GAS EXCHANGE RESPIRATION

PARTIAL PRESSURE

pressure exerted by a single gas within a mixture of gases measured in mmHg.

Partial pressure gradient

Gas moves from high to low pressure areas.

equation of partial pressure

% of gas x Total Pressure of all gases

Alveolar gas exchange (external respiration)

exchange between alveoli and blood determined by partial pressure gradient

partial pressure within alveoli of OXYGEN

104 mmHg

partial pressure within alveoli of CO2

40 mmHg

partial pressure of OXYGEN WITHIN BLOOD CAPILLARIES

40 mmHg

PCO2 within blood capillaries

45 mmHg

where do gases diffuse in alveolar gas exchange?

O2 diffuses into blood, CO2 moves into the alveoli from the blood, to lungs, to exhale

systemic gas exchange (internal respiration)

exchange between blood and the cells/ tissues of the body determined by pressurre gradient as it enters the SYSTEMIC CAPILLARIES

PO2 OF SYSTEMIC CAPILLARIES

95 mm Hg

PCO2 OF SYSTEMIC CAPILLARIES

40 mm Hg

PO2 WITHIN CELLS OF THE BODY

40 MMHG

PCO2 WITHIN CELLS OF THRE BODY

45 MMHG

gas transport

how O2 and CO2 move around

transport of oxygen within the blood

98% of O2 bound to Hb, 2% dissolved in plasma

oxyhemoglobin

O2 to Hb

deoxyhemoglobin

NOT bound

percent oxygen saturation of hemoglobin

amount of O2 bound to Hb expressed as % determined by PO2

oxygen saturated at sea level

98%

oxygen reserve

Oxygen that remains bound to hemoglobin after passing through the systemic circulation

Provides a means for additional oxygen to be delivered under increased metabolic demands

AT REST: ~20-25% OF HB IS RELEASED

transport of carbon dioxide within the blood

dissolved in plasma, carbaminohemoglobin, bicarbonate

dissolved in plasma

7%

carbaminohemoglobin

carbon dioxide bound to hemoglobin, 23%

bicarbonate

70% MAJORITY OF CO2 BECOMES THIS

converting CO2 into bicarbonate IN SYSTEMIC GAS EXCHANGE

diffuses into RBC

CO2+H2O= carbonic acid (highly unstable)

breaks into H+ and HCO3-

H+ binds to Hb, Bicarbonate exits RBC

where does bicarbonate become CO2 again?

pulmonary arterioles

bicarbonate to CO2

bicarbonate moves back into RBC and combines back with the H+ to create carbonic acid, carbonic acid breaks down into CO2 and H2O---> CO2 exits RBC and we exhale it!