the Table and Analysis and Conclusion. 7.3 Respiratory Health p. 256 • Upper respiratory tract infections: tonsillitis and laryngitis • Disorders of the lower respiratory tract impair delivery of O2 to our cells • bronchitis, pneumonia, pleurisy, emphysema, cystic fibrosis, asthma, lung cancer. Read pg. 256 – 262 and answer the following questions 1. A respiratory disorder in which the walls of the alveoli break down causing less surface area for gas exchange is called a. emphysema b. pneumonia c. bronchitis d. asthma 2. All disorders of the respiratory system share which of the following characteristics? a. They all decrease oxygen delivery to the tissues. b. They all involve the formation of carbaminohemoglobin. c. They are all caused by environmental factors. d. They are all virus infections. 3. Briefly describe the following respiratory illnesses: pneumonia, asthma, lung cancer, emphysema, bronchitis, cystic fibrosis, Include in your description: the specific part of the respiratory system affected, cause(s), symptoms, treatment/and or cure. 4. Describe the Heimlich maneuver which is a lifesaving technique for a choking person. 5. Discuss carbon monoxide poisoning. 6. Discuss the purpose of iron lungs. C7 Test Prep Study the chapter summaries: pg. 242, 247-8, 254, 262 – 263 Study the checklist Take the online practice test