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Respiratory System

Respiratory System. Biology 12. The respiratory systems main function is to exchange oxygen from the air with carbon dioxide from the blood Respiration- process of supplying O 2 to body cells Linked to cellular respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + 38 ATP.

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Respiratory System

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  1. Respiratory System Biology 12

  2. The respiratory systems main function is to exchange oxygen from the air with carbon dioxide from the blood • Respiration- process of supplying O2 to body cells • Linked to cellular respiration C6H12O6+ 6O2 6CO2 + 6H2O + 38 ATP

  3. The respiratory and circulatory systems work together to: • Exchange gases between blood and air (at lungs) • Transport gases from lungs to tissues • Exchange gases at tissues

  4. Respiration can be broken down into 4 parts • Breathing – movement of air into and out of lungs • inspiration(inhalation) + expiration(exhalation) • External respiration– in alveoli, exchange of O2 + CO2 between air and blood • Internal respiration– exchange of O2 and CO2 between blood and tissue fluid • Cellular respiration– production of ATP in mitochondria in cells

  5. Respiratory Tract As air travels through the air passages 3 things occur: • Filtering • Done by hairs, cilia, and mucus in nose and cilia in trachea • Cilia create an upward wave which moves mucus and dirt particles up towards the pharynx (throat)

  6. 2. Moistening • done by wet surface of passageways 3. Warming • done by heat from blood vessels lying close to surface lining the air passages

  7. Flow of Air • Nose/mouth  pharynx  larynx  trachea  bronchi  bronchioles  alveoli (gas exchange of O2 for CO2 occurs here)

  8. inspiration- breathing air in expiration- breathing air out 1. Air enters the nasal passages. • hairs and cilia trap dust and debris • the air is warmed and moistened. 2.The warmed and moistened air passes through the pharynx.

  9. 3. The air enters the larynx. • Vocal cords located here 4. The air enters the trachea (windpipe). • Held open by cartilaginous rings and lined with ciliatedmucous membranes.

  10. 5. The trachea divides into two bronchi 6. Bronchi branch into many smaller passages called bronchioles that extend into the lungs. 7. The bronchioles branch out, and their walls get thinner and diameter smaller. 8.Each bronchiole ends in sacs called ALVEOLI.

  11. The left and right lung are divided into lobes (3 and 2) • Each lobe is divided into lobules, each of which has a bronchiole with many alveoli • The lungs are enclosed by two pleural membranes (one on chest cavity, one that lines lung) • Lubricates and makes air tight

  12. Alveoli • Sac-like clusters at ends of bronchioles 6 features which help in function: • number of alveoli – millions in each lung, provide great surface area for exchange/diffusion of gases • thin-walled – one – cell thick, also aids in diffusion

  13. 3. lipoprotein “film” on inner surface – reduces surface tension of lining inside alveoli and prevents them from collapsing 4. Stretch receptors – nerve endings that signal alveoli are full 5. Moisture– ensures efficient diffusion of gases

  14. 6. pulmonary capillaries – surround alveoli and provide rich supply of blood for optimum gas exchange

  15. The Diaphragm • Sheet of muscle that extends across the bottom of the rib cage • Controls the volume of the thoracic cavity to allow air to be drawn in or out of the lungs

  16. Inspiration- The Active Stage • Chemoreceptors in the arteries signal to breathing center in the medulla oblongata • Carotid bodies (in carotid arteries) and aortic bodies (in aorta) • Detects rising levels of CO2 and H+ • Not affected by oxygen levels

  17. Chemoreceptors detect levels of H+ (indirectly CO2) and send messages to respiratory centre in medulla oblongata (brain)

  18. Medulla oblongata sends impulses to diaphragm and intercostal (ribcage) muscles to contract

  19. Contraction of these muscles increases the chest cavity volume, which then causes air pressure in the chest cavity to decrease • This causes the lungs to expand and as a result of the “negative pressure” air rushes into the lungs to equalize the pressure

  20. Expiration- The Passive Stage • When the alveoli are filled, the stretch receptors on the walls of the alveoli send signals to the medulla oblongata • The medulla oblongata stops sendingimpulses to the diaphragm and intercostal muscles

  21. As these muscles relax, the volume in the chest cavity decreases and the pressure increases • This causes the lungs to contract and forces air out of the lungs and the cycle starts over

  22. Inhalation and Expiration

  23. Hyperventilation – increased breathing rate leads to decreased levels of CO2 and H+ in blood and pH of blood increases (i.e becomes basic) • Hypoventilation – decreased breathing rate leads to increased levels of CO2 and H+ in blood and pH of blood decreases (i.e becomes acidic)

  24. Internal/External Respiration HCO3-bicarbonate ion (in plasma) Hb hemoglobin or deoxyhemoglobin HbO2oxyhemoglobin- found in RBC’s HbCO2carbaminohemoglobin HHb reduced hemoglobin H+ hydrogen ion

  25. External Respiration • Happens in lungs between alveoli and pulmonary capillaries • Exchange of O2 and CO2 • Movement of both gases is due to concentration gradients diffusion [O2 ] high in alveoli, [CO2] high in blood

  26. CO2returns to the lungs (from tissues) in 2 forms: 1. Dissolved in water as bicarbonate ion: HCO3- + H+ H2O + CO2 *catalyzed by carbonic anhydrasein plasma 2. Transported by hemoglobin HbCO2Hb + CO2

  27. Hemoglobin • Hemoglobin is an iron-containing polypeptide found within red blood cells. • It is more attracted to oxygen in cool, more basic lungs, and less attracted to oxygen in the more acidic, warmer tissues. • Hbwill bind O2 in the lungs, and release it in tissues.

  28. Temperature Effects: Hb takes up O2 more readily in low temperatures (lungs), gives up O2 more readily at higher temperature. • pH Effects: Hb takes up O2 more readily in the more basic or neutral lungs, and gives it up more readily in the more acidic tissues.

  29. Internal Respiration • Between blood and tissues • Exchange of CO2 in tissue fluid and O2 in bloodHbO2Hb + O2 • Tissue fluid is low in oxygen, high in carbon dioxide, therefor carbon dioxide diffuses into blood

  30. The Fate of Carbon Dioxide A small amount of carbon dioxide is take up by hemoglobin Hb+ CO2HbCO2

  31. Most CO2 combines with H2O to form carbonic acid, which then dissociates to H+ and HCO3-.

  32. Hemoglobin combines with the excess H+ that this reaction produces. Hb + H+HHb • Maintains blood pH levels

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