Massachusetts General Hospital: Cabg Surgery (a)
TRANSPORT OF BLOOD GASES
From The Lungs To The Tissues & Back
Dr. Sally Osborne Department of Cellular & Physiological Sciences University of British Columbia Room 3602, D.H Copp Building 604 822-3421 sally.osborne@ubc.ca www.sallyosborne.com
Objectives
1. Specify in what forms O2 & CO2 are carried in the blood. 2. Describe the physiological significance of the oxyhemoglobin dissociation curve. 3. Relates shifts in the position of this curve to affinity of Hb & oxygen loading / unloading in the blood. 4. Describe the effect of anemia & carbon monoxide poisoning on tissue oxygenation. 5. Identify the color of hemoglobin in the following forms: 1) oxyhemoglobin, 2) deoxyhemoglobin 3) caboxyhemoglobin. 6. Specify the significance of carbonic anhydrase in transport of CO2 7. Describe the “Bohr & Haldane Effects” illustrating the effect O2 & CO2 on the transport of each other.
1
TRANSPORT OF OXYGEN BY BLOOD
Oxygen Is Transported In Two Forms In The Blood—
1. physically dissolved [2 %] 2. chemically bound to the Hemoglobin, Hb, molecule [98 %]
OXYGEN PHYSICALLY DISSOLVED IN BLOOD Compared to carbon dioxide, oxygen is relatively insoluble in the blood-at PO2 = 100 mmHg, 100 ml blood contains 0.3 ml of O2
TRANSPORT OF OXYGEN BY BLOOD
Chemically Bound to the Hemoglobin Molecule
• •
Hb can combine rapidly & reversibly with O2. The reversibility of this chemical reaction allows O2 to be released to the tissues. Hb + deoxyhemoglobin a.k.a reduced hemoglobin O2 oxygen ⇔ O2Hb oxyhemoglobin
2
THE STRUCTURE OF THE HEMOGLOBIN MOLECULE
4 SUBUNITS EACH MADE OF – • a globular protein (soluble in aqueous solution) with an embedded heme group • Heme group contains an iron atom responsible for the binding of oxygen
PULSE OXIMETER
A Non-invasive Device Measuring Percentage of Oxyhemoglobin in the arterial blood [Hb Saturation/SaO2/SpO2] • colour of blood varies depending on how much oxygen it contains. • pulse oximeter shines 2 beams of light
From The Lungs To The Tissues & Back
Dr. Sally Osborne Department of Cellular & Physiological Sciences University of British Columbia Room 3602, D.H Copp Building 604 822-3421 sally.osborne@ubc.ca www.sallyosborne.com
Objectives
1. Specify in what forms O2 & CO2 are carried in the blood. 2. Describe the physiological significance of the oxyhemoglobin dissociation curve. 3. Relates shifts in the position of this curve to affinity of Hb & oxygen loading / unloading in the blood. 4. Describe the effect of anemia & carbon monoxide poisoning on tissue oxygenation. 5. Identify the color of hemoglobin in the following forms: 1) oxyhemoglobin, 2) deoxyhemoglobin 3) caboxyhemoglobin. 6. Specify the significance of carbonic anhydrase in transport of CO2 7. Describe the “Bohr & Haldane Effects” illustrating the effect O2 & CO2 on the transport of each other.
1
TRANSPORT OF OXYGEN BY BLOOD
Oxygen Is Transported In Two Forms In The Blood—
1. physically dissolved [2 %] 2. chemically bound to the Hemoglobin, Hb, molecule [98 %]
OXYGEN PHYSICALLY DISSOLVED IN BLOOD Compared to carbon dioxide, oxygen is relatively insoluble in the blood-at PO2 = 100 mmHg, 100 ml blood contains 0.3 ml of O2
TRANSPORT OF OXYGEN BY BLOOD
Chemically Bound to the Hemoglobin Molecule
• •
Hb can combine rapidly & reversibly with O2. The reversibility of this chemical reaction allows O2 to be released to the tissues. Hb + deoxyhemoglobin a.k.a reduced hemoglobin O2 oxygen ⇔ O2Hb oxyhemoglobin
2
THE STRUCTURE OF THE HEMOGLOBIN MOLECULE
4 SUBUNITS EACH MADE OF – • a globular protein (soluble in aqueous solution) with an embedded heme group • Heme group contains an iron atom responsible for the binding of oxygen
PULSE OXIMETER
A Non-invasive Device Measuring Percentage of Oxyhemoglobin in the arterial blood [Hb Saturation/SaO2/SpO2] • colour of blood varies depending on how much oxygen it contains. • pulse oximeter shines 2 beams of light