Gases in, Gases Out Page 447-451 Respiration Gases in, Gases Out Page 447-451

Gas Exchange The alveoli exchange gases with the blood as the gases move from ___________c oncentration

The Air We Breathe Air has relatively: High O2 Low CO2

The Air We Breathe Concentrations of gases are usually described in terms of __________ The more gas there is, the more _______ it exerts on surrounding environment The air at sea level has an atmospheric pressure of 101.3 kPa

The Air We Breathe Partial Pressure: the pressure of an _______________ in a sample The sum of the partial pressures in a sample will equal the _____________ As O2 makes up 20.9% of the air, it has a partial pressure of 21.2kPa (20.9% of 101.3 kPa) Carbon dioxide has a partial pressure of 0.0397kPa

Gas Exchange Gases move from _____ partial pressure to _____ partial pressure

Gas Exchange Explain this:

Gas Exchange Oxygen in the alveoli is 13.3 kPa while it is about 5.3 kPa in the blood Oxygen diffuses until blood oxygen is 13.3 kPa Using this mechanism, 1L of blood will carry 3 mL of O2

Hemoglobin Protein in the blood that binds to _______

Hemoglobin Made up of four subunits Each subunit surrounds a _______ group

Hemoglobin Heme group

Hemoglobin Heme group Circular, ring structure with an ___ ion in the middle The ___ ion is capable of binding to O2

Hemoglobin Works by binding to oxygen that has become dissolved in the blood Oxyhemoglobin gives blood a bright red color Allows the blood to carry much more oxygen than it normally could Blood with hemoglobin can carry 200mL of oxygen per 1L of blood An increase of 70x

Gas Exchange Oxygenated blood travels to the cells of the body where it diffuses into the cells The partial pressure in the blood is 13.3 kPa while it only 5.33 kPa in the cells As pressure in the blood decreases, hemoglobin releases it’s oxygen Carbon dioxide also diffuses out of the cell into the blood Partial pressure is 5.6 kPa in the cell and 5.33 kPa in the blood

Carbon dioxide in the blood Undergoes a serious of steps: CO2 + H2O  H2CO3 H2CO3  H+ + HCO3- The H+ causes the blood to be _______

Carbon dioxide in the blood The hemoglobin that is no longer carrying oxygen is able to bind to these H+ ions This reduces the _______ of the blood

Carbon dioxide in the blood Back in the lungs, the hemoglobin releases the H+ as it would much rather bind to the ________ The released H+ undergoes this reaction: H+ + HCO3-  CO2 + H2O Carbon dioxide diffuses out of blood into the alveoli Partial pressure of CO2 in blood is 5.6 kPa and only 5.33 kPa in alveoli

Thought questions for homework Why is it important for the partial pressures of O2 and CO2 to be different in the alveoli than it is in the surrounding air we breathe? How does altitude affect our breathing?