Gas Exchange and Its Regulation: A Study of the Respiratory System

1. Describe oxygen characteristics: - low boiling point - very chemically active 2. Describe ozone: - forms a blue gas 3. Why can simple organisms rely on simple diffusion? as they have a large SA: V ratio and diffusion distance is small 4. Why can't the skin be used for gas exchange? the skin is resistant to water + gaseous exchange 5. Why can't simple dffusion occur in larger animals? the cells of the body are too far away from the lungs 6. What are the 4 main functions of the respirstory system? 1) exchange of gases between the blood + atmosphere 2) homeostasis regulation of blood pH 3) protection from inhaled pathogens + irritating substances 4) vocalisaton 7. List the 3 parts of exchange that occurs in gas exchange: exchange I = between atmosphere + lungs exchange II = between lungs and blood exchange III = between blood and cells 8. What does the upper respiratory tract consist of? nose nasal cavity 1 / 13 mouth pharynx (throat) larynx (voice box) 9. What does the lower respiratory tract consist of? trachea bronchi bronchioles alveoli 10. How many lobes do the right and left lung have? right lung has 3 lobes left lung has 2 lobes 11. What does the conducting zone consist of? fairly rigid structures that conduct air to the sites of gaseous exchange 12. What does the conducting zone do? cleanses, humidifies and warms incoming air 13. What does the respiratory zone consist of? respiratory bronchioles alveolar ducts alveoli 14. What does the respiratory zone do? it's the site of gas exchange 15. What is the only externally visible part of the respi- the nose ratory tract? 16. Where does the nasal cavity lie? in and behind the nose 17. What divides the nasal cavity? the nasal septum 18. What do the hair follicles inside the nostril do? filter out large particulate matter 2 / 13 19. What are the 2 parts of the nasal cavity? olfactory mucosa respiratory mucosa 20. What is the olfactory mucosa important for? sense of smell 21. What does the respiratory mucosa do? secretes 1 litre of watery mucus a day which contains lysozymes, to help trap dust + microbes 22. What do the ciliated cells in respiratory mucosa do? move most of its contaminated mucus to the pharynx, where it gets swallowed + subsequently digested by the GI tract 23. What happens to mucus in cold environments? ciliary movements are slow, so more mucus remains in the nasal cavity and the nose is runny 24. Why is there air turbulence in the nasal cavity? it swirls air and deflects particulate matter onto mucus-coated surfaces, trapping them. 25. How does sneezing work? sensory nerves in the area respond to irritating particles by sneezing, which helps to expel irritants 26. Why are the risk of nosebleeds increased in suscep- In the cold, veins untible individuals when it's cold? der the nasal epithelium vasodilate to 3 / 13 help warm inhaled air 27. What do paranasal sinuses do? lighten the skull + long with the nasal cavity help to warm and moisten inhaled air 28. How do cold viruses affect the nasal mucosa and sinuses? - cause inflammation of the nasal mucosa, which also results in increased mucus production - can also spread to sinuses 29. What is sinusitis? the inflammation of the sinuses, can also result in a sinus headache 30. What is the pharynx? a muscular tube that's a common pathway food and air 31. Where is the pharynx located? it extends from the top of the oesophagus to the base of the skull 32. What does the pharynx act as? acts as a resonance chamber for the voice 33. What is the pharynx the opening to? opening to the eustachian tubes 34. What does the larynx sit? at the top of the trachea 4 / 13 35. What does the larynx do? - houses the vocal cords - keeps the airways open - diverts food into the oesophagus + air into the trachea 36. What happens to the larynx when only air is flowing? the inlet to the larynx is open 37. When is the larynx 'closed'? when swallowing 38. What happens to the larynx when swallowing? a reflex causes the larynx to pull up and the epiglottis to tip over to cover the laryngeal inlet 39. Why does the larynx pull up and the epiglottis tip over during swallowing? - so that food is kept out of the lower respiratory tract - this explains why breathing is interrupted when swallowing 40. What happens if swallowed matter enters the larynx? coughing occurs to expel the substance due to a reflex 41. Why is it a bad idea to attempt to orally administer when unconscious, fluids when trying to revive someone? the reflex does not work, so swallowed matter cannot be expelled from the larynx. 42. What is the trachea? 5 / 13 A flexible tube that descends from the larynx and ends up dividing into 2 primary bronchi 43. What is the trachea anterior to and why? the oesophagus to prevent it from collapsing 44. What prevents the trachea from collapsing? C-shaped rings of hyaline cartilage occur within its wall 45. How do epithelium cells stop debris from accumu- they contain goblet lating in the lungs? cells and express cilia, which waft debris towards the pharynx 46. How does smoking affect mucus in the airways? smoking destroys cilia so the only way smokers can clear away mucus from the airways is by coughing 47. When do bronchi form? when the trachea divides in 2 48. Why are inhaled objected more like to get stuck in right is wider, shortthe right primary bronchus? er, and more vertical than the left 49. What do terminal bronchioles divide into? respiratory bronchioles 50. What protrude from the respiratory bronchioles? alveoli 51. Describe the walls of the alveolar? very thin layer of type I squamous alveolar 6 / 13 cells, supported by a thin basal lamina 52. What do type II alveolar cells do? secrete a fluid containing a surfactant across the air side surface 53. What does the fluid secreted by type II alveolar cells reduces surface tendo? sion of the alveolar fluid, so prevents alveolar collapse 54. What is the alveoli fused with? the basal lamina of capillaries 55. What does the respiratory membrane consist of? - the cells of the alveoli wall - the basal lamina - cells of the capillary wall 56. Where does gas exchange occur? across the respiratory membrane 57. Describe the movement of oxygen and carbon diox- - via diffusion, O2 difide across the respiratory membrane: fuses from alveoli to the blood. - CO2 diffuses from the blood to the alveoli 58. What is the pleura? thin, double layered serous membrane that forms a closed sac 59. What is the serous membrane / serosa? a smooth transparent membrane that 7 / 13 lines some large body cavities. 60. What is the parietal portion of serosa line? the walls of the cavity 61. What is the visceral portion of serosa membrane? organs enclosed by the cavity 62. What does the parietal pleura line? thoracic wall, part of the diaphragm, continues around the heart, and between the lungs 63. What does the visceral pleura line cover? external lung surface 64. What do visceral pleurae produce? pleural fluid 65. What does pleural fluid do? acts as a lubricant to allow the lungs to easily move during breathing 66. What causes the lung to cling to the thorax wall? surface tension between the visceral pleurae resists seperation 67. What is pleurisy? inflammation causes decreased pleural fluid secretion, so surfaces become sticky and rough, causing painful breathing 68. What is dalton's law? the total pressure of a mixture of gases is the sum of the pres8 / 13 sures of the individual gases 69. What is boyle's law? if the volume of a container of gas changes, the pressure of the gas will change in an inverse manner 70. What are the 2 phases of pulmonary ventilation? inspiration + expiration 71. What causes the movement of air in and out of the the differences belungs? tween respiratory pressure + atmospheric pressure 72. What happens during quiet inspiration? - diaphragm contracts + flattens - external intercostal muscles contracts to lift the ribs and move the sternum forwards - this increases the volume of the thoracic cavity, lowering pressure + draws air in 73. How does forced inspiration cause the volume of the thoracic cavity to increase more? by the activity of accessory muscles 74. What are the accessory muscles used in forced inspiration? - the scalene + sternomastoid muscles ( found in the neck) + the pectoralis minor muscles ( in the 9 / 13 chest ) contract to further raise the ribs 75. What does the back do during forced inspiration? it extends to straighten the thoracic curvature 76. What happens during quiet expiration? - inspiratory muscles relax - internal intercostal muscles contract - the volume of the thoracic cavity decreases to force air out of the lungs 77. What happens during forced expiration? - the walls of the abdomen contracts to increase intra-abdominal pressure + move some abdominal organs up against the diaphragm - internal intercostal + latissimus dorsi muscles contract to depress the ribcage 78. Which groups in the medulla oblongata are impor- - dorsal respiratory tant for respiration? group (DRG) - ventral respiratory group (VRG) 79. What does the dorsal respiratory group do? 10 / 13 cyclically sends AP along the phrenic + intercostal nerves to cause contraction of the diaphragm + external intercostal muscles 80. What does the dorsal respiratory group do in severe generates gasping hypoxia (low oxygen)? breathing 81. What situations can the dorsal respiratory group be opioid / alcohol oversupressed? dose 82. What does the VRG do? controls muscles involved in forced inspiration + forced expiration 83. What do fibres from the VRG do? innervate muscles of the larynx, pharynx and tongue to keep the upper airways open during breathing 84. What monitors chemical indicators such as CO2, O2 chemoreceptors in and pH? the medulle (central) + carotid & arotic bodies (peripheral) 85. What happens if the production of CO2 exceeds removal of CO2? arterial partial pressure of CO2 increases 86. How does ventilation increase when CO2 increas- - CO2 from the es? blood diffuses into the cerebrospinal fluid + combines with H2O to form carbonic acid, H2CO3, which dissociates to form H+ ions - this lowers pH, excites central 11 / 13 chemoreceptors located in the medulla to stimulate the respiratory centres 87. Where are cells that are sensitive to O2 levels locat- some in the aortic + ed? carotid bodies 88. What happens when arterial partial pressure of oxy- mostly enhances the gen declines? effect of increasing CO2 partial pressure 89. How can changes in arterial pH affect respiration? - effect on central chemoreceptors is only slight, as H+ ions in the blood poorly diffuse through the BBB - more likely to affect the peripheral chemoreceptors 90. What causes bronchoconstriction + bronchodilation? The walls of smaller airways that contain smooth muscle + alter resistance 91. What receptors fo bronchoile smooth muscles have? B2-adrenoreceptors 92. What happens at the sympathetic ANS? bronchodilation 93. What drug is used to treat asthma in the sympathet- A B2 agonist ; e.g. ic ANS? salbutsmol, salmeterol 94. What drug is used to treat asthma in the parasym- muscarinic agonists pathetic ANS? e.g. ipatropium bromide 12 / 13 95. What happens at the parasympathetic ANS? bronchoconstriction 96. What receptors does the parasympathetic ANS con- Muscarinic type 3 retain? ceptors 13 / 13