1. Respiration and Breathing

2. Anatomy Know the pathway for inhaled and exhaled air in the respiratory system Know terms such as nasal cavity, oral cavity, pharynx, epiglottis, larynx, trachea, lung, bronchi, bronchioles, intercostal muscles, diaphragm, alveoli

3. Breathing Movements Know what happens to the diaphragm and the internal and external intercostal muscles when inhaling and exhaling –Understand the pressure of the chest cavity and how it facilitates the moving of air in and out

5. Regulation of Breathing Breathing movements are controlled by the medulla oblongata in the brain information about the amount of CO 2 and O 2 is directed by chemoreceptors which send a message to the medulla –there are separate receptors for CO 2 (more sensitive) and O 2

6. What Happens when CO 2 levels increase? chemoreceptors sense increase in CO 2 the diaphragm and intercostal muscles’ activity increases (stimulated by medulla oblongata) this increases breathing movements and therefore increases the amount of CO 2 being exhaled when CO 2 levels fall, the chemoreceptors become inactive and breathing rates return to normal

7. What Happens when CO 2 levels increase? Drugs like morphine and barbiturates (aka. Downers/depressants) can make the medulla less sensitive to CO 2 levels and as a result, breathing rate decreases which could eventually cause death Why can’t you hold your breath forever? Why do people breathe into paper bags when having an anxiety attack?

8. Feedback Loop High CO 2 Chemoreceptors Medulla DiaphragmIntercostals Breathing Rate Increases Less CO 2 absorbed in blood inactivates chemoreceptors

9. What Happens When O 2 Levels Are Low? oxygen chemoreceptors called the carotid and aortic bodies detect when oxygen levels are low and become stimulated a message is sent to the medulla the medulla sends nerve impulses to the diaphragm and the ribs begin breathing movements this will increase the amount of oxygen in the blood the O 2 receptors are only called into action when O 2 levels fall and CO 2 levels remain in the normal range

10. What Happens When O 2 Levels Are Low? Some examples – when you hold your breath, your O 2 levels drop while the CO 2 levels increase and the high CO 2 levels will initiate breathing movements –in high altitudes where there is less O 2 present, the opposite will happen. Low levels of O 2 is not accompanied by high CO 2 levels, the oxygen chemoreceptors initiate breathing movements –when carbon monoxide poisoning occurs, CO (carbon monoxide) competes with O 2 on the binding sites of the hemoglobin molecules in the blood. This reduces the O 2 levels in the blood, stimulating the oxygen chemoreceptors to initiate breathing movements

11. Feedback Loop Low Blood O 2 Chemoreceptors Medulla DiaphragmIntercostals Breathing Rate Increases

12. Breathing Graphs

13. Tidal Volume (TV) – volume of air being inhaled and exhaled during normal breathing. Inspiratory Reserve (IR) – maximum amount of air that is inhaled above tidal volume. Expiratory Reserve (ER) – amount of air that can be exhaled after normal exhalation/ Residual Volume – volume of air that always stays in the lungs Vital Capacity (VC) – total volume of air that the lungs can inhale and exhale. Vital Capacity = Tidal Volume + Inspiratory Reserve + Expiratory Reserve VC = TV + IR + ER Total capacity = vital capacity + residual volume

14. Respiration and Blood

15. Oxygen Transport –O 2 in the alveoli diffuses into the fluid around the cells surrounding the capillary bed –O 2 then diffuses through the capillary walls and into the blood plasma and the oxygen binds on the hemoglobin molecules in the red blood cell

16. Respiration and Blood Carbon Dioxide Transport –23% of CO 2 is carried on hemoglobin –7% is carried in plasma –70% of CO 2 (from cellular respiration) enters the red blood cells and in order to maintain blood pH, is chemically converted to carbonic acid (H 2 CO 3 ) in a reaction that is catalyzed by carbonic anhydrase (an enzyme) carbonic acid molecules dissociate forming bicarbonate ions and hydrogen ions bicarbonate diffuses out of RBC into the plasma

17. Respiration and Blood Carbon Dioxide Transport –when blood rich in CO 2 reaches the lungs, bicarbonate ions combine with hydrogen ions, reforming carbonic acid carbonic acid dissociates, forming water and CO 2 which diffuses out of the blood and into the alveoli when present in normal amounts, the ratio of carbonic acid to bicarbonate creates an acid-base balance in the blood, helping to keep the pH at a level where the body's cellular functions are most efficient

18. Respiration and Blood Carbon Dioxide Transport –CO 2 travels from the capillaries to the alveoli, this is driven by concentration differences (the concentration of CO 2 in the capillaries is slightly higher than in the alveoli) – CO 2 is then expelled out of the lungs in exhalation

19. Respiration and Blood Reaction Summary CO 2 + H 2 O H 2 CO 3 (carbonic acid)In RBC carbonic anhydrase

20. Respiration and Blood Reaction Summary CO 2 + H 2 O H 2 CO 3 (carbonic acid)In RBC carbonic anhydrase H 2 CO 3 HCO 3 - + H + In RBC then to plasma (bicarbonate)

21. Respiration and Blood Reaction Summary CO 2 + H 2 O H 2 CO 3 (carbonic acid)In RBC carbonic anhydrase H 2 CO 3 HCO 3 - + H + In RBC then to plasma (bicarbonate) HCO 3 - + H + H 2 CO 3 In RBC

22. Respiration and Blood Reaction Summary CO 2 + H 2 O H 2 CO 3 (carbonic acid)In RBC carbonic anhydrase H 2 CO 3 HCO 3 - + H + In RBC then to plasma (bicarbonate) HCO 3 - + H + H 2 CO 3 In RBC H 2 CO 3 CO 2 In RBC H 2 O

23. The Function of the Hydrogen Ions the H + ions help to dislodge O 2 from the hemoglobin causing O 2 to diffuse into the tissues by removing H + ions from the plasma, the hemoglobin acts as a buffer when the deoxygenated blood from the veins reaches the lungs, O 2 dislodges the H + from the hemoglobin the free H + combines with bicarbonate to eventually form CO 2 and H 2 O this is called blood buffering, it helps to maintain blood pH

24. Respiratory System Disorders Laryngitis – swelling of the larynx which leads to temporary voice loss Respiratory Distress Syndrome – newborn babies lack the lipoprotein coating the alveoli. Extreme force is required by the baby to breathe. May result in death Pleuracy – inflammation of the pleural membranes (a thin membrane that covers the outer surface of the lung) caused by rubbing together. This results in a fluid buildup in the chest. Exhaling becomes more difficult.

25. Respiratory System Disorders Bronchitis – caused by a bacterial or viral infection. It causes mucus cells of the respiratory pathway to secrete more mucus. Tissue swelling occurs and air passages narrow, restricting breathing in and out Asthma – sufferers require extreme force to exhale, as a result, more air comes in than goes out. Caused by allergies (causing tissues to swell), or muscle spasms on the surface of the bronchioles Sinusitis – inflammation of the sinuses, mucus discharge and blockage of the nasal passages. Leads to headaches.

26. Respiratory System Disorders Emphysema – inhalation is easier than exhalation. The buildup of pressure on the alveoli causes them to rupture, thus reducing the surface area for gas exchange. Breathing rate will increase Pneumonia – inflammation of the lungs caused by bacteria, viruses, or inhalation of irritating gases. Leads to cough and fever, shortness of breath, chills, sweating, blood in mucus Lung Cancer – cancer cells destroy healthy lung tissue Cystic Fibrosis – the mucus coating on the insides of the lungs becomes very sticky leading to breathing problems (genetic condition)