External and Internal Respiration Learning Outcomes Analyse internal

Learning Outcomes: Analyse internal and external respiration – State location – Describe conditions (ph,

4 Levels of respiration • Breathing • External respiration- in the lungs (what gas

1. External (lungs): O 2 • O 2 diffuses from the alveoli into the

• Binding of O 2 to hemoglobin occurs best at lower temperature, higher

2. Internal (tissues): O 2 • O 2 dissociates from Hb, leaving deoxyhemoglobin •

3. Internal (tissues): CO 2 What process produces CO 2? • CO 2 is

• Most CO 2 combines with H 2 O to form carbonic acid,

• HCO 3 - is carried in the plasma • H+ is picked

4. External (lungs): CO 2 • • Bicarbonate ions release CO 2 : H+

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External and Internal Respiration

Learning Outcomes: Analyse internal and external respiration – State location – Describe conditions (ph, temperature) – Describe roles of oxyhemoglobin, carbaminohemoglobin, reduced hemoglobin, bicarbonate ions, carbonic anydrase – Write Chemical equations for external and internal respiration

4 Levels of respiration • Breathing • External respiration- in the lungs (what gas exchange occurs here? ) • Internal respiration - in the tissues (what gas exchange occurs here? ) • Cellular respiration - in the mitochondria of cells (what is used and produced? )

Fig. 15. 8

Fig. 15. 4

Fig. 13. 15

1. External (lungs): O 2 • O 2 diffuses from the alveoli into the blood (why? ) What molecule in the blood does O 2 bind to? • O 2 binds to hemoglobin to form oxyhemoglobin • Hb + O 2 Hb. O 2

• Binding of O 2 to hemoglobin occurs best at lower temperature, higher p. H and higher PO 2 (oxygen pressure) of the lungs

Fig. 15. 9

2. Internal (tissues): O 2 • O 2 dissociates from Hb, leaving deoxyhemoglobin • Hb. O 2 Hb + O 2 • Bond is weaker due to higher temperature, lower p. H and lower PO 2 • O 2 diffuses into tissue fluid and cells, where it is used for cellular respiration

3. Internal (tissues): CO 2 What process produces CO 2? • CO 2 is produced by cellular respiration in all cells • CO 2 diffuses out of cells into tissue fluid, and then into capillaries • A small amount combines with Hb to form carbaminohemoglobin • Hb + CO 2 Hb CO 2

• Most CO 2 combines with H 2 O to form carbonic acid, which dissociates to form hydrogen ions and bicarbonate ions: • CO 2 + H 2 O H 2 CO 3 H+ + HCO 3 • This reaction is catalyzed by the enzyme carbonic anhydrase (found in red blood cells)

• HCO 3 - is carried in the plasma • H+ is picked up by hemoglobin, forming reduced hemoglobin: • H+ + Hb HHb • This prevents too much acidity in the blood

4. External (lungs): CO 2 • • Bicarbonate ions release CO 2 : H+ + HCO 3 H 2 CO 3 H 2 O + CO 2 Carbaminohemoglobin releases CO 2 diffuses out of the capillaries into the alveoli, to be breathed out